- Cyclization of Dimethyl Oxalate upon Electron Impact
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Isotope labelling experiments and also consecutive fragmentation investigations of metastable ions, a novel technique in mechanistic studies, have been carried out to elucidate structure and genesis of the m/z 45 ions from dimethyl oxalate as well as dimethyl carbonate.It is shown that the formation of the m/z 45 ions, CH3O(1+)=CH2, in the mass spectra of these compounds arises via single step processes.Mechanisms involving hydrogen transfer and subsequent formation of cyclic intermediates which then collapse to give CH3O(1+)=CH2 directly from molecular ions are suggested.No evidence was found for a two-step fragmentation route to m/z 45 from the molecular ions of either dimethyl oxalate or dimethyl carbonate.
- Liehr, J. G.,Larka, E. A.,Beynon, J. H.
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- Mechanistic study of the oxidative carbonylation of methanol catalyzed by palladium diphosphane complexes with nitrobenzene as oxidant
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The reactivity of Pd complexes having bidentate diarylphosphane ligands was studied in the oxidative carbonylation of CH3OH to dimethyl carbonate/oxalate (DMC/O) with PhNO2 as the oxidant. Different ligands were employed with variation in backbone length and aryl ring substituent, and the acidity, CO pressure, or the partial pressure of H 2 was varied. At two different stages in the catalytic cycle, one equivalent of DMC/O may evolve for every equivalent of PhNO2 reduced, which means that the efficiency with which nitrobenzene can function as the oxidant for the oxidative carbonylation of methanol (EOC) can potentially be 200a% relative to nitrobenzene conversion. The selectivity for DMC relative to DMO is thought to be determined by a species of the type [P 2PdC(O)OCH3(R)]; the DMO/DMC ratio can be increased by increasing the CO pressure, by addition of an acid, or by using a ligand with a relatively large bite angle. On the basis of the collected results, we conclude that an ideal catalyst for oxidative carbonylation would have a relatively acidic palladium center and be sterically undemanding in the axial positions but sterically demanding in the equatorial positions of palladium. The Pd complex of bis(diphenylphosphanyl)ferrocene meets these criteria and was found to function most efficiently with PhNO2 as oxidant for the oxidative carbonylation of methanol among the series of compounds studied, that is, with about 50a% of the theoretical maximum efficiency EOC. The catalytic reactivity of palladium complexes having bidentate diarylphosphane ligands was studied in the oxidativecarbonylation of methanol to dimethylcarbonate (DMC) and dimethyl oxalate (DMO) with nitrobenzene as terminal oxidant. Nitrobenzene can be reduced to aniline by the hydrogen atoms liberated, and thus a catalytic coupling between methanol oxidation and nitrobenzene hydrogenation is established.
- Mooibroek, Tiddo J.,Bouwman, Elisabeth,Drent, Eite
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- Catalytic Synthesis of Oxalate Esters
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A new catalyst system, palladium(II) acetate, cobalt(II) acetate, triphenylphosphine, and 1,4-benzoquinone, produces oxalate esters in high selectivity from carbon monoxide, oxygen, and alcohol.Up to 140 mol of dimethyl oxalate is obtained per mole of palladium while only traces of dimethyl carbonate or methyl formate are formed.
- Current, Steven P.
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- Lewis acid sites in MOFs supports promoting the catalytic activity and selectivity for CO esterification to dimethyl carbonate
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CO esterification to dimethyl carbonate (DMC) is an attractive route, although the catalyst is the main problem restricting the industrialization of this route. Supported palladium catalysts have been often used for this route. However, the effect of the support is not always clear. In this work, we firstly introduced three metal-organic frameworks (MOFs) materials as catalyst supports, namely UiO-66, MIL-101 and MOF-5, and studied the effect of Lewis acid sites in the MOFs supports on the catalytic activity and selectivity for CO esterification to DMC. Interestingly, the Pd(ii)/UiO-66 catalyst exhibits superior catalytic performance to the other catalysts, with 87.9% CO conversion and 98.5% DMC selectivity due to the abundant Lewis acid sites in UiO-66. It was proven that UiO-66 with more defects would have a large number of Lewis acid sites, and the catalytic performance was positively correlated with the number of Lewis acid sites in MOFs supports, which can be demonstrated by characterization by NH3-TPD, pyridine-IR, XPS and in situ DRIRS. The current work not only revealed the relationship between the Lewis acidity of the support and catalytic performance, but also promotes the development of practical catalysts for CO esterification to DMC.
- Guo, Guo-Cong,Jing, Kai-Qiang,Tan, Hong-Zi,Wang, Zhi-Qiao,Xu, Yu-Ping,Xu, Zhong-Ning
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- Catalyst design criteria and fundamental limitations in the electrochemical synthesis of dimethyl carbonate
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Dimethyl carbonate is an environmentally friendly precursor in various chemical reactions and is currently synthesized by hazardous processes. An electrocatalytic approach could result in a process abiding to the principles of Green Chemistry. Herein we demonstrate how density functional theory (DFT) calculations and experiment advance our understanding of electrocatalytic production of chemicals. Using density functional theory, we form design criteria for dimethyl carbonate electrosynthesis on metallic surfaces. The criteria are based on adsorption free energies of reactants and reaction energies of possible products. The design criteria allow us to identify copper as an interesting candidate for the electrode material as it is classified as being selective to dimethyl carbonate and requires ≈1 V lower potential than a gold electrode. By further addressing electrode stability copper was found to dissolve and produce copper-carbonyl species which lead to dimethyl carbonate as a consequence of a reaction in the solution, therefore not occurring by surface electrocatalysis. This shows that the design criteria presented herein are necessary but not sufficient requirements that the ideal electrode should satisfy.
- ?ari?, Manuel,Davies, Bethan Jane Venceslau,Schj?dt, Niels Christian,Dahl, S?ren,Moses, Poul Georg,Escudero-Escribano, María,Arenz, Matthias,Rossmeisl, Jan
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- A kinetic study of the solvolyses of methyl and ethyl chloroglyoxalates
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Solvolyses of methyl and ethyl chloroglyoxylates proceed about 10 6 times faster than the identical solvolyses of the corresponding chloroformates. The correlation parameters obtained from application of the extended Grunwald-Winstein equation are consistent with an addition-elimination (association-dissociation) mechanism over the full range of solvents, with the addition step being rate determining.
- Kevill, Dennis N.,Park, Byoung-Chun,Kyong, Jin Burm
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- Remarkable Decrease in Overpotential of Oxalate Formation in Electrochemical CO2 Reduction by a Metal-Sulfide Cluster
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Triangular metal-sulfide cluster, 3(μ3-S)2>2+ and 3(μ3-S)2>2+, catalyse the electrochemical CO2 reduction to selectively produce oxalate at -1.30 and -0.70 V (vs.Ag/AgCl), respectively, in MeCN.
