- X-ray crystal structure of the tetra(tert-butyl)erbate anion and attempts to prepare tetravalent organolanthanide complexes
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The new [Li(DME)3+] salt of the previously-known tetra(tert-butyl)erbate(III) anion [Er(t-Bu)4-] has been prepared and structurally characterized. The erbium(III) center is ligated by four tert-butyl groups in an approximately tetrahedral arrangement. The C-Er-C angles between the tert-butyl groups range from 108.8(3)° to 111.2(3)° and the Er-C distances range from 2.352(6) to 2.395(6) A?. The lithium cation is surrounded by three DME molecules, which form a distorted octahedral coordination sphere. Attempts to oxidize the analogous terbate complex [Li(DME)3][Tb(t-Bu)4] and its cerium analog to electrically neutral tetra(alkyl)lanthanide(IV) compounds are described.
- Noh, Wontae,Girolami, Gregory S.
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- Reactions of diols with dimethyl carbonate in the presence of W(CO) 6 and Co2(CO)8
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Dimethoxyalkanes and dimethyl alkanediyl biscarbonates were synthesized by reactions of diols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of dimethoxyalkanes or dimethyl alkanediyl biscarbonates.
- Khusnutdinov,Shchadneva,Mayakova
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- Niobia-modified aluminas prepared by impregnation with niobium peroxo complexes for dimethyl ether production
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Use of a water-soluble niobium peroxo complex allowed the preparation of niobium-modified aluminas containing up to 90% of the theoretical niobia monolayer in one impregnation step. There was a maximum in the density of surface Lewis acid sites at 45% of the theoretical monolayer. FTIR of adsorbed pyridine and adsorbed CO2 suggest the vertical growth of the Nb 2O5 layer for the largest niobium contents. The addition of 22.5% of the theoretical monolayer eliminated about 80% of the basic surface hydroxyls, inhibiting the adsorption of gas phase CO2 by the samples. The niobia/alumina catalysts suffered less inhibition by CO2 than the pure alumina in the methanol dehydration reaction, confirming that Nb 2O5 is mainly deposited on sites where the CO2 adsorption is stronger, leaving free sites that are active in catalytic dehydration and less inhibited by CO2, however none of the niobia/aluminas was more active than the pure alumina. Nevertheless, in the direct syngas to DME conversion using a mixed catalyst system comprised of a CuZnAl methanol synthesis catalyst and a methanol dehydration component, the activity was significantly larger with a niobia/alumina as a dehydrating component than with the pure alumina.
- Rocha, Angela S.,Da S. Forrester, Aline M.,Lachter, Elizabeth R.,Faro Jr., Arnaldo C.,Sousa-Aguiar, Eduardo F.
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- Organometallic compounds of the lanthanides. 42. Bis(dimethoxyethane)lithium bis(cyclopentadienyl)bis(trimethylsilyl)lanthanide complexes
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The trichlorides of Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu react with NaC5H5 in tetrahydrofuran in the presence of dimethoxyethane (dme) with formation of bis(cyclopentadienyl)lanthanide chloride complexes of the types (C5H5)2Ln(μ-Cl)2Na(dme). The reactions of these organolanthanide halide complexes with (trimethylsilyl)lithium in dme yield compounds of the type [Li(dme)2][(C6H5)2Ln(SiMe 3)2] (Ln = Sm, Dy, Ho, Er, Tm, Lu). (C5H5)2Sm(μ-Cl)2Na(dme) reacts with (trimethylgermyl)lithium in dme/pentane with formation of [Li(dme)3][(C5H5)3SmClSin(C 5H5)3] (7a). The new compounds have been characterized by elemental analyses and IR and NMR spectra. The structure of [Li(dme)3][(C5H5)3SmClSm(C 5H5)3] (7a) has been elucidated through complete X-ray analysis. The crystals are monoclinic with a = 14.00 (1) A?, b = 13.38 (2) A?, c = 23.49 (3) A?, β = 93.37 (9)°, space group P21/n, Z = 4, and R = 0.0411 for 4671 reflections. The [Cp3SmClSmCp3]- anion consists of two Cp3Sm unite bridged by a chlorine atom with Sm-Cl distances of 2.827 (2) and 2.798 (2) A?.
- Schumann, Herbert,Nickel, Siegbert,Loebel, J?rg,Pickardt, Joachim
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- Carbonylation of methanol to acetic acid using homogeneous Ru complex catalyst
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Carbonylation of methanol to give acetic acid catalysed by Ru complexes such as trans-Ru(CO)2Cl2(PPh3)2, cis-Ru(CO)2Cl2(PPh3)2 and H2Ru(CO)(PPh3)3 is reported.The highest activity and selectivity were obtained with H2Ru(CO)(PPh3)3 as the catalyst precursor.Hydrogen increases the activity and selectivity of catalysts such as trans-Ru(CO)2Cl2(PPh3)2, cis-Ru(CO)2Cl2(PPh3)2, but has no influence on the activity and selectivity in the case of H2Ru(CO)(PPh3)3.
- Kelkar, Ashutosh A.,Kolhe, Devidas S.,Chaudhari, Raghunath V.
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- Mechanistic Studies on Initial C-C Bond Formation in the Zeolite ZSM-5 Catalysed Methanol Conversion Reaction: Evidence against a Radical Pathway
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The behaviour of the methoxymethyl radical in the gas phase has been studied and the results provide strong evidence against a radical mechanism for the title reaction.
- Hunter, Roger,Hutchings, Graham J.,Pickl, Wolfgang
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- C-C Bond Formation from Dimethil Ether via a Radical Mechanism in the Presence of Strong Acid
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The selective radical dimerization of dimethyl ether by peroxodisulphuryl difluoride in fluorosulphuric acid, suggests that a radical intermediate for initial C-C bond formation in the conversion of methanol into hydrocarbons is a possibility.
