105-58-8Relevant articles and documents
Fabrication of solid strong bases with a molecular-level dispersion of lithium sites and high basic catalytic activity
Sun, Lin-Bing,Shen, Jie,Lu, Feng,Liu, Xiao-Dan,Zhu, Li,Liu, Xiao-Qin
, p. 11299 - 11302 (2014)
New solid strong bases were fabricated at room temperature by grafting lithium-containing molecular precursors onto β-cyclodextrin. The solid bases show strong basicity with a molecular-level dispersion of lithium sites, which are highly active in transesterification reactions and impossible to realize through the traditional high-temperature method. the Partner Organisations 2014.
Ambident ethyl N-nitrosocarbamate anion: Experimental and computational studies of alkylation and thermal stability
Benin, Vladimir,Kaszynski, Piotr,Radziszewski, J. George
, p. 14115 - 14126 (2002)
Alkylation of N-nitrosourethane tetrabutylammonium salt (2-Bu4N) with four electrophiles (Mel, Etl, i-Prl, and PhCH2Br) was studied by 1H NMR in CD2Cl2 and CD3CN solutions. The ratio of the three regioisomers N-alkyl-N-nitrosourethane 3, azoxy 4, and O-alkyldiazotate 5 was practically independent of solvent but dependent on the nature of the electrophile. The anion 2 and O-alkyl derivative 5 are thermally unstable and decompose to ethyl carbonates 9 and 10, respectively, with a first-order rate constant (2-Bu4N: k = 18.5 ± 0.1 × 10-5 S-1; 5b (R = Et): k = 1.77 ± 0.02 × 10-5 s-1; 5d (R = PhCH2): k = 4.78 ± 0.08 × 10-5 s-1 at 35 °C in CD2Cl2). Further kinetic measurements gave activation parameters for the decomposition of 2 (Ea = 24.2 ± 0.3 kcal/mol and In A = 30.9 ± 0.1). Gas-phase calculations at the MP2(fc)/6-31+G(d)//MP2(fc)/6-31G(d) level showed that the alkylation of 2 involves the lone electron pairs of the N-N-O atoms, and the calculated activation energies correspond well to the observed ratio of regioisomers 3-5. The theoretical analysis of the decomposition processes supports a concerted mechanism with a four-center transition state in the first step for all four compounds. The calculated activation energy order (2 5 3 4) is consistent with the observed order of stability. Decomposition of 2 and 5 is a unimolecular process, giving carbonates 9 and 10 in a single step. In contrast, rearrangement of 3 and 4 leads to alkyl diazonium ions. A detailed theoretical analysis indicates that the rate-determining step for thermal decomposition of 2 is the loss of molecular nitrogen, while in 5 it is the trans-cis isomerization process. The nonconcerted process involving homolytic cleavage of the O-N bond in 5 was found to be significantly less favorable.
Eisenhauer et al.
, p. 245,248 (1952)
Mesostructured graphitic carbon nitride as a new base catalyst for the efficient synthesis of dimethyl carbonate by transesterification
Xu, Jie,Long, Kai-Zhou,Chen, Ting,Xue, Bing,Li, Yong-Xin,Cao, Yong
, p. 3192 - 3199 (2013)
Mesostructured graphitic carbon nitride (CN-MCF) material has been prepared using carbon tetrachloride and ethylenediamine as precursors and mesocellular silica foam as a hard template, and characterized by XRD, N2 adsorption-desorption, TEM, FT-IR, and XPS techniques. The material was employed as a catalyst for the production of dimethyl carbonate (DMC) via transesterification of ethylene carbonate (EC) with methanol (MeOH). The influences of reaction conditions, including time, temperature, and the molar ratios of MeOH to EC, on the catalytic performance have been investigated in detail. Catalytic results revealed that CN-MCF could catalyze the transesterification reaction with high efficiency, affording a high DMC yield of 78% and stable catalytic activity for several running cycles. Furthermore, a possible reaction mechanism for the g-CN-catalyzing transesterification of EC with MeOH has been proposed. The Royal Society of Chemistry.