- Kushi, Yoshinori,Nagao, Hirotaka,Nishioka, Takanori,Isobe, Kiyoshi,Tanaka, Koji
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- New aspects of the synthesis of dimethyl carbonate via carbonylation of methyl alcohol promoted by methoxycarbonyl complexes of palladium(II)
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suspended in MeOH reacts with carbon monoxide (40-80 atm, 50 deg C), in the presence of a base such as NEt3 to give the methoxycarbonyl complex trans-.When the carbonylation reaction is carried out at 90-100 deg C reduction to Pd0 carbonyl-phosphine complexes occurs, with formation of dimethyl carbonate, selectively and in an almost quantitative yield.The above complexes are less reactive than the acetato-analogues, which give dimethyl oxalate as the main organic carbonylation product even at 50 deg C.
- Cavinato, G.,Toniolo, L.
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- Active Pd(II) complexes: Enhancing catalytic activity by ligand effect for carbonylation of methyl nitrite to dimethyl carbonate
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Palladium (Pd)-based catalysts have been widely used for carbonylation of methyl nitrite to dimethyl carbonate (DMC), but a high-performance chloride free catalyst combining both excellent carbon monoxide (CO) conversion and DMC selectivity has not been developed yet. In this work, a chloride free, Pd-based catalyst with good activity and selectivity (conversion of CO: 60.1%, selectivity to DMC: 99.9%) has been successfully fabricated. By thorough characterization and analysis, it is found that the good catalytic activity is positively correlated with the high oxidation states of the Pd species, which could be tuned by their ability to accept the backdonation electron of the ligands. The strong electron backdonation from Pd to π? antibonding orbitals of the ligand in the palladium acetylacetonate [Pd(acac)2] complex accelerates the step where Pdδ+ reoxidizes to Pd(ii), resulting in the higher catalytic activity. In addition, a catalytic mechanism was proposed based on the results of X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared spectroscopy. This work not only explains the positive relationship between the catalytic activity and the oxidation state of the Pd species, but also provides a new way to enhance catalytic performance by utilizing the abilities of accepting the backdonation electron of the ligands.
- Tan, Hong-Zi,Wang, Zhi-Qiao,Xu, Zhong-Ning,Sun, Jing,Chen, Zhe-Ning,Chen, Qing-Song,Chen, Yumin,Guo, Guo-Cong
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- MgO: An excellent catalyst support for CO oxidative coupling to dimethyl oxalate
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Pd/MgO catalysts are found, for the first time, to be extraordinarily active and stable for CO oxidative coupling to dimethyl oxalate. A series of Pd/MgO catalysts with Pd loadings of 0.1, 0.3, 0.5, 1 and 2 wt% were prepared by a wet impregnation method and systematically characterized by XRD, TEM, ICP, UV-DRS, H2-TPR and CO2-TPD. It has been demonstrated that the amount of Pd loading has a pronounced effect on the catalytic activity for CO oxidative coupling to dimethyl oxalate. CO conversion increases with the increase of the Pd loading due to high dispersion and similar sizes of Pd nanoparticles, as well as, the increase in number of surface active sites. The Royal Society of Chemistry 2014.
- Peng, Si-Yan,Xu, Zhong-Ning,Chen, Qing-Song,Wang, Zhi-Qiao,Chen, Yumin,Lv, Dong-Mei,Lu, Gang,Guo, Guo-Cong
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- Low-temperature synthesis of α-alumina nanosheets on microfibrous-structured Al-fibers for Pd-catalyzed CO oxidative coupling to dimethyl oxalate
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We reported the low-temperature synthesis of α-Al2O3 nanosheets on the microfibrous-structured Al-fibers at 800 oC. The boehmite (AlOOH) nanosheets were initially formed on the Al-fibers through in situ endogenous growth. Then the AlOOH/Al-fibers was transformed to the α-Al2O3/Al-fibers composite at 800 °C by a single heating step. The low-temperature phase transformation was tentatively attributed to the Al metal in the AlOOH/Al-fibers. Palladium was then dispersed on the α-Al2O3/Al-fibers composite, and the resulting Pd/α-Al2O3/Al-fibers catalyst was examined in the strongly exothermic CO oxidative coupling to dimethyl oxalate (DMO) reaction. High CO conversion of 58percent and DMO selectivity of 95percent were obtained and maintained for at least 150 h using a feedgas of CH3ONO / CO / N2 (1 / 1.4 / 7.6, mole) at 150 oC with a gas hourly space velocity of 20,000 mL g―1 h―1. Computational fluid dynamics calculations and experimental results indicated that the Pd/α-Al2O3/Al-fibers catalyst remarkably decreased the hot-spot temperature of catalyst bed due to its enhanced thermal conductivity.
- Wang, Chunzheng,Xu, Weisong,Qin, Zhengxing,Liu, Xinmei,Mintova, Svetlana
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- A Stable Lithium–Oxygen Battery Electrolyte Based on Fully Methylated Cyclic Ether
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Ether-based electrolytes are commonly used in Li–O2 batteries (LOBs) because of their relatively high stability. But they are still prone to be attacked by superoxides or singlet oxygen via hydrogen abstract reactions, which leads to performance decaying during long-term operation. Herein we propose a methylated cyclic ether, 2,2,4,4,5,5-hexamethyl-1,3-dioxolane (HMD), as a stable electrolyte solvent for LOBs. Such a compound does not contain any hydrogen atoms on the alpha-carbon of the ether, and thus avoids hydrogen abstraction reactions. As the result, this solvent exhibits excellent stability with the presence of superoxide or singlet oxygen. In addition the CO2 evolution during charge process is prohibited. The LOB with HMD-based electrolyte was able to run up to 157 cycles, 4 times more than with 1,3-dioxolane (DOL) or 1,2-dimethoxyethane (DME) based electrolytes.
- Huang, Zhimei,Zeng, Haipeng,Xie, Meilan,Lin, Xing,Huang, Zhaoming,Shen, Yue,Huang, Yunhui
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- Selectivity Control of Carbonylation of Methanol to Dimethyl Oxalate and Dimethyl Carbonate over Gold Anode by Electrochemical Potential
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New and unique electrocatalysis of gold for the carbonylation of methanol to dimethyl oxalate (DMO) and dimethyl carbonate (DMC) was found. The selectivity to DMO and DMC could be controlled over gold anode by electrochemical potential, as you like. Drastic changes of gold electrocatalysis was due to changes of the oxidation state of gold, Au0 or Au3+. Copyright
- Funakawa, Akiyasu,Yamanaka, Ichiro,Takenaka, Sakae,Otsuka, Kiyoshi
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- Palladium catalyzed oxidative carbonylation of alcohols: Effects of diphosphine ligands
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The catalytic activity of a series of palladium diphosphine complexes of the type [PdX2(P∩P)] has been studied in the oxidative carbonylation of i-PrOH with p-benzoquinone as an oxidant. Diphosphine ligands have been chosen in order to cover a wide range of bite angles and electronic and steric parameters. Their properties have been correlated with the catalytic activity and selectivity of the reaction. The best catalytic performance has been achieved with weakly coordinating anions as well as non-bulky and electron-donating P∩P ligands with a relatively wide bite angle yet capable of maintaining a cis-coordination, such as cis-[Pd(OTs)2(pMeO-dppf)]. These results and those on the reactivity of dicarboalkoxy species of the type cis-[Pd(COOMe)2(P∩P)] toward reductive elimination, which is a crucial step in oxalate formation, suggest that the slow step of the catalysis depends on the nature of the P∩P ligand.