- Choukroun, Henri,Brunel, Daniel,Germain, Alain
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- Synthesis, characterization and properties of carbon nanotubes microspheres from pyrolysis of polypropylene and maleated polypropylene
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Microspheres assembled from carbon nanotubes (MCNTs), with the diameters ranging from 5.5 to 7.5 μm, were synthesized by means of pyrolysis of polypropylene and maleated polypropylene in an autoclave. The characterization of structure and morphology was carried out by X-ray diffractometer (XRD), field-emission scanning electron microscopy (FESEM), (high resolution) transmission electron microscope [(HR)TEM)], selected-area electron diffraction (SAED) and Raman spectrum. As a typical morphology, the possible growth process of MCNTs was also investigated and discussed. The results of nitrogen adsorption-desorption indicate that the Brunauer-Emett-Teller (BET) surface area (140.6 m2/g) of the MCNTs obtained at 600 °C is about twice as that (74.5 m2/g) of carbon nanotubes obtained at 700 °C. The results of catalytic experiment show that MCNTs based catalyst has higher catalytic activity than the carbon nanotubes based catalyst for the preparation of methanol and dimethoxy-ethane by oxidation of dimethyl ether.
- Zhang, Junhao,Du, Jin,Qian, Yitai,Xiong, Shenglin
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- Visualizing Element Migration over Bifunctional Metal-Zeolite Catalysts and its Impact on Catalysis
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The catalytic performance of composite catalysts is not only affected by the physicochemical properties of each component, but also the proximity and interaction between them. Herein, we employ four representative oxides (In2O3, ZnO, Cr2O3, and ZrO2) to combine with H-ZSM-5 for the hydrogenation of CO2 to hydrocarbons directed by methanol intermediate and clarify the correlation between metal migration and the catalytic performance. The migration of metals to zeolite driven by the harsh reaction conditions can be visualized by electron microscopy, meanwhile, the change of zeolite acidity is also carefully characterized. The protonic sites of H-ZSM-5 are neutralized by mobile indium and zinc species via a solid ion-exchange mechanism, resulting in a drastic decrease of C2+ hydrocarbon products over In2O3/H-ZSM-5 and ZnO/H-ZSM-5. While, the thermomigration ability of chromium and zirconium species is not significant, endowing Cr2O3/H-ZSM-5 and ZrO2/H-ZSM-5 catalysts with high selectivity of C2+ hydrocarbons.
- Cheng, Kang,Wang, Genyuan,Wang, Ye,Wang, Yuhao,Zhang, Qinghong,de Jong, Krijn P.,van der Wal, Lars I.
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- Decomposition of Methanol to Syngas over AlPO4-Supported Nickel Catalyst
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An AlPO4-supported nickel catalyst exhibited significantly higher activity and selectivity for the title reaction than such conventional catalysts as Ni/Al2O3, Ni/SiO2, Ni/TiO2, and CuO-ZnO-Cr2O3.The effects of Ni loading and temperatures of reduction and reaction on its catalytic property were also investigated.
- Tada, Akio,Yoshino, Takumi,Itoh, Hidenobu
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- Synthesis, characterization and molecular structures of barium(II) trichloroacetate DME/1,4-dioxane compounds
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Two new barium(II) trichloroacetate compounds, [Ba(H2O)(DME) (μ-O2CCCl3)2]n (1) and [{Ba(H2O)2(diox)0.5(μ-O2CCCl 3)2}(diox)]n (2) were synthesized and characterized by elemental analyses, physiochemical studies, FT-IR, 1H NMR, thermogravimetric analyses (TG/DTG/DSC) and single crystal X-ray studies. The reaction of hydrated barium(II) trichloroacetate monohydrate with excess DME (1,2-dimethoxyethane) and diox (1,4-dioxane) in methanol at room temperature led to the isolation of the novel compounds 1 and 2, respectively. Bridging trichloroacetate groups are anticipated on the basis of FT-IR studies and this was confirmed by the X-ray studies. Both compounds dissociate to produce ions in water, as shown by molar conductance values. 1H NMR spectroscopy confirms that DME and 1,4-dioxane are coordinated to the metal ion in these compounds. Single crystal X-ray diffraction studies reveal that the barium cation is coordinated to nine O atoms in a deformed coordination polyhedron in both compounds. Structural data of barium(II) trichloroacetates compounds have been obtained for the first time in the present investigation.
- Singh, Sukhjinder,Saini, Deepika,Mehta,Kaur, Ravneet,Ferretti, Valeria
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- Initiator Control of Conjugated Polymer Topology in Ring-Opening Alkyne Metathesis Polymerization
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Molybdenum carbyne complexes [RCequiv;Mo(OC(CH3)(CF3)2)3] featuring a mesityl (R = Mes) or an ethyl (R = Et) substituent initiate the living ring-opening alkyne metathesis polymerization of the strained cyclic alkyne, 5,6,11,12-tetradehydrobenzo[a,e][8]annulene, to yield fully conjugated poly(o-phenylene ethynylene). The difference in the steric demand of the polymer end-group (Mes vs Et) transferred during the initiation step determines the topology of the resulting polymer chain. While [MesCequiv;Mo(OC(CH3)(CF3)2)3] exclusively yields linear poly(o-phenylene ethynylene), polymerization initiated by [EtCequiv;Mo(OC(CH3)(CF3)2)3] results in cyclic polymers ranging in size from n = 5 to 20 monomer units. Kinetic studies reveal that the propagating species emerging from [EtCequiv;Mo(OC(CH3)(CF3)2)3] undergoes a highly selective intramolecular backbiting into the butynyl end-group.
- Von Kugelgen, Stephen,Bellone, Donatela E.,Cloke, Ryan R.,Perkins, Wade S.,Fischer, Felix R.
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- The Ionic Hydrogen Bond. 2. Multiple NH+...O and CH?+...O Bonds. Complexes of Ammonium Ions with Polyethers and Crown Ethers
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Complexes of ammonium ions RNH3+ (R = CH3, c-C6H11), (CH3)3NH+, and pyridineH+ with polyethers and crown ethers are observed in the gas phase in the abscence of the solvent effects.The dissociation energies, ΔH0D, of the RNH3+ polyether complexes range from 29.4 kcal mol-1 (for RNH3+*CH3OCH2CH2OCH3) to 46 kcal mol-1 (RNH3+*18-crown-6).The large ΔH0D values for complexes of polydentate ligands indicate multiple -NH+...O-hydrogen bonding.Such mutiple bonding can contribute up to 18 kcal mol-1 to the bonding in RNH3+*CH3(OCH2CH2)3OCH3 and 21 kcal mol-1 in RNH3+*18-crown-6.Multiple interactions are also evident in the (CH3)3NH+*polyether complexes where -CH?+...O-hydrogen bonding seems to occur; and consecutive -CH?+...O-bonds contribute approximately 6, 4, and 2 kcal/mol-1 respectively for up to three such bonds.Total ΔH0D values in the (CH3)3NH+*polyether complexes thus range from 26.7 kcal mol-1 in (CH3)3NH+*CH3O(CH2)2OCH3 to 41 kcal mol-1 in (CH3)3NH+*18-crown-6.Multiple interaction effects, possibly including van der Waals dispersion forces, are observed also in pyridineH+*polyether complexes.Large negative entropies in RNH3+*acyclic polyether complexes vs.RNH3+*cyclic crown ethers make the acyclic polyethers less efficient ligands.