Construction of Polycyclic β-Ketoesters Using a Homoconjugate Addition/Decarboxylative Dieckmann Annulation Strategy
Chen, Zhiwei,Hong, Allen Y.,Linghu, Xin
, p. 6225 - 6234 (2018)
The construction of arene-fused cyclic β-ketoesters from 2-iodoaryl esters and 1,1-cyclopropane diesters is detailed. The synthetic method takes advantage of a CuI·SMe2-mediated homoconjugate addition followed by a decarboxylative Dieckmann cyclization to afford valuable polycyclic building blocks. Various iodoaryl esters and 1,1-cyclopropane diesters were evaluated, and the limitations of both reactions are discussed. Several mechanistic probes are detailed and synthetic applications are described.
Tsuyuki, T.,Simamura, O.
, p. 1079 - 1080 (1958)
Direct condensation reaction of carbon dioxide with alcohols using trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent
Kadokawa, Jun-Ichi,Habu, Hideyuki
, p. 2205 - 2208 (1999)
This paper describes the preparation of carbonates by the direct condensation of CO2 with alcohols using a trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent. The yield of dibenzyl carbonate from CO2 and benzyl alcohol was at most 90.7%. The reaction of CO2 with the other primary alcohols such as methanol, ethanol, butan-1-ol, hexan-1-ol, allyl alcohol, and ethylene glycol also gave corresponding carbonates in relatively high yields, whereas yields of carbonates from CO2 and secondary alcohols were low. Copyright 1999 by the Royal Society of Chemistry.
A FACILE PREPARATION OF DIALKYL CARBONATES FROM POTASSIUM CARBONATE AND ALKYL BROMIDES BY USING ORGANOSTANNYL COMPOUND AS A CATALYST
Fujinami, Tatsuo,Sato, Shinichi,Sakai, Shizuyoshi
, p. 749 - 752 (1981)
Dialkyl carbonates were easily prepared by the heterogeneous reaction of solid potassium carbonate with alkyl bromides in dimethylformamide or dimethylsulfoxide in the presence of organostannyl compound such as hexabutyldistannoxane or chlorotributylstannane.Mixed catalytic system consisting of a tributylstannyl compound and 18-Crown-6 was much effective even in less polar solvents.
Readily-fabricated supported MgO catalysts for efficient and green synthesis of diethyl carbonate from ethyl carbamate and ethanol
Li, Fengjiao,Wang, Liguo,Xu, Shuang,Liang, Shuting,Zhang, Ningning
, p. 15477 - 15485 (2021)
Developing cost-effective, high-efficiency and heterogeneous catalysts is of prime importance for the green synthesis of diethyl carbonate (DEC) from ethyl carbamate (EC) and ethanol. Herein, a series of MgO/γ-Al2O3 catalysts were readily fabricated by an impregnation method for DEC synthesis from EC and ethanol. The activities of the as-prepared MgO/γ-Al2O3 catalysts as well as the individual MgO or γ-Al2O3 were first tested in the batch reactor. Among the investigated samples, the MgO/γ-Al2O3 with a MgO loading of 10 wt% (denoted as 10% MgO/γ-Al2O3) exhibited the largest amount of stronger basic sites, and the highest activities with EC conversion of 41.8% and DEC yield of 30.4%, respectively. Furthermore, the DEC yield was greatly boosted to 52.1% with a high DEC selectivity of 93.8% over the 10% MgO/γ-Al2O3 catalyst under the optimized reaction conditions in the fixed bed reactor, outperforming most of the reported catalysts.
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Nefedov et al.
, (1972)
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Synthesis of diethyl carbonate from ethyl carbamate and ethanol over ZnO-PbO catalyst
An, Hualiang,Zhao, Xinqiang,Guo, Lian,Jia, Chunyao,Yuan, Baoguo,Wang, Yanji
, p. 229 - 235 (2012)
The synthesis of diethyl carbonate (DEC) from ethyl carbamate and ethanol was investigated over a series of double metal oxides. Among the catalysts, ZnO-PbO showed the best catalytic activity and the highest DEC yield was 20.6%. Furthermore, ZnO-PbO had an excellent reusability. According to the results of XRD measurement, IR and element analysis, ZnO and PbO in ZnO-PbO catalyst were separately converted to Zn(NCO)2(NH3)2 and metal Pb during the reaction, indicating that the mixture of Zn(NCO) 2(NH3)2 and metal Pb may be the real active composition for DEC synthesis and ZnO-PbO is the precursor. In addition, a possible reaction mechanism for DEC synthesis was proposed.