- Amadio, Emanuele,Freixa, Zoraida,Van Leeuwen, Piet W. N. M.,Toniolo, Luigi
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- An ultra-low Pd loading nanocatalyst with high activity and stability for CO oxidative coupling to dimethyl oxalate
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A Pd/α-Al2O3 nanocatalyst with ultra-low Pd loading exhibits high activity and stability for CO oxidative coupling to dimethyl oxalate, which was prepared by a Cu2+-assisted in situ reduction method at room temperature. The small size and high dispersion of Pd nanoparticles facilitated by Cu2+ ions are responsible for the excellent catalytic activity.
- Peng, Si-Yan,Xu, Zhong-Ning,Chen, Qing-Song,Chen, Yu-Min,Sun, Jing,Wang, Zhi-Qiao,Wang, Ming-Sheng,Guo, Guo-Cong
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- New series of γ-pyrone based podands: Synthesis, characterization and study of their application in acetate salts cation trapping for nucleophilic substitution reactions
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Dialkyl 4-oxo-4H-pyran-2,6-dicarboxylates are synthesized via esterification of chelidonic acid or via intramolecular cyclization of dialkyl-2,4,6-trioxoheptanedioates. Reaction of the dialkyl 4-oxo-4H-pyran-2,6-dicarboxylates with a variety of glycol monoalkyl ethers produces a series of new podands in good yields. To demonstrate the use of these podands in cation trapping, nucleophilic substitution reactions are carried out with various acetate salts. The results indicate that the cation diameter’s compatibility with binding site leads to the best yield of reaction.
- Teimuri-Mofrad, Reza,Aghaiepour, Alireza,Rahimpour, Keshvar
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- Pd/Mg(OH)2 Heterogeneous Nanocatalysts Synthesized by a Facile One-Pot Hydrothermal Method for CO Direct Esterification to Dimethyl Oxalate
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Pd-based heterogeneous nanocatalysts have wide application in chemical industry. However, the traditional synthesis process contains multi-steps such as impregnation, dry, calcination and reduction. The pre-synthesis nanoparticles process can reduce the steps, but need to remove the surfactants, which are added in the synthesis process. In this work, a facile one-pot hydrothermal synthesis process named as single molecular precursor method was successfully developed to prepare Pd/Mg(OH)2 heterogeneous nanocatalysts with clean surface. The as-synthesized Pd/Mg(OH)2 heterogeneous nanocatalysts show excellent performance for CO direct esterification to dimethyl oxalate (DMO). The WTY (weight time yield) of DMO can reach the high-performance of 2544?g?kgcat.?1?h?1, while the conversion of CO is 62.6% and selectivity to DMO is 90.8%. The single molecular precursor method developed by this work can be extended to other supported noble metal nanocatalysts. Graphic Abstract: [Figure not available: see fulltext.].
- Lin, Xiao-Qi,Wang, Zhi-Qiao,Xu, Zhong-Ning,Guo, Guo-Cong
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- Dynamic Kinetic Cross-Electrophile Arylation of Benzyl Alcohols by Nickel Catalysis
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Catalytic transformation of alcohols via metal-catalyzed cross-coupling reactions is very important, but it typically relies on a multistep procedure. We here report a dynamic kinetic cross-coupling approach for the direct functionalization of alcohols. The feasibility of this strategy is demonstrated by a nickel-catalyzed cross-electrophile arylation reaction of benzyl alcohols with (hetero)aryl electrophiles. The reaction proceeds with a broad substrate scope of both coupling partners. The electron-rich, electron-poor, and ortho-/meta-/para-substituted (hetero)aryl electrophiles (e.g., Ar-OTf, Ar-I, Ar-Br, and inert Ar-Cl) all coupled well. Most of the functionalities, including aldehyde, ketone, amide, ester, nitrile, sulfone, furan, thiophene, benzothiophene, pyridine, quinolone, Ar-SiMe3, Ar-Bpin, and Ar-SnBu3, were tolerated. The dynamic nature of this method enables the direct arylation of benzylic alcohol in the presence of various nucleophilic groups, including nonactivated primary/secondary/tertiary alcohols, phenols, and free indoles. It thus offers a robust alternative to existing methods for the precise construction of diarylmethanes. The synthetic utility of the method was demonstrated by a concise synthesis of biologically active molecules and by its application to peptide modification and conjugation. Preliminary mechanistic studies revealed that the reaction of in situ formed benzyl oxalates with nickel, possibly via a radical process, is an initial step in the reaction with aryl electrophiles.
- Guo, Peng,Wang, Ke,Jin, Wen-Jie,Xie, Hao,Qi, Liangliang,Liu, Xue-Yuan,Shu, Xing-Zhong
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supporting information
p. 513 - 523
(2021/01/12)
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- Ultralow-Molecular-Weight Stimuli-Responsive and Multifunctional Supramolecular Gels Based on Monomers and Trimers of Hydrazides
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The simpler, the better. A series of simple, neutral and ultralow-molecular-weight (MW: 140–200) hydrazide-derived supramolecular gelators have been designed and synthesized in two straightforward steps. For non-conjugated cyclohexane-derived hydrazides, their monomers can self-assemble to form gels through intermolecular hydrogen bonds and dipole-dipole interactions. Significantly, conjugated phthalhydrazide can self-aggregate into planar and circular trimers through intermolecular hydrogen bonds and then self-assemble to form gels through intermolecular π–π stacking interactions. It is interesting that these simple gelators exhibit unusual properties, such as self-healing, multi-response fluorescence, and visual and selective recognition of chiral (R)/(S)-1,1′-binaphthalene-2,2′-diamine and S2? through much different times of gel re-formation and blue-green color change, respectively. These results underline the importance of supramolecular gels and extend the scope of supramolecular gelators.
- Wu, Dehua,Song, Jintong,Qu, Lang,Zhou, Weilan,Wang, Lei,Zhou, Xiangge,Xiang, Haifeng
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supporting information
p. 3370 - 3378
(2020/10/02)
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- DISUBSTITUTED OXALATE AND DISUBSTITUTED CARBONATE PRODUCTION FROM AN OXALATE SALT AND ALCOHOL
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Processes for producing a disubstituted oxalate and/or disubstituted carbonate are disclosed. The processes use a water removal agent to tune the amount of disubstituted oxalate and/or disubstituted carbonate in the product mixture. One process includes contacting a cesium salt with one or more alcohols in the presence of an effective amount of a water removal agent under a carbon dioxide (CO2) atmosphere and reaction conditions sufficient to produce a composition that includes a disubstituted oxalate. Methanol can be used to produce dimethyl oxalate.
