Optimizing Research Of The Dimethyl Carbonate Synthesis Operating Conditions

Dimethyl carbonate has unique molecular structure (CH₃-O-CO-O-CH₃), Containing -CO-,-CH₃,–COOCH₃ and other functional groups with very lively chemistry. It was important methylation and carbonylation reagent. It can replace highly toxic substances such as phosgene, dimethyl sulface, Halogenated methane and so on. It has been through Europe non-toxic chemicals register in 1992. DMC also has been widely used in pesticides, medicine, spices, fuel additives, solvents and in the electronics industrial fields.At present, the methods to Large-scale product DMC have phosgene method, Transesterification, Oxidation of methanol carbonylation law. Transesterification have been become the mainstream production technology of DMC because its ratio of production capacity was about 90% of the total.This paper studied 10 000 tons /year DMC transesterification plant of Hi-tech spring. This device used extracrive distillation's method to separating azeotrope of methanol and DMC. Through the optimization study to the operating conditions aimed at improving the product capacity and product quality of DMC. In improving the handling capacity of the device, We have major research operating pressure, reflux ratio, feed ratio of ME/PC, feed charge of the catalyst of the reaction distillation tower to optimizing the operating parameters. Research shows the handling capacity of device increased 40% from 10 000 tons/year to current 14 000 tons/year when operating pressure of the top of the tower was -20kPa, the ratio of methanol and PC was 2.1:1, the reflux ratio was 1.2¹.5, the concentration of catalyst was 0.3⁰.4%. In increasing the quality of the product, We optimized operation condition on feed ratio of extractant and azeotrope and reflux ratio of the extraction tower. Research shows when the ratio of extractant and azeotrope was 1.45 and the ratio of reflux was 0.5 could be ensure low content of methanol in the bottom of the extraction tower, the purity of DMC was above 99.5% in the regeneration tower, the purity of DMC was above 99.9% in the product tower of DMC, the content of methanol was lower than 100ppm in the product. These results coincide with the actual production. They have important realistic meaning for improving production device and operation conditions, optimizing process conditions and reducing the cost of producting.