Production of diethyl carbonate from ethylene carbonate and ethanol over supported fluoro-perovskite catalysts
Iida, Hajime,Kawaguchi, Ryuhei,Okumura, Kazu
, p. 7 - 11 (2018)
The KCaF3/C (K-Ca(A)) catalyst was shown to be effective as heterogeneous basic catalysts for the transesterification of ethylene carbonate (EC) and ethanol among fluoro-perovskite (XYF3)/C (X = K, Cs, Y = Mg, Ca) catalysts. Although the KMgF3/C (K-Mg (A)) catalyst exhibited the highest catalytic activity among the XYF3/C catalysts studied, the potassium leaching was observed on K-Mg (A). CO2 temperature programmed desorption (TPD) revealed that the superior catalytic activity of the XYF3/C was due to its strong basic sites. CO2-TPD and XPS measurements indicated that strong basic sites are generated by an increase in the electron density of fluorine.
Catalytic decomposition of dialkyl pyrocarbonates to dialkyl carbonates and carbon dioxide in dichloromethane by a discrete cobalt(II) alkoxide species generated in situ
Greener, Bryan,Walton, Paul H.
, p. 3733 - 3740 (1997)
Dimethyl pyrocarbonate (dmpc) [dimethyl μ-oxo-bis(dioxocarbonate)] and diethyl pyrocarbonate (depc) were catalytically decomposed to dimethyl and diethyl carbonate respectively and carbon dioxide in the presence of [CoL(OR)]+ [L = cis,cis-1,3,5-tris(E,E-cinnamylideneamino)cyclohexane, R = methyl or ethyl] which we propose to be generated in situ during reaction in dichloromethane. The activity of the catalyst is undiminished after 60 000 turnovers. In both cases the catalytic rate enhancement for the decomposition is in excess of 107 dm3 mol-1 of catalyst. The catalytic process follows Michaelis-Menten type kinetics and kobs is 2.2(2) s-1 for dmpc decomposition and 1.3(2) s-1 for depc decomposition. Activation energies for the catalytic decomposition are Edmpc = 113(5) and Edepc = 120(11) kJ mol-1. A mechanism involving cobalt-bound alkoxide attack on dialkyl pyrocarbonate is proposed. The crystal structure of [CoL(Cl)] BPh4 has been determined by single-crystal X-ray diffraction.
Fast and facile preparation of metal-doped g-C3N4 composites for catalytic synthesis of dimethyl carbonate
Xu, Jie,Long, Kai-Zhou,Wang, Yue,Xue, Bing,Li, Yong-Xin
, p. 1 - 8 (2015)
Zn-doped g-C3N4 materials (Zn-g-C3N4) were prepared by a simple mixing and calcination, using dicyandiamide as a precursor and zinc halide as a dopant. The characterization results of CO2 temperature-programmed desorption and elemental analysis revealed that the introduction of Zn species enhanced the overall basic quantity of g-C3N4. In the transesterification of ethylene carbonate with CH3OH to dimethyl carbonate (DMC), the Zn-g-C3N4 catalysts showed superior catalytic activity to the pure g-C3N4, and the highest DMC yield reached 83.3%, along with stable catalytic reusability and reproducibility. Furthermore, other transition-metal halides (including FeCl3, CuCl2, NiCl2, etc.) could be utilized as dopants for g-C3N4, and the obtained doped g-C3N4 materials also showed high EC conversions above 70%. The upgradation of basic quantity of g-C3N4 was attributed to the reaction between metal halide and the active amine species of g-C3N4. Despite their low surface areas, under the same catalytic conditions, Zn-g-C3N4 catalysts demonstrated remarkably higher catalytic activity than other mesoporous carbon nitride materials.