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Paragraph 0071-0073
(2020/02/16)
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- 1,3-Dibromo-5,5-dimethylhydantoin as a Precatalyst for Activation of Carbonyl Functionality
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Activation of carbonyl moiety is one of the most rudimentary approaches in organic synthesis and is crucial for a plethora of industrial-scale condensation reactions. In esterification and aldol condensation, which represent two of the most important reactions, the susceptibility of the carbonyl group to nucleophile attack allows the construction of a variety of useful organic compounds. In this context, there is a constant need for development of and improvement in the methods for addition-elimination reactions via activation of carbonyl functionality. In this paper, an advanced methodology for the direct esterification of carboxylic acids and alcohols, and for aldol condensation of aldehydes using widely available, inexpensive, and metal-free 1,3-dibromo-5,5-dimethylhydantoin under neat reaction conditions is reported. The method is air- and moisture-tolerant, allowing simple synthetic and isolation procedures for both reactions presented in this paper. The reaction pathway for esterification is proposed and a scale-up of certain industrially important derivatives is performed.
- ?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
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supporting information
(2019/08/01)
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- Base-free conversion of glycerol to methyl lactate using a multifunctional catalytic system consisting of Au-Pd nanoparticles on carbon nanotubes and Sn-MCM-41-XS
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Multifunctional catalytic systems consisting of physical mixtures of (i) bimetallic Au-Pd nanoparticles (average size of 3-5 nm) supported on functionalised carbon nanotubes (CNTs) and (ii) Sn-MCM-41 nanoparticles (50-120 nm), were synthesised and investigated for the base-free, selective conversion of glycerol to methyl lactate in a batch reactor. The catalysts were characterised by means of transmission electron microscopy, N2-physisorption, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and by Boehm titration. The catalyst based on bimetallic AuPd/CNTs showed much higher activity than the monometallic Au or Pd counterparts, thus indicating synergetic effects. Functionalisation of the CNTs by oxidative treatments had a positive effect on catalyst performance, which was correlated to the observed increase in surface acidity and hydrophilicity. The highest yield of methyl lactate achieved in this work was 85% at 96% glycerol conversion (140 °C, 10 h at 30 bar air), which is the highest yield ever reported in the literature so far. Insights in the reaction pathway were obtained by monitoring the conversion-time profiles for intermediates and their possible role as inhibitors. Batch recycling experiments demonstrated the excellent reusability of the catalyst.
- Tang, Zhenchen,Boer, Dina G.,Syariati, Ali,Enache, Mihaela,Rudolf, Petra,Heeres, Hero J.,Pescarmona, Paolo P.
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p. 4115 - 4126
(2019/08/12)
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- Method for synthesizing propionate through ester-ester exchange path
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The invention provides a method for synthesizing propionate through an ester-ester exchange path and relates to a method for synthesizing the propionate. According to the method, reaction raw materials include, but are not limited to ethyl formate, propyl formate, butyl formate, ethyl acetate, propyl acetate, butyl acetate and the like; the method for synthesizing the propionate through an ester exchange one-step method is adopted. A catalyst comprises alkaline materials including ionic liquid, soluble strong base, solid base and the like respectively; the catalyst has the advantages of high catalysis efficiency and no pollution. By taking methyl propionate and ethyl acetate reaction as an example, KOH is used as the catalyst, the mol ratio of the raw materials is 1 to 1, the reaction temperature is 60 DEG C and the reaction time is 5 min; the conversion ratios of the methyl propionate and the ethyl acetate can reach 70 percent or more; products comprise ethyl propionate and the methylacetate. The whole reaction path has the characteristics of short synthetic route, simple technological flow and high yield and the catalyst is stable, does not become inactive and can be repeatedlyutilized.
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Paragraph 0030-0031
(2019/04/04)
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- Esterification of aryl/alkyl acids catalysed by n-bromosuccinimide under mild reaction conditions
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N-halosuccinimides (NXSs) are well-known to be convenient, easily manipulable and low-priced halogenation reagents in organic synthesis. In the present work, N-bromosuccinimide (NBS) has been promoted as the most efficient and selective catalyst among the NXSs in the reaction of direct esterification of aryl and alkyl carboxylic acids. Comprehensive esterification of substituted benzoic acids, mono-, di- and tri-carboxy alkyl derivatives has been performed under neat reaction conditions. The method is metal-free, air- and moisture-tolerant, allowing for a simple synthetic and isolation procedure as well as the large-scale synthesis of aromatic and alkyl esters with yields up to 100%. Protocol for the recycling of the catalyst has been proposed.
- ?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
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- PROCESS FOR THE PREPARATION OF OXALIC ACID ESTERS FROM CESIUM OXALATE
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Processes for producing a disubstituted oxalate are disclosed. The process includes contacting a cesium salt with one or more alcohols and carbon dioxide (CO2) under reaction conditions sufficient to produce a composition comprising a disubstituted oxalate.
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Paragraph 0051
(2018/09/08)
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- PRODUCTION OF CESIUM OXALATE FROM CESIUM CARBONATE
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Processes for producing cesium oxalate are disclosed. The process includes contacting cesium carbonate, cesium hydrogenbicarbonate or a mixture thereof with carbon dioxide and carbon monoxide, carbon dioxide and hydrogen or carbon monoxide and oxygen at elevenated temperatures and pressures.
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Paragraph 0060; 0061; 0062
(2018/08/20)
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- CONVERSION OF CESIUM CARBONATE TO CESIUM OXALATE
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Processes for producing a disubstituted oxalate are disclosed. The process includes contacting a cesium salt with one or more alcohols and carbon dioxide (CO2) under reaction conditions sufficient to produce a composition comprising a disubstituted oxalate.
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Paragraph 0089
(2018/08/20)
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- Preparation method of methylallyl alcohol
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The invention discloses a preparation method of methylallyl alcohol. The method is characterized in that the methylallyl alcohol and a carboxylate compound are obtained by adopting methylallyl chloride and carboxylate as raw materials and alcohol as a solvent. The solvent creatively adopts the alcohol, not an alkali or other solvents, so reaction conditions are mild, and the irritation to the rawmaterials is low; and more importantly, the carboxylate also can be obtained, the content of ether and salt products is low, the yield of the target product is high, so the method in the invention hasadvantages over traditional technologies characterized by adoption of the alkali as a hydrolysis agent, a two-step reaction and high byproduct content.
