- Preparation and catalytic properties of resin bound binuclear rhodium tetracarboxylate complexes
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4-(4'-Polystyryimethyloxy)-3-carboxylatomethyloxy-1-phenylacetate bis- μ-coordinated rhodium(II) diacetate complex, a resin-bound analogue of dirhodium tetraacetate in which two adjacent μ-bridging acetate moleties are covalently linked, serves as an efficient, stable and re-useable immobilised alkene hydrofomylation and hydrogenation catalyst.
- Andersen, Jo-Ann M.,Karodia, Nazira,Miller, David J.,Stones, Duane,Gani, David
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- Selectivity of catalytic systems RhCl3·polycation in hydroformylation of hex-1-ene under conditions of biphase catalysis
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Approaches to increasing the selectivity of water-soluble catalytic systems based on RhCl3 and polycation in hydroformylation of hex-1-ene were studied. The introduction of a long-chain alkyl radical into the polycation or the use of a higher fatty acid anion results in an increase in the selectivity of the catalytic system at pH > 7 with respect to n-aldehyde to 60 %. This effect is presumably associated with the suppression of isomerization processes due to steric hindrances.
- Kolesnichenko,Sharikova,Murzabekova,Markova,Slivinskii
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- Low pressure catalytic hydroformylation of 1-hexene by the carbonylhydrido-tris(triphenylphosphine)rhodium(I), RhH(CO)(PPh3)3, in association with phosphinomethylzirconium complexes
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Low pressure catalytic hydroformylation of 1-hexene was performed in the presence of RhH(CO)(PPh3)3 in association with diphenylphosphinomethylzirconium complexes such as Cp2Zr(CH2PPh2)2 and 2O or in the presence of bis(diphenylphosphine)butane.An isolated rhodium-zirconium complex, formulated as , was found to be catalytically active.
- Choukroun, R.,Gervais, D.,Kalck, P.,Senocq, F.
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- Investigations on the kinetics of hydroformylation of 1-hexene using HRh(CO)(PPh3)3 encapsulated hexagonal mesoporous silica as a heterogeneous catalyst
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Kinetics of HRh(CO)(PPh3)3 encapsulated in hexagonal mesoporous silica has been investigated for the heterogeneous catalyzed hydroformylation of 1-hexene. The rates of hydroformylation of C5-C12 alkenes, determined under identical conditions, indicated a decreasing trend on increasing the chain length of the alkenes. The representative alkene, 1-hexene has been subjected for detail kinetic investigations. The 1-hexene hydroformylation kinetics has been studied as the function of the amount of catalyst, concentration of 1-hexene, partial pressure of CO and H2, and temperature. All these parameters were found to influence the rate of hydroformylation. The rate was observed to be first order with respect to partial pressure of hydrogen. The rate was observed to increase with the increase in the amount of the catalyst and approached saturation on increasing the catalyst amount. Rates increased on increasing the CO pressure and 1-hexene concentration up to certain values, and on further increasing these parameters, substrate inhibited kinetics was observed for both CO and 1-hexene at higher pressures and concentrations, respectively. A kinetic rate model based on the mechanism of hydroformylation of 1-hexene was found to fit with the experimental rate with ±15% deviation.
- Sudheesh,Sharma, Sumeet K.,Shukla, Ram S.,Jasra, Raksh V.
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- Sulphur-containing Dinuclear Rhodium Complexes as Catalyst Precursors for the Selective Hydroformylation of Alkenes
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Dinuclear thiolato bridged complexes, particularly 2>, catalyse the hydroformylation of hex-1-ene at low pressure and temperature to afford selectively and with high turnover rates the corresponding aldehydes.
- Kalck, Philippe,Frances, Jean-Marc,Pfister, Pierre-Marie,Southern, Timothy G.,Thorez, Alain
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- Hydroformylation of 1-Hexene in Supercritical Carbon Dioxide: Characterization, Activity, and Regioselectivity Studies
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The hydroformylation of alkenes is a major commercial process used for the production of oxygenated organic compounds. When the hydroformylation reaction is performed using a homogeneous catalyst, an organic or aqueous solvent is employed, and a significant effort must be expended to recover the catalyst so it can be recycled. Development of a selective heterogeneous catalyst would allow simplification of the process design in an integrated system that minimizes waste generation. Recent studies have shown that supercritical carbon dioxide (scCO2) as a reaction solvent offers optimal environmental performance and presents advantages for ease of product separation. In particular, we have considered the conversion of 1-hexene to heptanal using rhodium- and platinum-phosphine catalysts tethered to supports insoluble in scCO2 to demonstrate the advantages and to understand the limitations of a solid-catalyzed process. One of the historical limitations of supported catalysts is the inability to control product regioselectivity. To address this concern, we have developed tethered catalysts with phosphinated silica and controlled pore size MCM-41 and MCM-20 supports that provide improved regioselectivity and conversion relative to their nonporous equivalents. Platinum catalysts supported on MCM-type supports were the most regioselective whereas the analogous rhodium catalysts were the most active for hydroformylation of 1-hexene in scCO2.
- Marteel, Anne E.,Tack, Timothy T.,Bektesevic, Selma,Davies, Julian A.,Mason, Mark R.,Abraham, Martin A.
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- Study of reaction and kinetics in pyrolysis of methyl ricinoleate
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The effects of pyrolysis temperature, space-velocity, and dilution ratio of starting materials on the reaction have been studied in the pyrolysis of methyl ricinoleate. The reaction parameters were optimized to obtain yield ranges of 25.8-26.7% for heptaldehyde and 45.7-46.5% for methyl undecenoate. The kinetic study showed that pyrolysis of methyl ricinoleate is a first-order reaction at 828-878 K, and the activation energy is 1.729 × 105 J/mol.
- Guobin, Han,Zuyu, Liu,Suling, Yao,Rufeng, Yan
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- Highly regioselective hydroformylation of higher olefins catalysed by rhodium-phosphine complexes in ionic liquid medium
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Hydroformylation of higher olefins was performed efficiently in ionic liquids 1-n-alkyl-3-methylimidazolium p-toluenesulfonate ([Rmim][p-CH 3C6H4SO3], R = n-butyl, n-octyl, n-dodecyl, n-cetyl) with the rhodium-phosphine complex Rh-BISBIS (Rh = rhodium complex catalyst precursor; BISBIS = sodium salt of sulfonated 2,2′-bis (diphenylphosphinomethyl)-1,1′-biphenyl) as catalyst. The catalytic system offers excellent regioselectivity towards the linear aldehyde with high activity and chemoselectivity for aldehyde. Furthermore, the ionic liquid containing catalyst can be facilely separated and reused three times without a significant decrease in the activity and selectivity. The ionic liquids [Rmim][p-CH3C6H4SO3] used as the reaction media bring some definitive advantages over the halogen-containing analogues [bmim]BF4 and [bmim]PF6.
- Lin, Qi,Fu, Haiyan,Jiang, Weidong,Chen, Hua,Li, Xianjun
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- Hydroformylation in perfluorinated solvents; improved selectivity, catalyst retention and product separation
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The hydroformylation of linear terminal alkenes using rhodium based catalysts under fluorous biphasic conditions in the presence and absence of toluene is reported. Using fluorinated ponytails to modify triarylphosphites and triarylphosphines, good selectivities and reactivities can be obtained, along with good retention of the catalyst and ligand within the fluorous phase. Using P(O-4-C6H4C6F13)3 (P/Rh=3:1) as the ligand in toluene/perfluoro-1,3-dimethylcyclohexane, good results are obtained at 60°C, but decomposition of the catalyst and/or ligand occurs on increasing the temperature. More impressive results are obtained by omitting the toluene, with higher rates, better l/b ratios, and better retention of the catalyst and the phosphite within the perfluorocarbon solvent. Competing isomerisation restricts linear aldehyde selectivities to 6H4C6F13)3 is used as the ligand in the absence of toluene, even more impressive results can be obtained, with linear aldehyde selectivities up to 80.9%, high rates, and the retention of up to 99.95% of the rhodium and up to 96.7% of the phosphine within the fluorous phase. These results are compared with those of commercial systems for propene hydroformylation and with those previously reported in the literature for hydroformylation under fluorous biphasic conditions. Phase behaviour studies show that 1-octene is completely miscible with the fluorous solvent under the conditions used for the hydroformylation experiments, but that the product nonanal, phase separates.
- Foster, Douglas F,Gudmunsen, David,Adams, Dave J,Stuart, Alison M,Hope, Eric G,Cole-Hamilton, David J,Schwarz, Gary P,Pogorzelec, Peter
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- Synthesis and Catalytic Evaluation of Phosphanylferrocene Ligands with Cationic Guanidinium Pendants and Varied Phosphane Substituents
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This contribution expands the still narrow class of functional ferrocene phosphanes with polar cationic groups, focusing on the synthesis and catalytic use of a series of phosphanylferrocene ligands bearing positively charged guanidinium tags, [R2PfcCH2NHC(NH2)2]Cl (3a–d), where fc = ferrocene-1,1′-diyl, R = isopropyl (a), cyclohexyl (b), phenyl (c), and 2-furyl (d). To probe the influence of phosphane substituents, these compounds were studied as supporting ligands in Pd-catalyzed Suzuki–Miyaura cross-coupling of acyl chlorides with arylboronic acids, in analogous coupling of aryl bromides with arylboronic acids, and in Rh-catalyzed hydroformylation of 1-hexene using trans-[RhCl(CO){R2PfcCH2NHC(NH2)2-κP}2]Cl2 complexes (4a–d) as pre-catalysts. The outcome of the cross-coupling reactions strongly depended on the starting materials, and no ligand generated a universally applicable catalyst when combined with Pd(OAc)2. In the hydroformylation reactions, the catalyst based on 4d led to lower conversions than all others, which performed rather similarly. Overall, the phenyl-substituted phosphane 3c emerged as a good compromise, giving rise to reasonably efficient and stable catalysts in most cases (except for Suzuki–Miyaura biaryl cross-couplings, wherein electron-rich alkylphosphanes performed better than 3c).
- Bárta, Ond?ej,Císa?ová, Ivana,Mieczyńska, Ewa,Trzeciak, Anna M.,?těpni?ka, Petr
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- Selective Hydroformylation with a Recoverable Dirhodium μ-Thiolato Complex
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The dimeric precursor complex 2(cod)2>, (cod=cyclo-octa-1,5-diene), with PPh3 catalyses the hydroformylation of hex-1-ene, under mild conditions, into heptanals with high yields and selectivities; owing to the presence of the amine group the rhodium catalyst can be quantitatively recovered from the reaction mixture by adding dilute H2SO4, and reused without loss of activity.
- Bayon, J. C.,Real, J.,Claver, C.,Polo, A.,Ruiz, A.
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- Hydroformylation of olefins catalysed with bimetallic systems: HRh{P(OPh) 3}4 + cp2ZrH(CH2PPh2) and HRh(CO) {P(OPh) 3}3 + cp2ZrH(CH2PPh2)
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The catalytic activity of bimetallic systems containing the rhodium complex HRh{P(OPh)3}4 or HRh(CO){P(OPh)3}3 and the Zr(IV) complex cp2ZrH(CH2PPh2) was tested in the hydroformylation reaction of 1-hexene and E-,Z-2-hexene. An increase in n/iso ratio (from 2.2 to 3.5 in the case of HRh{P(OPh)3}4 and from 0.4 to 3.7 in the case of HRh(CO){P(OPh)3}3) was observed in 1-hexene hydroformylation in the presence of cp2ZrH(CH2PPh2).