Gold nanoparticles promote the catalytic activity of ceria for the transalkylation of propylene carbonate to dimethyl carbonate
Juarez, Raquel,Corma, Avelino,Garcia, Hermenegildo
, p. 949 - 952 (2009)
A series of metal oxide nanoparticles with acid or basic properties exhibit low to moderate activity towards the transalkylation of propylene carbonate with methanol; deposition of gold nanoparticles on nanoparticulated ceria significantly increases the activity of this metal oxide towards transalkylation.
Effect of hydrophobic modification on the catalytic performance of PdCl2/Cu-HMS with different silylation temperatures
Zhang, Pingbo,Zhou, Yan,Fan, Mingming,Jiang, Pingping,Huang, Xianglan,Lou, Jiang
, p. 320 - 324 (2014)
A new class of organic-inorganic hybrid materials were prepared by combining Cu-HMS with a silylation agent, trimethylchlorosilane (TMCS) via a simple silylation process at different silylation temperatures. They were characterized by a series of techniques including FT-IR, powder XRD, Nitrogen adsorption-desorption, TG analysis and water adsorption capacity test. It was demonstrated that silylation of PdCl2/Cu-HMS catalysts with TMCS enhanced their hydrophobicity, improved their activity and stability and importantly kept the excellent selectivity to diethyl carbonate (DEC) by oxidative carbonylation of ethanol in the gas-phase reaction. Moreover, the silylated samples obtained at 60 °C showed a better conversion of EtOH of 6.1 % and STY of DEC of 140.8 mg g-1 h-1. Springer Science+Business Media New York 2013.
Synthesis of nitrogen-containing ordered mesoporous carbon materials with tunable nitrogen distributions and their application for metal-free catalytic synthesis of dimethyl carbonates
Gan, Yu-Lin,Wen, Lin-Zhi,Xu, Jie,Xue, Bing
, (2020)
Dicyandiamide (DCDA) was utilized as a facile nitrogen source for the fabrication of nitrogen-containing ordered mesoporous carbon (NOMC) samples via a one-pot soft-templating approach under aqueous phase. X-ray diffraction, N2 adsorption–desorption, Transmission electron microscopy, Scanning electron microscopy, Raman and X-ray photoelectron spectroscopy have been applied to analyze the physicochemical properties of the synthesized NOMC materials. The characterization results showed that the textural parameters (545–589 m2 g?1), graphitic crystallinity and distribution of various nitrogen species of the synthesized NOMC materials were largely dependent on the adding mass of DCDA. Besides DCDA, NOMC materials have been also successfully fabricated by employing urea and melamine as nitrogen sources. As metal-free heterogeneous catalysts, the NOMC materials showed good catalytic activity and selectivity in the transesterification of ethylene carbonate to dimethyl carbonate, affording a maximum yield of dimethyl carbonate up to 76 % at 3 h under 120 °C.
Effects of support composition and pretreatment on the activity and selectivity of carbon-supported PdCunClx catalysts for the synthesis of diethyl carbonate
Briggs, Daniel N.,Bong, Gerry,Leong, Eric,Oei, Kevin,Lestari, Gabriella,Bell, Alexis T.
, p. 215 - 228 (2010)
The oxidative carbonylation of ethanol to diethyl carbonate (DEC) has been investigated on catalysts prepared by dispersing CuCl2 and PdCl 2 on activated carbon and carbon nanofibers. The objectives of this work were to establish the effects of support structure and pretreatment on the dispersion of the catalytically active components and, in turn, on the activity and selectivity of the catalyst for DEC synthesis. At the same surface loading of CuCl2 and PdCl2, partially oxidized carbon nanofibers resulted in a higher dispersion of the active components and a higher DEC activity than could be achieved on activated carbon. Catalyst characterization revealed that nearly atomic dispersion of CuCl2 and PdCl2 could be achieved on the edges of the graphene sheets comprising the carbon nanofibers. Over oxidation of the edges or their removal by heat treatment of the nanofibers resulted in a loss of catalyst activity. The loss of catalyst activity with time on stream could be overcome by the addition of ppm levels of CCl4 to the feed. While catalysts prepared with CuCl2 alone were active, a fivefold increase in activity was realized by using a PdCl2/CuCl2 ratio of 1/20. It is proposed that the Pd 2+ cations interact with [CuCl2]- anions to form Pd[CuCl2]2 complexes that are stabilized through dative bonds formed with oxygen groups present at the edges of the graphene sheets of the support. A mechanism for DEC synthesis is discussed, and a role for the Pd2+ cations as part of this mechanism is proposed.