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Paragraph 0022-0023
(2018/06/04)
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- CESIUM OXALATE PRODUCTION FROM CESIUM CARBONATE
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Processes for producing a disubstituted oxalate are disclosed. The process includes contacting a mixture of cesium salt and gamma alumina with one or more alcohols and carbon dioxide (CO2) under reaction conditions sufficient to produce a composition comprising a disubstituted oxalate.
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Paragraph 0057; 0058
(2019/01/11)
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- Novel bis(aminoalcohol)oxalamide organogelators and their diglycolylamide analogs: Evaluation of gelation efficiency in various organic fluids
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Three modular types of bis(aminoalcohol)oxalamides (1, 4, and 7) and bis(aminoalcohol)diglycolylamide (8) gelators have been prepared by the reaction of the respective aminoalcohols with oxalyl and digycolyl methylesters as potential low-molecular-weight organogelators. The gelation properties of these amides have been evaluated in various aromatic organic solvents (xylene, toluene, isopropyl benzene, and aromatic ether type organic uids such as anisole or α-phenylethylmethylether) as well as the long-chain aliphatic alcohols (1-hexanol, 1-octanol, 2-octanol, and aromatic 1- phenylethanol). The compounds with sec-butyl and ethyl side chains produce good gelation properties in both aromatic and other organic uids. Furthermore, the common oxalamide linker present in the gelators was replaced by an extended diglycolylamide linker (8) and its behaviors were compared with the benzylic oxalamide analog (3). The gelator (8) gives the best results with aromatic fluid and lauric acid ethyl ester. 1H NMR studies reveal the existence of temperature- dependent network assembly/dissolution equilibrium and produce Kgel. FTIR was employed to see the effect of hydrogen bonding in the formation of gel network. Thermodynamic parameters regarding gel-to-sol transition were collected with van't Hoff relationships.
- ?olak, Mehmet,Bari?, Deniz,Pirin??io?lu, Necmettin,Ho?g?ren, Halil
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p. 658 - 671
(2017/11/20)
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- Template-free sol–gel synthesis of high surface area mesoporous silica based catalysts for esterification of di-carboxylic acids
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High surface area mesoporous silica based catalysts have been prepared by a simple hydrolysis/sol–gel process without using any organic template and hydrothermal treatment. A controlled hydrolysis of ethyl silicate-40, an industrial bulk chemical, as a silica precursor, resulted in the formation of very high surface area (719?m2/g) mesoporous (pore size 67?? and pore volume 1.19?cc/g) silica. The formation of mesoporous silica has been correlated with the polymeric nature of the ethyl silicate-40 silica precursor which on hydrolysis and further condensation forms long chain silica species which hinders the formation of a close condensed structure thus creating larger pores resulting in the formation of high surface mesoporous silica. Ethyl silicate-40 was used further for preparing a solid acid catalyst by supporting molybdenum oxide nanoparticles on mesoporous silica by a simple hydrolysis sol–gel synthesis procedure. The catalysts showed very high acidity as determined by NH3-TPD with the presence of Lewis as well as Br?nsted acidity. These catalysts showed very high catalytic activity for esterification; a typical acid catalyzed organic transformation of various mono- and di-carboxylic acids with a range of alcohols. The in situ formed silicomolybdic acid heteropoly-anion species during the catalytic reactions were found to be catalytically active species for these reactions. Ethyl silicate-40, an industrial bulk silica precursor, has shown a good potential for its use as a silica precursor for the preparation of mesoporous silica based heterogeneous catalysts on a larger scale at a lower cost.
- More, Pavan M.,Umbarkar, Shubhangi B.,Dongare, Mohan K.
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p. 1247 - 1253
(2016/10/13)
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- Organogels as novel carriers for dermal and topical drug delivery vehicles
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Aminoalcohol based bis-(aminoalcohol)oxalamides (BAOAs) (1,6-amino alcohol=leucinol, isoleucinol, valinol, phenylglycinol, phenylalaninol and 2-amino-1-butanol) have been explored to develop drug depot systems and illustrated as a novel dermal and topical drug delivery vehicle for non-steroidal anti-inflammatory drug molecules. FAE's (Fatty acid ethyl and isopropyl esters) with different chain lengths, ethyl laurate, ethyl myristate, ethyl palmitate, isopropyl laurate, isopropyl myristate, isopropyl palmitate, have been chosen as they are biocompatible organic fluids used typically in cosmetic industry. Ibuprofen (Ib), acting as a model drug, was entrapped in the supramolecular organogels. The release behavior of Ib molecules in the supramolecular organogels was investigated by using UV–vis spectroscopy. The influence of the organogelator and drug concentration, pH values of the accepting media, and nature of solvent (different FAE's) on the release behavior of Ib was investigated under static conditions. The results indicated that the release rate of Ib from the supramolecular organogels was effectively retarded with an increase of the organogelator concentration. Also, the release rates of Ib increased on increasing the Ib content. Furthermore, the release behavior of Ib was found to be different at various pH values in buffers as accepting media. The study of the release kinetics indicated that the release behavior of Ib was in accord with the Higuchi equation and the diffusion-controlled mechanism involved in the Fickian model. These observations indicate that bis-(aminoalcohol)oxalamides gels may act as delivery vehicles for non-steroidal anti-inflammatory drug molecules and also show that the release profiles for such systems can be fine-tuned by the correct choice of gelator-FAE combination.
- Uzan, Serhat,Bar??, Deniz,?olak, Mehmet,Ayd?n, Haluk,Ho?g?ren, Halil
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supporting information
p. 7517 - 7525
(2016/11/11)
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- Method for production of oxalate CO in gaseous phase
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The invention relates to a method for CO gas phase coupling production of oxalate, and mainly solves the problem of low space time yield of oxalate due to the large particle size and low dispersion of an active component Pd crystal grain in catalysts in the prior art. A technical scheme adopted in the invention is characterized in that carbon monoxide and organic nitrite raw materials contact with a palladium-containing catalsty under coupling reaction conditions, and a complexation additive is added into a dipping during the preparation of the catalyst. The technical scheme well solves the problem, and the method can be used in the industrial for the carbon monoxide gas phase coupling production of oxalate.
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Paragraph 0037; 0038; 0040-0061; 0073
(2017/11/09)
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- A levulinic acid and levulinate catalytic oxidation process for the conversion of
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The invention relates to a method for catalytic oxidation conversion of levulinic acid and levulinic acid ester. The method adopts air or oxygen as the oxidant, and a bivalent manganese compound and nitric acid, nitrate or nitrous acid, nitrite are employed as a composite catalyst to catalyze levulinic acid or levulinic acid ester liquid phase selective oxidation and esterification reaction under mild conditions, thus obtaining succinic acid diester. The method has the characteristics of high catalytic oxidation efficiency and mild reaction condition, the bivalent manganese compound and nitric acid, nitrate or nitrous acid, nitrite involved in the composite catalyst are cheap and easily available, and the product is easy to separate and purify, so that the method has very good practicability and broad application prospects.