- Trzeciak, Anna M.,Ziotkowski, Jozef J.,Choukroun, Robert
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- Selective hydroformylation of 1-hexene to branched aldehydes using rhodium complex of modified bulky phosphine and phosphite ligands
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The selective hydroformylation of 1-hexene to branched aldehydes was investigated using rhodium complex of tri-1-naphthylphosphine PNp3 and tri-1-naphthylphosphite P(ONp)3. The PNp3 and P(ONp)3 ligands having more steric nature than PPh3 enhanced the formation of branched aldehydes at 110 °C and 4.0 MPa syngas pressure. The branched aldehyde selectivity increased remarkably (82%) by adding P(ONp)3 as auxiliary ligand in Rh/PNp3 catalyzed hydroformylation of 1-hexene. The high selectivity for the branched aldehydes is due to rapid alkene isomerization producing internal alkenes followed by hydroformylation to yield branched aldehydes.
- Dabbawala, Aasif A.,Jasra, Raksh V.,Bajaj, Hari C.
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- Hydroformylation of 1-hexene in the presence of rhodium complexes immobilized on polyorganosiloxanes
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It was demonstrated that the catalyst system based on acacRh(CO)2 and polyorganosiloxanes exhibits high activity and stability in hydroformylation of 1-hexene. The effects of the nature of the oligomer, the ratio of oligomers, and the oligomer : rhodium ratio in the polymer on the synthesis and catalytic properties of the system were studied.
- Kolesnichenko,Terekhova,Teleskev,Alekseeva,Slivinsky
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- Describing the Reaction of the Hydrocarboxylation of 1-Hexene, Catalyzed by Co2(CO)8, in Marcelin–de Donde Kinetics
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Abstract: An equation is derived for calculating the rate coefficient of the 1-hexene hydrocarboxylation reaction in Marcelin–de Donde kinetics. The equation correctly describes experimental data in the range of concentrations of an unsaturated substrate,
- Vigranenko, Yu. T.,de Vekki,Krylova,Koluzhnikova
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- Highly active cationic cobalt(II) hydroformylation catalysts
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The cobalt complexes HCo(CO)4 and HCo(CO)3(PR3) were the original industrial catalysts used for the hydroformylation of alkenes through reaction with hydrogen and carbon monoxide to produce aldehydes. More recent and expensive rhodium-phosphine catalysts are hundreds of times more active and operate under considerably lower pressures. Cationic cobalt(II) bisphosphine hydrido-carbonyl catalysts that are far more active than traditional neutral cobalt(I) catalysts and approach rhodium catalysts in activity are reported here. These catalysts have low linear-to-branched (L:B) regioselectivity for simple linear alkenes. However, owing to their high alkene isomerization activity and increased steric effects due to the bisphosphine ligand, they have high L:B selectivities for internal alkenes with alkyl branches. These catalysts exhibit long lifetimes and substantial resistance to degradation reactions.
- Carpenter, Alex E.,Hood, Drew M.,Johnson, Ryan A.,Stanley, George G.,Vinyard, David J.,Younker, Jarod M.
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- Biphase hydroformylation catalyzed by rhodium in combination with a water-soluble pyridyl-triazole ligand
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[RhCl(COD)]2in combination with a water soluble sulphonated pyridyl-triazolyl N,N-bidentate ligand efficiently catalyzes styrene and 1-hexene hydroformylation in water/organic solvent biphasic systems. The catalyst displays a good activity affording mixtures of linear and branched aldehydes with complete chemoselectivity. The aqueous catalytic phase may be recycled four times giving complete substrate conversion by 18 h. Mercury-poisoning experiments and transmission electron microscopy indicate that, after the first catalytic run, rhodium is present in the aqueous phase in nanoparticle form.
- Scrivanti, Alberto,Beghetto, Valentina,Alam, Md. Mahbubul,Paganelli, Stefano,Canton, Patrizia,Bertoldini, Matteo,Amadio, Emanuele
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- Enhancing the activity, selectivity, and recyclability of Rh/PPh3 system-catalyzed hydroformylation reactions through the development of a PPh3-derived quasi-porous organic cage as a ligand
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In contrast to heterogeneous network frameworks (e.g., covalent organic frameworks and metal-organic frameworks) and porous organic polymers, porous organic cages (POCs) are soluble molecules in common organic solvents that provide significant potential for homogeneous catalysis. Herein, we report a triphenylphosphine-derived quasi-porous organic cage (denoted as POC-DICP) as an efficient organic molecular cage ligand for Rh/PPh3 system-catalyzed homogeneous hydroformylation reactions. POC-DICP not only displays enhanced hydroformylation selectivity (aldehyde selectivity as high as 97% and a linear-to-branch ratio as high as 1.89) but can also be recovered and reused via a simple precipitation method in homogeneous reaction systems. We speculate that the reason for the high activity and good selectivity is the favorable geometry (cone angle = 123.88°) and electronic effect (P site is relatively electron-deficient) of POC-DICP, which were also demonstrated by density functional theory calculations and X-ray absorption fine-structure characterization.
- Wang, Wenlong,Li, Cunyao,Zhang, Heng,Zhang, Jiangwei,Lu, Lanlu,Jiang, Zheng,Cui, Lifeng,Liu, Hongguang,Yan, Li,Ding, Yunjie
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- THE SYNTHESIS OF PGF1α BY RE-STRUCTURING OF CASTOR OIL
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Castor oil has been transformed - via methyl ricinoleate - to PGF1α by strategy wherein 16 of the 18 carbons of the castor oil backbone are incorporated in the C-20 PGF1α, involving, inter alia, a novel procedure for the regiospecific functionalisation of terminal olefins, a novel degradation of aldehyde to lower acid and strategies useful for the generation of the highly functionalised prostanoid system, which specially illustrate the utility of MEM protecting group in diverse types of chemical transformations.Additionally, this work describes the preparation of synthons having potential utility and the synthesis of novel homo-PGF1α.
- Ranganathan, D.,Ranganathan, S.,Mehrotra, M. M.
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- Cubic group 13 heterosiloxanes with four Co3(CO)9C cluster units as substituents: Novel soluble model compounds for synthetic zeolites showing catalytic activity in hydroformylation reactions
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The reactions between the cobalt carbonyl anchored silanetriol Co3(CO)9CSi(OH)3 (1) and EMe3 (E = Al, Ga and In) in THF result in the formation of the respective group 13 heterosiloxanes [Co3(GO)9CSiO3E·THF]4 (Al (2); Ga (3); In (4)) in good yields. The new heterosiloxanes have been extensively characterized by means of their analytical and spectroscopic (mass, IR, and NMR) data. Additionally, the molecular structure of the Al complex 2 has been determined by X-ray diffraction studies. The compound contains a cubic Al4O12Si4 core with four Co3(CO)9C cluster units anchored on each of the silicon atoms at the alternating corners of the cube. Interestingly, there are three different types of Co3(CO)9C cluster units within the same molecule based on the mode of coordination of the CO ligands. In order to test the utility of these compounds in catalytic conversions, hydroformylation reactions involving 1-hexene as substrate have been carried out at 120 °C under a H2/CO initial pressure of 70 bar. A series of solution studies of the catalytic mixture (such as time-dependent IR, NMR and MS) have been carried out in order to identify the catalytic active species in the process. The Al- and Ga-containing heterosiloxanes show a better hydroformylation activity compared to the In analogue. The regioselectivity of the hydroformylation reactions with 2 is found to be over 60%. The hydroformylation presumably proceeds via the decomposition of Co3(CO)9C cluster fragments into Co2(CO)8 units in the case of catalysts 2 and 3.
- Ritter, Uwe,Winkhofer, Norbert,Murugavel, Ramaswamy,Voigt, Andreas,Stalke, Dietmar,Roesky, Herbert W.
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- New glycosphingolipids from the fungus Catathelasma ventricosa
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Three new glycosphingolipids with a cis-Δ17-fatty acyl moiety, namely, catacerebrosides A-C (1-3), along with two known glycosphingolipids, cerebrosides B and D, six known ergostane-type sterols, and tyrosamine were isolated from the fungus Catathelasma ventricosa. The structures of 1-3 were elucidated on the basis of spectroscopic analysis and chemical methods.
- Zhan, Zha-Jun,Yue, Jian-Min
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- Acyl silanes as synthetic intermediates: Formation of acyl anions and unusual fluoride-initiated silicon to carbon alkyl group migration
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Acyl silanes react with fluoride ion in the presence of water to give products arising either from intermediates equivalent to acyl anions or from rearrangements involving alkyl group migration from silicon to carbon, depending upon the reaction conditions.
- Bulman Page, Philip C.,Rosenthal, Stephen,Williams, Richard V.
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- Impact of structured catalysts in amine oxidation under mild conditions
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A structured graphene/graphite catalyst grown on a commercial austenitic stainless steel sheet providing a micromonolith was obtained by submitting the nude stainless steel structure to a carbon-rich atmosphere (first 300 mL/min of a reductive H2/N2 (1:1) flow, then to 180 mL/min of a CH4/H2 (1:5)) at high temperature (900 °C) for 2 h. The preparation procedure resulted in a homogenous surface coated with a carbon-rich film as observed by EDX and SEM images. Further characterizations by Raman spectroscopy revealed characteristic Raman lines of graphene and crystalline graphite disposed in a hierarchical organization. The disposal of the obtained surface layers was also confirmed by grazing incidence X-ray diffraction. Besides this, XRD indicated the overlapping diffraction lines of graphite, cementite and M7C3 carbides. The graphene nature of the outermost layer was also confirmed by XPS. The catalytic behavior of the structured graphene/graphite catalyst was evaluated in the selective oxidation of heptylamine. At 200 °C it afforded a total conversion with a combined selectivity in heptanonitrile and N-heptylidene-heptylamine of 67% (10% heptanonitrile) that corresponds indeed to a very efficient system in the absence of any metal. Kinetic experiments with the scope to calculate the activation energies were also performed.
- Santos, Jose Luis,Navarro, Pablo,Odriozola, Jose Antonio,Centeno, Miguel Angel,Pavel, Octavian D.,Jurca, Bogdan,Parvulescu, Vasile I.
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- MCM-41 supported water-soluble TPPTS-Rh complex in ionic liquids: A new robust catalyst for olefin hydroformylation
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MCM-41 mesoporous silicas-supported water-soluble TPPTS-Rh complex in the ionic liquid TMGL exhibited high performance and stability for the hydroformylation of 1-hexene, and the catalyst system could be reused many times without reducing the activity and selectivity. Copyright
- Yang, Yong,Lin, Haiqiang,Deng, Changxi,She, Jiarong,Yuan, Youzhu
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- Implication of oxidant activation on olefin epoxidation catalysed by Molybdenum catalysts with aroylhydrazonato ligands: Experimental and theoretical studies
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Dinuclear and mononuclear molybdenum(VI) complexes with aroylhydrazonato ligands were studied as catalysts for cyclooctene and oct-1-ene epoxidation. Different isomers of the OH and NH2 functionalised aroylhydrazones led to four specific [MoO2L] units showing different catalytic activity. Three oxidants have been investigated: tert-butylhydroperoxide (TBHP) in water or in decane, and hydrogen peroxide (H2O2). Catalytic processes with TBHP in decane provided outstanding results in the case of cyclooctene epoxidation: TOF2.5 min > 9000 with 0.25 mol % [Mo] loading. DFT calculations confirmed the relationship between the ligand nature and reactivity with TBHP and H2O2 as oxidant agents. In the case of TBHP as oxidant, calculations considered the solvent in which the oxidant is delivered to the olefin. A plausible mechanism with H2O2 has been proposed after considering various pathways.