- Meot-Ner (Mautner), Michael
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- Ethanol and Higher Alcohols Synthesis from Syngas over CuCoM (M=Fe, Cr, Ga and Al) Nanoplates Derived From Hydrotalcite-Like Precursors
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A series of CuCoM (M=Fe, Cr, Ga and Al) nanoplates derived from hydrotalcite-like precursors were synthesized by co-precipitation method and evaluated for ethanol and higher alcohols (HA) from syngas. The CuCoAl nanoplates demonstrated prominently improved HA selectivity of 54.9 %, and the fraction of ethanol/HA reached up to 55.9 % level. As revealed by XRD and HAADF-STEM results, the presence of Al species in the CuCoAl nanoplates obviously enhanced the dispersion ability of Cu and Co species. Moreover, the abundance of basic sites (surface hydroxyl groups) on CuCoAl nanoplates resulted in the formation of formate species, which was a significant C1 species for the generation of CHx intermediates. More importantly, a high probability of CO bridge adsorption on metallic Co atoms was found over optimized CuCoAl catalyst, which provided a favorable effect for CO dissociation, leading to the formation of CHx intermediates. Therefore, more CHx intermediates were generated from the formate species and CO bridge adsorption on metallic Co atoms, which provided a beneficial role for C?C chain growth in the higher alcohols production in CO hydrogenation reaction. Furthermore, a moderate ratio of surface Cu/Co was observed over optimized CuCoAl nanoplates, which can exert a synergetic effect between Cu and Co species. Ultimately, the enhanced catalytic performance was attributed to the combination of the Cu and Co species and the basic property of the CuCoAl nanoplates.
- Sun, Kai,Wu, Yingquan,Tan, Minghui,Wang, Liyan,Yang, Guohui,Zhang, Min,Zhang, Wei,Tan, Yisheng
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- Alkali Metal Adducts of an Iron(0) Complex and Their Synergistic FLP-Type Activation of Aliphatic C-X Bonds
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We report the formation and full characterization of weak adducts between Li+ and Na+ cations and a neutral iron(0) complex, [Fe(CO)3(PMe3)2] (1), supported by weakly coordinating [BArF20] anions, [1·M][BArF20] (M = Li, Na). The adducts are found to synergistically activate aliphatic C-X bonds (X = F, Cl, Br, I, OMs, OTf), leading to the formation of iron(II) organyl compounds of the type [FeR(CO)3(PMe3)2][BArF20], of which several were isolated and fully characterized. Stoichiometric reactions with the resulting iron(II) organyl compounds show that this system can be utilized for homocoupling and cross-coupling reactions and the formation of new C-E bonds (E = C, H, O, N, S). Further, we utilize [1·M][BArF20] as a catalyst in a simple hydrodehalogenation reaction under mild conditions to showcase its potential use in catalytic reactions. Finally, the mechanism of activation is probed using DFT and kinetic experiments that reveal that the alkali metal and iron(0) center cooperate to cleave C-X via a mechanism closely related to intramolecular FLP activation.
- Tinnermann, Hendrik,Sung, Simon,Csókás, Dániel,Toh, Zhi Hao,Fraser, Craig,Young, Rowan D.
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supporting information
p. 10700 - 10708
(2021/07/31)
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- The promoting role of Ga in ZnZrOx solid solution catalyst for CO2 hydrogenation to methanol
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Catalytic conversion of CO2 into methanol utilizing green hydrogen produced from renewable energy is a promising route to realize carbon neutrality. Although ZnZrOx solid solution catalyst displays excellent catalytic performance, it is still highly desired to make any further improvement. Herein, we found the promoting effect of incorporating Ga into ZnZrOx solid solution catalyst in CO2 hydrogenation to methanol. Ga promoted ZnZrOx (GaZnZrOx) solid solution catalyst exhibits CO2 conversion of 8.8% and methanol space time yield of 630 mg gcat?1 h?1 that are higher than those of ZnZrOx solid solution catalyst (7.7%, 556 mg gcat?1 h?1) at 320 °C, while the highly selectivity toward methanol remains unchanged. Chemisorption and H2-D2 exchange results show that GaZnZrOx solid solution catalyst displays higher capacity for the adsorption and activation of H2 than ZnZrOx solid solution catalyst. Electron paramagnetic resonance result suggests that more oxygen vacancies are derived after incorporating Ga into ZnZrOx solid solution catalyst. In situ diffuse reflectance infrared Fourier transform spectra indicate that the HCOO* and CH3O* species are the main intermediate species. The higher IR intensity of intermediate species and lower CH3O*/HCOO* ratio on GaZnZrOx solid solution catalyst suggest that the hydrogenation of HCOO* to CH3O* is boosted. These results reveal the promoting effect of incorporated Ga into ZnZrOx solid solution catalyst that improves the adsorption and activation of H2 and CO2, thus enhancing catalytic performance of methanol synthesis from CO2 hydrogenation.
- Han, Zhe,Li, Can,Sha, Feng,Tang, Chizhou,Tang, Shan,Wang, Jijie,Wang, Qingnan
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p. 383 - 392
(2021/11/09)
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- PROCESSES FOR FORMING GLYCOLS
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This disclosure provides processes for forming glycols by upgrading hydrocarbons. In one embodiment, a process for forming a glycol includes introducing a first ether to a dihydrocarbyl peroxide to form a diether and a first alcohol. The process includes introducing the diether to water to form a glycol and a second alcohol. Processes of this disclosure may include one or more of: introducing a hydrocarbyl hydroperoxide to a third alcohol to form the dihydrocarbyl peroxide; oxidizing a first feed stream comprising a branched hydrocarbon to form the hydrocarbyl hydroperoxide and the first alcohol; and/or introducing the second alcohol to a catalyst to form a second ether.