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Paragraph 0024
(2017/03/08)
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- Catalytic oxidative C-C bond cleavage route of levulinic acid and methyl levulinate
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Recently, obtaining value-added chemicals from biomass resources has attracted considerable attention. Levulinic acid is one of the most important biomass platform compounds, which could be obtained from carbohydrate biomass. In this work, levulinic acid was selectively converted into C4 product, including succinic anhydride, via catalytic oxidation with a manganese catalyst in acetic anhydride. Moreover, an unexpected product of maleic anhydride was obtained, which greatly differs from that of levulinate ester. The pathway for formation of maleic anhydride was studied by monitoring and confirming intermediates α-angelica lactone and its derivative 2-methyl-5-oxotetrahydro-2-furanyl acetate. Based on the obtained mechanistic information, the different behaviour between the oxidative cleavage of levulinic acid and levulinate ester was further discussed.
- Xia, Fei,Du, Zhongtian,Liu, Junxia,Ma, Yangyang,Xu, Jie
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p. 72744 - 72749
(2016/08/09)
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- Synthesis of rigid and C2-symmetric pyridino-15-crown-5 type macrocycles bearing diamide-diester functions: Enantiomeric recognition for chiral primary organoammonium perchlorate salts
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Four novel C2-symmetric macrocyclic compounds with a pyridine function and possessing amide and ester lingeages were prepared. The enantiomeric discrimination abilities of these macrocycles against α-phenylethylammonium and α-(1-naphthyl)ethylammonium perchlorate salts were measured by standard 1H NMR titration techniques in DMSO-d6. A binding constant ratio of 31 (Kbind(S)/Kbind(R)) for two enantiomers of α-(1-naphthyl)ethylammonium salt with the macrocyclic host (S,S)-4 bearing phenyl arms was observed, which corresponds to an enantiomeric discrimination of approximately 94%. Molecular dynamic calculations were performed for some of the supramolecular complexes to in order to gain insight into the mode of molecular recognition between the macrocyclic compounds and ammonium salts; these results were consistent with experimental observations, which may be relevant to those in biochemical processes occurring in organisms.
- ?eker, Sevil,Bari?, Deniz,Arslan, Nevin,Turgut, Yilmaz,Pirin??io?lu, Necmettin,To?rul, Mahmut
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p. 411 - 417
(2014/04/17)
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- Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine
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Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe III(μ-N)FeIV(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)FeIV(μ-N)FeIV(F) (Pc+?)], which was isolated and characterized by UV-vis, EPR, 19F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)FeIII(μ-N)Fe IV(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H 3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.
- Colomban, Cédric,Kudrik, Evgenij V.,Afanasiev, Pavel,Sorokin, Alexander B.
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supporting information
p. 11321 - 11330
(2014/11/07)
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- Promoted role of Cu(NO3)2 on aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran over VOSO4
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The promoted effect of Cu(NO3)2 on aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) catalyzed by VOSO4 in acetonitrile was intensively investigated. It was revealed that Cu(NO3)2 facilitated the activation of VOSO 4 to generate active V5+ species via the generation of NOx gas. The high DFF selectivity is ascribed to Cu2+ cation which can effectively prohibit oxidative CC bond cleavage reaction of HMF and prevent radical reaction of DFF to humins. In addition, the polarity of solvent plays a great role on high selectivity of DFF.
- Jia, Xiuquan,Ma, Jiping,Wang, Min,Du, Zhongtian,Lu, Fang,Wang, Feng,Xu, Jie
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p. 231 - 236
(2014/07/08)
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- Dinuclear vanadium, copper, manganese and titanium complexes containing O,O,N-dichelating ligands: Synthesis, crystal structure and catalytic activity
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O,O,N-or O,N-dichelating ligands, H4L1, H 4L2, derived from new bis(hydroxybenzylidene)-substituted terephthalo and oxalo hydrazides were prepared and characterized by FT-IR and NMR spectroscopy (H4-L1 = dicondensation of salicylaldehyde and terephthalic acid dihydrazide, H4L2 = dicondensation of sali-cylaldehyde and oxalic acid dihydrazide). [{VO 2}2(H2L1)] (1), [{Cu(CH 3OH)}2(L1)] (2), [{Mn(CH3OH)} 2(L1)] (3) and [TiO(H3L1) 2] (4) complexes of the potentially hexadentate 2[ONO] donor hydrazone ligand [L1]4 were synthesized by reaction of the appropriate metal salts with H4L1. The complexes [{VO(CH3O)(CH3OH)}2(L2)] (5), [{Cu(CH3OH)}2(L2)] (6), [{Mn(H 2O)2(CH3OH)}2(L2)] (7) and [{TiO(CH3OH)}2(L2)]·2H2O (8) were synthesized by the reaction of corresponding metal salts with H 4L2. All complexes were characterized by microanalyses, FT-IR, UV-Vis and NMR spectroscopic methods. The crystal structures of 1 and 5 were established by X-ray analyses. Compound 1 is a one-dimensional coordination polymer. The catalytic potential of the complexes was evaluated for oxidation of hydrocarbons including cycloalkenes, cyclic alkanes and benzylalcohol using H2O2 as terminal oxidant. Of the studied aroylhydrazone complexes, 4 showed the best selectivity and activity as catalyst.
- Hosseini-Monfared, Hassan,Asghari-Lalami, Nasim,Pazio, Aleksandra,Wozniak, Krzysztof,Janiak, Christoph
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p. 241 - 250
(2013/10/22)
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- PROCESS OF PRODUCING OXALATE BY CO GAS PHASE METHOD
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The present invention relates to a process of producing oxalate by CO gas phase method for chiefly solving the technical problem of the low utilization efficiency of nitrogen oxides or nitrous acid esters in the prior art. The present invention solves the problem in a better way by using the following steps including: a gas phase stream V containing NO and methanol and oxygen enter a supergravity rotating bed reactor II and are subjected to the oxidative esterification reaction to produce an effluent VI containing methyl nitrite; a methyl nitrite effluent VII obtained from separating said effluent VI together with a CO gas II enter a coupling reactor II and is contacted with a catalyst II to react to form a dimethyl oxalate effluent VIII and a gas phase effluent IX containing NO; the resultant dimethyl oxalate effluent VIII is separated to obtain a dimethyl oxalate product I; optionally, the gas phase effluent IX containing NO is returned to the step above so as to be mixed with the gas phase stream V containing NO for being recycled. Therefore, the process is applicable to the industrial production of oxalate by CO gas phase method.
