- Fabrication of solid strong bases with a molecular-level dispersion of lithium sites and high basic catalytic activity
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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.
- Sun, Lin-Bing,Shen, Jie,Lu, Feng,Liu, Xiao-Dan,Zhu, Li,Liu, Xiao-Qin
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- Magnesium oxide nanosheets as effective catalysts for the synthesis of diethyl carbonate from ethyl carbamate and ethanol
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A series of MgO catalysts were prepared by thermal decomposition and precipitation methods. Their catalytic performance was evaluated in the synthesis of diethyl carbonate (DEC) from ethyl carbamate (EC) and ethanol. Among them, MgO prepared using sodium carbonate as the precipitant and calcined at 450°C (MgO-SC-450) exhibited much higher catalytic activity. An excellent DEC yield of 58.0% with a high DEC selectivity of 92.1% could be achieved over the MgO-SC-450 catalyst under optimized reaction conditions: 210°C, ethanol/EC molar ratio of 10, and 3 h. Moreover, the catalytic activity could be essentially retained during recycling experiments. The structure and surface basicity of the MgO catalysts were characterized by X-ray diffraction (XRD), Mastersizer 2000, N2 adsorption, field-emission scanning electron microscopy (FE-SEM), and temperature-programmed desorption of CO2 (CO2-TPD). It was found that MgO-SC-450 possessed nanosheet morphology. Furthermore, a larger amount of appropriate medium basic β sites of MgO-SC-450 with the peak located between 225°C and 275°C was favourable for obtaining much superior catalytic activity. Quasi in situ FT-IR experiments were carried out to elucidate the adsorption behaviours of reactants. It was found that EC could be effectively activated and ethanol could be dissociated to a strong nucleophilic ethoxy group by MgO. In addition, theoretical calculation proved the co-adsorption of EC and ethanol on the MgO surface. Based on the results of quasi in situ FT-IR experiments and theoretical calculation, a plausible reaction mechanism has been proposed for the catalytic reaction.
- Li, Fengjiao,Li, Huiquan,Wang, Liguo,He, Peng,Cao, Yan
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- Ambident ethyl N-nitrosocarbamate anion: Experimental and computational studies of alkylation and thermal stability
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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.
- Benin, Vladimir,Kaszynski, Piotr,Radziszewski, J. George
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- Au (III)/N-containing ligand complex: A novel and efficient catalyst in carbonylation of alkyl nitrite
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High catalytic activity of a gold N-containing ligand complex in the homogenous carbonylation of alkyl nitrite to dialkyl carbonate with KI as the promoter is reported. [AuCl2(phen)]Cl/KI (phen = 1,10-phenanthroline) complex has been used as a catalyst in the carbonylation of ethyl nitrite. The use of iodide as a promoter resulted in a significant increase in activity (TOF: 35.8 mol?molAu- 1?h- 1) and selectivity (91.7%) for diethyl carbonate at 3.0 MPa, 80 °C and 5 h. Based on the results of ESI-MS, UV-Vis, and cyclic voltammetry (CV) experiments, a mechanism is proposed for the carbonylation of alkyl nitrite in a homogeneous system using a gold N-containing ligand complex as a catalyst.
- Li, Jinjin,Hu, Jianglin,Li, Guangxing
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- Mesostructured graphitic carbon nitride as a new base catalyst for the efficient synthesis of dimethyl carbonate by transesterification
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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.
- Xu, Jie,Long, Kai-Zhou,Chen, Ting,Xue, Bing,Li, Yong-Xin,Cao, Yong
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- An effective combination catalyst of CeO2and zeolite for the direct synthesis of diethyl carbonate from CO2and ethanol with 2,2-diethoxypropane as a dehydrating agent
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The combination catalyst of CeO2 and H-FAU zeolite was effective for the direct synthesis of diethyl carbonate from CO2 and ethanol with 2,2-diethoxypropane as a dehydrating regent, where H-FAU catalyzed hydrolysis of 2,2-diethoxypropane. The combination catalyst provided high activity and a high diethyl carbonate yield of 72% based on 2,2-diethoxypropane at a low temperature of 393 K. This journal is
- Chang, Tao,Choi, Jun-Chul,Fukaya, Norihisa,Hamura, Satoshi,Matsumoto, Seiji,Mishima, Takayoshi,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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- Construction of Polycyclic β-Ketoesters Using a Homoconjugate Addition/Decarboxylative Dieckmann Annulation Strategy
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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.
- Chen, Zhiwei,Hong, Allen Y.,Linghu, Xin
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- Synthesis of ethyl octyl ether from diethyl carbonate and 1-octanol over solid catalysts. A screening study
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The synthesis of ethyl octyl ether (EOE) from a mixture of diethyl carbonate (DEC) and 1-octanol (1:2 molar ratio) over several solid catalysts was studied in batch mode at 150 °C and 25 bar. Catalyst screening revealed that EOE could be successfully obtained over some acid catalysts. In particular the highest yield was achieved over acid ion-exchange resins (33% after 8 h). A reaction scheme of the process is proposed. Selectivity to EOE was mainly affected by the production of diethyl ether (DEE) and di-n-octyl ether (DNOE). However, EOE was the main ether obtained (60 mol%), followed by DEE (20 mol%) and DNOE (20 mol%). By comparing the behavior of several acid resins, it was seen that the synthesis of EOE was highly related to the structural resin properties. It was found that the accessibility of DEC and 1-octanol to acid centers was improved over highly swollen and low polymer density resins. Thus, gel-type resins with low divinylbenzene content are the most suitable to produce EOE (e.g., Amberlyst 121, Dowex 50Wx2-100 and CT224).
- Guilera,Bringué,Ramírez,Iborra,Tejero
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- Highly active and reusable ternary oxide catalyst for dialkyl carbonates synthesis
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The application of ternary oxides, prepared through calcination of rare-earth modified Mg/Al-hydrotalcite (HT), as highly active, selective, and reusable solid catalysts for dialkyl carbonates synthesis by transesterification reaction is reported. Dimethyl carbonate, for example, was prepared by reacting ethylene carbonate with methanol in 100 mol% selectivity at a yield of 95 mol%. Among several rare-earth modified precursors, La (10 mol%)-HT showed the highest activity. This catalyst was active even at ambient conditions. Basicity of the catalyst played crucial role on its performance. The activity of these catalysts was superior to the hitherto known solid catalysts for this reaction.
- Unnikrishnan,Srinivas
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- Direct condensation reaction of carbon dioxide with alcohols using trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent
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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.
- Kadokawa, Jun-Ichi,Habu, Hideyuki
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- A FACILE PREPARATION OF DIALKYL CARBONATES FROM POTASSIUM CARBONATE AND ALKYL BROMIDES BY USING ORGANOSTANNYL COMPOUND AS A CATALYST
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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.
- Fujinami, Tatsuo,Sato, Shinichi,Sakai, Shizuyoshi
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- Radical Cations of Organic Carbonates, Trimethyl Borate and Methyl Nitrate
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Exposure of a range of dialkyl carbonates as dilute solutions in trichlorofluoromethane at 77 K gave rearranged cations in which hydrogen is transferred from carbon to the carbonyl oxygen.Similar species were obtained from the cyclic derivatives, ethylene and propylene carbonates.No evidence has been found for complex formation with solvent molecules such as occurs for methyl formate cations.For the dimethyl derivative the rearrangement appeared to occur even at ca. 4 K.For trimethyl borate a similar reaction occurred, giving either or H2COC(OMe)+MeOH.However, methyl nitrate gave NO2H+ radicals, thought to be derived from H2CONO2H+.These results are compared with those for ester and lactone cations and also with those for trimethyl phosphate and dimethyl sulphate cations.
- Ganghi, Nader S.,Rao, D. N. Ramakrishna,Symons, Martyn C. R.
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- Readily-fabricated supported MgO catalysts for efficient and green synthesis of diethyl carbonate from ethyl carbamate and ethanol
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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.