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Paragraph 0096
(2020/05/28)
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- Simple and Strong Dative Attachment of α-Diimine Nickel (II) Catalysts on Supports for Ethylene Polymerization with Controlled Morphology
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Abstract: In this article, preparation of novel spherical MgCl2 supported α-diimine nickel (II) catalysts for ethylene polymerization in slurry phase is reported. α-Diimine ligands were synthesized by condensation reaction of 2, 6-disubstituted alkyls or aryls anilines and Ace naphthoquinone Which have hydroxyl functionality in their para-position. Hydroxyl functionalized α-diimine attached strongly on to the spherical MgCl2 support surface by dative bonding. No linker was needed to attach the complexes onto the support surface and the amount of loaded Nickel was controllable to improve morphology and especially bulk density of polymer powder. A significant reduction in catalysts activity has happened when homogeneous catalysts were supported onto silica but this reduction was decreased when they were supported onto thermally treated spherical MgCl2. As homogeneous bis(N,N′-(4-(3-hydroxyl-propyl)-2,6-di[(4-tert-butyl-phenyl)-phenyl) amino] Ace naphthoquinone Nickel dibromide(d) showed the highest activity among other evaluated homogeneous catalysts, its MgCl2 supported catalyst (d/S-MgCl2) has shown the highest activity among MgCl2 supported catalysts too. These MgCl2 supported catalysts were pre-polymerized in presence of ethylene monomer in the mild polymerization condition to yield a pre-polymerized catalyst with polymer/catalyst weight ratio equal to six. Ethylene polymerization was carried out to make spherical particles of polyethylene without reactor fouling by these pre-polymerized catalysts. Clearly, it is shown in SEM images that the spherical morphology of MgCl2 support is replicated in the produced polymer. The molecular weight and molecular weight distribution of produced polymer with MgCl2 supported catalysts were higher than those produced by homogeneous catalysts. Graphic Abstract: α–Diimine nickel (II) complexes have hydroxy functionality where produce strong dative bonding onto spherical MgCl2. This bonding is strong enough that these catalysts are suitable for slurry polymerization of ethylene without reactor fouling due to catalyst leaching from support. The chemical structure of MgCl2 leads to high active supported catalysts. The molecular weight and polydispersity index of produced polymrers using these supported catalysts are higher than those produced by equivalent homogeneous catalysts and are controllable by selection of appropriate ligand for used α–diimine nickel (II) complex or hydrogen concentration in ethylene polymerization.[Figure not available: see fulltext.].
- Kianfar, Ehsan,Azimikia, Reza,Faghih, Seyed Mohammad
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p. 2322 - 2330
(2020/02/25)
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- METHOD FOR DIRECTLY PREPARING GLYCOL DIMETHYL ETHER AND CO-PRODUCING ETHYLENE GLYCOL FROM ETHYLENE GLYCOL MONOMETHYL ETHER
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The present invention provides a method for directly preparing glycol dimethyl ether and co-producing ethylene glycol from ethylene glycol monomethyl ether. More specifically, the method comprises passing a feedstock containing a raw material of ethylene glycol monomethyl ether and a carrier gas through a reactor loaded with a solid acid catalyst to produce glycol dimethyl ether and ethylene glycol, at a reaction temperature range from 40° C. to 150° C. and a reaction pressure range from 0.1 MPa to 15.0 MPa; wherein a carrier gas is an optional inactive gas; and the feedstock contains water whose volume concentration in the feedstock is in a range from 0% to 95%; and the weight hourly space velocity of the raw material of ethylene glycol monomethyl ether is in a range from 0.05 h?1 to 5.0 h?1; and the volume concentration of the raw material of ethylene glycol monomethyl ether in the feedstock is in a range from 1% to 100%; and the volume concentration of the carrier gas in the feedstock is in a range from 0% to 99%. In the method of the present invention, using a solid acid as a catalyst and ethylene glycol monomethyl ether as a raw material, under a low temperature condition, glycol dimethyl ether and ethylene glycol are prepared directly with high selectivity; moreover, there is substantially or completely no production of by-product 1,4-dioxane that causes pollution to the environment and is harmful to the human body or animal bodies.
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Paragraph 0042-0043
(2018/10/19)
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- Ni-Catalyzed Regioselective Alkylarylation of Vinylarenes via C(sp3)-C(sp3)/C(sp3)-C(sp2) Bond Formation and Mechanistic Studies
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We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and arylzinc reagents to generate 1,1-diarylalkanes. The reaction proceeds well with primary, secondary and tertiary alkyl halides, and electronically diverse arylzinc reagents. Mechanistic investigations by radical probes, competition studies and quantitative kinetics reveal that the current reaction proceeds via a Ni(0)/Ni(I)/Ni(II) catalytic cycle by a rate-limiting direct halogen atom abstraction via single electron transfer to alkyl halides by a Ni(0)-catalyst.
- Kc, Shekhar,Dhungana, Roshan K.,Shrestha, Bijay,Thapa, Surendra,Khanal, Namrata,Basnet, Prakash,Lebrun, Robert W.,Giri, Ramesh
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supporting information
p. 9801 - 9805
(2018/08/06)
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- Influence of Boiling on the Radiolysis of Diglyme
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The radiolysis of diethylene glycol dimethyl ether (diglyme) in a boiling state has been studied for the first time. Boiling facilitates the cleavage of internal C–O bonds, weakens the cage effect and diglyme regeneration processes, and facilitates the exchange and dimerization reactions of radicals. As compared with radiolysis at room temperature, the amount of unsaturated products of diglyme fragmentation formed during irradiation in the boiling state is smaller by a factor of 4, and the disproportionation products of heavy radicals are found in negligible amounts, if any. The yield of radiolytic decomposition of diglyme under boiling conditions is ~15 molecule/100 eV, which is higher than that at room temperature by a factor of almost 1.5.
- Vlasov,Kholodkova,Ponomarev
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p. 312 - 318
(2018/08/01)
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- Selective synthesis of dimethoxyethane via directly catalytic etherification of crude ethylene glycol
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Etherification of ethylene glycol with methanol provides a sustainable route for the production of widely used dimethoxyethane; dimethoxyethane is a green solvent and reagent that is applied in batteries and used as a potential diesel fuel additive. SAPO-34 zeolite was found to be an efficient and highly selective catalyst for this etherification via a continuous flow experiment. It achieved up to 79.4% selectivity for dimethoxyethane with around 96.7% of conversion. The relationship of the catalyst's structure and the dimethoxyethane selectivity was established via control experiments. The results indicated that the pore structure of SAPO-34 effectively limited the formation of 1,4-dioxane from activated ethylene glycol, enhanced the reaction of the activated methanol with ethylene glycol in priority, and thus resulted in high selectivity for the desired products. The continuous flow technology used in the study could efficiently promote the complete etherification of EG with methanol to maintain high selectivity for dimethoxyethane.