- Bafti, Arijeta,Razum, Marta,Topi?, Edi,Agustin, Dominique,Pisk, Jana,Vrdoljak, Vi?nja
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- Rh/Cu2O nanoparticles: Synthesis, characterization and catalytic application as a heterogeneous catalyst in hydroformylation reaction
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In this work, we report a rapid protocol for the synthesis of Rh/Cu2O nanoparticles (Rh/Cu2O NPs) in aqueous medium using microwave route. The microwave energy acts as driving force in synthesis which makes the process economical. The obtained nanoparticles were characterized with the help of FEG-SEM, TEM, HRTEM, EDS, XRD, FT-IR and ICP-AES techniques. The prepared Rh/Cu2O nanoparticles gave 100% yield of uniform spherical morphology. This is a simple, inexpensive and time saving protocol for synthesis of Rh/Cu2O nanoparticles than conventional methods. Furthermore, we showed the catalytic application of Rh/Cu2O nanoparticles in hydroformylation reaction for the conversion of 1-hexene to 1-hexanal at mild reaction conditions such as Rh/Cu2O NPs (10 mg), 35 bar pressure of H2/CO at 360 K. The reaction provides 99% conversion and high selectivity (>90%) toward aldehydes with branched aldehyde is a major product. Notably the reaction does not require the any phosphine ligand source, low catalyst loading, low temperature with major advantage of catalyst recyclability.
- Jagtap, Samadhan A.,Bhosale, Manohar A.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
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- Synthesis, Structural Characterization, and Hydroformylation Activity of Rhodium(I) Complexes with a Polar Phosphinoferrocene Sulfonate Ligand
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1′-(Diphenylphosphino)ferrocene-1-sulfonic acid (HL), isolated from the salt (Et3NH)L on an ion exchanger, reacts with Rh(I) complexes [Rh(acac)(CO)(PR3)] (acac = acetylacetonato-κ2O,O′) to give complexes of the type [Rh(CO)(PR3)(Ph2PfcSO3-κ2O,P)] (1a-d; R = Ph (a), Cy (b), 2-furyl (c), and OMe (d); fc = ferrocene-1,1′-diyl). In an analogous reaction with [Rh(acac)(nbd)] (nbd = n 2: n 2-norbornadiene), HL produces [Rh(nbd)(Ph2PfcSO3-κ2O,P)] (2). Adding (Et3NH)L (2 equiv per Rh) to [Rh(μ-Cl)(CO)2]2 and [Rh(acac)(CO)2] gives rise to the cationic complexes trans-(Et3NH)2[RhCl(CO)(Ph2PfcSO3-κP)2] (3) and (Et3NH)[Rh(CO)(Ph2PfcSO3-κ2O,P)(Ph2PfcSO3-κP)] (4), respectively. In complex 4, resulting from the simultaneous substitution of a CO ligand and acid-base replacement of the acac ligand, the P-monodentate and O,P-chelating phosphinoferrocene sulfonate ligands rapidly interconvert (in a solution). All compounds were characterized by spectroscopic methods and by elemental analysis, and the crystal structures of 1a·Me2CO, solvated 1b, 2, and 4·H2O were determined. Furthermore, the catalytic activity of all Rh(I) complexes was assessed in hydroformylation of vinyl acetate under solvent-free conditions at 80 °C and at 20 bar of synthesis gas (H2/CO = 1:1). High conversion with good selectivity to iso-aldehyde was observed for 1a·1/2H2O and 4·1/2H2O. When applied to "on-water" hydroformylation of 1-hexene (80 °C/10 bar), the complexes mainly promoted 1-hexene isomerization to 2-hexene. However, two of them, 1a·1/2H2O and 1c, exhibited reasonable selectivity to aldehydes and preferentially produced the linear product (n/iso ratios up to 3).
- Zábransky, Martin,Císa?ová, Ivana,Trzeciak, Anna M.,Alsalahi, Waleed,?těpni?ka, Petr
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- Rhodium complexes supported on nanoporous activated carbon for selective hydroformylation of olefins
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Activated carbon with nanoporous structure, high surface area (2500 m2/g) and total pore volume (2.35 cm3/g) was prepared from Mango seed shell (Mangifera indica L.) via chemical activation method and used as support to impregnate active hydroformylation rhodium complexes HRhCO(PPh3)3 and Rh(acac)(CO)2. The prepared catalysts were characterized by XRD, SEM, TEM, NMR, IR, TGA, and N2 adsorption/desorption techniques. The supported catalysts have shown excellent selectivity for aldehydes (~ 99%) in the hydroformylation of olefins with good stability and recyclability up to 4 cycles.
- Ganga, Venkata Subba Rao,Dabbawala, Aasif A.,Munusamy,Abdi, Sayed H.R.,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Bajaj, Hari C.
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- Reactions of stabilized Criegee intermediates from the gas-phase reactions of O3 with selected alkenes
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The gas-phase reactions of O3 with 1-octene, trans-7-tetradecene, 1,2-dimethyl-l-cyclohexene, and α-pinene have been studied in the presence of an OH radical scavenger, primarily using in situ atmospheric ionization tandem mass spectrometry (API-MS), to investigate the products formed from the reactions of the thermalized Criege intermediates in the presence of water vapor and 2-butanol (1-octene and trans-7-tetradecene forming the same Criege intermediate). With H3O+(H2O)n as the reagent ions, ion peaks at 149 u ([M + H]+) were observed in the API-MS analyses of the l-octene and trans-7-tetradecene reactions, which show a neutral loss of 34 u (H2O2) and are attributed to the α-hydroxyhydroperoxide CH3(CH2)5CH(OH)OOH, which must therefore have a lifetime with respect to decomposition of tens of minutes or more. No evidence for the presence of α-hydroxyhyroperoxides was obtained in the 1,2-dimethyl-1-cyclohexene or α-pinene reactions, although the smaller yields of thermalized Criegee intermediates in these reactions makes observation of α-hydroxyhydroperoxides from these reactions less likely than from the 1-octene and trans-7-tetradecene reactions. Quantifications of 2,7-octanedione from the 1,2-dimethyl-1-cyclohexene reactions and pinonaldehyde from the α-pinene reactions were made by gas chromatographic analyses during reactions with cyclohexane and with 2-butanol as the OH radical scavenger. The measured yields of 2,7-octanedione from 1,2-dimethyl-1-cyclohexene and of pinonaldehyde from α-pinene were 0.110 ± 0.020 and 0.164 ± 0.029, respectively, and were independent of the OH radical scavenger used. Reaction mechanisms are presented and discussed.
- Baker,Aschmann,Arey,Atkinson
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- Csp3Csp3 bond cleavage in the palladium-catalyzed aminohydroxylation of allylic hydrazones using atmospheric oxygen as the sole oxidant
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A C-C bond cleavage was observed in the palladium-catalyzed aminohydroxylation of allylic hydrazones, using atmospheric oxygen as the sole oxidant. This reaction could also proceed in a one-pot manner, starting from keto-alkene compounds and phenylhydrazine.
- Chen, Yu-Chen,Zhu, Ming-Kui,Loh, Teck-Peng
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- Anisole: A further step to sustainable hydroformylation
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Hydroformylation, also known as the "oxo" process, is a major industrial process that employs rhodium or cobalt catalysts in solution; therefore the solvent of this process is a critical issue for its sustainability. Although several innovative solutions have been proposed recently, traditional fossil-derived solvents dominate the scenario for this reaction. In this paper, we studied a series of solvents considered more sustainable in recent ranks in the hydroformylation of a series of olefins. Anisole, a solvent with an impressive sustainability rank and very scarcely exploited in hydroformylation, proved to be an excellent alternative for this reaction.
- Delolo, Fábio G.,Dos Santos, Eduardo N.,Gusevskaya, Elena V.
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- Cationic Dinuclear Rhodium Complexes as Catalysts Precursors for the Hydroformylation of Alkenes
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The dimeric cationic complexes (2+) have been prepared as chloride and tetrafluoroborate salts.The activity of these complexes as hydroformylation and hydrogenation catalysts under mild conditions has been tested, in an attempt to elucidate the importance of functional groups in the ligand and the effect of counter ions.In hydroformylations, best results have been obtained with 2 plus added PPh3 or P(OPh)3, with turnover rates of ca. 2.7 mmol of olefin per mmol of catalyst per minute, and conversions up to 80percent; when P(OMe)3 was used, the activity decreased but the normal:isoaldehyde ratio increased.An important anion effect was observed, namely that all the chlorides were found to be inactive.In hydrogenation, activities are only moderate but unaffected by the nature of the counter ion.However, the (1-) salts caused isomerization of the olefins, while the chlorides did not.The iridium complexes were found to be inactive.
- Bayon, J. Carles,Esteban, Pedro,Real, Julio,Claver, Carmen,Ruiz, Aurora
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- High-pressure investigations under CO/H2 of rhodium complexes containing hemispherical diphosphites
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The two rhodium complexes [Rh(acac)(LR)] (LR=(S,S)-5, 11,17,23-tetra-tert-butyl-25,27-di(OR)-26,28-bis(1,1'-binaphthyl-2, 2'-dioxyphosphanyloxy)calix[4]arene; 6: R=benzyl, 7: R=fluorenyl), each based on a hemispherical chelator forming a pocket about the metal centre upon chelation, are active in the hydroformylation of 1-octene and styrene. As expected for this family of diphosphanes, both complexes resulted in remarkably high selectivity towards the linear aldehyde in the hydroformylation of 1-octene (l/b≈15 for both complexes). Linear aldehyde selectivity was also observed when using styrene, but surprisingly only 6 displayed a marked preference for the linear product (l/b=12.4 (6) vs. 1.9 (7)). A detailed study of the structure of the complexes under CO or CO/H2 in toluene was performed by high-pressure NMR (HP NMR) and FT-IR (HP-IR) spectroscopies. The spectroscopic data revealed that treatment of 6 with CO gave [Rh(acac)(CO) (I·1-Lbenzyl)] (8), in which the diphosphite behaves as a unidentate ligand. Subsequent addition of H2 to the solution resulted in a well-defined chelate complex with the formula [RhH(CO)2(Lbenzyl)] (9). Unlike 6, treatment of complex 7 with CO only led to ligand dissociation and concomitant formation of [Rh(acac)(CO)2], but upon addition of H2 a chelate complex analogous to 9 was formed quantitatively. In both [RhH(CO)2(L R)] complexes the diphosphite adopts the bis-equatorial coordination mode, a structural feature known to favour the formation of linear aldehydes. As revealed by variable-temperature NMR spectroscopy, these complexes show the typical fluxionality of trigonal bipyramidal [RhH(CO)2(diphosphane)] complexes. The lower linear selectivity of 7 versus 6 in the hydroformylation of styrene was assigned to steric effects, due to the pocket in which the catalysis takes place being less adapted to accommodate CO or larger olefins and, therefore, possibly leading to facile ligand decoordination. This interpretation was corroborated by an X-ray structure determination carried out for 7. Rhodium in confinement: As revealed by high-pressure NMR/IR spectroscopic studies, the reaction of rhodium complexes containing hemispherical diphosphites with CO/H2 leads to trigonal bipyramidal intermediates in which the phosphorus atoms exclusively occupy equatorial sites (see figure). The resulting metal confinement selectively drives olefin hydroformylation reactions to form aldehydes that best fit the cavity. Copyright
- Semeril, David,Matt, Dominique,Toupet, Loic,Oberhauser, Werner,Bianchini, Claudio
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- Selective conversion of castor oil derived ricinoleic acid methyl ester into jet fuel
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The selective conversion of ricinoleic acid methyl ester into jet fuel was realized through the integration of feedstock properties and rational catalytic design strategy. A unique hydroxyl group in the ricinoleic acid chain induced a special thermal rearrangement reaction in medium chain fatty acid methyl ester (FAME) and heptanal formation. Such a reaction was used as the starting point for our proposed process. Methyl 10-undecenoate was converted into a branched paraffin with limited carbon loss. Both Pt/Al2O3 and Pt/ZSM-22 catalysts resulted in selective hydrogenation (with limited decarbonylation) and hydro-isomerization (with negligible cracking), respectively. Another product, heptanal, was also converted into jet fuel through selective dimerization and hydrodeoxygenation with a supported amine and commercially available Pt/Al2O3 catalyst, respectively. With the right integration of these technologies, the carbon selectivity in the castor oil to jet fuel process is as high as 90%.