Characterization of KF/γ-Al2O3 catalyst for the synthesis of diethyl carbonate by transesterification of ethylene carbonate
Qiu, Peng,Yang, Bolun,Yi, Chunhai,Qi, Suitao
, p. 232 - 238 (2010)
KF/γ-Al2O3 catalysts were prepared by impregnation method and investigated for the transesterification of ethylene carbonate (EC) with ethanol to synthesize diethyl carbonate (DEC). The KF/γ-Al2O3 catalysts were characterized by nitrogen physisorption, XRD and FT-IR techniques, and three new species: K 3AlF6, KOH and K2CO3 were found on the catalysts. Experimental results indicate that KOH and K2CO 3 are the major active species and K3AlF6 is inactive for DEC synthesis. Increasing the KF loading favors the formation of K2CO3 and consequently menhances the activity of the KF/γ-Al2O3 catalysts. However, when KF loading exceeded 50 mmol/g, the activity of the KF/γ-Al2O3 catalysts decreased. This may be due to the presence of intact KF on the catalyst, which may dilute the content of active species in the catalyst and cover the active species. The KF/γ-Al2O3 (50 mmol/g) catalyst exhibits the best catalytic performance. With this catalyst, a 72 mol% yield of DEC (based on EC) was obtained at 298 K. Springer Science+Business Media, LLC 2010.
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Douglass,Marascia
, p. 1899 (1955)
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Catalytic alcoholysis of urea to diethyl carbonate over calcined Mg-Zn-Al hydrotalcite
Wang, Peixue,Liu, Shimin,Zhou, Feng,Yang, Benqun,Alshammari, Ahmad S.,Deng, Youquan
, p. 19534 - 19540 (2015)
The synthesis of diethyl carbonate (DEC) from urea and ethanol was carried out over Mg-Zn-Al composite oxide catalysts derived from hydrotalcites (HTs). The catalytic results showed that the ternary hydrotalcites calcined at 450 °C with Mg:Zn:Al = 1:1.7:1 exhibited superior catalytic activity, and the highest DEC yield was 67.8%. Similar to ethanol, other alcohols such as methanol and butanol can also be transformed to corresponding dialkyl carbonates. Catalysts were characterized by XRD, BET, SEM and TPD with the aim of establishing a relationship between performance and structure. The results indicated that MgZn1.7Al-450 with nanoplate morphology and more accessible active medium basic sites were favourable for obtaining much superior catalytic activity. Recycling experiments demonstrated that the catalyst could be successfully reused. This journal is
Dittmar,Cranston
, (1869)
Catalysis by lead oxide for diethyl carbonate synthesis from ethyl carbamate and ethanol
Guo, Lian,Zhao, Xinqiang,An, Hualiang,Wang, Yanji
, p. 595 - 600 (2012)
The catalysis by lead oxide in the reaction of ethyl carbamate (EC) with ethanol to form diethyl carbonate (DEC) was studied. The lead oxide catalyst exhibited an excellent stability, which could be reused five times without a significant loss in catalytic activity. X-Ray powder diffraction analysis showed that the recovered catalyst was a mixture of cubic metal Pb and orthorhombic PbO2, with the latter shown to be the real active component for the synthesis of DEC. Verification experiments showed that the reaction between DEC and PbO was the main reason for the reduction of PbO to metal Pb.