- Yu, Weiqiang,Lu, Fang,Huang, Qianqian,Lu, Rui,Chen, Shuai,Xu, Jie
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supporting information
p. 3327 - 3333
(2017/07/28)
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- METHOD FOR PREPARING DOUBLE-SEALED-END GLYCOL ETHER
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Disclosed is a method for preparing a double end capped glycol ether, the method comprising: introducing into a reactor a raw material comprising a glycol monoether and a monohydric alcohol ether, and enabling the raw material to contact and react with an acidic molecular sieve catalyst to generate a double end capped glycol ether, a reaction temperature being 50-300° C., a reaction pressure being 0.1-15 MPa, a WHSV of the glycol monoether in the raw material being 0.01-15.0 h?1, and a mole ratio of the monohydric alcohol ether to the glycol monoether in the raw material being 1-100:1. The method of the present invention enables a long single-pass lifespan of the catalyst and repeated regeneration, has a high yield and selectivity of a target product, low energy consumption during separation of the product, a high economic value of a by-product, and is flexible in production scale and application.
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Paragraph 0042; 0044; 0046
(2017/12/27)
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- Oxidative dehydrogenation of dimethyl ether to 1,2-dimethoxyethane over oxide catalysts
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Catalysts based on silica-supported Ga2O3, In2O3, La2O3 possess higher activity in oxidative dehydrogenation of dimethyl ether to dimethoxyethane than co-precipitated CaO–SnO2, S
- Greish, Alexander A.,Glukhov, Lev M.,Kustov, Leonid M.
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- Semiconducting Material Comprising Aza-Substituted Phosphine Oxide Matrix and Metal Salt
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The present invention relates to a semiconducting material including at least one salt or complex of a metal cation and an aza-substituted phosphine oxide compound with improved electrical properties, and to a compound suitable for this organic semiconducting material and an electronic device utilizing the improved electrical properties of the semiconducting material.
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- Preparation method for double-terminated glycol ether
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The invention relates to a preparation method for double-terminated glycol ether. The preparation method comprises a step of introducing raw materials containing glycol monoether and monohydric ether alcohol into a reactor for contact and reaction with an acidic molecular sieve catalyst so as to produce double-terminated glycol ether, wherein reaction temperature is 50 to 300 DEG C, reaction pressure is 0.1 to 15 MPa, the mass space velocity of the glycol monoether in the raw materials is 0.01 to 15.0/h, and a mol ratio of monohydric ether alcohol to glycol monoether in the raw materials is 1-100: 1. The preparation method has the advantages that the catalyst has long single-pass life and can be repeatedly regenerated; the target product, i.e., double-terminated glycol ether has high yield and selectivity; energy consumption in separation of products is low; by-products have high economic value; production scale can be large or small; and application of the method is flexible.
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Paragraph 0048; 0049
(2017/07/25)
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- Method of purifing ethylene glycol dialkyl ether
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The present invention relates to a method to purify ethylene glycol dialkyl ether. According to the present invention, the method to purify ethylene glycol dialkyl ether comprises a step of: agitating diethylene glycol dialkyl ether and caustic soda, heating the same at high temperatures, injecting methylchloride and water in the same, agitating the mixture then waiting until layer separation is made and preparing the unpurified ethylene glycol dialkyl ether by removing base liquid in the lower layer; and filtering the unpurified ethylene glycol dialkyl ether into fine powder consisting of magnesium silicate compounds, making high purity ethylene glycol dialkyl ether.
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Paragraph 0026; 0028-0030
(2017/04/05)
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- Preparation method for double-terminated glycol ether
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The invention discloses a preparation method for double-terminated glycol ether. The preparation method comprises the following steps: a) introducing raw materials containing glycol monoether and monohydric ether alcohol into a reactor for contact and reaction with an acidic molecular sieve catalyst under the conditions that reaction temperature is 50 to 300 DEG C, reaction pressure is 0.1 to 15 MPa, the mass space velocity of the glycol monoether in the raw materials is 0.01 to 15.0/h, and a mol ratio of monohydric ether alcohol to glycol monoether in the raw materials is 1-100: 1, and separating obtained products so as to obtain a double-terminated glycol ether product, unreacted glycol monoether and monohydric ether alcohol, by-product components and other components; and b) returning the unreacted glycol monoether and monohydric ether alcohol and the by-product components obtained in the step a) to the reactor. The preparation method has the advantages that the catalyst has long single-pass life; the target product, i.e., double-terminated glycol ether has high yield and selectivity; energy consumption in separation of the products is low; by-products have high economic value; production scale can be large or small; and application of the method is flexible.
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Paragraph 0066; 0067; 0097
(2017/04/03)
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- Immobilization of Carbonylcobalt Catalyst by Poly(4-vinylpyridine) (P4VP) through N→Co Coordination Bonds: The Promotional Effect of Pyridine and the Reusability of Polymer Catalyst
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A carbonylcobalt catalyst, immobilized by poly(4-vinylpyridine) (P4VP) through N→Co coordination bonds, has been prepared by solvothermal method. It has been revealed that the pyridine fragments in the polymer catalyst act not only as promoters to improve the catalytic performance of the carbonylcobalt catalyst for alkoxycarbonylation of ethylene oxide to methyl 3-hydroxypropanoate but also as stabilizers to enhance the reusability of the polymer catalyst. Furthermore, the polymer catalyst could be easily separated by filtration and reused with only a slight loss of catalytic efficiency.