- Zhou, Yuping,Huang, Yong,Fang, Yunming,Tan, Tianwei
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- On rhodium complexes bearing H-spirophosphorane derived ligands: Synthesis, structural and catalytic properties
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We investigated the coordination properties of H-spirophosphoranes towards rhodium ion. Symmetrical phosphorus ligands: HP(OCH2CH 2NH)2 L1, HP(OCH2CM-2NH)2 L2, HP(OCMe2CMe 2O)2 L3, HP(OC6H4NH)2 L4, and unsymmetrical phosphorus ligands: HP(OCMe2CMe2O)(OCH2CM-2NH) L5, HP(OCMe2CMe2O)(OC6H4NH) L6 were found to coordinate to rhodium precursor [Rh(CO)2Cl]2 exclusively in protonated k2-P,E (E =N, O) bidentate fashion, yielding complexes [Rh(CO)ClL] 1-6. The complexes were characterised by spectroscopic methods. The molecular structures of the ligand L6 complexes 3, 5 and 6 were determined by single-crystal X-ray diffraction. The catalytic activity of the complexes was determined in hydroformylation reaction of 1-hexene. Complexes 1 and 2 appeared to be active in isomerisation reactions yielding 76 and 62% of 2-hexene. When used with six-fold excess of triphenylphosphite P(OPh)3 as a modified ligand, the most active catalyst 1 in hydroformylation reaction produced 66% of aldehydes and 22% of 2-hexene.
- Skarzyńska, Anna,Mieczynska, Ewa,Siczek, Miosz
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- Acetonitrile-assisted highly selective photocatalytic epoxidation of olefins on Ti-containing silica with molecular oxygen
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Highly selective photocatalytic epoxidation of olefins proceeds on Ti-containing silica with tetrahedrally coordinated Ti-oride species with molecular oxygen and a simple addition of MeCN. The Royal Society of Chemistry 2005.
- Shiraishi, Yasuhiro,Morishita, Masatsugu,Hirai, Takayuku
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- Tris(2-pyridyl)phosphine Complexes of Ruthenium(II) and Rhodium(I). Hydroformylation of Hex-1-ene by Rhodium Complexes
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Complexes of ruthenium(II) and rhodium(I) containing tris(2-pyridyl)phosphine are described, examples being RuHCl3 and RhCl2.In certain cases, as in these, the nitrogen atom of one of the 2-pyridyl groups can act as a donor to give a P,N chelate ligand.In the presence of an excess of P(py)3 and at low CO + H2 (1 : 1) pressures, the complex RhH(CO)(PPh3)2 acts as a catalyst for the selective hydroformylation of hex-1-ene to n-heptanal.
- Kurtev, Kurti,Ribola, Dominique,Jones, Richard A.,Cole-Hamilton, David J.,Wilkinson, Geoffrey
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- Tri(3-pyridyl)phosphine as amphiphilic ligand in the rhodium-catalysed hydroformylation of 1-hexene
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The molecular structure of carbonylchlorobis(tri(3-pyridyl)phosphine) rhodium, 1, has been determined by X-ray diffraction methods. The N-protonated trifluoromethanesulfonate (triflate) complex 3 was synthesised as a model compound for the extraction of a rhodium complex bearing amphiphilic ligands which can allow catalyst recycling in the hydroformylation of alkenes by using their distribution behavior in organic and aqueous solvents of different pH. The high water-solubility of the employed ligand renders the recycling method as only partly successful due to insufficient extraction from the water phase into the organic phase. In the hydroformylation of 1-hexene the production of rt-heptanal is slightly disfavoured when using the ligand tri(3-pyridyl) phosphine as compared to triphenylphosphine which can be ascribed to a higher amount of ligand-deficient active rhodium complexes of the less basic pyridyl phosphine ligand under CO pressure.
- Meyer, Wolfgang H.,Bowen, Richard J.,Billing, David G.
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- Benzoquinones from Embelia angustifolia
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Three new 2,5-dihydroxy-3-alkyl-1,4-benzoquinones, (Z)-2,5-dihydroxy-3- (pentadec-8-enyl)-1,4-benzoquinone, (Z,Z)-2,5-dihydroxy-3-(heptadeca-8,11- dienyl)-1,4-benzoquinone and (Z)-2,5-dihydroxy-3-(heptadec-8-enyl)-1,4- benzoquinone and the known 2,5-dihydroxy-3-pentadecyl-1,4-benzoquinone were isolated from the leaves of Embelia angustifolia. Their structures have been established on the basis of spectral analysis and by chemical methods.
- Lund, Anne-Kristine,Lemmich, John,Adsersen, Anne,Olsen, Carl E.
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- Rhodium catalysed hydroformylation using slim phosphate ligands to improve selectivity
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Catalysts based on 1COCHCOR1)(CO)2> and a phosphite are active for hydroformylation of hex-1-ene under very mild conditions; very bulky phosphites such as (2-tBu-4-MeC6H3O)3P, 3, give much olefin isomerization, while the slim caged phosphite ligands, P(OCH2)3CR2, show high regioselectivity towards formation of n-C6H13CHO.
- Poelsma, Sybout N.,Maitlis, Peter M.
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- Decreasing Side Products and Increasing Selectivity in the Tandem Hydroformylation/Acyloin Reaction
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A highly selective catalyst system was developed for the recently discovered tandem hydroformylation/acyloin reaction by systematic investigations and changes of reaction conditions. This new catalyst system is characterized by an excellent selectivity of the desired reaction pathway with negligible amounts of side products. A successful application of the tandem hydroformylation/acyloin reaction to a variety of olefins is enabled with comparable excellent selectivities up to >99% for the first and second reaction step, therefore a general synthesis for the conversion of olefins into acyloins is found. Furthermore, very good to excellent yields for the intermediates and final acyloin products were observed within two catalysed reactions in one preparative step. The acyloin product was applied as a nonpolar precursor for surfactants. After attaching a polar head group to the acyloin and determination of tensiometric data, the molecule showed industrial relevant surface-active properties. Jointly successful: New catalyst systems for the tandem hydroformylation/acyloin reaction display excellent selectivities within two catalyzed reactions in one preparative step. A variety of olefins can be converted efficiently, and the acyloin product is applied successfully as a nonpolar precursor for surfactants.
- Ostrowski, Karoline A.,Fassbach, Thiemo A.,Vogelsang, Dennis,Vorholt, Andreas J.
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- Rhodium-catalyzed Two-phase Hydroformylation of Hex-1-ene with Sulfonated Tris(4-fluorophenyl)phosphine as Water-soluble Complex Ligands
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Tris(4-fluorophenyl)phosphine (TFPP) was prepared from 1-bromo-4-fluoro-benzene in 35percent yield.This phosphine was quantitatively sulfonated by using a H2SO4-SO3 mixture containing 25.5percent SO3 and 14-fold excess of SO3 to phosphine.The desired product was the trisodium salt of the trisulfonated tris(4-fluorophenyl)phosphine (TFPPTS).After 410 hours of sulfonation, hydrolysis and pH-selective separation, the resulting mixture contained 6percent TFPPTS and 94percent disodium salt of the disulfonated tris(4-fluorophenyl)phosphine (TFPPDS).Hex-1-ene was hydroformylated in a two-phase system by using the water-soluble catalytic systems Rh4(CO)12 with a mixture of 94percent TFPPDS + 6percent TFPPTS and Rh4(CO)12 with the trisodium salt of trisulfonated triphenylphosphine (TPPTS).The TFPP or TFPPTS ligand possesses a stronger ?-acidity than the TPP or TPPTS and at low P/Ph-ratios higher selectivities to linear aldehydes are achieved with the Rh/TFPP or Rh/TFPPDS + TFPPTS than with the Rh/TPP or Rh/TPPTS catalytic system.The Rh/TFPPDS + TFPPTS complex is quantitatively recovered by simple separation of the aqueous layer from the organic layer which contains the substrate and the products.
- Fell, Bernhard,Papadogianakis, Georgios
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- Synthesis of electron-withdrawing butane- and arene-sulfonylamino phosphines and use in rhodium-catalyzed hydroformylation
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Reaction of RSO2N(H)CH2CH2N(H)SO2R [R = Bu (1), 4-nitrobenzene (7), 1-naphthalene (9a), 2-naphthalene (9b)] with PhPCl2 or EtPCl2 gives monodentate phosphorus compounds 2 and 3 (R = Bu, PhP and EtP), and 8 (R = 4-nitrobenzene, PhP), and with Ph2PCl gives the corresponding bidentate phosphine ligands Ph2PN(SO2R)CH2CH2N(SO2R)P Ph2 [R = Bu (10), 4-nitrobenzene (11), 1- and 2-naphthalene (12a,b)]; similar reactions of N,N′-(1-butanesulfonyl)-2,2′-diaminobiphenyl (4) give monodentate 5 (PhP) and 6 (EtP) and N,N′-bis(diphenylphosphino)-N,N′-(1-butanesulfonyl)-2,2′-diami nobiphenyl (16). A monodentate analogue of 10 was also prepared, Ph2PN(Et)SO2Bu (14). Diphosphorus compounds with two butanesulfonylamino groups on phosphorus were also prepared from 1 and Cl2P(CH2)nPCl2 (n = 2, 4) to give 19 and 20. Details of the 13C NMR false AA′X systems are reported for 19 and 20. Rhodium-catalyzed hydroformylation reactions were run at 60 and 80 °C, at CO/H2 pressures from 4-11 atm, and in THF, toluene, CH2Cl2, and dioxane. Results show that the highest ratios of linear (n) to branched (iso) aldehydes were obtained with arenesulfonamides (n:iso > 10) while the bidentate alkanesulfonamide 10 gave a lower n:iso ratio of 7.2 but the highest rate [k1 = 1.98 h-1, turnover frequency = 1130 mol aldehyde (mol Rh)-1 h-1] in THF at 80 °C. Both the rate and n:iso ratio for 10 were found to increase with decreasing CO/H2 pressure in THF and in toluene, although the rate change was small for toluene. Both the rate and n:iso ratio for 10 also increased in CH2Cl2, but this was found not to be due to lower CO/H2 concentrations in solution, on the basis of solubility measurements in THF and CH2Cl2.
- Magee, Matthew P.,Li, Huan-Qiu,Morgan, Oma,Hersh, William H.
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- On the mechanism and regioselectivity of alkane photocarbonylation catalyzed by Rh(PMe3)2(CO)Cl
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Photochemical carbonylation of hexane catalyzed by Rh(PMe3)2(CO)Cl (1) is found to proceed via at least two different mechanisms.One requires a secondary photochemical reaction and gives primarily (ca. 98percent) linear aldehyde, while the other is radical-based, much less regioselective, and apparently involves only one photochemical step.In accord with this mechanistic understanding, it has proven possible to find conditions leading simultaneously to high photoefficiency and regioselectivity, and greatly increased chemical yields.The presumed photointermediate in the two-photoprocess pathway has been photochemically generated at low temperature and characterized by NMR spectroscopy. Keywords: Rhodium; Alkane activation; Carbonylation; Photochemistry
- Rosini, Glen P.,Zhu, Keming,Goldman, Alan S.
