Study On The Membrane Reaction Process For Continuous Synthesis Of Dimethyl Adipate

Hexylene glycol has promising industry application, nowadays, it mainly uses dimethyl adipate as intermediate for the production of hexylene glycol in the industry. In order to obtain high conversion ratio of adipic acid, water generated by esterification reaction need to be removed in the process of synthetic reaction. Currently, distillation method is mainly used in industrial production, but plenty of methanol was also taken out of reaction system while the water was removed, it consume a lot of energy, meanwhile, recycling methanol also need to consume large amounts of energy in the subsequent process. Therefore, it is necessary to improve the production process.As a new technology, pervaporation has its unique advantage. By coupling of pervaporation and esterification, water can be removed timely in the esterification reaction and the conversion ratio of adipic acid would increase, in addition, It would also decrease the usage of methanol, and greatly reduce the energy consumption in the process of production. Our laboratory researchers have studied the batch process of the esterification of adipic acid with methanol by coupling pervaporation and got good results. In this paper, the method of the continuous synthesis of dimethyl adipate has been designed to meet requirement of mass production in the industry.Based on the batch experimental device, the continuous setup of coupling of pervaporation and esterification has been built. With the continuous synthesis of dimethyl adipate as a target reaction system, the effects of the major operating and apparatus parameters, such as temperature, flow rate, membrane area and feed molar ratio of alcohol to acid, were investigated. It was found from experimental results that high temperature, small feed flow rate, large membrane area and high molar ratio of alcohol to acid are favorable to the conversion ratio of adipic acid. When the parameters are kept at a molar ratio of alcohol to acid of 4, temperature of 60℃, feed flow rate of 0.24ml/min and membrane area of 291.6 cm~2, the conversion ratio of the esterification process can be raised to 99.2%.In this paper, we also compared conversion ratio of adipic acid when the feed molar ratio of alcohol to acid was 2, 3, 4, 5, 6 respectively, keeping temperature of 60℃, feed flow rate of 0.24ml/min and membrane area of 291.6 cm~2. It was found from experimental results, that the equilibrium conversion and eventual conversion of esterification all become higher with the increase of molar ratio of alcohol to acid, and that at a molar ratio of alcohol to acid of 4, the increase between equilibrium conversion and eventual conversion is at most.The method of coupling, operation model, research result and research experience in this thesis can be used to guide the production of dimethyl adipate, and provide reference for synthesis of other esters.