- Liu, Yu-Bing,Wang, Yi-Ning,Lu, Hai-Meng,Liang, Shuang,Xu, Bo-Lian,Fan, Yi-Ning
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supporting information
p. 3159 - 3164
(2016/11/29)
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- A method of manufacturing an alkylene glycol ether (poly)
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PROBLEM TO BE SOLVED: To provide a method for producing a (poly)alkylene glycol diether, introducing the oxyalkylene groups of the optional mole number of addition and optional terminal alkyl groups by using a metallosilicate catalyst having 10 to 1,000 ratio of SiO2/M2O3as an ether interchange reaction catalyst. SOLUTION: This method for producing the (poly)alkylene glycol diether includes a process of obtaining the (poly)alkylene glycol diether by the ether interchange reaction of a first (poly)alkylene glycol monoether with a second (poly)alkylene glycol monoether in the presence of the metallosilicate catalyst having 10 to 1,000 ratio of SiO2/M2O3(wherein, M is ≥1 kind selected from the group consisting of Al, Ga, Ge, B, Zn, P, Zr, Ti, Cr, Be, V and As). COPYRIGHT: (C)2012,JPOandINPIT
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Paragraph 0048; 0049
(2016/10/17)
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- Activation reactions of 1,1-dialkoxoalkanes and unsaturated O-donors by titanium tetrafluoride
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The reactivity of TiF4 with a variety of non cyclic 1,1-dialkoxoalkanes [CH2(OR)2, R = Me, Et, Me 2C(OMe)2, MeCH(OEt)2, ClCH2CH(OEt) 2, CH(OMe)3, PhCCCH(OEt)2], 1,3-dioxolane, N2CHCO2Et and 1,2-epoxybutane has been investigated. Activation, including fragmentation and/or rearrangement of the organic moiety, has been observed at room temperature in some cases; it generally occurs unselectively via C-O bond fission and the formation of new C-O, C-H and C-C bonds. Small differences in the structure of the organic substrate may determine significant differences in the reactivity with TiF4.
- Marchetti, Fabio,Pampaloni, Guido,Biancalana, Lorenzo
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experimental part
p. 135 - 139
(2012/05/20)
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- Further insights into the chemistry of niobium and tantalum pentahalides with 1,2-dialkoxyalkanes: Synthesis of bromo- and iodoalkoxides, spectroscopic and computational studies
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The room temperature reactions of a series of 1,2-dialkoxyalkanes ROCH 2CH(R′)OR′′ with MX5 (M = Nb, Ta; X = Br, I) in 1:1 ratio result in single C-O bond cleavage and high-yield formation of the halo-alkoxides MBr4[κ2-OCH 2CH(R′)OR′′] or [NbI4{κ 1-OCH2CH(R′)OR′′}]2, and equimolar amounts of the corresponding alkyl halides RX. The reaction of NbBr5 with 1,2-dimethoxyethane, dme, proceeds with preliminary formation of the ionic species [NbBr4(κ2-dme) (κ1-dme)][NbBr6], 3b, which has been identified by solution NMR at low temperature and conductivity analyses. The gas-phase structure of 3b has been optimized by DFT calculations, confirming that the dme ligands adopt bidentate and monodentate coordination, respectively. Although the formation of NbOBr3(dme), 4b, 1,4-dioxane and MeBr from NbBr 5/dme (ratio 1:2) is an exoergonic process (calculated ΔGr° = -115.96 kcal mol-1), it is inhibited at room temperature. High temperature conditions enhance the production of 1,4-dioxane at the expense of selectivity. The dinuclear species NbOBr3(dme)NbBr5 (Nb-O-Nb), 5b, (X-ray) has been isolated in modest yield as byproduct of the room temperature reaction of NbBr5 with dme. In general, the 1:2 molar reactions of NbX5 (X = Br, I) with ROCH2CH(R′) OR′′ occur with the exclusion of nearly one equivalent of organic reactant.
- Bini, Riccardo,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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experimental part
p. 1412 - 1419
(2011/06/22)
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- Catalytic performance of [Bmim][Co(CO)4] functional ionic liquids for preparation of 1,3-propanediol by coupling of hydroesterification- hydrogenation from ethylene oxide
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In this paper, synthesis of 1,3-propanediol (1,3-PDO) through coupling of hydroesterification-hydrogenation from ethylene oxide (EO) catalyzed by 1-butyl-3-methylimidazolium cobalt tetracarbonyl [Bmim][Co(CO)4] functional ionic liquid which was prepared by metathesis reaction between [Bmim]Cl and KCo(CO)4 has been studied. The structure of [Bmim][Co(CO)4] was characterized by FT-IR and 1H NMR. Using [Bmim][Co(CO)4] as catalyst and [Bmim]PF6 as solvent, 1,3-PDO was prepared for the first time by coupling of hydroesterifaction of EO and hydrogenation of methyl 3-hydroxypropionate (3-HPM). The yield of 3-HPM can reach 90.8%, while the yield of 1,3-PDO up to 82.9%. The catalyst can be separated from the product mixture by extraction with deionized water and recycled several times without significant loss of catalytic efficiency. A possible reaction mechanism has also been proposed.
- Guo, Zhenmei,Wang, Hengsheng,Lv, Zhiguo,Wang, Zhihui,Nie, Tao,Zhang, Weiwei
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experimental part
p. 3668 - 3672
(2011/12/02)
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- The pentamethylcyclopentadienylsilicon(II) cation as a catalyst for the specific degradation of oligo(ethyleneglycol) diethers
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Catalytic open sandwiches: Oligo(ethyleneglycol) diethers RO(CH 2CH2O)nR are degraded by the unusual catalyst Cp Si+ (see scheme). The open coordination sphere at silicon allows up to four Si-O contacts; crystal structure data of the reactive compounds [Cp Si(dme)]+BR4- and [Cp Si([12]crown-4)] +BR4- (R=C6F5) show weakly bound ether molecules. Copyright
- Leszczynska, Kinga,Mix, Andreas,Berger, Raphael J. F.,Rummel, Britta,Neumann, Beate,Stammler, Hans-Georg,Jutzi, Peter
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supporting information; experimental part
p. 6843 - 6846
(2011/09/19)
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- Ferric perchlorate as an efficient and useful catalyst for the selective benzylation and methylation of alcohols with benzyl chloride and methyl iodide
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A mild and efficient method was developed for selective benzylation and methylation of hydroxyl compounds in the presence of a catalytic amount of ferric perchlorate. We showed that ferric perchlorate was very effective in selectively promoting the benzylation and methylation of primary aliphatic and benzylic alcohols versus secondary aliphatic alcohols and phenolic hydroxy groups. Graphical abstract: [Figure not available: see fulltext.]
- Behbahani, Farahnaz K.,Heravi, Majid M.,Oskooie, Hossien A.