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- Solvent-free oxidation of straight-chain aliphatic primary alcohols by polymer-grafted vanadium complexes
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Oxidovanadium(IV) complexes [VO(tertacac)2] (1), [VO(dipd)2] (2), and [VO(phbd)2] (3) were synthesized by reacting [VO(acac)2] with 2,2,6,6-tetramethyl-3,5-hepatanedione, 1,3-diphenyl-1,3-propanedione, and 1-phenyl-1,3-butanedione, respectively. Imidazole-modified Merrifield resin was used for the heterogenization of complexes 1–3. During the process of heterogenization, the V4+ center in complex 2 converts into V5+, whereas the other two complexes 1 and 3 remain in the oxidovanadium(IV) state in the polymer matrix. Theoretically, calculated IPA values of 1–3 suggest that 2 is prone to oxidation compared with 1 and 3, which was also supported by the absence of EPR lines in 5. Polymer-supported complexes Ps-Im-[VIVO(tertacac)2] (4), Ps-Im-[VVO2(dipd)2] (5), and Ps-Im-[VIVO(phbd)2] (6) were applied for the solvent-free heterogenous oxidation of a series of straight-chain aliphatic alcohols in the presence of H2O2 at 60°C and showed excellent substrate conversion specially for the alcohols with fewer carbon atoms. Higher reaction temperature improves the substrate conversion significantly for the alcohols containing more carbon atoms such as 1-pentanol, 1-hexanol, and 1-heptanol while using optimized reaction conditions. However, alcohols with fewer carbon atoms seem less affected by reaction temperatures higher than the optimized temperature. A decreasing trend in the selectivity(%) of carboxylic acid was observed with increasing carbon atoms among the examined alcohols, whereas the selectivity towards aldehydes increased. The order of efficiency of the supported catalysts is 4 > 6 > 5 in terms of turnover frequency (TOF) values and substrate conversion, further supported by theoretical calculations.
- Chaudhary, Nikita,Haldar, Chanchal,Kachhap, Payal
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- Directing Selectivity to Aldehydes, Alcohols, or Esters with Diphobane Ligands in Pd-Catalyzed Alkene Carbonylations
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Phenylene-bridged diphobane ligands with different substituents (CF3, H, OMe, (OMe)2, tBu) have been synthesized and applied as ligands in palladium-catalyzed carbonylation reactions of various alkenes. The performance of these ligands in terms of selectivity in hydroformylation versus alkoxycarbonylation has been studied using 1-hexene, 1-octene, and methyl pentenoates as substrates, and the results have been compared with the ethylene-bridged diphobane ligand (BCOPE). Hydroformylation of 1-octene in the protic solvent 2-ethyl hexanol results in a competition between hydroformylation and alkoxycarbonylation, whereby the phenylene-bridged ligands, in particular, the trifluoromethylphenylene-bridged diphobane L1 with an electron-withdrawing substituent, lead to ester products via alkoxycarbonylation, whereas BCOPE gives predominantly alcohol products (n-nonanol and isomers) via reductive hydroformylation. The preference of BCOPE for reductive hydroformylation is also seen in the hydroformylation of 1-hexene in diglyme as the solvent, producing heptanol as the major product, whereas phenylene-bridged ligands show much lower activities in this case. The phenylene-bridged ligands show excellent performance in the methoxycarbonylation of 1-octene to methyl nonanoate, significantly better than BCOPE, the opposite trend seen in hydroformylation activity with these ligands. Studies on the hydroformylation of functionalized alkenes such as 4-methyl pentenoate with phenylene-bridged ligands versus BCOPE showed that also in this case, BCOPE directs product selectivity toward alcohols, while phenylene-bridge diphobane L2 favors aldehyde formation. In addition to ligand effects, product selectivities are also determined by the nature and the amount of the acid cocatalyst used, which can affect substrate and aldehyde hydrogenation as well as double bond isomerization.
- Aitipamula, Srinivasulu,Britovsek, George J. P.,Nobbs, James D.,Tay, Dillon W. P.,Van Meurs, Martin
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p. 1914 - 1925
(2021/06/28)
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- Methyl-modified cage-type phosphorus ligand and preparation method thereof Preparation method and application thereof
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The invention discloses a methyl-modified cage-type phosphorus ligand, a preparation method and application thereof, in particular to a synthesis design, wherein methyl is further introduced on a phenyl ring of triphenylphosphine, and a methyl-modified cage-type phosphorus ligand is synthesized, and when a methyl meta-substituted cage-type phosphorus ligand is used as a hydroformylation reaction catalyst the proportion of n-structural aldehyde and isomeric aldehyde is 2.6. TOF-1 The methyl-substituted cage-type phosphorus ligand is excellent in performance, stable in property and recyclable, has excellent substrate applicability in the hydroformylation catalytic reaction, has a good industrial application prospect, and has very important significance in metal organic catalysis.
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Paragraph 0075-0084; 0087-0088
(2021/09/15)
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- Catalyst composition containing bidentate phosphine ligand and application thereof
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The catalyst composition comprises a bidentate phosphine ligand and a rhodium complex, wherein the skeleton of the bidentate phosphine ligand not only has C. 2 The symmetry and the appropriate rigidity, and the phosphine ligand derived based on the skeleton can provide effective steric hindrance around the catalyst center metal, so that the selectivity of the catalyst can be remarkably improved, the aldehyde yield is not lower 92% when the catalyst combination is applied to the hydroformylation reaction, and the selectivity of n-aldehyde is not lower 90%. In addition, the raw materials olefins with different structures can obtain outstanding reaction rate and normal aldehyde selectivity as compared with the existing catalyst systems, and can be suitable for the hydroformylation reaction of more types of olefins.
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Paragraph 0068; 0069-0072; 0093-0094
(2021/11/03)
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- Intermetallic Nanocatalyst for Highly Active Heterogeneous Hydroformylation
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Hydroformylation is an imperative chemical process traditionally catalyzed by homogeneous catalysts. Designing a heterogeneous catalyst with high activity and selectivity in hydroformylation is challenging but essential to allow the convenient separation and recycling of precious catalysts. Here, we report the development of an outstanding catalyst for efficient heterogeneous hydroformylation, RhZn intermetallic nanoparticles. In the hydroformylation of styrene, it shows three times higher turnover frequency (3090 h-1) compared to the benchmark homogeneous Wilkinson's catalyst (966 h-1), as well as a high chemoselectivity toward aldehyde products. RhZn is active for a variety of olefin substrates and can be recycled without a significant loss of activity. Density functional theory calculations show that the RhZn surfaces reduce the binding strength of reaction intermediates and have lower hydroformylation activation energy barriers compared to pure Rh(111), leading to more favorable reaction energetics on RhZn. The calculations also predict potential catalyst design strategies to achieve high regioselectivity.
- Chen, Minda,Gupta, Geet,Ordonez, Claudio W.,Lamkins, Andrew R.,Ward, Charles J.,Abolafia, Celia A.,Zhang, Biying,Roling, Luke T.,Huang, Wenyu
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supporting information
p. 20907 - 20915
(2021/12/14)
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- The effect of the position of cross-linkers on the structure and microenvironment of PPh3moiety in porous organic polymers
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Three trivinyl functionalization triphenylphosphine (3vPPh3)-based porous organic ligands (3vPPh3-POLs) with cross-linkers in different positions were obtained through solvothermal polymerization. By simply changing the position of the cross-linkers (vinyl groups) attached to the PPh3monomer, the resulting porous organic polymer (POP) materials acquired diverse hierarchical porous structures, and the microenvironment of POPs was sequently regulated. Among the three 3vPPh3-POLs, the BET surface areas ranged from 168 to 1583 m2g?1, while the proportion of micropores changed from 0.0% to 52.0%. Benefiting from the unique structure, Rh ions could be coordinated and dispersed as a single site inm-3vPPh3-POL to form HRh(CO)2(PPh3-POL)2species, which endowed the Rh/m-3vPPh3-POL catalyst with an activity similar to that in the homogeneous system, anl/bratio (the ratio of the linear aldehyde to the branched aldehyde) approximately as high as 10, and stability for a duration of more than 500 h in the hydroformylation of 1-octene.
- Ji, Guangjun,Li, Cunyao,Xiao, Dong,Wang, Guoqing,Sun, Zhao,Jiang, Miao,Hou, Guangjin,Yan, Li,Ding, Yunjie
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p. 9165 - 9174
(2021/04/16)
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- Atomically dispersed Rh on hydroxyapatite as an effective catalyst for tandem hydroaminomethylation of olefins
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Tandem hydroaminomethylation is an efficient and green route for one-pot synthesis of amines directly from olefins. Herein, heterogeneous hydroxyapatite (HAP) supported single-atom Rh catalyst was prepared and used for tandem hydroaminomethylation of olefins. Characterization techniques confirmed the atomic dispersion of Rh species on HAP. Up to 99% conversion of 1-hexene with high selectivity to the desired amines (93.2%) was obtained over 0.5Rh1/HAP catalyst. Mechanism study demonstrated that the first hydroformylation step during the tandem catalytic process was rate-determining. Compared with the Rh nanoparticles on other oxide supports (Mg3Al, MgO and Al2O3), the atomically dispersed Rh sites on HAP ensured the high hydroformylation activity, thereby guaranteed the outstanding catalytic performance for the total tandem process. Furthermore, various corresponding amines can be obtained with satisfactory yields over 0.5Rh1/HAP catalyst from a wide scope of olefins or amines substrates.
- Gun, Gong,Li, Liusha,Li, Xiao,Lin, Tiejun,Qin, Tingting,Zhong, Liangshu
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- PhIO-Mediated oxidative dethioacetalization/dethioketalization under water-free conditions
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Treatment of thioacetals and thioketals with iodosobenzene in anhydrous DCM conveniently afforded the corresponding carbonyl compounds in high yields under water-free conditions. The mechanistic studies indicate that this dethioacetalization/dethioketalization process does not need water and the oxygen of the carbonyl products comes from the hypervalent iodine reagent.
- Du, Yunfei,Ouyang, Yaxin,Wang, Xi,Wang, Xiaofan,Yu, Zhenyang,Zhao, Bingyue,Zhao, Kang
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- Green, homogeneous oxidation of alcohols by dimeric copper(II) complexes
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Three pyrazole derivatives, 3,5-dimethyl-1H-pyrazole (DMPz) (I), 3-methyl-5-phenyl-1H-pyrazole (MPPz) (II), and 3,5-diphenyl-1H-pyrazole (DPPz) (III), were prepared via reacting semicarbazide hydrochloride with the acetylacetone, 1-phenylbutane-1,3-dione, and 1,3-diphenylpropane-1,3-dione, respectively. Complexes 1–3 were isolated by reacting CuCl2·2H2O with I–III, respectively, and characterized by CHNS elemental analyses, FT-IR, UV-Vis, 1H and 13C NMR, EPR spectra, and TGA/DTA. Molecular structures of the pyrazole derivatives I–III and copper(II) complexes 2 and 3 were studied through single-crystal XRD analysis to confirm their molecular structures. Overlapping of hyperfine splitting in the EPR spectra of the dimeric copper(II) complexes 1–3 indicates that both copper centers do not possess the same electronic environment in solution. The copper(II) complexes are dimeric in solid state as well as in solution and catalyze the oxidation of various primary and secondary alcohols selectively. Catalysts 1–3 show more than 92% product selectivity toward ketones during the oxidation of secondary alcohols. Surprisingly primary alcohols, which are relatively difficult to oxidize, produce carboxylic acid as a major product (48%–90% selectivity) irrespective of catalytic systems. The selectivity for carboxylic acid rises with decreasing the carbon chain length of the alcohols. An eco-friendly and affordable catalytic system for oxidation of alcohols is developed by the utilization of H2O2, a green oxidant, and water, a clean and greener solvent, which is a notable aspect of the study.