- Li, Fengjiao,Wang, Liguo,Xu, Shuang,Liang, Shuting,Zhang, Ningning
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- Synthesis of diethylcarbonate by ethanolysis of urea: A study on the recoverability and recyclability of new Zn-based heterogeneous catalysts
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New Zn-based catalysts are described that act as heterogenized or heterogeneous catalysts, with easy recovery and re-utilization with a limited or even zero Zn-leaching. For stabilizing in the heterogeneous form the catalytically active Zn centre, mixed oxides, ZIF-8 and Zn-tethered systems have been synthesized and found to sensibly reduce the leaching of Zn in solution with respect to ZnO, making possible their recovery and reuse. ZIF-8 can be used for long time of reaction, reaching high DEC yields (comparable or higher than those obtained with ZnO) without any significant loss of zinc.
- Dibenedetto, Angela,Angelini, Antonella,Aresta, Michele,Fasciano, Stefania,Cucciolito, Maria Elena,Ruffo, Francesco,Aresta, Brunella Maria,Curulla-Ferré, Daniel,De Giglio, Elvira
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- Alkaline Earth (Ca, Mg) and Transition (La, Y) Metals Promotional Effects on Zn–Al Catalysts During Diethyl Carbonate Synthesis from Ethyl Carbamate and Ethanol
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Diethyl carbonate, an important member in the family of organic carbonates, is a fuel additive like dimethyl carbonate (DMC). It holds an extra edge of having better gasoline/water distribution coefficient than DMC, and also DEC is widely used as an electrolyte in lithium ion batteries. Ethanolysis of ethyl carbamate (EC) is the most economical and greener route for DEC synthesis. Zn–Al–M (M=Ca, La, Mg and Y) have been synthesized using two methods and their activity have been explored DEC systhesis from EC and ethanol. The catalysts were characterized using thermogravimetric analysis, Brunauer, Emmett and Teller surface area, N2 adsorption–desorption textural analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy, temperature-programmed desorption (TPD), atomic-force microscopy and Raman spectroscopy. Pure metal oxides were observed during the XRD analysis and Al2O3 was found to be in amorphous form. Third metal oxide prepared from impregnation method was found to be present on the surface as well as in impregnated form. CO2-TPD analysis showed close correlation between the basicity and the DEC yield. Zn–Al–Mg, prepared from precipitation method, being most basic, was found to be most effective although the performances of Zn–Al–Ca and Zn–Al–La were good. The effect of precipitants was also studied by synthesizing Zn–Al–Mg using NaOH and liquid NH3 as precipitants. DEC yield of 40.2% and turn over frequency of 1055?mgDEC?gcat?1?h?1 was obtained in 5?h at 190 °C using Zn–Al–Mg prepared from precipitation method. Effect of reaction conditions was also studied and equilibrium constant of the reaction was estimated using the Benson group contribution method. Graphical Abstract: [Figure not available: see fulltext.].
- Shukla, Kartikeya,Srivastava, Vimal Chandra
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- Synthesis of diethyl carbonate from ethyl carbamate and ethanol over ZnO-PbO catalyst
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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.
- An, Hualiang,Zhao, Xinqiang,Guo, Lian,Jia, Chunyao,Yuan, Baoguo,Wang, Yanji
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- Dimethyl carbonate synthesis catalyzed by DABCO-derived basic ionic liquids via transesterification of ethylene carbonate with methanol
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Easily prepared DABCO-derived (1,4-diazobicyclo[2.2.2]octane) basic ionic liquids were developed for an efficient synthesis of dimethyl carbonate (DMC) via the transesterification of ethylene carbonate (EC) with methanol. 1-Butyl-4-azo-1-azoniabicyclo[2.2.2]octane hydroxide ([C4DABCO]OH) exhibited high catalytic activity and 81% DMC yield together with 90% EC conversion was obtained under mild reaction conditions. Notably, the catalyst could be recycled for four times without loss of catalytic activity. Moreover, a possible mechanism was also discussed.
- Yang, Zhen-Zhen,He, Liang-Nian,Dou, Xiao-Yong,Chanfreau, Sébastien
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- Production of diethyl carbonate from ethylene carbonate and ethanol over supported fluoro-perovskite catalysts
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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.
- Iida, Hajime,Kawaguchi, Ryuhei,Okumura, Kazu
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- Single-Pulse shock tube studies of the decomposition of ethoxy compounds
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Tetraethyl orthocarbonate (TEOC), diethyl carbonate (DEC), and diethoxymethane (DEM) have been decomposed in single-pulse shock tube experiments. TEOC decomposes to give DEC, ethylene, and ethanol as organic products, while DEC results in only the latter two. In both cases the ethylene to ethanol ratio is equal to 1, and the mechanisms appear to involve molecular eliminations. The rate expressions for the initial processes are the following: k(TEOC → products) = 1013.91±0.14 exp((-27 529 ± 348)K/T) s-1, T = 1005-1180 K; k(DEC → C2H5OCO2H + C2H4) = 1013.03±0.11 exp((-23 290 ± 26 7 K/T) s-1, T = 955-1095 K. The listed uncertainties are one standard deviation. DEM decomposes more slowly than the other two compounds. For each DEM reacted, 1.2 ethylene and 0.5 ethanol are produced. Methane and ethane are also observed as products. The mechanism is postulated to involve both molecular and bond-breaking channels. It is concluded that ethanol arises only through the molecular channel, and on this basis the following rate expressions have been derived: k(DEM → products) = 1015.93±0.15 exp((-36 179 ± 403 K/T) s-1, T = 1150-1260 K; k(DEM → ethanol + products) = 1015.07±0.45 exp((-34 517 ± 1090 K/T) s-1, k(DEM → ethyl + OCH2OC2H5) = 1016.32±0.45 exp((-38 214 ± 1160 K/T) s-1. The results are compared with those dealing with the stability of analogous ethers, esters, and silicon compounds. For carbon compounds the addition of ethoxy groups to the compound destabilizes the molecule. It is further concluded that rate data on the molecular decompositions of ethoxy carbon compounds cannot be easily extrapolated to silicon-containing species.
- Herzler, Juergen,Manion, Jeffrey A.,Tsang, Wing
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- Catalytic decomposition of dialkyl pyrocarbonates to dialkyl carbonates and carbon dioxide in dichloromethane by a discrete cobalt(II) alkoxide species generated in situ
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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.
- Greener, Bryan,Walton, Paul H.
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- Catalytic CO2esterification with ethanol for the production of diethyl carbonate using optimized CeO2as catalyst
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The direct conversion of (bio)ethanol and CO2is a promising route to diethyl carbonate (DEC) since both reactants are cheap and originate from renewable resources in bioethanol production. In this work we present a detailed characterization and correlation between catalyst synthesis parameters and catalytic activity of pure ceria for DEC formation. An interaction between surface acidity and basicity as well as sufficiently high specific surface area is required for optimal catalytic activity which is obtained by using urea as the precipitation agent. Catalytic activity towards DEC formation is increased when adding both cerium nitrate solution and aqueous ammonia solution in a controlled manner at a pH of 10 at 50 °C for precipitation. When combining temperature-programmed desorption (TPD) experiments and catalytic testing, mainly weak basic sites appear to be relevant for the DEC formation.
- Buchmann, Marco,Lucas, Martin,Rose, Marcus
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- Fast and facile preparation of metal-doped g-C3N4 composites for catalytic synthesis of dimethyl carbonate
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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.
- Xu, Jie,Long, Kai-Zhou,Wang, Yue,Xue, Bing,Li, Yong-Xin
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- Synthesis of Ditetrahydrofurfuryl Carbonate as a Fuel Additive Catalyzed by Aminopolycarboxylate Ionic Liquids
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Abstract: A new series of aminopolycarboxylate ionic liquids were designed, synthesized, and applied for efficient and selective synthesis of ditetrahydrofurfuryl carbonate (DTC). Tetraethylammonium nitrilotriacetate ([N2222]3[NTA]) was demonstrated to show the best catalytic performance, in which DTC could be obtained at a yield of 80% under optimum conditions. Graphical Abstract: [Figure not available: see fulltext.].