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experimental part
p. 181 - 184
(2010/03/26)
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- PROCESS FOR PREPARING AN 1,2-ALKYLENE CARBONATE
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The invention relates to a process for producing an 1,2-alkylene carbonate comprising (i) transporting liquid carbon dioxide to an 1,2-alkylene carbonate production plant; (ii) feeding the liquid carbon dioxide to an evaporation vessel; (iii) evaporating the liquid carbon dioxide such that a partial pressure of gaseous carbon dioxide of at least 5 x 105 N/m2 is generated; (iv) feeding the gaseous carbon dioxide to a reactor; and (v) contacting the gaseous carbon dioxide with an 1,2- alkylene oxide and a carbonation catalyst to produce 1,2- alkylene carbonate.
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Page/Page column 12
(2009/12/27)
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- Effects of zeolite structure and composition on the synthesis of dimethyl carbonate by oxidative carbonylation of methanol on Cu-exchanged Y, ZSM-5, and Mordenite
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The aim of this work was to establish the effects of zeolite structure/chemical composition on the activity and selectivity of Cu-exchanged Y (Si/Al = 2.5), ZSM-5 (Si/Al = 12), and Mordenite (Si/Al = 10) for the oxidative carbonylation of methanol to DMC. Catalysts were prepared by solid-state ion-exchange of the H-form of each zeolite with CuCl and were then characterized by FTIR and X-ray absorption spectroscopy (XAS). The XANES portion of the XAS data showed that all of the copper was present as Cu+ cations, and analysis of the EXAFS portion of the data shows the Cu+ cations had a Cu{single bond}O coordination number of ~2.1 on Cu-Y and ~2.7 on Cu-ZSM-5 and Cu-MOR. Dimethyl carbonate (DMC) was observed as the primary product when a mixture of CH3OH/CO/O2 was passed over Cu-Y, whereas dimethoxy methane was the primary product over Cu-ZSM-5 and Cu-MOR. The higher activity and selectivity of Cu-Y for the oxidative carbonylation of methanol can be attributed to the weaker adsorption of CO on the Cu+ cations exchanged into Y zeolite. In situ IR observations revealed that under reaction conditions, adsorbed CO was displaced by methoxide groups bound to the Cu+ cations. The kinetics of DMC synthesis suggests that the rate-limiting step in the formation of this product was the insertion of CO into Cu{single bond}OCH3 bonds. The yield of DMC decreased with methanol conversion, likely due to the hydrolysis of DMC to methanol and carbon dioxide.
- Zhang, Yihua,Briggs, Daniel N.,de Smit, Emiel,Bell, Alexis T.
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p. 443 - 452
(2008/09/18)
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- Process for producing olefin product from syngas
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This invention is directed to a process for making an olefin product from a mixed alcohol feed stream. The alcohol product that is formed using this invention contains significant quantities of methanol and ethanol, and is relatively in higher alcohols (i.e., C3+ alcohols) and in branched alcohols. One of the catalysts used to form the mixed alcohol is an oxide-containing catalyst that has been modified to contain a Fischer-Tropsch metal (i.e., cobalt, iron, and nickel).
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Page/Page column 10-11
(2008/06/13)
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- SUPRAMOLECULAR COMPLEX OF PYRIDYLNAPHTHALENEDIIMIDE WITH ZINC PORPHYRIN DENDRIMER HAVING MULTIPLICITY OF ARTIFICIAL PHOTOSYNTHETIC REACTION CENTER
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A light energy conversion system having a multiplicity of artificial photosynthetic reaction centers and exhibiting a high light-harvesting capability and charge separation capability, constructed by the use of a zinc porphyrin dendrimer supramolecular complex formed by the use of a coordinate bond. Using a zinc porphyrin dendrimer as a spherical zinc porphyrin oligomer, a supramolecule with pyridylnaphthalenediimide was constructed. With respect to the zinc porphyrin dendrimer/pyridylnaphthalenediimide supramolecule, when photoexcitation of the zinc porphyrin was realized, a charge-separated state was generated by photoinduced electron transfer and the lifetime thereof was strikingly long, up to 830 microseconds.
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- METHOD FOR PRODUCING ALKYLENE GLYCOL DIETHERS
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The invention concerns a method for producing alkylene glycol diethers by reacting a linear or cyclic ether with an alkylene oxide in the presence of a Lewis acid. The invention is characterized in that the reaction is continuously carried out in a microreactor.
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Page/Page column 7-9
(2008/06/13)
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- SELECTIVE DECOMPOSITION OF ETHERS
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A process for selectively converting a dialkyl ether to the corresponding alkene and alkanol comprises contacting a feed containing at least one dialkyl ether with a catalyst comprising a mixed metal oxide which comprises at least one metal selected from Group 4 of the Periodic Table of Elements and at least one metal selected from Group 3 (including the Lanthanides and Actinides) and Group 6 of the Periodic Table of Elements.
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Page/Page column 16-17
(2008/06/13)
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- METHOD OF PRODUCING GLYCOL ETHERS
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The present invention provides a method of producing glycol ethers, which are also commonly known as glymes. The method according to the invention includes contacting a glycol with a monohydric alcohol in the presence of a polyperfluorosulfonic acid resin catalyst under conditions effective to produce the glyme. The method of the invention can be used to produce, for example, monoglyme, ethyl glyme, diglyme, ethyl diglyme, triglyme, butyl diglyme, tetraglyme, and their respective corresponding monoalkyl ethers. The present invention also provides a method of producing 1,4-dioxane from mono- or diethylene glycol and tetrahydrofuran from 1,4-butanediol.
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- Conversion of dimethyl ether to diesel fuel additives via dielectric barrier discharges
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A high-efficient conversion of dimethyl ether (DME) to diesel fuel additives at ambient condition via dielectric-barrier discharges has been performed. The conversion of DME reaches a high value of 66.56% at a gas flow rate of 30 mL·min-1. The liquid obtained is a cetane number promoter of diesel fuels. The selectivity of liquid product is more than 40%.