- Maurya, Abhishek,Haldar, Chanchal
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p. 885 - 904
(2020/12/18)
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- The invention relates to a bidentate phosphine ligand and a preparation method thereof. Application
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The invention discloses a bidentate phosphine ligand and a preparation method and application thereof, and a ligand skeleton adopted by the bidentate phosphine ligand not only has C. 2 The phosphine ligand derived from the skeleton can provide effective steric hindrance around the catalyst center metal, so that selectivity of the catalyst can be remarkably improved, and furthermore, the phosphine ligand skeleton is simple in synthesis route, easy to obtain in large quantities, capable of effectively improving production efficiency and reducing industrial production cost.
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Paragraph 0054-0061
(2021/11/03)
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- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
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As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
- Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
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supporting information
p. 8040 - 8046
(2021/11/01)
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- One-pot Synthesis of Acetals by Tandem Hydroformylation-acetalization of Olefins Using Heterogeneous Supported Catalysts
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Abstract: A green route for one?pot synthesis of acetals by tandem hydroformylation?acetalization of olefins using supported Rh?based?catalysts was developed. Experimental results demonstrated that suitable Rh loading (1 wt%) with appropriate reaction temperature (120?°C) and reaction time (8?h) were favorable for the formation of acetals, and a high acetals selectivity of 94.6% was achieved. More importantly, the selectivity to valuable linear products was enhanced in this tandem catalysis. Based on the catalytic mechanism study, highly dispersed RhOx nanoparticles and abundant acid sites on the supports were responsible for the hydroformylation and acetalization, respectively. Graphical abstract: One-pot synthesis of acetals directly from olefins with high selectivity was achieved over heterogeneous bifunctional catalysts via tandem hydroformylation-acetalization. [Figure not available: see fulltext.]
- Li, Xiao,Qin, Tingting,Li, Liusha,Wu, Bo,Lin, Tiejun,Zhong, Liangshu
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p. 2638 - 2646
(2021/01/05)
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- Low-Temperature Hypergolic Ignition of 1-Octene with Low Ignition Delay Time
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The attainment of the efficient ignition of traditional liquid hydrocarbons of scramjet combustors at low flight Mach numbers is a challenging task. In this study, a novel chemical strategy to improve the reliable ignition and efficient combustion of hydrocarbon fuels was proposed. A directional hydroboration reaction was used to convert hydrocarbon fuel into highly active alkylborane, thereby leading to changes in the combustion reaction pathway of hydrocarbon fuel. A directional reaction to achieve the hypergolic ignition of 1-octene was designed and developed by using Gaussian simulation. Borane dimethyl sulfide (BDMS), a high-energy additive, was allowed to react spontaneously with 1-octene to achieve the hypergolic ignition of liquid hydrocarbon fuel at -15 °C. Compared with the ignition delay time of pure 1-octene (565 °C), the ignition delay time of 1-octene/BDMS (9:1.2) decreased by 3850% at 50 °C. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry confirmed the directional reaction of the hypergolic ignition reaction pathway of 1-octene and BDMS. Moreover, optical measurements showed the development trend of hydroxyl radicals (OH·) in the lower temperature hypergolic ignition and combustion of 1-octene. Finally, this study indicates that the enhancement of the low-temperature ignition performance of 1-octene by hydroboration in the presence of BDMS is feasible and promising for jet propellant design with tremendous future applications.
- Sheng, Haoqiang,Huang, Xiaobin,Chen, Zhijia,Zhao, Zhengchuang,Liu, Hong
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p. 423 - 434
(2021/02/05)
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- Liquid-phase oxidation of olefins with rare hydronium ion salt of dinuclear dioxido-vanadium(V) complexes and comparative catalytic studies with analogous copper complexes
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Homogeneous liquid-phase oxidation of a number of aromatic and aliphatic olefins was examined using dinuclear anionic vanadium dioxido complexes [(VO2)2(salLH)]? (1) and [(VO2)2(NsalLH)]? (2) and dinuclear copper complexes [(CuCl)2(salLH)]? (3) and [(CuCl)2(NsalLH)]? (4) (reaction of carbohydrazide with salicylaldehyde and 4-diethylamino salicylaldehyde afforded Schiff-base ligands [salLH4] and [NsalLH4], respectively). Anionic vanadium and copper complexes 1, 2, 3, and 4 were isolated in the form of their hydronium ion salt, which is rare. The molecular structure of the hydronium ion salt of anionic dinuclear vanadium dioxido complex [(VO2)2(salLH)]? (1) was established through single-crystal X-ray analysis. The chemical and structural properties were studied using Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), 1H and 13C nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR) spectroscopy, and thermogravimetric analysis (TGA). In the presence of hydrogen peroxide, both dinuclear vanadium dioxido complexes were applied for the oxidation of a series of aromatic and aliphatic alkenes. High catalytic activity and efficiency were achieved using catalysts 1 and 2 in the oxidation of olefins. Alkenes with electron-donating groups make the oxidation processes easy. Thus, in general, aromatic olefins show better substrate conversion in comparison to the aliphatic olefins. Under optimized reaction conditions, both copper catalysts 3 and 4 fail to compete with the activity shown by their vanadium counterparts. Irrespective of olefins, metal (vanadium or copper) complexes of the ligand [salLH4] (I) show better substrate conversion(%) compared with the metal complexes of the ligand [NsalLH4] (II).
- Maurya, Abhishek,Haldar, Chanchal
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- Tetradentate nitrogen phosphine ligand and preparation method and application thereof
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The invention provides a novel tetradentate nitrogen phosphine ligand as well as a preparation method and an application thereof in an unsaturated olefin hydroformylation reaction. The tetradentate nitrogen phosphine ligand is used for the hydroformylation reaction of olefin, so that the catalyst is more stable in the reaction, is not easy to inactivate at high temperature (more than 200 DEG C), the pressure of synthesis gas required by the reaction is lower, the reaction positive-to-negative ratio is improved, and the selectivity of a main product can be effectively improved.
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Paragraph 0062; 0065-0066
(2021/04/07)
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- Method for preparing aldehyde compounds by oxidative cleavage of carbon-carbon bonds of terminal alkene compounds
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The invention discloses a method for preparing aldehyde compounds by oxidizing and breaking carbon-carbon bonds of terminal alkene compounds. The method comprises the following steps: adding an alkene-terminated compound, an additive and a nitrogen-doped mesoporous carbon-loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1MPa and the reaction temperature to be 80-150 DEG C, and obtaining a reaction product, namely the aldehyde compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the aldehyde compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
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Paragraph 0081-0082; 0089-0090
(2021/06/06)
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- Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction
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The function of ammonium salts on the epoxidation performance over Ti-BEA zeolite was investigated in detail. Experiments of alkene epoxidation, side reactions of epoxide and decomposition of H2O2 with or without ammonium salts were designed, and the UV-Vis spectroscopy was employed to analyze the structure of Ti-hydroperoxo species. It is revealed that the ammonia (or amines) dissociated from the ammonium salt would chelate with the linear Ti-η1(OOH) species and form a bridged Ti-η2(OOH)-R species, which is more stable, more weaker in epoxide adsorption and acidity as well. Therefore, side reactions and H2O2 decomposition would be suppressed, and both alkene conversion and epoxide selectivity would be promoted simultaneously. On the other hand, the excessive NH3?H2O (NH3/Ti>1) or NaOH bond with the Ti-η2(OOH)-R species and generate salt-like Ti-η2(OO)-M+ species, resulting in the deactivation of Ti active center. While for ammonium salts, e.g. NH4Cl, the limited dissociation degree along with the acidic environment help the Ti active center to maintain in highly active. In short, this work provides a practical Ti active center tuning method for Ti-BEA zeolite, as well as a thorough understanding of its Ti-hydroperoxo species.
- Liang, Xiaohang,Liu, Dan,Luo, Yibin,Peng, Xinxin,Shu, Xingtian,Xia, Changjiu
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
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- Rh-catalyzed highly regioselective hydroformylation to linear aldehydes by employing porous organic polymer as a ligand
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In this work, we developed a new structural porous organic polymer containing biphosphoramidite unit, which can be used as a solid bidentate phosphorous ligand for rhodium-catalyzed solvent-free higher olefins hydroformylation. The resultant catalyst demonstrated unprecedently high regioselectivity to linear aldehydes and could be readily recovered for successive reuses with good stability in both catalytic activity and regioselectivity. This journal is
- Wang, Zhaozhan,Yang, Yong
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p. 29263 - 29267
(2020/10/06)
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- Highly uniform Rh nanoparticles supported on boron doped g-C3N4 as a highly efficient and recyclable catalyst for heterogeneous hydroformylation of alkenes
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A series of boron doped g-C3N4 supported rhodium nanoparticle catalysts has been synthesized for the first time and exhibited excellent catalytic activity and easy recycling properties in the hydroformylation of styrene due to the boron doping, which modified the delocalized conjugated π structure of g-C3N4 and increased the adsorption and dispersion of Rh nanoparticles.
- Shi, Yukun,Ji, Gang,Hu, Qiqige,Lu, Yang,Hu, Xiaojing,Zhu, Baolin,Huang, Weiping
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supporting information
p. 20 - 23
(2019/12/26)
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- Organic Ligand-Free Hydroformylation with Rh Particles as Catalyst?
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An efficient and organic ligand-free heterogeneous catalytic system for hydroformylation of olefins is highly desirable for both academy and industry. In this study, simple Rh black was employed as a heterogeneous catalyst for hydroformylation of olefins in the absence of organic ligand. The Rh black catalyst showed good catalytic activity for a broad substrate scope including the aliphatic and aromatic olefins, affording the desired aldehydes in good yields. Taking the hydroformylation of ethylene as an example, 86% yield of propanal and TOF of 200 h–1 were obtained, which was superior to the reported homogeneous catalytic systems. In addition, the catalyst could be reused five times without loss of activity under identical reaction conditions, and the Rh leaching was negligible after each cycle.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Wang, Xinzhi,Shi, Feng
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supporting information
p. 139 - 143
(2020/01/03)
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- Triphenylphosphine-Based Covalent Organic Frameworks and Heterogeneous Rh-P-COFs Catalysts
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The synthesis of phosphine-based functional covalent organic frameworks (COFs) has attracted great attention recently. Herein, we present two examples of triphenylphosphine-based COFs (termed P-COFs) with well-defined crystalline structures, high specific surface areas, and good thermal stability. Furthermore, rhodium catalysts with these P-COFs as support material show high turnover frequency for the hydroformylation of olefins, as well as excellent recycling performance. This work not only extends the phosphine-based COF family, but also demonstrates their application in immobilizing homogeneous metal-based (e.g., Rh-phosphine) catalysts for application in heterogeneous catalysis.
- Liu, Yubing,Dikhtiarenko, Alla,Xu, Naizhang,Sun, Jiawei,Tang, Jie,Wang, Kaiqiang,Xu, Bolian,Tong, Qing,Heeres, Hero Jan,He, Songbo,Gascon, Jorge,Fan, Yining
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supporting information
p. 12134 - 12139
(2020/09/01)
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- Hydroformylation of higher olefins in aqueous biphasic medium using rhodium-sulfoxantphos catalyst: Activity and selectivity study
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Hydroformylation of higher olefins such as 1-hexene, 1-octene, 1-decene and 1-dodecene has been studied in an aqueous biphasic medium using water-soluble Rh-sulfoxantphos complex catalyst. The effect of temperature, presence of various co-solvents and concentration of co-solvent on the reaction rate and chemo and regioselectivity was investigated. N-Methyl pyrrolidone (NMP) was found to be the best co-solvent, which enhances the rate dramatically (4-96 fold) as compared to the reactions in aqueous-organic biphasic medium for hydroformylation of higher olefins. Catalyst recycle study was performed to check the leaching of metal in organic phase.