- Huang, Wei,Tao, Duan-Jian,Chen, Feng-Feng,Hui, Wei,Zhu, Jia,Zhou, Yan
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- Gold nanoparticles promote the catalytic activity of ceria for the transalkylation of propylene carbonate to dimethyl carbonate
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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.
- Juarez, Raquel,Corma, Avelino,Garcia, Hermenegildo
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- NaZSM-5-catalyzed dimethyl carbonate synthesis via the transesterification of ethylene carbonate with methanol
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NaZSM-5 zeolite was found to be an efficient heterogeneous catalyst for the synthesis of dimethyl carbonate (DMC), which can serve as a building block, an additive to fuel oil, and an electrolyte in batteries, via the transesterification of ethylene carbonate (EC) with methanol. Notably, 77% DMC yield and 97% selectivity were achieved under mild reaction conditions. Furthermore, the effects of various reaction parameters such as catalyst loading, reaction time, and methanol/EC molar ratio on the catalytic performance were investigated in detail. This protocol was found to be applicable to a variety of alcohols, producing the corresponding dialkyl carbonates with moderate yields and selectivities. Moreover, the catalyst can be recovered by simple filtration with retention of catalytic activity; a stable crystal configuration and a slight alteration of its superficial structure were observed by X-ray diffraction and BET measurements.
- Yang, Zhen-Zhen,Dou, Xiao-Yong,Wu, Fang,He, Liang-Nian
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- Effect of hydrophobic modification on the catalytic performance of PdCl2/Cu-HMS with different silylation temperatures
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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.
- Zhang, Pingbo,Zhou, Yan,Fan, Mingming,Jiang, Pingping,Huang, Xianglan,Lou, Jiang
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- Efficient synthesis of dimethyl carbonate via transesterification of ethylene carbonate over a new mesoporous ceria catalyst
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Mesoporous ceria materials (CeO2-meso) have been prepared through a soft-templating method using cetyltrimethylammonium bromide as a template and cerium nitrate as a precursor. The synthesized CeO2-meso materials possess narrow pore size distributions of 5.1-5.4 nm and tunable surface areas (109-182 m2 g-1). As heterogeneous catalysts in the transesterification of ethylene carbonate (EC) with methanol to dimethyl carbonate (DMC), CeO2-meso materials demonstrate superior catalytic performance to the commercial ceria. N2 adsorption-desorption and CO2-TPD characterization results indicate that the catalytic activity obtained over various CeO2-meso samples depends on their surface areas and basicity. The highest activity is achieved over CeO 2-meso-400, affording a DMC yield as much as 73.3%, together with excellent recycling ability. Besides the transesterification of EC with methanol, CeO2-meso is found to be able to catalyze the reactions of other cyclic carbonates and alcohols. In view of the high catalytic performance along with the convenience in catalyst preparation, CeO2-meso-400 compares favorably with the ionic liquids as well as other ceria-based catalytic systems.
- Xu, Jie,Long, Kai-Zhou,Wu, Fei,Xue, Bing,Li, Yong-Xin,Cao, Yong
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- Synthesis of nitrogen-containing ordered mesoporous carbon materials with tunable nitrogen distributions and their application for metal-free catalytic synthesis of dimethyl carbonates
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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.
- Gan, Yu-Lin,Wen, Lin-Zhi,Xu, Jie,Xue, Bing
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- (n-Bu2Sn)2O(CO3): An active, robust and recyclable organotin(IV) for the direct synthesis of linear organic carbonates from carbon dioxide and alcohols
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Organotin(IV) compounds are known to promote the direct synthesis of organic carbonates from carbon dioxide and alcohols. In the past, structural studies have highlighted that the carbonato moiety is a recurring ligand of tin species collected during CO2 pressurized reactions. In a mimetic approach and in order to achieve an available and recyclable precursor, the title compound (n-Bu2Sn)2O(CO3) (1) was prepared in a single step by reacting commercial di-n-butyltin dichloride with an aqueous solution of sodium carbonate. Compound 1 was characterized using infrared spectroscopy and thermogravimetric and elemental analyses. Multinuclear NMR investigations in solution were also conducted. Compound 1 was then evaluated for the direct carbonation of alcohols (methanol, ethanol, n-butanol and isopropanol) under CO2 pressure. Recycling experiments were performed showing the efficient reuse of 1 without loss of activity. Furthermore, the infrared fingerprint of 1 was preserved even after several runs demonstrating a good stability. The effects of pressure and of reaction time on dimethyl carbonate formation were also studied.
- Sanapureddy, Sreevardhan Reddy,Plasseraud, Laurent
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- Effects of support composition and pretreatment on the activity and selectivity of carbon-supported PdCunClx catalysts for the synthesis of diethyl carbonate
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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.
- Briggs, Daniel N.,Bong, Gerry,Leong, Eric,Oei, Kevin,Lestari, Gabriella,Bell, Alexis T.
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- Characterization of KF/γ-Al2O3 catalyst for the synthesis of diethyl carbonate by transesterification of ethylene carbonate
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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.
- Qiu, Peng,Yang, Bolun,Yi, Chunhai,Qi, Suitao
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- Tetrachloromethane Hydrodechlorination over Palladium-Containing Nanodiamonds
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Abstract: Using nanodiamonds of the UDD-STP brand 1 wt % palladium-containing nanodiamonds are obtained and tested as catalysts of tetrachloromethane hydrodechlorination under mild conditions (solvents, ethanol and methanol; Т = 298–318 K; PH2 = 0.1 MPa). The catalytic properties of the obtained material and a palladium-containing analog based on activated carbon are compared. It is shown that the hydrodechlorination reaction occurs in a stepwise manner via two pathways: to form products with a smaller content of chlorine, for example, chloroform, and to yield oxygen-containing products, for example, diethyl carbonate. The qualitative and quantitative compositions of reaction products are determined by gas chromatography/mass spectrometry.
- Belkina, E. G.,Gruzdev, M. S.,Kalmykov, P. A.,Klyuev, M. V.,Lysenok, A. A.,Magdalinova, N. A.
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- A catalyst-free novel synthesis of diethyl carbonate from ethyl carbamate in supercritical ethanol
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Diethyl carbonate has been synthesized via the alcoholysis of ethyl carbamate in supercritical ethanol under catalyst-free conditions. The influences of various parameters such as reaction temperature, reaction time, reaction pressure, ethanol/ethyl molar ratios and reaction loading volume on the yield of DEC were studied systematically. The experimental results indicated that the alcoholysis of ethyl carbamate was greatly improved in supercritical ethanol. The optimal reaction conditions were as follows: a reaction temperature of 573 K, a reaction time of 30 min, a reaction pressure of 13.2 MPa, an ethanol/ethyl carbamate molar ratio of 10 and a reactor loading volume of 285 μL respectively. The optimal yield of DEC was 22.9%.
- Zhao, Li-Cai,Hou, Zhi-Qiang,Liu, Chun-Ze,Wang, Yuan-Yuan,Dai, Li-Yi
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- Catalytic alcoholysis of urea to diethyl carbonate over calcined Mg-Zn-Al hydrotalcite
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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
- Wang, Peixue,Liu, Shimin,Zhou, Feng,Yang, Benqun,Alshammari, Ahmad S.,Deng, Youquan
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- Development of complex approach to the synthesis of trimethylene carbonate as a monomer for biodegradable polymers
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With the aim of production of polymers for medicine a new preparation method was developed for trimethylene carbonate based on transesterification with trimethylene glycol of dialkyl carbonates obtained without the use of phosgene. As initial reagents alkylene carbonates or polycarbonates and titanium alkoxides can be utilized. The advantages of this approach consist in obtaining some additional useful substances and the possibility of reprocessing polycarbonate wastes.
