Performance of ionic liquid as catalysts in the synthesis of dimethyl carbonate from ethylene carbonate and methanol

Abstract

The synthesis of dimethyl carbonate (DMC) from methanol and ethylene carbonate (EC) without using any solvent was investigated in the presence of ionic liquids as catalysts. The conversion of ethylene carbonate was affected by the structure of ionic liquid. For a series of 1-alkyl-3-methylimidazolium ionic liquids, the one with shorter alkyl chain and the one with more nucleophilic anion showed higher reactivity. The conversion of EC also increased with CO 2 pressure and reaction temperature. Esterification of EC and methanol can be considered as a pseudo-first order reaction with respect to EC concentration. The activation energy was estimated as 50.1 kJ/mol.

Ionic Liquids in Green Carbonate Synthesis

“…The PC conversion was in the order of Cl -> Br -> I -. This order is different from that observed for the cycloaddition of CO 2 [91]. The most active IL of [EMIm]Cl gave the largest DMC yield of 76% at 140°C for 6 h. The difference in the DMC yield by the alkyl chain length was ascribed to that in the solubility of ILs.…”

A Novel One-Pot and One-Step Microwave-Assisted Cyclization-Methylation Reaction of Amino Alcohols and Acetylated Derivatives with Dimethyl Carbonate and TBAC

“…Their unique chemical and physical properties have attracted their use as organic catalysts and many catalytic reactions proceeded in ionic liquids with excellent performance [ 19 – 23 ]. Recently, the using of ionic liquids for cycloaddition of CO 2 to epoxides to produce cyclic carbonates has been extensively studied [ 24 , 25 ].…”

The Effect of Alkoxide Ionic Liquids on the Synthesis of Dimethyl Carbonate from CO2 and Methanol over ZrO2–MgO

“…RTILs have demonstrated excellent performance as catalysts or as reaction media in catalytic reactions [26][27][28] for example, DMC has been synthesised by the oxidative carbonylation of methanol at 120°C and 2.4 MPa using Cu salts as catalysts and ionic liquids as promoters, affording 17% conversion of methanol and 97.8% selectivity to DMC [26]. In addition, the transesterification of propylene and ethylene carbonate at 140°C, occurred in the presence of [C 2 -mim][Cl] as a catalyst, resulting in 15 and 75% yield, respectively [27,29]. In the transesterification, however, the low atom economy (59 wt%) and the use of toxic cyclic ethers make this process unsatisfactory.…”