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Paragraph 0031
(2013/08/14)
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- Conversion of levulinate into succinate through catalytic oxidative carbon-carbon bond cleavage with dioxygen
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Grand Cleft Oxo: Levulinate, available from biomass, is oxidized into succinate through manganese(III)-catalyzed selective cleavage of C-C bonds with molecular oxygen. In addition to levulinate, a wide range of aliphatic methyl ketones also undergo oxidative C-C bond cleavage at the carbonyl group. This procedure offers a route to valuable dicarboxylic acids from biomass resources by nonfermentive approaches. Copyright
- Liu, Junxia,Du, Zhongtian,Lu, Tianliang,Xu, Jie
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p. 2255 - 2258
(2014/01/06)
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- Methyl formate as a carbonylating agent for the catalytic conversion of phenol to methyl phenyl carbonate
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Methyl formate was used as a green and efficient carbonylating agent in the synthesis of methyl phenyl carbonate from phenol. Methyl formate showed better performance compared to toxic CO gas and the ability to produce other useful carbonylated products, e.g., dimethyl carbonate and dimethyl oxalate.
- Yalfani, Mohammad S.,Lolli, Giulio,Wolf, Aurel,Mleczko, Leslaw,Mueller, Thomas E.,Leitner, Walter
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supporting information
p. 1146 - 1149
(2013/06/05)
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- PROCESS OF PRODUCING OXALATE BY CO GAS PHASE METHOD
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A process of producing oxalate by CO gas phase method includes the following steps: a) introducing nitrite salt, water and an inorganic acid first into a reactor I to produce a NO containing effluent I; and separating the resultant effluent to obtain the effluent II of NO; b) introducing the effluent II of NO, a C1-C4 alkanol and oxygen into a reactor II to be subjected to the reaction, and separating the resultant effluent to obtain the effluent IV of C1-C4 alkyl nitrites; c) introducing the effluent IV of C1-C4 alkyl nitrites and a CO gas stream into a coupling reactor where they are reacted to produce a NO containing effluent VI. The reactor I and/or the reactor II are preferably rotating supergravity reactors. Therefore, the process is applicable to the industrial production of oxalate by CO gas phase method.
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Paragraph 0032
(2013/04/10)
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- Palladium phthalocyaninesulfonate functionalized mesoporous polymer: A highly efficient photocatalyst for degradation of 4-chlorophenol under visible light irradiation
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A novel sulfonated palladium phthalocyanine (PdPcS) modified FDU-15 mesoporous polymer (FDU-PdPcS) has been prepared by rationally chemical modification process. The PdPcS molecules were highly dispersed inside the confined mesopores, and were further stabilized through a π-π interaction with mesopolymer, which may prevent the PdPcS molecules from agglomerating and deactivating in photodegradation reactions. The physicochemical properties of thus prepared FDU-PdPcS material were characterized by XRD, N2 adsorption-desorption, UV-vis and inductively coupled plasma techniques. FDU-PdPcS proved to be highly efficient heterogeneous photocatalyst for the degradation of 4-chlorophenol (4-CP) in the presence of H2O 2 under visible light irradiation. The photodegradation of 4-CP with an initial concentration 0.6 mM was completed within 5 h at pH 11 using a dose of 0.2 g/L of the 0.12 wt% FDU-PdPcS photocatalyst. The photodegradation intermediates were identified by GC-MS. A possible mechanism involved in the photodegradation of 4-CP has also been discussed.
- Xing, Rong,Wu, Lin,Fei, Zhenghao,Wu, Peng
-
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- Catalytic oxidative decarboxylation of malic acid into dimethyl malonate in methanol with dioxygen
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If you've got it, use it: Malic acid is converted into dimethyl malonate by a direct, one-pot process. The process is cyanide- and halide-free. Phosphovanadomolybdates serve as bifunctional catalysts, effecting the oxidative decarboxylation and esterification in a consecutive manner. Oxidative C-C bond cleavage first forms hemiacetals. The results serve as example for the production of valuable chemicals by fully utilizing the oxygen atoms and basic structure inherent to biomass products.
- Liu, Junxia,Du, Zhongtian,Yang, Yanliang,Lu, Tianliang,Lu, Fang,Xu, Jie
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p. 2151 - 2154
(2013/01/15)
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- PROCESS FOR PREPARING DIARYL OXALATE
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Disclosed is a process for preparing a diaryl oxalate which comprises the step of transesterifying a dialkyl oxalate or/and an alkylaryl oxalate with an aryl alcohol in the presence of a tetra(aryloxy)titanium as a catalyst, wherein the tetra(aryloxy)titanium is fed into a reaction system of the transesterification as an aryl alcohol solution of the tetra(aryloxy)titanium which is prepared by reacting a tetraalkoxy titanium and an excess amount of the aryl alcohol and removing a by-producing alkyl alcohol.
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Page/Page column 18
(2012/12/13)
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- Oxidative carbonylation of ethene catalyzed by Pd(II)-PPh3 complexes in MeOH using benzoquinone as stoichiometric oxidant
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The complexes [Pd(COOMe)nX2-n(PPh3) 2] (n = 0, 1, 2; X = TsO, OAc, ONO2, Cl, Br), [Pd(SO 4)(PPh3)2], [PdCl2(PPh 3)]2 and PdX2 (X = Cl, Br, I) catalyze the oxidative ethene carbonylation in MeOH using benzoquinone (BQ) as stoichiometric oxidant. The main products dimethyl succinate (DMS) and dimethyl oxalate (DMO) are formed together with minor amounts of methyl propanoate and dimethyl carbonate. The formation of DMS unambiguously proves that ethene inserts into a Pd-COOMe bond. The influence of the CO/ethene ratio at constant total pressure and of the BQ/Pd ratio on the product distribution has been studied. Model reactions of a Pd-hydride with BQ, of trans-[Pd(COOMe)(TsO)(PPh 3)2] with ethene in the presence of BQ and of trans-[Pd(COOMe)2(PPh3)2] with BQ have been studied by 31P{1H} NMR. BQ consumes the Pd-hydride and directs the catalysis toward a Pd-COOMe initiator leading to DMS. In the catalysis to DMO, BQ is likely to favour the formation of a Pd-(COOMe) 2 species having the two carbomethoxy ligands in vicinal position such to favour the elimination of the product. The proposed catalytic cycles for the formation of the products are discussed.
- Cavinato, Gianni,Facchetti, Sarah,Toniolo, Luigi
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experimental part
p. 63 - 69
(2012/02/02)
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- Carbonylation of nitrobenzene in methanol with palladium bidentate phosphane complexes: An unexpectedly complex network of catalytic reactions, centred around a Pd-imido intermediate
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The reactivity of palladium complexes of bidentate diaryl phosphane ligands (P2) was studied in the reaction of nitrobenzene with CO in methanol. Careful analysis of the reaction mixtures revealed that, besides the frequently reported reduction products of nitrobenzene [methyl phenyl carbamate (MPC), N,N′-diphenylurea (DPU), aniline, azobenzene (Azo) and azoxybenzene (Azoxy)], large quantities of oxidation products of methanol were co-produced (dimethyl carbonate (DMC), dimethyl oxalate (DMO), methyl formate (MF), H 2O, and CO). From these observations, it is concluded that several catalytic processes operate simultaneously, and are coupled via common catalytic intermediates. Starting from a P2Pd0 compound formed in situ, oxidation to a palladium imido compound P2PdII=NPh, can be achieved by de-oxygenation of nitrobenzene 1) with two molecules of CO, 2) with two molecules of CO and the acidic protons of two methanol molecules, or 3) with all four hydrogen atoms of one methanol molecule. Reduction of P 2PdII=NPh to P2Pd0 makes the overall process catalytic, while at the same time forming Azo(xy), MPC, DPU and aniline. It is proposed that the Pd-imido species is the central key intermediate that can link together all reduction products of nitrobenzene and all oxidation products of methanol in one unified mechanistic scheme. The relative occurrence of the various catalytic processes is shown to be dependent on the characteristics of the catalysts, as imposed by the ligand structure.