- Kuznetsov,Pervova,Pestov
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- Synthesis of diethylcarbonate by ethanolysis of urea catalysed by heterogeneous mixed oxides
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New Zn- and Ca-based mixed oxides have been tested in the ethanolysis of urea. Cerium and magnesium have revealed to be able to stabilize and enhance the activity of Zn and Ca. All the used compounds act as heterogeneous catalysts in a batch reactor and can be easily recovered and re-used in several catalytic runs. However, although ZnO dissolves as Zn(NCO)2(NH3)2 in the reaction medium under the operative conditions and then partly precipitates at room temperature ensuring a modest immediate recoverability and recyclability, 2CaO/CeO2 is insoluble also at the reaction temperature that makes it well suited even for the use in a flow reactor. MgO-ZnO and SiO2-ZnO have also been tested. The former has an interesting performance, but still not equal to that of 2CaO-CeO2. Interestingly, the latter catalyst is able to convert urea and ethanol into DEC with 91% conversion of urea and 98% selectivity in the long term.
- Angelini,Dibenedetto,Curulla-Ferré,Aresta
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- Catalysis by lead oxide for diethyl carbonate synthesis from ethyl carbamate and ethanol
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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.
- Guo, Lian,Zhao, Xinqiang,An, Hualiang,Wang, Yanji
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- Sensitized Photooxygenation of 6-Heteroatom-Substituted Fulvenes: Primary Products and Their Chemical Transformations
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Sensitized photooxygenation of 6,6-diethoxyfulvene (1) and 6,6-(ethylenedithio)fulvene (9) at -78 deg C afforded diethoxyfulvene endoperoxide 2 and (ethylenedithio)fulvene endoperoxide 10, respectively, as primary products.Further irradiation resulted in formation of the novel bisperoxides 3 and 11 from cycloaddition of 1O2 to the exocyclic double bond of the corresponding endoperoxides.The initial endoperoxides were characterized by NMR at low temperature and underwent a variety of chemical transformations to give highly oxygenated cyclopentane derivatives.In contrast, photooxygenation of 6,6-dipiperidinofulvene (16) and 6-(dimethylamino)fulvene (17) did not lead to chemical reaction; these compounds physically quench 1O2 with rate constants on the order of 1E8 M-1 s-1.
- Zhang, Xiaojun,Lin, Feng,Foote, Christopher S.
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- 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
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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.
- 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
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- Highly efficient and selective synthesis of dibutyl carbonate via the synergistic dual activation catalysis of tetraethylammonium prolinate ionic liquids
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A facile, highly efficient and phosgene-free synthesis process of dimethyl carbonate (DMC) with nbutanol (BuOH) to dibutyl carbonate (DBC) by transesterification reaction has been studied in detail using tetraethylammonium-based amino acid ionic liquids ([N2222][AA]) as homogeneous catalysts. The results indicated that tetraethylammonium prolinate ([N2222][Pro]) exhibited the best catalytic activity in compared to other four [N2222][AA], and DBC could be obtained at a yield of 72% under optimum conditions. Furthermore, quantum-mechanical calculations manifested that such high DBC yield originated from the synergistic dual activation catalysis of [N2222][Pro]. [N2222][Pro] could activate BuOH and DMC well at the same time, which enhances the electrophilicity of BuOH and the nucleophilicity of DMC respectively, leading to the excellence catalytic performance.
- Ouyang, Fan,Wang, Zhen-Zhen,Zhou, Yan,Cheng, Zheng,Lu, Zhang-Hui,Yang, Zhen,Tao, Duan-Jian
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- Organic carbonate synthesis from CO2 and alcohol over CeO 2 with 2-cyanopyridine: Scope and mechanistic studies
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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.
- Honda, Masayoshi,Tamura, Masazumi,Nakagawa, Yoshinao,Nakao, Kenji,Suzuki, Kimihito,Tomishige, Keiichi
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- Visible-Light-Initiated Hydrooxygenation of Unactivated Alkenes─A Strategy for Anti-Markovnikov Hydrofunctionalization
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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.
- Quach, Linda,Dutta, Subhabrata,Pflüger, Philipp M.,Sandfort, Frederik,Bellotti, Peter,Glorius, Frank
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p. 2499 - 2504
(2022/02/17)
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- Synthesis of dimethyl carbonate from methanol and CO2under low pressure
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A mild and highly efficient approach has been developed for the direct synthesis of dimethyl carbonate (DMC) from methanol and CO2 under low initial pressure. The key to a successful transformation is the use of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), CH2Br2 and ionic liquid. Under the optimized reaction conditions, the yield of DMC was obtained up to 81% under 0.25 MPa. The direct synthesis of DMC can be carried out at balloon pressure using CH2Br2 and DBU. In this case, after the reaction, DBU was proved to be recyclable after having been treated with KOH in ethanol. In addition, a plausible mechanism for this synthetic reaction was proposed according to the experimental results.
- Liu, Chun,Liu, Kai
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p. 35711 - 35717
(2021/12/04)
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- METHOD FOR PRODUCING CARBONATE ESTERS, AND CATALYTIC STRUCTURE FOR PRODUCING CARBONATE ESTERS
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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.
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Paragraph 0148-0149; 0179-0180
(2021/09/17)
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- Method for producing organic carbonate
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To provide a method for producing organic carbonate from carbon dioxide as a raw material without producing water as a by-product.SOLUTION: Provided is a method for producing an organic carbonate, which comprises reacting alkoxysilane with carbon dioxide.SELECTED DRAWING: None
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Paragraph 0034; 0066; 0078
(2021/12/07)
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- Boosting the methanolysis of polycarbonate by the synergy between ultrasound irradiation and task specific ionic liquids
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In an attempt to perform polycarbonate chemical recycling in a more sustainable way, we took into consideration the combined use of ultrasound irradiation and task specific ionic liquids. Towards this aim, the methanolysis of polycarbonate, into dimethylcarbonate and bisphenol A, was carried out in the presence of cholinium-based ionic liquids featuring anions derived from amino acids and other eco-friendly species. The target process was optimized in terms of both energy and material amounts as well as in terms of the nature of the catalysts used. The proposed protocol allowed high conversion and yields of bisphenol A to be obtained, under milder conditions compared to the ones so far reported in the literature, perfectly fulfilling green chemistry principles. The best performing catalyst can be reused without significant loss in performance and the methodology can be successfully applied to post-consumer polycarbonate samples. This journal is
- D'Anna, Francesca,Sbacchi, Maria,Infurna, Giulia,Dintcheva, Nadka Tz.,Marullo, Salvatore
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supporting information
p. 9957 - 9967
(2021/12/24)
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- Sustainable Catalytic Synthesis of Diethyl Carbonate
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New sustainable approaches should be developed to overcome equilibrium limitation of dialkyl carbonate synthesis from CO2 and alcohols. Using tetraethyl orthosilicate (TEOS) and CO2 with Zr catalysts, we report the first example of sustainable catalytic synthesis of diethyl carbonate (DEC). The disiloxane byproduct can be reverted to TEOS. Under the same conditions, DEC can be synthesized using a wide range of alkoxysilane substrates by investigating the effects of the number of ethoxy substituent in alkoxysilane substrates, alkyl chain, and unsaturated moiety on the fundamental property of this reaction. Mechanistic insights obtained by kinetic studies, labeling experiments, and spectroscopic investigations reveal that DEC is generated via nucleophilic ethoxylation of a CO2-inserted Zr catalyst and catalyst regeneration by TEOS. The unprecedented transformation offers a new approach toward a cleaner route for DEC synthesis using recyclable alkoxysilane.
- Putro, Wahyu S.,Ikeda, Akira,Shigeyasu, Shinji,Hamura, Satoshi,Matsumoto, Seiji,Lee, Vladimir Ya.,Choi, Jun-Chul,Fukaya, Norihisa
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p. 842 - 846
(2020/12/07)
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- Method for synthesizing organic carbonate from carbon dioxide, alcohol and brominated alkane under mild conditions
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The invention discloses a method for synthesizing organic carbonate from carbon dioxide, alcohol and brominated alkane under mild conditions, belonging to the field of chemical synthesis. According tothe method, carbon dioxide, alcohol and brominated alkane are used as raw materials, 1,8-diazabicycloundec-7-ene (DBU) is used as an activating agent, and acetonitrile is used as a solvent to preparethe organic carbonate. The target product, namely the organic carbonate with excellent yield can be obtained under optimized reaction conditions. The method is mild in reaction conditions, simple andconvenient to operate and high in yield, and is an excellent system for preparing the organic carbonate.