- Pagar, Nitin S.,Deshpande, Raj M.
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p. 2061 - 2066
(2020/09/01)
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- Donor-Flexible Bis(pyridylidene amide) Ligands for Highly Efficient Ruthenium-Catalyzed Olefin Oxidation
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An exceptionally efficient ruthenium-based catalyst for olefin oxidation has been designed by exploiting N,N′-bis(pyridylidene)oxalamide (bisPYA) as a donor-flexible ligand. The dynamic donor ability of the bisPYA ligand, imparted by variable zwitterionic and neutral resonance structure contributions, paired with the redox activity of ruthenium provided catalytic activity for Lemieux–Johnson-type oxidative cleavage of olefins to efficiently prepare ketones and aldehydes. The ruthenium bisPYA complex significantly outperforms state-of-the-art systems and displays extraordinary catalytic activity in this oxidation, reaching turnover frequencies of 650 000 h?1 and turnover numbers of several millions.
- Albrecht, Martin,Salzmann, Kevin,Segarra, Candela
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supporting information
p. 8932 - 8936
(2020/04/22)
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- Functional hexanuclear Y(III) cluster-based MOFs supported Pd(II) single site catalysts for aerobic selective oxidation of styrene
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Oxidation of styrene is one of the significant reactions in organic synthesis. In this work, a serious of PdCl2 moiety-decorated Y6-MOFs adopting post-synthetic strategy were fabricated as applicable single-site catalysts for oxidation of styrene. Specifically, the functional organic linker, H2bpydc (2,2′-bipyridine-5,5′-dicarboxylic acid), was first incorporated quantitatively into Y6 clusters-based MOF, [(CH3)2NH2]2[Y6(μ3-OH)8(bpdc)6] (bpdc = 4,4′-biphenyl dicarboxylic acid) via post-synthetic ligand exchange. Then post-synthetic Pd(II) metalation was performed to enhance the density of isolated single sites. The obtained Pd(II)-Y-bpydcx/bpdc1-x can be used as highly efficient heterogeneous single-site catalysts to promote selective oxidative cleavage of styrene to benzaldehyde using O2 as a oxidant under solvent-free and mild reaction conditions (1 atm and 80 °C). Importantly, when using Pd(II)-Y-bpydc0.8/bpdc0.2 (0.024 mmol Pd) as catalyst, the high conversion of styrene and the selectivity for benzaldehyde can reach 88.7 % and 82.2 %, respectively.
- Han, Zheng-Bo,Wei, Na,Xing, Zhiqiang,Zhang, Yue
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- Method for preparing aldehyde by olefin hydroformylation
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The invention relates to a method for preparing aldehyde through olefin hydroformylation. The method comprises the steps: enabling alpha-olefin and synthesis gas to enter a hydroformylation reactor; carrying out a contact reaction on alpha-olefin and synthesis gas with a catalyst to generate an aldehyde-containing product, wherein the catalyst comprises a main catalyst and a co-catalyst, the maincatalyst is a complex catalyst and comprises a rhodium complex and a phosphine ligand, the phosphine ligand is tris[2,4-di-tert-butylphenyl]phosphite, and the co-catalyst is a nickel-palladium bimetallic phosphinate. The method has the advantages of high normal-to-abnormal ratio in the product, good selectivity and yield, mild reaction conditions and the like.
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Paragraph 0032-0034; 0035-0039
(2020/07/15)
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- Concurrent Formation of N-H Imines and Carbonyl Compounds by Ruthenium-Catalyzed C-C Bond Cleavage of β-Hydroxy Azides
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A commercial cyclopentadienylrutenium dicarbonyl dimer ([CpRu(CO)2]2) efficiently catalyzes the formation of N-H imines and carbonyl compounds simultaneously from β-hydroxy azides via C-C bond cleavage under visible light. Density functional theory calculations for the cleavage reaction support the mechanism involving chelation of alkoxy azide species and liberation of nitrogen as the driving force. The synthetic utility of the reaction was demonstrated by a new amine synthesis promoted by chemoselective allylation of imine and synthesis of isoquinoline.
- Lee, Jeong Min,Bae, Dae Young,Park, Jin Yong,Jo, Hwi Yul,Lee, Eunsung,Rhee, Young Ho,Park, Jaiwook
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p. 4608 - 4613
(2020/06/05)
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- Kolbe Electrolysis of Biomass-Derived Fatty Acids Over Pt Nanocrystals in an Electrochemical Cell
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Electrochemical valorization of non-food biomass-derived carboxylates into fuels is promising for the conversion, storage, and distribution of renewable electricity. Herein, we demonstrate that biofuels, hydrogen, and bicarbonate can be simultaneously produced in an electrochemical cell by one-step electrolysis of free fatty acids under ambient conditions on 3D self-supported ultralow Pt loading (2 wt %) electrode. The three valuable products can naturally separate from each other during the electrolysis in the alkaline aqueous solution. The experimental suggests that Pt(100) and Pt(110) are favorable for the production of non-Kolbe and Kolbe hydrocarbons, respectively. DFT calculation further clarifies the adsorption and stabilization of the reaction intermediates on Pt(100) and Pt(110).
- Yuan, Gang,Wu, Chan,Zeng, Guorong,Niu, Xiaopo,Shen, Guoqiang,Wang, Li,Zhang, Xiangwen,Luque, Rafael,Wang, Qingfa
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p. 642 - 648
(2019/12/24)
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- H2-free Synthesis of Aromatic, Cyclic and Linear Oxygenates from CO2
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The synthesis of oxygenate products, including cyclic ketones and phenol, from carbon dioxide and water in the absence of gas-phase hydrogen has been demonstrated. The reaction takes place in subcritical conditions at 300 °C and pressure at room temperature of 25 barg. This is the first observation of the production of cyclic ketones by this route and represents a step towards the synthesis of valuable intermediates and products, including methanol, without relying on fossil sources or hydrogen, which carries a high carbon footprint in its production by conventional methods. Inspiration for these studies was taken directly from natural processes occurring in hydrothermal environments around ocean vents. Bulk iron and iron oxides were investigated to provide a benchmark for further studies, whereas reactions over alumina and zeolite-based catalysts were employed to demonstrate, for the first time, the ability to use catalyst properties such as acidity and pore size to direct the reaction towards specific products. Bulk iron and iron oxides produced methanol as the major product in concentrations of approximately 2–3 mmol L?1. By limiting the hydrogen availability through increasing the initial CO2/H2O ratio the reaction could be directed to yield phenol. Alumina and zeolites were both observed to enhance the production of longer-chained species (up to C8), likely owing to the role of acid sites in catalysing rapid oligomerisation reactions. Notably, zeolite-based catalysts promoted the formation of cyclic ketones. These proof-of-concept studies show the potential of this process to contribute to sustainable development through either targeting methanol production as part of a “methanol economy” or longer-chained species including phenol and cyclic ketones.
- Gomez, Laura Quintana,Shehab, Amal K.,Al-Shathr, Ali,Ingram, William,Konstantinova, Mariia,Cumming, Denis,McGregor, James
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p. 647 - 658
(2020/01/24)
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- Two-way homologation of aliphatic aldehydes: Both one-carbon shortening and lengthening via the same intermediate
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Aliphatic aldehydes can be homologated to both one-carbon shorter and one-carbon longer homologous carbonyl compounds through the 2–4 steps of reactions via the same intermediates, β,γ-unsaturated α-nitrosulfones, prepared from the proline-catalyzed sequential reactions of several aliphatic aldehydes with phenylsulfonylnitromethane. While the oxidative cleavage of the key intermediates gave one-carbon less homologous carbonyl compounds, the reduction of the same key intermediates followed by an oxidation produced one-carbon more homologous carbonyl compounds.
- Yoo, Jae Won,Seo, Youngran,Park, Jong Beom,Kim, Young Gyu
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- TRANSFER HYDROFORMYLATION FOR THE PRODUCTION OF OXYGENATES
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The present disclosure provides a method for forming oxygenates from olefins which includes hydroformylation of aldehydes as a formyl source alternative to syngas. In at least one embodiment, a hydroformylation process is performed at low-temperature and at or near ambient pressure for the conversion of olefins into aldehydes, thus reducing the formation of by-products such as via double bond or skeletal isomerization of the feedstock; or via further conversion of the formed aldehydes and alcohols. In at least one embodiment, the use of gaseous olefinic products (e.g., ethylene) instead of strained olefins (e.g., norbornene) improves the control equilibria in transfer hydroformylation reactions.
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Paragraph 0102
(2020/04/25)
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- Deoxygenation of heptanoic acid to hexene over cobalt-based catalysts: A model study for α-olefin production from renewable fatty acid
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Deoxygenation of heptanoic acid, a model compound, over bimetallic cobalt (Co-Pt, Co-Au, Co-Pd, Co-Ru) supported silica catalysts, was examined for α-olefin production. The catalysts were prepared by conventional impregnation of the metal precursors on silica and characterized by XRF, TEM, H2-TPR, acetic acid-TPD, and XANES. Catalytic testing was performed in a fixed-bed flow reactor under atmospheric H2 pressure. Monometallic cobalt catalysts yielded mainly 1-hexene, but rapid deactivation was observed. Incorporation of 0.5percentwt secondary metal, particularly Pt, increases activity and stability under H2. A relatively higher olefin/paraffin ratio can be obtained from the reaction over 5percentCo+0.5percentPt/SiO2 when compared to that with higher Pt loading. The co-impregnation method offers Co-Pt catalysts with stability higher than that prepared by the sequential impregnation method. Over cobalt-based catalysts, the deoxygenation is proposed to proceed via reduction of heptanoic acid to heptanal that is an intermediate for decarbonylation to hexene; while other side reactions are suppressed.
- Choojun, Kittisak,Phichitsurathaworn, Ploynisa,Poo-arporn, Yingyot,Sooknoi, Tawan
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- The formyloxyl radical: Electrophilicity, C-H bond activation and anti-Markovnikov selectivity in the oxidation of aliphatic alkenes
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In the past the formyloxyl radical, HC(O)O, had only been rarely experimentally observed, and those studies were theoretical-spectroscopic in the context of electronic structure. The absence of a convenient method for the preparation of the formyloxyl radical has precluded investigations into its reactivity towards organic substrates. Very recently, we discovered that HC(O)O is formed in the anodic electrochemical oxidation of formic acid/lithium formate. Using a [CoIIIW12O40]5- polyanion catalyst, this led to the formation of phenyl formate from benzene. Here, we present our studies into the reactivity of electrochemically in situ generated HC(O)O with organic substrates. Reactions with benzene and a selection of substituted derivatives showed that HC(O)O is mildly electrophilic according to both experimentally and computationally derived Hammett linear free energy relationships. The reactions of HC(O)O with terminal alkenes significantly favor anti-Markovnikov oxidations yielding the corresponding aldehyde as the major product as well as further oxidation products. Analysis of plausible reaction pathways using 1-hexene as a representative substrate favored the likelihood of hydrogen abstraction from the allylic C-H bond forming a hexallyl radical followed by strongly preferred further attack of a second HC(O)O radical at the C1 position. Further oxidation products are surmised to be mostly a result of two consecutive addition reactions of HC(O)O to the CC double bond. An outer-sphere electron transfer between the formyloxyl radical donor and the [CoIIIW12O40]5- polyanion acceptor forming a donor-acceptor [D+-A-] complex is proposed to induce the observed anti-Markovnikov selectivity. Finally, the overall reactivity of HC(O)O towards hydrogen abstraction was evaluated using additional substrates. Alkanes were only slightly reactive, while the reactions of alkylarenes showed that aromatic substitution on the ring competes with C-H bond activation at the benzylic position. C-H bonds with bond dissociation energies (BDE) ≤ 85 kcal mol-1 are easily attacked by HC(O)O and reactivity appears to be significant for C-H bonds with a BDE of up to 90 kcal mol-1. In summary, this research identifies the reactivity of HC(O)O towards radical electrophilic substitution of arenes, anti-Markovnikov type oxidation of terminal alkenes, and indirectly defines the activity of HC(O)O towards C-H bond activation.
