• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.416-420
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• 2018

A comprehensive kinetic study has been conducted on dimethyl carbonate synthesis by transesterification reaction of ethylene carbonate with methanol. An alkali base metal (KOH) was used as catalyst in the synthesis of DMC, and its catalytic ability was investigated in terms of kinetics. The experiment was performed in a batch reactor at atmospheric pressure. The reaction orders, the activation energy and the rate constants were determined for both forward and backward reactions. The reaction order for forward and backward reactions was 0.87 and 2.15, and the activation energy was 12.73 and 29.28 kJ/mol, respectively. Using the general factor analysis in the design of experiments, we analyzed the main effects and interactions according to the MeOH/EC, reaction temperature and KOH concentration. DMC yield with various reaction conditions was presented for all ranges using surface and contour plot. Furthermore, the optimal conditions for DMC yield were determined using response surface method.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1834-1838
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• 2012

A facile route for the synthesis of dimethyl glutarate (DMG) from cyclobutanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclobutanone (CMCB) was produced from cyclobutanone with DMC in the first step, and then CMCB was further converted to DMG by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclobutanone $via$ the abstraction of a proton in the ${\alpha}$-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DMG.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.622-624
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• 2014

• KEPCO Journal on Electric Power and Energy
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• v.2 no.2
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• pp.187-192
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• 2016

Chemical utilization of $CO_2$ is recognized as the technology for the reduction of greenhouse gas as well as the use of carbon to resources. Although various chemicals are commercially produced, the innovative development is still necessary to utilize large quantity of $CO_2$. In this report, the current status of technology to preserve -CO-O- linkage into the molecules was introduced, particularly for the synthesis of dimethyl carbonate (DMC) and polyols, which are raw materials of polycarbonate and polyurethane, respectively. RIST developed the novel process for the DMC production via urea methanolysis and the new catalytic system for polyol synthesis. Because of high contents of $CO_2$ in both chemicals, it is expected that they are able to contribute for the reduction of greenhouse gas.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.766-771
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• 2012

PC (polycarbonate) is one of the widely used engineering plastics. Polycarbonate (PC) is traditionally produced by the reaction of phosgene and bisphenol-A. This phosgene process has the disadvantage as the high toxicity and corrosiveness of phosgene. The main point of focus to overcome the disadvantage of phosgene based process has been a route through dimethyl carbonate (DMC) to diphenyl carbonate (DPC). In this paper, for the DPC synthesis reaction using PBO as a catalyst, the effect of reaction temperature, reactant ratio, catalyst concentration on the reaction yield was investigated. A kinetic model for the DPC synthesis reaction was proposed and kinetic parameters for the proposed model was determined from batch reactor experiments. The predicted results by the proposed model were in good agreement with the experimental results.

• Clean Technology
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• v.22 no.3
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• pp.196-202
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• 2016

In this study, ceria- based catalysts were prepared for dimethyl carbonate (DMC) synthesis and reaction conditions were evaluated for finding the optimal reaction route. In order to find optimal catalysts for DMC synthesis, calcination temperature and Cu(II) impregnation amount were evaluated. The oxidative carbonylation using methanol, carbon monoxide and oxygen and the direct synthesis using methanol and carbon dioxide were introduced for producing DMC. Following the law of Le Chatelier, the dehydration reaction was applied for enhancing the reactivity (methanol conversion) as removing water during the reaction. 2-cyanopyridine, as a chemical dehydration agent, was used. In the case of the oxidative carbonylation, methanol conversion rate increased from 15.1% to 38.7% and the DMC selectivity increased from 0% to 98.8%. In the case of the direct synthesis, methanol conversion rate increased from 1.0% to 77.8% and the DMC selectivity increased from 41.2% to 100.0%.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3163-3168
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• 2014

Three kinds of lanthanum oxides ($La_2CO_3$) were synthesized from different methods and used as a catalyst in the transesterification of dimethyl carbonate (DMC) with glycerol for the synthesis of glycerol carbonate (GLC). Lanthanum oxide synthesized using a surfactant (S-La) showed a much higher GLC yield of 89.9% compared to other lanthanum oxides synthesized by calcination (C-La) and precipitation (P-La) at the reaction conditions of $90^{\circ}C$, DMC/glycerol = 2, and catalyst/glycerol = 5 wt %. The best catalyst was obtained when the surfactant/La weight ratio was 12. XRD study revealed that S-La has large amount of monoclinic and hexagonal $La_2O_2CO_3$ phases, which are assumed as active sites of the catalyst for the reaction.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1103-1105
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• 2002

H-ZSM-5 and γ-alumina were treated with formaldehyde and sodium carbonate. The treatment increased the amounts of weak acid sites, removing strong acid sites. The maximum temperature of weak acid sites in their ammonia TPD spectra shifted in the direction of high temperature. The modified H-ZSM-5 and g-alumina were mixed with the methanol synthesis catalyst to perform dimethyl ether synthesis from syn-gas. The modified catalysts showed better selectivity to dimethyl ether, minimizing the reforming reaction to carbon dioxide. The maximum yield of 53.3% to dimethyl ether was achieved under the reaction conditions of 54.4 atm, 523 K, and the feed rate of 4500 Lhr-1 .gcat-1.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.550-554
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• 2008

The synthesis of dimethyl carbonate (DMC) from methanol and supercritical carbon dioxide over $K_2CO_3/ZrO_2$ catalysts have been studied. The catalysts were prepared by impregnating $ZrO_2$ with an aqueous $K_2CO_3$ solution. The optimum calcination temperature to disperse K species on the $ZrO_2$ surface was found to be 673 K. Monoclinic $ZrO_2$ was not active, as itself, for the DMC production. However, when the $K_2CO_3$ was impregnated on the $ZrO_2$, the catalytic performance was improved. Besides the catalyst, $CH_3I$ was used as a promoter. The $CH_3I$ promoter as well as the $K_2CO_3/ZrO_2$ catalyst was found to take an important role to improve the production of DMC. The optimum quantities for the catalyst and the promoter were estimated. The effect of the catalyst and the promoter for the DMC synthesis from methanol and supercritical carbon dioxide was investigated and the reaction mechanism was proposed.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.554-559
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• 2007

In order to improve the reactivity for the direct synthesis of dimethyl carbonate (DMC) using methanol and carbon dioxide, the various additives were used in the DMC synthesis using $Ce_{0.8}Zr_{0.2}O_2$ catalyst, and then effect of the additives was investigated. The various additives were molecular sieves 3A and the compounds having the various functional groups such as sulfate, carbonate, nitrate and phosphate. As a result, the compound such as $K_2SO_4$ and $Na_2SO_4$ having sulfate group were the most effective additive among the various additives. When $K_2SO_4$ was used as an additive in the direct synthesis of DMC, the amount of DMC was about 0.91 mmol, which was the highest mount of DMC among using only-$Ce_{0.8}Zr_{0.2}O_2$ catalyst and the various additives.