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Paragraph 0016-0017; 0018-0020; 0022; 0024
(2020/06/02)
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- Preparation Method of Dialkylcarbonate using selenite catalyst and Composition Comprising Dialkylcarbonate Prepared Therefrom
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The present invention relates to a composition which contains: an alkali metal selenite catalyst of chemical formula 2, an alkali metal alkyl selenite catalyst of chemical formula 3, or dialkyl carbonate (DAC) of chemical formula 1, obtained by an oxidation carbonylation process which conducts a reaction of alcohol of chemical formula 4: ROH with a mixed gas of carbon monoxide (CO) and oxygen (O_2); and a selenium-containing by-product, wherein the content of the selenium-containing by-product is 7,000 ppm or less. In addition, the present invention provides a method for manufacturing DAC of the chemical formula 1. The composition according to the present invention can produce DAC of the chemical formula 1 in an economically feasible yield compared to a conventional carbonylation process.COPYRIGHT KIPO 2020
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Paragraph 0095-0102; 0116-0120
(2020/05/13)
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- Protic ionic liquid-promoted synthesis of dimethyl carbonate from ethylene carbonate and methanol
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In this work, the protic ionic liquid [DBUH][Im] (1,8-diazabicyclo[5.4.0]-7-undeceniumimidazolide) was developed as an efficient catalyst for the transesterification of ethylene carbonate with methanol to produce dimethyl carbonate. At 70 °C, up to 97% conversion of ethylene carbonate and 91% yield of dimethyl carbonate were obtained with 1 mol% [DBUH][Im] (relative to ethylene carbonate) as catalyst in 2 h. Even at room temperature, the conversion of ethylene carbonate can reach 94% and the yield of dimethyl carbonate can approach 81% for 6 h. Catalytic mechanism investigation showed the high catalytic efficiency of this ionic liquid results from the synergistic activation effect, wherein the cation can activate ethylene carbonate and the anion can activate methanol through hydrogen bond formation. Although the reusability of the ionic liquid need to be further improved, high efficiency and commercial availability of [DBUH][Im] render it a promising catalyst for the preparation of dimethyl carbonate.
- Song, Yu,He, Xing,Yu, Bing,Li, Hong-Ru,He, Liang-Nian
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supporting information
p. 667 - 672
(2019/08/16)
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- Metal-free synthesis of dimethyl carbonate: Via transesterification of ethylene carbonate catalyzed by graphitic carbon nitride materials
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Catalytic transesterification reaction between a cyclic carbonate and a low alcohol is the most important and practical strategy for the manufacture of dimethyl carbonate and other alkyl carbonates. However, most developed heterogeneous catalysts have potential metal and halide contamination. Herein, a graphitic carbon nitride (g-C3N4) material has been synthesized, thermally exfoliated, and treated with an alkaline solution. The physicochemical properties of eg-C3N4 materials have been analyzed by XRD, TG, N2 adsorption-desorption, FT-IR, UV-vis, and XPS spectroscopy. The characterization results reveal that the exfoliation has effectively enhanced the surface area of g-C3N4, and alkaline treatment could lead to the deprotonation of eg-C3N4, depending on the treatment temperature and alkaline solution. In the transesterification reaction between ethylene carbonate and CH3OH, the eg-C3N4-NH3 catalyst demonstrates superior catalytic activity to the pure g-C3N4, eg-C3N4 and eg-C3N4-HCl, affording a maximum DMC yield of 60% at 393 K. Furthermore, the eg-C3N4-NH3 shows good catalytic reproducibility and versatility for other substrates.
- Gan, Yu-Lin,Hu, Xiao-Qian,Wen, Lin-Zhi,Xu, Jie,Xue, Bing
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supporting information
p. 3215 - 3223
(2020/03/06)
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- Method for synthesizing aryl pyrazonitrile and by-producing carbonic acid diester
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The invention discloses a method for synthesizing aryl pyrazonitrile and by-producing carbonic acid diester. The method comprises the steps: taking 2,6-dichloro-4-trifluoromethylaniline, 2,3-dicyanopropionate and nitrite as main raw materials, carrying out diazotization and coupling reaction in a solvent containing fatty alcohol, adding a reaction terminating agent after coupling, and then carrying out alcoholysis and cyclization under an alkaline condition to generate aryl pyrazonitrile and carbonic acid diester. Different raw materials and process conditions are selected, the quality and theyield of the aryl pyrazonitrile are not influenced, and the generated by-product is purposefully controlled, so that after the cyclization liquid for synthesizing aryl pyrazonitrile is distilled andseparated, the distillate is subjected to multi-stage rectification, and solvents (methanol, ethanol or propanol and the like) can be recycled; meanwhile, carbonic acid diester of which the quality meets the industrial standard is obtained, and reduction and resource utilization of aryl pyrazonitrile synthesis waste liquid are realized.
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Paragraph 0008; 0023; 0026-0028
(2020/05/01)
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- Room temperature and normal pressure preparation method of organic carbonate
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The invention relates to the technical field of organic synthesis, and provides a room temperature and normal pressure preparation method of organic carbonate. The method comprises the following steps: introducing carbon dioxide into an imidazole ionic liquid to obtain a mixture; mixing the obtained mixture with alcohol and halogenated hydrocarbon, and carrying out addition-substitution reactionsto obtain organic carbonate. The whole reaction process is carried out at a room temperature under a normal pressure. The activation energy of the reaction is reduced by using imidazole ionic liquid and halogenated hydrocarbon, and finally, organic carbonate is prepared from CO2 at a room temperature under a normal pressure.
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Paragraph 0067-0069
(2020/07/15)
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- METHOD FOR PRODUCING AROMATIC NITRILE COMPOUND AND METHOD FOR PRODUCING CARBONATE ESTER
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Provided is a method for regenerating an aromatic amide compound into a corresponding aromatic nitrile compound, the method realizing a dehydration reaction of providing a target compound selectively at a high yield with generation of a by-product being suppressed. Also provided is a method for producing an aromatic nitrile compound that decreases the number of steps of dehydration reaction and significantly improves the reaction speed at a pressure close to normal pressure. Furthermore, the above-described production method is applied to a carbonate ester production method to provide a method for producing carbonate ester efficiently. The above-described objects are achieved by a method for producing an aromatic nitrile compound including a dehydration reaction of dehydrating an aromatic amide compound, in which the dehydration reaction uses diphenylether.
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Paragraph 0113
(2019/07/03)
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- METHOD FOR PRODUCING AROMATIC NITRILE COMPOUND AND METHOD FOR PRODUCING CARBONIC ACID ESTER
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Provided is a method for regenerating an aromatic amide compound into a corresponding aromatic nitrile compound, the method realizing a dehydration reaction of providing a target compound selectively at a high yield, with generation of a by-product being suppressed. Also provided is a method for producing an aromatic nitrile compound that decreases the number of steps of the dehydration reaction and significantly improves the reaction speed even at a pressure close to normal pressure. In addition, the above-described production method is applied to a carbonate ester production method to provide a method for producing a carbonate ester efficiently. The above-described methods are realized by a method for producing an aromatic nitrile compound including a dehydration reaction of dehydrating an aromatic amide compound, in which the dehydration reaction uses, as a solvent, any of 1,2-dimethoxybenzene, 1,3-dimethoxybenzene and 1,3,5-trimethoxybenzene.
