Synthesis of Diethyl Carbonate from Carbon Dioxide, Propylene Oxide and Ethanol over KNO3-CeO2 and KBr-KNO3-CeO2 Catalysts

Yanlou Wang,Zhen Zhu,Yongyue Sun,Dongdong Jia

doi:10.3390/catal6040052

Yanlou Wang, Zhen Zhu + Show 2 more

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https://doi.org/10.3390/catal6040052

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Abstract

One-pot syntheses of diethyl carbonate (DEC) from CO2, propylene oxide and ethanol were carried out using different solid catalysts. The supercritical CO2 extraction method was used to separate the liquid products and reactants from the catalysts after reaction. The KNO3-CeO2 and KBr-KNO3-CeO2 were found to be active for the reaction after calcinations. The catalyst was also reusable. The thermodynamic properties of the reaction were also evaluated. The effects of various conditions, such as reaction time, amount of catalysts, molar ratio of the reactants, the composition and calcination temperature of the catalysts on the conversion and yields, were investigated, and the yield of DEC was about 13.0% with a selectivity of 38.5% over KBr-KNO3-CeO2. The yield of DEC was improved about 10-fold by using KBr-KNO3-CeO2 catalyst compared to CeO2.

Highlights

The synthesis of chemicals using CO2 as a raw material is characterized at present by increasing industrial and academic efforts to use this carbon renewable [1]
The one-pot reaction in Diethyl carbonate (DEC) synthesis might be composed of two steps, the cycloaddition reaction one‐pot transesterification reaction in DEC synthesis might be composed ofreaction two steps, cycloaddition andThe subsequent reaction
The results indicate that the oxides with acid-base properties, especially ZrO2, γ-Al2 O3 and CeO2 combined with KNO3, are more active for DEC synthesis

Summary

Introduction

The synthesis of chemicals using CO2 as a raw material is characterized at present by increasing industrial and academic efforts to use this carbon renewable [1]. Diethyl carbonate (DEC) is one of the most important green chemicals among carbonate esters. It is an excellent solvent and an intermediate for various pharmaceuticals, such as antibiotics and phenobarbital [8]. The reaction hardly occurs spontaneously, even under harsh conditions, due to the thermodynamic limitations (yield of less than 0.5%) [8]. To address this issue, chemical dehydration reagent was usually involved to shift the reaction forward to the carbonate side. Acetonitrile [17] and amines [18]

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