- Mooibroek, Tiddo J.,Schoon, Lodi,Bouwman, Elisabeth,Drent, Eite
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supporting information; experimental part
p. 13318 - 13333
(2012/02/06)
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- C2 symmetric synthesis of Bis(amino alcohol)oxalamides and its catalytic activity
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The aim of this study is to evaluate C2 symmetric synthesis of bis(amino alcohol)oxalamides and the catalytic activity diethyl zinc to benzaldehyde. Syntheses of diamidediols were achieved nearly quantitatively by reacting oxalic acids methyl esters with amino alcohols directly in a single step reactions and mild conditions. Four modular and rigid diamidediols having C2-symmetry were synthesized forming oxalic moiety main core. The catalytic effects of the N,N′-bis[(1R)-1-ethyl-2- hydroxyethyl] ethanediamide, N,N′-bis[(1S)-1-benzyl-2-hydroxyethyl]- ethanediamide, N,N′-bis[(1S)-1-isobutyl-2-hydroxyethyl]ethanediamide and N,N′-bis[(1S)-1-secbutyl-2-hydroxyethyl]ethanediamide were tested and also N,N′-bis[(1S)-1-benzyl-2-hydroxyethyl]ethanediamide, N,N′- bis[(1S)-1-isobutyl-2-hydroxyethyl]ethanediamide were synthesized. The catalytic activity of C2-symmetric diamidediols on the addition reaction of diethyl zinc to benzaldehyde and effects of alkyl moiety bonded to stereogenic center on enantioselectivity were conducted out.
- ?etin, Adnan
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experimental part
p. 5086 - 5092
(2012/07/28)
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- Processes for Producing an Oxalate by Coupling of CO
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Provided are processes for producing an oxalate by coupling of CO in the presence of a nitrite, wherein two or more reaction zones in series are used, and at least a portion of the oxalate as reaction product is separated between the reaction zones, and/or the nitrite is fed stagewise. The processes described herein can effectively enhance the selectivity to the oxalate and the single-pass conversion of the feedstock.
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Page/Page column 5
(2010/07/04)
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- Novel C2-symmetric macrocycles bearing diamide-diester groups: Synthesis and enantiomeric recognition for primary alkyl ammonium salts
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(Chemical Equation Presented) We synthesized a series of novel macrocycles with diamide-diester groups (S,S)-1, (S,S)-2, (S,S)-3, and (R,R)-1, derived from dimethyloxalate and amino alcohols by high dilution technique, and evaluated enantiomeric recognition properties of these macrocycles toward primary alkyl ammonium salts by 1H NMR titration. Taking into account the host employed, important differences were observed in the Ka values of (R)-Am and (S)-Am for (S,S)-1 and (R,R)-1 hosts, KS/KR = 5.55 and KR/KS = 3.65, ΔΔGo = 0.43 and -0.32 kJ mol-1, respectively. There seems a general tendency for the host to include the guests with the same absolute configuration.
- Sunkur, Murat,Baris, Deniz,Hosgoren, Halil,Togrul, Mahmut
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p. 2570 - 2575
(2008/09/19)
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- Simple, rapid procedure for the synthesis of chloromethyl methyl ether and other chloro alkyl ethers
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Zinc(II) salts catalyze the reaction between acetals and acid halides to provide haloalkyl ethers in near-quantitative yield. Reactions from millimole to mole scale are typically complete in 1-4 h with 0.01 mol % catalyst. The solutions of haloalkyl ethers thus obtained can be utilized directly in reactions in which the presence of the ester byproduct does not interfere. Excess haloalkyl ether is destroyed on workup, thereby minimizing exposure to this class of carcinogenic compounds.
- Berliner, Martin A.,Belecki, Katherine
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p. 9618 - 9621
(2007/10/03)
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- Identification and quantification of aerosol polar oxygenated compounds bearing carboxylic or hydroxyl groups. 1. Method development
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In this study, a new analytical technique was developed for the identification and quantification of multifunctional compounds containing simultaneously at least one hydroxyl or one carboxylic group, or both. This technique is based on derivatizing first the carboxylic group(s) of the multifunctional compound using an alcohol (e.g., methanol, 1-butanol) in the presence of a relatively strong Lewis acid (BF3) as a catalyst. This esterification reaction quicldy and quantitatively converts carboxylic acids to their ester forms. The second step is based on silylation of the ester compounds using bis(trimethylsilyl) trifluoroacetamide (BSTFA) as the derivatizing agent. For compounds bearing ketone groups in addition to carboxylic and hydroxyl groups, a third step was used based on PFBHA derivatization of the carbonyls. Different parameters including temperature, reaction time, and effect due to artifacts were optimized. A GC/MS in EI and in methane-CI mode was used for the analysis of these compounds. The new approach was tested on a number of multifunctional compounds. The interpretation of their EI (70 eV) and CI mass spectra shows that critical information is gained leading to unambiguous identification of unknown compounds. For example, when derivatized only with BF3-methanol, their mass spectra comprise primary ions at m/z M .+ + 1, M.+ + 29, and M.- - 31 for compounds bearing only carboxylic groups and M.- + 1, M.+ + 29, M.+ - 31, and M+. - 17 for those bearing hydroxyl and carboxylic groups. However, when a second derivatization (BSTFA) was used, compounds bearing hydroxyl and carboxylic groups simultaneously show, in addition to the ions observed before, ions at m/z M.+ + 73, M .+ - 15, M.+ - 59, M.+ - 75, M.+ - 89, and 73. To the best of our knowledge, this technique describes systematically for the first time a method for identifying multifunctional oxygenated compounds containing simultaneously one or more hydroxyl and carboxylic acid groups.
- Jaoui,Kleindienst,Lewandowski,Edney
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p. 4765 - 4778
(2007/10/03)
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- Method for producing diol derivatives
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A method of producing a diol derivative efficiently and to high purity is provided. Specifically, the present invention relates to a method of producing a diol derivative having, as a fundamental step, a step of obtaining an α-hydroxycarboxylic acid ester by reacting (i) one or more 1,2-diols or (ii) a 1,2-diol and a primary alcohol as starting material(s) with oxygen in the presence of a catalyst comprising metal loaded on a carrier.
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