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Paragraph 0165-0166
(2020/01/08)
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- Method of manufacturing Dialkyl carbonate using carbon dioxide
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In the embodiment of the present invention consists of a carbon dioxide using the d alkyl car this [thu [thu] which it sees a manufacturing method is provided other [...] number one, alcohol, imidazolium cation and bicarbonate mixing negative catalyst and bases the solvent to form a mixture, said mixture by mixing said reactants including injecting carbon dioxide for generating an agitating the manufacturing method characterized in that the d alkyl car this [thu [thu] which it sees a number [...] substrate. (by machine translation)
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Paragraph 0073-0079; 0088; 0149-0151
(2019/08/12)
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- METHOD OF CONVERTING CARBON DIOXIDE INTO CARBONYL COMPOUNDS
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The present invention provides a method for fixing carbon dioxide gas as a carbonyl compound represented by formula (3) as depicted by Figure 1 and comprising, purging of carbon dioxide in a solution of a nucleophile represented by the formula (1) in presence of a solvent at a temperature ranging from -40 Degree Celsius to 35 Degree Celsius, followed by adding a reagent at temperature ranging from -40 degree to 35 degree and thereafter adding another nucleophile represented by the formula (2) to obtain carbonyl compound represented by formula (3). The present invention can be advantageously used to obtain commercially important carbonyl compounds and clean unwanted carbon dioxide gas from the atmosphere and industrial effluents.
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Page/Page column 15; 16
(2019/05/02)
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- Homogeneous phase ionic liquid catalyzed high-purity diethyl carbonate synthesizing technology
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The invention discloses a homogeneous phase ionic liquid catalyzed high-purity diethyl carbonate synthesizing technology, and relates to a catalyzed synthesizing technology. The technology is a catalytic distillation technology for preparing high-purity diethyl carbonate ionic liquid for a lithium battery through ethylene carbonate and alcohol ester exchange by repeatedly using a homogeneous phasecatalyst. In a reaction, a crude product of the initial reaction is a small amount of ethylene carbonate, ethyl alcohol, ethylene glycol, diethyl carbonate and ionic liquid, and a large amount of theethyl alcohol, the ethylene carbonate and the ionic liquid can be recovered and recycled for reproducing diethyl carbonate after the reaction is completed, finally the high-purity diethyl carbonate is obtained; in a reaction process, ethylene glycol is further generated, and the ethylene glycol is bulk chemicals, and can be used as a product for directly separating. In addition, the used catalystcan be repeatedly used, green, pollution-free, and high in catalytic activity. The production technology for diethyl carbonate one-step synthesis is short in synthetic route, simple in technologicalprocess, high in product selectivity and yield, and capable of more effectively producing the diethyl carbonate relative to an existing technology.
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Paragraph 042-0047
(2019/03/31)
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- PROCESS FOR PREPARING ALKANEDIOL AND DIALKYL CARBONATE
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The invention relates to a process for the preparation of an alkanediol and a dialkyl carbonate comprising reacting an alkylene carbonate and an alkanol in the presence of a catalyst, wherein the catalyst is aluminum phosphate.
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Page/Page column 10; 11; 12; 13
(2019/02/06)
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- Synthesis method of tert-butyl cyclohexyl ethyl carbonate spice
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The invention discloses a synthesis method of tert-butyl cyclohexyl ethyl carbonate spice and relates to the technical field of fine chemical engineering. The synthesis method includes: using phenol and tert-butanol as starting raw materials for alkylation reaction, hydrogenating, being in acetylation reaction with diethyl carbonate to generate tert-butyl cyclohexyl ethyl carbonate. The synthesismethod is easy-to-get in raw material and high in yield, a ratio of o-tert-butyl phenol and p-tert-butyl phenol generated by reaction of phenol and tert-butanol reaches 7:3, and p-tert-butyl phenol which is a byproduct can generate iris ester for use after being hydrogenated and esterified; the spice is high in purity and pure and gentle in fragrance and meets flavoring requirements of essence andspice.
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Paragraph 0025; 0038
(2018/03/26)
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- Direct synthesis of diethyl carbonate from ethanol and carbon dioxide over ceria catalysts
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Direct synthesis of diethyl carbonate (DEC) by carboxylation of ethanol with CO2 was investigated over ceria catalysts. 2-Cyanopyridine (2-CP) was used for trapping water formed in the reaction and to shift the equilibrium towards the product side. An optimal dependence (“volcanic plot”) of the catalytic activity on the acidity/basicity molar ratio was observed. “Neat” ceria (procured from Daiichi Kigenso Kagaku Kogyo Co. Ltd, Japan) showed higher catalytic activity than metal incorporated ceria catalysts. CeO2 had the right kind of acidity/basicity ratio to activate ethanol and CO2 simultaneously, yielding DEC. The catalyst was reusable. The yield of DEC obtained in this study using the commercial catalyst was higher than that reported by others using ceria catalysts prepared by other methods. Under optimum conditions (ethanol?:?2-CP molar ratio = 2?:?1, catalyst = 2.17 wt% with respect to ethanol, CO2 pressure = 40 bar, reaction temperature = 150 °C and reaction time = 3 h) in a batch reaction, a DEC yield as high as 45 mol% (i.e., 38.7 mmol mmol?1 of CeO2) was obtained.
- Giram, Ganesh G.,Bokade, Vijay V.,Darbha, Srinivas
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p. 17546 - 17552
(2018/11/01)
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- Method for preparing dialkyl carbonate by alcoholysis of urea
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The invention relates to a method for preparing dialkyl carbonate by alcoholysis of urea, belonging to the field of chemical synthesis. More specifically, the invention relates to preparation of dialkyl carbonate. The method comprises the following step: subjecting urea and alkyl monohydric alcohol to a reflux reaction under stirring for 6 to 30 hours under the condition of normal pressure or reduced pressure at a reaction temperature of 70 to 150 DEG C by using one or more selected from the group consisting of metal magnesium, calcium, aluminum, chromium, manganese, iron, cobalt, nickel, copper or zinc as a main catalyst and one or more compounds containing donor atom nitrogen, phosphorus, oxygen or sulfur as an auxiliary catalyst so as to prepare the dialkyl carbonate. The preparation method provided by the invention has the following advantages: the dialkyl carbonate is prepared with high selectivity and high yield at a low reaction temperature under the condition of normal pressureor reduced pressure; simple operation, high safety and low cost are achieved in the processing process; and good industrial application prospects are obtained.
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Paragraph 0044
(2018/09/08)
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- Acid–base sites synergistic catalysis over Mg–Zr–Al mixed metal oxide toward synthesis of diethyl carbonate?
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In heterogeneous catalysis processes, development of high-performance acid–base sites synergistic catalysis has drawn increasing attention. In this work, we prepared Mg/Zr/Al mixed metal oxides (denoted as Mg2ZrxAl1x–MMO) derived from Mg–Zr–Al layered double hydroxides (LDHs) precursors. Their catalytic performance toward the synthesis of diethyl carbonate (DEC) from urea and ethanol was studied in detail, and the highest catalytic activity was obtained over the Mg2Zr0.53Al0.47MMO catalyst (DEC yield: 37.6%). By establishing correlation between the catalytic performance and Lewis acid–base sites measured by NH3-TPD and CO2-TPD, it is found that both weak acid site and medium strength base site contribute to the overall yield of DEC, which demonstrates an acid–base synergistic catalysis in this reaction. In addition, in situ Fourier transform infrared spectroscopy (in situ FTIR) measurements reveal that the Lewis base site activates ethanol to give ethoxide species; while Lewis acid site facilitates the activated adsorption of urea and the intermediate ethyl carbamate (EC). Therefore, this work provides an effective method for the preparation of tunable acid–base catalysts based on LDHs precursor approach, which can be potentially used in cooperative acid–base catalysis reaction.
- Yan, Tingting,Bing, Weihan,Xu, Ming,Li, Yinwen,Yang, Yusen,Cui, Guoqing,Yang, Lan,Wei, Min
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p. 4695 - 4702
(2018/02/07)
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- Method for synthesizing diakyl carbonate from biomass-based synthesis gas
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The invention belongs to synthesis methods of ester compounds in organic chemistry and particularly relates to a method for synthesizing diakyl carbonate from biomass-based synthesis gas. Biomass-based synthesis gas obtained from biomass-based agricultural and forestry residues used as initial materials is further catalyzed to form dimethyl ether, the obtained dimethyl ether is further catalyzed to form dimethyl carbonate, then, dimethyl carbonate is subjected to transesterification with monohydric alcohol or polyhydric alcohol, and diakyl carbonate is obtained. According to the method, diakylcarbonate is produced from the cheap agricultural and forestry residues used as raw materials, the production cost is saved, environmental pollution is reduced, and a new way is provided for industrial production of diakyl carbonate and efficient and comprehensive utilization of agricultural and forestry residues, and the method has significant economic and social benefits.