- Jiang, Tao,Liu, Chang-Jun,Fan, Guo-Liang
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p. 322 - 323
(2007/10/03)
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- Thermolysis of substituted tert-butyl-(2-phenyl-prop-2-yl) peroxides
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tert-Butyl-(2-phenyl-1-methoxy-prop-2-yl)-peroxide (1a), tert-butyl-(2-phenyl-1-acetoxy-prop-2-yl)-peroxide (1b) and tert-butyl-(1,2-diphenyl-prop-2-yl)-peroxide (1c) were prepared from t-BuOOH and 1-methoxy-2-phenyl-prop-2-ol (a), 2-phenyl-2-methyl-oxirane (b) and, respectively, 1,2-diphenyl-propan-2-ol (c). The peroxides 1a-c were characterized by NMR spectroscopy and elemental analysis. Kinetic data were determined and the products analyzed from thermolysis of 1a-c at 110-155°C in cumene as the solvent. The major thermolysis product from 1a-c was acetophenone, formed via fragmentation of intermediate alkoxy radicals: R-CH2-C(Ph)(Me)O (R: MeO (a); AcO (b); Ph (c)). Wiley-VCH Verlag GmbH, 1999.
- Suprun
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p. 363 - 368
(2007/10/03)
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- Free radical chemistry associated with H(RSiH) nH
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Polysilanes of the type H(RSiH)nH, where R = n-hexyl or phenyl, have been used as radical-based reducing agents for organic halides. They rival the effectiveness of the other group 14 hydrides in reduction processes. The repetitive hydrogen transfer from the same molecule of H(RSiH)nH allows these compounds to be used in small quantities. Lower (5 × 104 M-1 s-1) and higher (6 × 105 M-1 s-1) limit values for the rate constant of the reaction of primary alkyl radicals with each SiH moiety of H(PhSiH)nH have been obtained by using unimolecular radical reactions as timing devices. The photochemical behavior of these polysilanes in the presence or absence of di-tert-butyl peroxide have been studied by EPR spectroscopy, and the -SiHR-SiR-SiHR radical (R = n-hexyl) has been identified as a transient species. Silyl radicals, obtained from H(RSiH)nH and thermally generated tert-butoxyl radicals, add to a variety of substrates containing double bonds to give the corresponding adducts for which EPR spectra have been recorded.
- Chatgilialoglu,Ferreri,Vecchi,Lucarini,Pedulli
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p. 475 - 481
(2007/10/03)
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- Kinetic studies of the oxidation of dimethyl ether and its chain reaction with Cl2
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The reaction between dimethyl ether radicals and molecular oxygen proceeds along two distinct pathways at temperatures between 230 and 350 K. Above about 100 Torr total pressure the peroxy radical, CH3OCH2O2, is predominantly formed. As the pressure is reduced, a channel leading to the formation of OH and two formaldehyde molecules becomes progressively more important. Real time kinetic measurements of these reactions are made using time-resolved UV spectroscopy to monitor CH3OCH2 loss and CH3OCH2O2 formation along with transient IR absorption to probe formaldehyde production. The OH radicals are identified via their UV spectrum. The reaction can be described via a modified Lindemann mechanism using the three parameters kro2,∞, kro2,0, and kprod,0, which represent the high- and low-pressure limits of the O2 addition reaction and the low-pressure limit of the OH/formaldehyde channel. At 295 K they have values of (1.1 ± 0.1) × 10-11 cm3 s-1, (2.6 ± 0.9) × 10-29 cm6 s-1, and (6 ± 2) × 10-12 cm3 s-1, respectively. At Ptot = ~120 Torr the reaction exhibits a negative temperature dependence with kr+o2 = (3.1+1.0-0.8) × 10-12 e(326±80)/T cm3 s-1. Experiments in the absence of oxygen were performed to investigate the CH3OCH2-mediated chain reaction between chlorine and dimethyl ether. Analysis of time-resolved UV spectra reveals rate constants of kr+c12 = (1.8+0.7-0.5) × 10-11 e(360±120)/T cm3 s-1 and kr+r = (1.8+0.6-0.5) × 10-11 e(200±100)/T cm3 s-1, respectively, for the chain propagation reaction between CH3OCH2 and molecular chlorine and for the chain-terminating recombination reaction.
- Maricq, M. Matti,Szente, Joseph J.,Hybl, John D.
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p. 5155 - 5167
(2007/10/03)
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- Lithium diisopropylamide solvated by monodentate and bidentate ligands: Solution structures and ligand binding constants
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6Li and 15N NMR spectroscopic studies of lithium diisopropylamide ([6Li]LDA and [6Li,15N]LDA) in toluene/pentane solutions containing a variety of mono- and polydentate ligands are reported. LDA forms exclusively dimers in the presence of n-BuOMe, Et2O, t-BuOMe, THF, 2- methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, dimethoxyethane, N,N,N',N'-tetramethylethylenediamine, and MeOCH2CH2NR2 (NR2 = NMe2, NEt2, pyrrolidino). Addition of 1,2-dipyrrolidinoethane and (2-pyrrolidinoethyl)dimethylamine provides monomer-dimer mixtures. Treatment of LDA with trans-N,N,N',N'-tetramethylcyclohexanediamine (TMCDA) or trans- 1-(dimethyl-amino)-2-isopropoxycyclohexane in hydrocarbons afford exclusively monomers. Sparteine binds only reluctantly, giving a mixture of unsolvated oligomers and monomer. Competitions of the ethereal ligands vs TMCDA afford binding constants and associated free energies for dimer solvation which are correlated with those obtained previously for lithium hexamethyldisilazide.
- Remenar, Julius F.,Lucht, Brett L.,Collum, David B.
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p. 5567 - 5572
(2007/10/03)
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- ALKYLATING PROPERTIES OF ACID ORGANIC PHOSPHATES
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Under the action of phenols and alcohols, acid alkyl phosphates undergo transesterification, which is accompanied by dealkylation of the latter and alkylation of the alcohols (phenols) at the hydroxy groups and aromatic rings.Isopropyl phosphates are stronger alkylating agents than methyl phosphates.Diphenyl methyl and phenyl dimethyl phosphates yield products of methylation of their own aromatic rings only upon prolonged pyrolysis.In all cases organic polyphosphates are formed.
- Munik, S. N.,Eliseenkov, V. N.,Ivanov, B. E.
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p. 378 - 382
(2007/10/03)
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- Sorbitol derivatives
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A dibenzylidenesorbitol derivative having at least one nuclear substituent selected from an ester group represented by --COOR1 and an amido group represented by --CONR2 R3, wherein R1 represents a hydrocarbon group having 1 to 20 carbon atoms, and R2 and R3 are identical or different and each independently represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group.
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