The influence of various synthesis methods on the catalytic activity of cerium oxide in one-pot synthesis of diethyl carbonate starting from CO 2, ethanol and butylene oxide
Leino, Ewelina,M?ki-Arvela, P?ivi,Eta, Valerie,Kumar, Narendra,Demoisson, Frédéric,Samikannu, Ajaikumar,Leino, Anne-Riikka,Shchukarev, Andrey,Murzin, Dmitry Yu.,Mikkola, Jyri-Pekka
, p. 47 - 54 (2013)
Different synthesis methods such as homogeneous precipitation at room temperature and supercritical water (T > 647 K and P > 22.1 MPa) were employed for cerium oxide preparation. Additionally, deposition of ceria on silica mesoporous material, SBA-15, was carried out. The obtained materials were characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen physisorption, X-ray photoelectron spectroscopy and CO2 temperature programmed desorption. Considerable variations in physico-chemical properties of the resulting materials were observed. The catalytic activities of pristine cerium oxide and ceria loaded on SBA-15 support were compared. The test reaction was synthesis of diethyl carbonate starting from carbon dioxide and ethanol using butylene oxide as the dehydrating agent.
Organic carbonate synthesis from CO2 and alcohol over CeO 2 with 2-cyanopyridine: Scope and mechanistic studies
Honda, Masayoshi,Tamura, Masazumi,Nakagawa, Yoshinao,Nakao, Kenji,Suzuki, Kimihito,Tomishige, Keiichi
, p. 95 - 107 (2014)
The combination system of CeO2-catalyzed carboxylation and 2-cyanopyridine hydration (CeO2 + 2-cyanopyridine system) is effective for the direct synthesis of organic carbonates from CO2 and alcohols. This catalyst system can be applied to various alcohols to afford the corresponding carbonates in high alcohol-based yields. The hydration of 2-cyanopyridine over CeO2 rapidly proceeds under the low concentration of water, which can remove the water from the reaction media. Since the reaction is limited by the chemical equilibrium, the removal of water remarkably shifts the chemical equilibrium to the carbonate side, leading to high carbonate yields. In addition, 2-picolinamide that is produced by hydration of 2-cyanopyridine forms an intramolecular hydrogen bonding between H atom of the amide group and N atom of the pyridine ring, which weakens the adsorption of 2-picolinamide on CeO2 by reduction of the acidity. The reaction mechanism of DMC formation in CeO2 + 2-cyanopyridine system is also proposed.
Visible-Light-Initiated Hydrooxygenation of Unactivated Alkenes─A Strategy for Anti-Markovnikov Hydrofunctionalization
Quach, Linda,Dutta, Subhabrata,Pflüger, Philipp M.,Sandfort, Frederik,Bellotti, Peter,Glorius, Frank
, p. 2499 - 2504 (2022/02/17)
Hydrofunctionalization of unactivated alkenes is an indispensable mean in synthetic chemistry. Given that addition of electrophilic species into alkenes intrinsically follows the Markovnikov rule, a regioselectivity switch presents a major challenge. Herein, we present a visible-light-promoted strategy for the selective anti-Markovnikov hydrooxygenation of unactivated alkenes. Therefore, an innovative reagent was carefully designed to release a highly reactive and strongly underdeveloped alkoxycarbonyloxyl radical upon reduction, which selectively adds into alkenes. Hydrogen atom abstraction from 2-phenylmalononitrile is the key to form the product. We believe that this methodology enlarges the toolbox for regioselective hydrofunctionalization and could serve as a complementary strategy to the established hydroboration/oxidation protocol.
METHOD FOR PRODUCING CARBONATE ESTERS, AND CATALYTIC STRUCTURE FOR PRODUCING CARBONATE ESTERS
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Paragraph 0148-0149; 0179-0180, (2021/09/17)
Provided are a method for producing carbonate esters, and a catalytic structure for producing carbonate esters, whereby solid catalyst powder formation and detachment are suppressed and superior carbonate ester reaction efficiency is yielded when a catalytic structure constituted by a sufficient quantity of a cerium-oxide-containing solid catalyst supported on a substrate is used. The method for producing carbonate esters includes reacting a monohydric alcohol and carbon dioxide in the presence of a catalytic structure and a hydrating agent. The catalytic structure includes a substrate and a catalytic layer that is formed on at least a portion of the surface of the substrate and contains a solid catalyst and an inorganic binder. The solid catalyst contains cerium oxide. The supported quantity of the solid catalyst is 15 g/m2 to 200 g/m2, inclusive. The inorganic binder contains silica and/or alumina.