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Paragraph 0026; 0038; 0039; 0040
(2018/11/22)
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- Method for preparing asymmetric carbonate esters
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The invention discloses a method for preparing asymmetric carbonate esters, and relates to a preparation method of a chemical raw material. At the same time, the invention provides a high-efficiency alkaline catalyst with a composite pore structure used for one-step synthesis of asymmetric carbonate esters from ethylene carbonate, methanol and various alcohols (ROH, wherein R can be various alcohols such as linear alcohols, isomeric alcohols, aromatic alcohols, phenols, and glycols such as ethylene glycol, diethylene glycol and polyols). The obtained crude product of the reaction contains dimethyl carbonate, asymmetric carbonate esters, symmetric carbonate esters and ethylene glycol, wherein the conversion rate of ethylene carbonate can reach up to 99% at maximum, and the byproduct ethylene glycol as a bulk raw material can be separated through simple distillation. The entire reaction process is clean, efficient, non-polluting and free of generating any waste. When the molar ratio of ethylene carbonate: methanol: various alcohols is 1:3:2, the reaction pressure is 5 MPa, the reaction temperature is 100 DEG C, and the space velocity is 5 h, the catalyst does not lose activity after being used for 5000 h, and the stability is better.
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Paragraph 0052; 0053; 0059; 0061
(2018/07/30)
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- Continuous CO2 esterification to diethyl carbonate (DEC) at atmospheric pressure: Application of porous membranes for: In situ H2O removal
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The direct synthesis of diethyl carbonate (DEC) from ethanol and carbon dioxide over Ce0.8Zr0.2O2 catalysts was investigated in continuous mode at atmospheric pressure. Three main parameters, namely molar ratio of ethanol/CO2, flux and temperature, have significant influence on the formed DEC amount and were studied systematically. With 32 mmolDEC L-1cat h-1 achieved at ambient pressure, an ethanol/CO2 molar ratio of 3 and a temperature of 100 °C the continuous approach offers a higher productivity compared to batch reactions, normally performed in autoclaves under much higher pressure. Moreover, in order to shift the equilibrium to promote the formation of DEC, four inorganic porous membranes, (i) MFI zeolite, Si/Al ratio ~57; (ii) MFI zeolite, Si/Al ratio ~270; (iii) LTA (NaA) zeolite; and (iv) a microporous carbon membrane, have been applied for product removal in a catalytic membrane reactor. A relationship between the amount of removed water achieved by the membranes and the enhancement of formed DEC amount was found. The productivity can be increased to 47 mmolDEC L-1cat h-1 using an MFI-57 membrane.
- Wang, Junhui,Hao, Zhengping,Wohlrab, Sebastian
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supporting information
p. 3595 - 3600
(2017/08/15)
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- Method of converting amide and urea into ester
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The invention provides a method of converting amide and urea into ester. In the method, different types of amide and urea are used as substrate, alcohol or phenol is used as nucleophile, iron salt is used as catalyst, and acid is used as additive, the conversion of amide and urea into ester is achieved under a mild condition. The method is characterized in that cheap iron salt is used as the catalyst, the commercialized amide, urea, and alcohol are used as the substrate, and the conversion of amide to ester is achieved in one step. The method has the advantages that the reaction condition is mild, the raw materials are cheap and easy to obtain, the reaction substrate is wide in adaptability, the selectivity and yield of the product are very high, the product is green and environmentally friendly and the like, and the method has good prospects for industrial applications.
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Paragraph 0066-0068
(2017/08/30)
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- PROCESS FOR THE PREPARATION OF ORGANIC CARBONATE DERIVATES
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The present invention relates in general terms to a new process for the preparation of organic carbonate derivatives, cyclic or linear by a trans carbonation reaction between PCC and a suitable aliphatic alcohol, in the presence of a homogeneous or heterogeneous basic catalyst; the process allows to optimize yields and selectivities of the obtained products, especially in the case of the preparation of symmetrical linear or cyclic carbonates starting from the corresponding primary alcohols.
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Page/Page column 27
(2017/04/11)
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- The design of efficient carbonate interchange reactions with catechol carbonate
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Catechol carbonate (CC) has been investigated as an innovative and highly active reactant for carbonate interchange reactions (CIRs). Under mild conditions (atmospheric pressure, and 60-80°C), the selective synthesis of symmetric aliphatic carbonates (ROCO2R) has been achieved by the reaction of a slight excess of both primary and secondary alcohols with CC in the presence of NaOMe or MgO as a catalyst. Quantitative conversions have been reached in only 1 hour and products have been isolated in yields of up to 58% for dibutylcarbonate. Of note is that the reaction of glycerol with CC also proceeded under similar conditions (40-60°C, 1 atm) to afford glycerol carbonate (96-98%). The comparison of the reactivity of CC with that of conventional dialkyl carbonates, including dimethyl carbonate (DMC) and ethylene carbonate (EC), proved the superior performance of CC in all the investigated CIR processes. Accordingly, a mechanism has been formulated based on the leaving group ability of a catecholate anion originating from CC.
- Tabanelli,Monti,Cavani,Selva
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p. 1519 - 1528
(2017/05/01)
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- Method for preparation of methyl ethyl carbonate with co-precipitation catalyst
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The invention relates to a preparation method of chemical raw materials, in particular to a method for preparation of methyl ethyl carbonate with a co-precipitation catalyst. The method adopts coprecipitation technique to carry one or more of the active components Al2O3, CaO, La2O3, Fe2O3, Mn2O3, Cs2O, MgO, BaO, SrO and K2O, wherein Y is one or more oxides of Si and Al, and Z is one or more oxides of Si, Al and Ti. The invention has the advantages that: macropore can significantly improve the mass transfer effect, and micropore can significantly increase the specific surface area of the carrier and improve the dispersity of the active center. Magnesium nitrate, aluminum chloride and lanthanum sulfate are adopted as the active components and are mixed with a precursor to obtain the 15%MgO-5%Al2O3-3%La2O3/Al2O3-SiO2 catalyst, which can be applied to dimethyl carbonate and ethanol ester exchange fixed bed continuous reaction. The catalyst active center metal oxide prepared by precipitation method has smaller crystal grains, higher dispersity and surface area, and the prepared catalyst has catalytic effect superior to the catalyst prepared by impregnation method.
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027-0075
(2018/01/11)
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- Method for preparing ethyl methyl carbonate through ester exchange method
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The invention provides a method for preparing ethyl methyl carbonate through an ester exchange method, and relates to a method for preparing a chemical raw material. A first catalyst prepared by the method simultaneously has macropore and micropore structures, wherein the macropores can obviously improve the mass transfer effect; and the micropores can obviously improve the specific surface area of a carrier and simultaneously improve the dispersity of active centers. Meanwhile, the prepared first catalyst simultaneously has an alkali active center and a Lewis acid catalytic active center. The prepared 15%MgO-5%MgCl2-2%La2O3/Al2O3-SiO2 is used in a dimethyl carbonate and ethanol ester exchange fixed bed continuous reaction; when the reaction temperature is 200 DEG C and the space velocity is 30h, the catalyst is not inactivated after 5000h of continuous reaction, the dimethyl carbonate conversion rate can be kept at 70%, the ethanol conversion rate can be kept at 80%, and the yield of the product ethyl methyl carbonate is 56%; and after the reaction, the catalyst can be reused through simple filtration treatment, and the activity of the catalyst can still be kept unchanged after the catalyst is reused for multiple times.