- Iron, Mark A.,Khenkin, Alexander M.,Neumann, Ronny,Somekh, Miriam
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p. 11584 - 11591
(2020/11/23)
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- A Cp-based Molybdenum Catalyst for the Deoxydehydration of Biomass-derived Diols
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Dioxo-molybdenum complexes have been reported as catalysts for the deoxydehydration (DODH) of diols and polyols. Here, we report on the DODH of diols using [Cp*MoO2]2O as catalyst (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl). The DODH reaction was optimized using 2 mol % of [Cp*MoO2]2O, 1.1 equiv. of PPh3 as reductant, and anisole as solvent. Aliphatic vicinal diols are converted to the corresponding olefins by [Cp*MoO2]2O in up to 65 % yield (representing over 30 turnovers per catalyst) and 91 % olefin selectivity, which rivals the performance of other Mo-based DODH catalysts. Remarkably, cis-1,2-cyclohexanediol, which is known as quite a challenging substrate for DODH catalysis, is converted to 30 % of 1-cyclohexene under optimized reaction conditions. Overall, the mass balances (up to 79 %) and TONs per Mo achievable with [Cp*MoO2]2O are amongst the highest reported for molecular Mo-based DODH catalysts. A number of experiments aimed at providing insight in the reaction mechanism of [Cp*MoO2]2O have led to the proposal of a catalytic pathway in which the [Cp*MoO2]2O catalyst reacts with the diol substrate to form a putative nonsymmetric dimeric diolate species, which is reduced in the next step at only one of its Mo-centers before extrusion of the olefin product.
- Li, Jing,Lutz, Martin,Klein Gebbink, Robertus J. M.
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p. 6356 - 6365
(2020/11/30)
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- A new air-stable and reusable tetraphosphine ligand for rhodium-catalyzed hydroformylation of terminal olefins at low temperature
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Tetraphosphine and bisphosphine ligands were synthesized, characterized and employed in Rh-catalyzed hydroformylation of 1-octene and 1-hexene. Conversion of over 97.7% and aldehyde yield of 94.1% were achieved at 60°C, 20?bar. This remarkable performance could also be retained at lower temperature (i.e. 40°C) by prolonging the reaction time. The tetraphosphine ligand-modified Rh catalyst could be reused for at least seven successive runs with catalytic activity and selectivity almost unchanged; the catalyst was separated from the products and recycled directly in homogeneous hydroformylation, indicating that the catalyst might have good stability. 31P NMR and high-resolution mass spectral characterization hinted that the reason for the reusability of the catalyst might be that the tetraphosphine ligand is relatively air-stable and is probably slowly oxidized during the recycling runs. The tetraphosphine ligand has four phosphorus atoms to be partially oxidized and could still coordinate with the Rh center via the unoxidized phosphorus atoms to stabilize the catalyst, based on the multiple chelating modes of the tetraphosphine ligand. Hence, the catalytic activity and selectivity could be retained for a certain number of runs.
- Zhou, Fanding,Zhang, Lin,Wu, Qianhui,Guo, Fuya,Tang, Songbai,Xu, Bin,Yuan, Maolin,Fu, Haiyan,Li, Ruixiang,Zheng, Xueli,Chen, Hua
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- Homogeneous hydroformylation of long chain alkenes catalyzed by water soluble phosphine rhodium complex in CH3OH and efficient catalyst cycling
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The hydroformylation of long chain alkenes catalyzed by a water soluble Rh/TPPTS complex (TPPTS: sodium salt of sulfonated triphenylphosphine) in methanol was investigated. The mixture of rhodium precursor HRh(CO)(TPPTS)3, ligand TPPTS, methanol and a long chain alkene becomes a single phase under reaction conditions, which make the hydroformylation reaction proceed homogeneously. Both the conversion of long chain alkene and the selectivity to aldehydes (including the aldehydes forming methylacetals) could reach up to 97.8% and 97.6%, respectively, with 3323 h?1 of TOF (TOF: turnover frequency is defined as the moles of converted alkene per mole of Rh per hour). After the solvent methanol was removed under the reaction temperature, two phases were formed automatically. The colourless product phase could be efficiently separated from the precipitate rhodium catalyst phase by centrifuge. The catalyst was reused for five times without obvious loss of rhodium and the catalytic activity. The rhodium leaching in product mixture was less than 0.03% of the total rhodium.
- Liu, Yan-li,Zhao, Jian-gui,Zhao, Yuan-jiang,Liu, Hui-Min,Fu, Hai-yan,Zheng, Xue-li,Yuan, Mao-lin,Li, Rui-xiang,Chen, Hua
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p. 7382 - 7387
(2019/03/19)
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- Encapsulated liquid nano-droplets for efficient and selective biphasic hydroformylation of long-chain alkenes
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Aqueous nano-droplets of homogeneous Rh-TPPTS catalyst encapsulated within the cavity of hollow silica nanospheres were fabricated for biphasic hydroformylation of long-chain alkenes, which showed significant reaction rate enhancement effects and improved aldehyde selectivity.
- Zhang, Xiaoli,Wei, Juan,Zhang, Xiaoming
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supporting information
p. 14134 - 14138
(2019/09/18)
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- Porous organic polymer supported rhodium as a reusable heterogeneous catalyst for hydroformylation of olefins
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A new porous organic polymer has been prepared via copolymerization of divinyl-functionalized phosphoramidite ligand and tris(4-vinylphenyl)phosphine. The porous polymer was loaded with Rh(acac)CO2 to yield a supported Rh catalyst, which demonstrated good regioselectivity (l/b = 6.7-52.8) and high catalytic activity (TON up to 45.3 × 104) in hydroformylation of terminal and internal olefins. Remarkably, the heterogeneous catalyst can be reused at least 10 cycles without losing activity and selectivity in hydroformylation of 1-hexene.
- Jia, Xiaofei,Liang, Zuyu,Chen, Jianbin,Lv, Jinhe,Zhang, Kai,Gao, Mingjie,Zong, Lingbo,Xie, Congxia
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supporting information
p. 2147 - 2150
(2019/03/26)
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- Racemic gem disilyl alkane compound containing four silicon-hydrogen bonds, and sybthesis method and application of compound
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The invention discloses a racemic gem disilyl alkane compound containing four silicon-hydrogen bonds. The compound is as shown in a formula IV. The invention further discloses a synthesis method of the racemic gem disilyl alkane compound. The synthesis method comprises the following step of carrying out a reaction by taking alkyne as shown in a formula I and trihydrosilane as shown in a formula IIas raw materials and taking a chiral CoX-IIP complex as a catalyst in the presence of a reducing agent to obtain the racemic gem disilyl alkane compound containing four silicon-hydrogen bonds, wherein the compound is as shown in the formula IV. The method disclosed by the invention has mild reaction conditions, is simple and convenient to operate and has high atom economy. In addition, the reaction does not need addition of any salts of toxic transition metals (such as ruthenium, rhodium, palladium and the like), and the method has a relatively large practical application value in synthesis of medicines and materials. In addition, the reaction has a medium to excellent yield (51-99%) and high area selectivity (10:1-19:1, most parts larger than 19:1).
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Paragraph 0263-0268; 0269
(2019/05/15)
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- Chiral geminal disilyl alkane compound, synthesis method and applications thereof
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The present invention discloses a chiral geminal disilyl alkane compound, which is represented by a formula V, wherein * represents a chiral carbon atom in the formula V. The invention discloses a synthesis method of the chiral geminal disilyl alkane compound, wherein the synthesis method comprises: carrying out a reaction in the presence of a reducing agent by using alkyne represented by a formula I, dihydrosilane represented by a formula II and trihydrosilane represented by a formula III as raw materials and using Xantphos-CoBr2 and a chiral CoX2-OIP complex as catalysts under an inert gas to prepare the chiral geminal disilyl alkane compound represented by the formula V. According to the present invention, the method has characteristics of mild reaction condition, simple operation, highatomic economy, no requirement of the addition of any other toxic transition metals (such as ruthenium, rhodium, palladium and the like) salts, high yield and high enantioselectivity, and has great practical value in the synthesis of drugs and materials, wherein the yield is generally 50-85%, and the enantioselectivity is generally 93-99%. The formulas I, II, III and V are defined in the specification.
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Paragraph 0204; 0205; 0206; 0207; 0209
(2019/01/14)
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- HYDROFORMYLATION METHOD AND CATALYST USING RHODIUM-RUTHENIUM DUAL METAL AND TETRADENTATE PHOSPHINE LIGAND
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A homogeneous catalytic reaction method and a catalyst for isomerization and hydroformylation of long-chain internal olefins are disclosed. A rhodium-ruthenium metal complex is used as a catalyst; and the ligands are tetradentate phosphine ligands. By means of the catalytic system, homogeneous internal olefin isomerization aid hydroformylation can be performed under a certain temperature and pressure to obtain aldehyde products having high normal to iso ratios. The present invention is applicable to not only long-chain internal olefins (≥C8) but also internal olefins having a carbon number less than 8.
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Paragraph 0044
(2019/11/19)
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- A Redox Strategy for Light-Driven, Out-of-Equilibrium Isomerizations and Application to Catalytic C-C Bond Cleavage Reactions
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We report a general protocol for the light-driven isomerization of cyclic aliphatic alcohols to linear carbonyl compounds. These reactions proceed via proton-coupled electron-transfer activation of alcohol O-H bonds followed by subsequent C-C β-scission of the resulting alkoxy radical intermediates. In many cases, these redox-neutral isomerizations proceed in opposition to a significant energetic gradient, yielding products that are less thermodynamically stable than the starting materials. A mechanism is presented to rationalize this out-of-equilibrium behavior that may serve as a model for the design of other contrathermodynamic transformations driven by excited-state redox events.
- Ota, Eisuke,Wang, Huaiju,Frye, Nils Lennart,Knowles, Robert R.
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supporting information
p. 1457 - 1462
(2019/01/25)
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- On/Off O2 Switchable Photocatalytic Oxidative and Protodecarboxylation of Carboxylic Acids
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Photoredox catalysis in recent years has manifested a powerful branch of science in organic synthesis. Although merging photoredox and metal catalysts has been a widely used method, switchable heterogeneous photoredox catalysis has rarely been considered. Herein, we open a new window to use a switchable heterogeneous photoredox catalyst which could be turned on/off by changing a simple stimulus (O2) for two opponent reactions, namely, oxidative and protodecarboxylation. Using this strategy, we demonstrate that Au@ZnO core-shell nanoparticles could be used as a switchable photocatalyst which has good catalytic activity to absorb visible light due to the localized surface plasmon resonance effect of gold, can decarboxylate a wide range of aromatic and aliphatic carboxylic acids, have multiple reusability, and are a reasonable candidate for synthesizing both aldehydes/ketones and alkane/arenes in a large-scale set up. Some biologically active molecules are also shown via examples of the direct oxidative and protodecarboxylation which widely provided pharmaceutical agents.
- Bazyar, Zahra,Hosseini-Sarvari, Mona
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p. 13503 - 13515
(2019/10/11)
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