Transesterification Of Ethylene Carbonate Research Articles

Synthesis of dimethyl carbonate by transesterification with various MgO–CeO2 mixed oxide catalysts

The transesterification of ethylene carbonate (EC) with methanol to co-generate dimethyl carbonate (DMC) and ethylene glycol over the MgO, CeO2 and mixed oxide thereof was studied using a fixed-bed isothermal tube reactor. In all mixed oxide, the presence of cerium led to a decrease of BET surface area and pore volume as compared to pure magnesia. X-ray diffraction (XRD) revealed that no mixed phases were observed, but MgO (periclase) and CeO2 (cerianite) phases. The catalytic activity intensely depends on the surface basicity and the base strength distribution, but not on the surface area and pore volume. It was found that a high EC conversion of 67% with DMC selectivity of 95% could be obtained by catalyst with cerium content around 25 mol%.

Transesterification of Ethylene Carbonate with Dimethyl Terephthalate over Various Metal Acetate Catalysts

The reaction between ethylene carbonate and dimethyl terephthalate was carried out for the simultaneous synthesis of dimethyl carbonate and poly (ethylene terephthalate). This reaction is an excellent chemical process that is environmentally friendly and produces no poisonous substance. The metal acetate catalysts used for this reaction are discussed in detail. Lithium acetate dihydrate was found to be a novel and efficient catalyst for this reaction. Compared with other metal acetates, lithium acetate dihydrate can attain a maximum catalytic activity at a lower concentration. When the reaction was carried out under the following conditions: the reaction temperature from 230 to 250 °C, molar ratio of ethylene carbonate(EC) to dimethyl terephthalate(DMT) 3: 1, reaction time 3 h, and a catalyst amount of 0.4% (molar fraction to DMT), the yield of dimethyl carbonate(DMC) was 79.1%.

Transesterification of cyclic carbonates with methanol at ambient conditions over tungstate-based solid catalysts

Dimethyl carbonate synthesis with 80 mol% yield is achieved through transesterification of ethylene carbonate with methanol at ambient conditions (RT and atmospheric pressure) using alkali and alkaline-earth tungstates as solid catalysts. The catalysts are efficient even at the sub-ambient temperatures. Reactions under CO 2 pressure indicate that CO 2 atmosphere retards the transesterification reaction completely below 100 °C. Experimental conditions of 150 °C and 3.4 MPa CO 2 pressure are required to obtain maximum DMC yield of 71 mol%. Synthesis of DMC by one-pot synthesis using epoxide, CO 2 and methanol is not as effective as that by two-step method with the present catalyst system. Raman and IR spectra of methanol-interacting tungstates indicate the formation of a methoxide ion species adsorbed at the catalyst surface as one possible reaction intermediates.

Synthesis of dimethyl carbonate (dmc) from co2, ethylene oxide and methanol using heterogeneous anion exchange resins as catalysts

A two-step synthesis of dimethyl carbonate (DMC) from ethylene oxide (EO), carbon dioxide and methanol using heterogeneous anion exchange resins as catalysts is reported. The first step is the reaction of EO with CO2 to form ethylene carbonate (EC), and the second one the transesterification of EC with methanol to yield DMC. Effect of various reaction parameters on the activity and selectivity of the catalysts used was investigated. After the first step, the crude mixture containing EC was directly reacted with methanol in the presence of a heterogeneous anion exchange resin catalyst to produce DMC in high yield and selectivity. Our process is highly economic.

Isobaric Vapor−Liquid Equilibria of Binary Mixtures Containing the Carbonate Group −OCOO−

Isobaric vapor−liquid equilibria (VLE) data for the four systems of dimethyl carbonate + ethylene carbonate, methanol + ethylene carbonate, dimethyl carbonate + ethylene glycol, and ethylene glycol + ethylene carbonate containing the carbonate group −OCOO−, which exist in the process of synthesizing DMC by transesterification of ethylene carbonate with methanol, have been measured at atmospheric pressure or under vacuum in an Ellis equilibrium still. The experimental VLE data are thermodynamically consistent, and the activity coefficients have been evaluated with the Wilson and NRTL equations, showing that the systems of dimethyl carbonate + ethylene glycol and ethylene glycol + ethylene carbonate have stronger nonideality. The results of this work are useful to the research on DMC synthesis by transesterification.

Chemical Fixation of Carbon Dioxide: Synthesis of Cyclic Carbonate, Dimethyl Carbonate, Cyclic Urea and Cyclic Urethane

Chemical fixation of carbon dioxide (CO 2 ) may be very important in the future as a solution for the problem of increased atmospheric CO 2 levels. Recent developments for chemical fixation of CO 2 to cyclic carbonate, dimethyl carbonate (DMC), cyclic urea and cyclic urethane are reviewed. Synthesis of cyclic carbonate via CO 2 addition to epoxide has been already applied on the industrial scale, but catalyst development continues. Direct oxidative carboxylation of olefin is preferable for the synthesis of cyclic carbonate, but requires the development of catalysts for the epoxidation step in the presence of CO 2 . Direct synthesis of DMC is not in practical use at present because of the reaction equilibrium and chemical inertness of CO 2 . The preferred alternative is transesterification of ethylene carbonate and methanol for converting CO 2 to DMC indirectly. Moreover, combination of this reaction with CO 2 addition to epoxide or reaction of ethylene glycol and urea to synthesize DMC is promising. Application of these ideas depends on the development and optimization of catalysts and reaction conditions. Synthesis of cyclic urea and urethane without catalyst should use either CO 2 or urea depending on the structures of diamine and amino alcohol.

Kinetic Study on the One-Pot Synthesis of Dimethyl Carbonate in Supercritical CO2 Conditions

The kinetics of one-pot synthesis of dimethyl carbonate (DMC) was investigated using ethylene epoxide (EO), methanol, and CO2 as raw materials and a mixture of KI and K2CO3 as a catalyst under supercritical CO2 conditions. The reaction pathway of the one-pot process is that EO first reacts with CO2 to form ethylene carbonate (EC) and then EC reacts with methanol to produce DMC and ethylene glycol (EG). EC formation is a relatively fast reaction, whereas the transesterification of EC with methanol to form DMC is a relatively slow reaction and the rate-control step of the one-pot synthesis. 2-Methoxyethanol (ME), which is the exclusive byproduct, is predominantly formed by the reaction of EC with methanol. An isothermal kinetics model and an isobaric kinetics model for the one-pot synthesis of DMC were developed. The relative standard deviations of the models from the experiment data were less than ±15% and ±10%, respectively. The effects of temperature and CO2 density on the reaction rates and selectivity ...

Concurrent Synthesis of Dimethyl Carbonate and Ethylene Glycol via Transesterification of Ethylene Carbonate and Methanol Using Smectite Catalysts Containing Mg and/or Ni

Smectites containing magnesium and/or nickel in the lattice were found to be excellent heterogeneous catalysts for the concurrent synthesis of dimethyl carbonate and ethylene glycol by transesterification of ethylene carbonate with methanol. The catalytic activity strongly depends on the elemental composition of the catalysts and is correlated with the number of moderately basic sites present on the catalyst.