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Paragraph 0026; 0027; 0030; 0032; 0034; 0041; 0044; 0048
(2018/03/24)
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- Oxidation of a highly efficient and safe method of synthesizing carbon ester carbonyl (by machine translation)
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The invention discloses an efficient and safe method for synthesizing carbonic ester by using oxidative carbonyl. The method comprises the steps of oxidative glycosylation reaction, flash separation, gas-liquid separation and product separation. The method can be used for overcoming the defects of heterogeneous catalytic system, complex process, poor recyclability and potential safety hazard of reaction process in the prior art; a novel process device is adopted; the feeding mole ratio of carbon monoxide (CO) to oxygen (O2) can be controlled; CO and O2 are taken as the reaction raw material gases; the catalyst solution is recyclable; a catalyst system applied to the reaction is a catalyst solution prepared from a solvent and a complex which is formed by homogeneous active components and ligands. The method has the advantages that the process is efficient, safe and simple, and the catalyst solution is easily recyclable; and the method has a good prospect of industrial application.
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Paragraph 0035-0036
(2017/06/21)
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- Using alkaline ionic liquid as catalyst method of synthesizing ethyl carbonate (by machine translation)
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The invention relates to the chemical field, in particular to a kind of the alkaline ionic liquid as catalyst method of synthesis of diethyl carbonate. To propylene carbonate and ethanol as the raw material, the alkaline ion [Bmim]OH liquid as catalyst, synthetic ester exchange reaction of ethylene carbonate esters and 1,2-propylene glycol. Transesterification reaction temperature is 40-115°C, ester exchange reaction to the pressure of 0.05-0.5 MPa, ester exchange reaction of the stirring speed is 300-1000r/min. The beneficial effect of the invention is:to alkaline ionic liquid as catalyst solves the problem that the catalyst is not stable, low activity of the catalyst, catalyst and the like is difficult to separate. (by machine translation)
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Paragraph 0015; 0016
(2017/04/03)
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- A cyclic carbonic acid ester and ester exchange reaction method for synthesizing linear carbon ester
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The invention relates to reaction to synthesize linear carbonic ester by catalyzing cyclic carbonate by taking cerium oxide with high specific surface as a catalyst. According to the reaction, the cerium oxide with high specific surface (50-180mg) is taken as the catalyst, the cyclic carbonate and alcohol are taken as raw materials, the reaction temperature is 70-160 DEG C, the reaction time is 2-12 hours, the selectivity of the linear carbonic ester is 73-99%, the yield of the linear carbonic ester is 23-84%, and the catalyst can particularly effectively catalyze ethylene carbonate. Compared with a conventional ordinary catalyst for catalysis reaction, the catalyst, namely, the cerium oxide with high specific surface has the advantages of convenient recycling, high catalysis, good repeated use effect and the like.
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Paragraph 0063-0067
(2017/03/14)
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- A PROCESS FOR THE SYNTHESIS OF DIALKYL CARBONATES
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The patent discloses a process for the synthesis of dialkyl carbonates catalysed by a catalyst composition AB oxides, wherein A and B are rare earth metals or A and B are combination of rare earth and transition metals with ratios ranging from 0.5:10 to 10:0.5.
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Page/Page column 18
(2016/10/11)
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- Method for preparing ethyl methyl carbonate
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The invention relates to a method for preparing ethyl methyl carbonate to mainly solve the problems that a catalyst used for preparing methyl ethyl carbonate through a reaction of dimethyl carbonate and ethyl alcohol at present is difficult to prepare and cannot be reused. Ethyl methyl carbonate is prepared from, by mass, 90.8 kg of dimethyl carbonate, 92.14 kg of ethyl alcohol and 3.64 kg of calcium methoxide. All the raw materials are continuously put into a reaction kettle according to the mass ratio, a backflow reaction is carried out for one hour at the normal pressure, and the reaction temperature is 80 DEG C; after balancing is achieved, methyl alcohol generated in the reaction is distilled out through reduced pressure distillation, is condensed and then enters a methyl alcohol storage tank, diethyl carbonate and ethyl methyl carbonate which are generated in the reaction, unreacted ethyl alcohol and unreacted dimethyl carbonate enter a rectifying tower for rectification separation, separated ethyl alcohol and separated dimethyl carbonate return to the reaction kettle to continue to participate in the reaction, ethyl methyl carbonate separated and distilled out enters a ethyl methyl carbonate storage tank, and diethyl carbonate separated and distilled out enters a diethyl carbonate storage tank. The method has the advantages that a catalyst is easy to prepare, and reuse can be achieved.
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Paragraph 0007
(2016/10/27)
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- Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6 H)-carboxylates: A practical alternative to chloroformates for the synthesis of symmetric and asymmetric carbonates
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Symmetric and asymmetric carbonates were synthesized by using alkyl or aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates. Five aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates were converted into the corresponding diaryl carbonates in good to excellent yields by treatment with potassium carbonate in refluxing THF. When the 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates were treated with aliphatic or aromatic alcohols in the presence of potassium tert-butoxide in toluene at room temperature, they gave the corresponding symmetric or asymmetric carbonates in moderate to excellent yields. Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates are therefore efficient, stable, and ecofriendly alternatives to chloroformates.
- Moon, Hyun Kyung,Sung, Gi Hyeon,Yoon, Yong-Jin,Yoon, Hyo Jae
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supporting information
p. 1577 - 1581
(2016/06/14)
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- METHOD FOR PRODUCING DIALKYL CARBONATE
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PROBLEM TO BE SOLVED: To provide a production method that efficiently produces dialkyl carbonate from alkyl carbamate. SOLUTION: A method for producing dialkyl carbonate comprises: disproportionating O-alkyl carbamate in the presence of a catalyst under reduced pressure to produce dialkyl carbonate; and extracting the produced dialkyl carbonate from a reaction system. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0048; 0051
(2017/02/09)
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- Continuous synthesis of diethyl carbonate from ethanol and CO2 over Ce-Zr-O catalysts
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CexZr1-xO2 (x = 0, 0.2, 0.5, 0.8 and 1.0) solids were prepared by a citrate method and characterized by various techniques such as N2-adsorption (BET-SA), XRD, XPS, TEM, H2-TPR, NH3- and CO2-TPD. The catalytic performance of these solids was evaluated for the direct synthesis of diethyl carbonate (DEC) from ethanol and CO2 in continuous mode using a plug-flow reactor (PFR). According to thermodynamic data, the reaction is favourable at low reaction temperatures and high reaction pressures. Thus, the catalytic experiments were carried out at reaction temperatures ranging from 80 to 180 °C and at reaction pressures from 80 to 180 bar. The CexZr1-xO2 catalysts exhibited significant differences in their performance mainly depending on (i) their Ce:Zr ratio and (ii) the different acid-base characteristics. Among the series Ce0.8Zr0.2O2 (C80Z) and Ce0.5Zr0.5O2 (C50Z) catalysts displayed the most efficient performance. Moreover, C80Z, pretreated at 700 °C, yielded DEC at the equilibrium conversion level of YDEC ~ 0.7% at 140 °C and 140 bar at a CO2:ethanol ratio of 6:1 at a LHSV of 42 Lliq kgcat-1 h-1. This journal is
- Prymak, Iuliia,Kalevaru, Venkata Narayana,Wohlrab, Sebastian,Martin, Andreas
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p. 2322 - 2331
(2015/04/14)
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- SINGLE-POT SYNTHESIS OF DIALKYL CARBONATES USING CATALYST FROM NATURAL RESOURCE
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The present invention relates to a single-pot method for preparing dialkyl carbonates, the method comprises reaction of alkylene oxide with aliphatic or cyclic aliphatic alcohol, using wood ash catalyst, under CO2 pressure and heating the reaction mixture thereof to obtain dialkyl carbonates.
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Page/Page column 13-14
(2015/11/02)
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- Production of carbonate
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PROBLEM TO BE SOLVED: To provide a production method which can also obtain a carbonic ester at even a mild reaction condition, controls the discharge of a by-product, and can easily separate/purify the carbonic ester.SOLUTION: The method of producing a carbonic ester includes a step in which a compound of formula (1) is made to react with carbon dioxide under the presence of a polar organic solvent. In the formula, R-Reach independently are a monovalent hydrocarbon group; and Rand Rmay mutually combine directly or through other groups.
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Paragraph 0051-0054
(2017/01/02)
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