Process Development For Maleic Anhydride To Succinic Anhydride

Succinic anhydride(SA)is an important organic synthesis intermediate product and raw material of fine chemicals,which has been widely used in the food service,coating,pharmaceutical,pesticide and plastic material.Its hydrolysis product succinic acid can be used to synthesize biodegradable plastic(PBS)with 1,4-butanediol.PBS is a new-style biodegradable thermoplastic.It is one of the best biodegradable plastic in the world.At present,continuous production of SA from hygrogenation of maleic anhydride(MA)has a strong competitive,because of its high recovery of product,wide of source,simple of the process,lower reaction pressure,lower costs and ease of continuous mass production.Its large scale industrialization has not been reported.The method was established to analysis the products of hydrogenation.Gas chromatography was used to analysis samples,internal standard method and area normalization method were used for quantitative analysis main component of the product,drew the calibration curve for MA,SA,γ-butyrolactone and verified its accuracy.The relative error was less than 2%.Then the optimum process conditions,the stability of the catalyst and the removal of the reaction heat were investigated by monotube test.Then according to volatilizes,hydrogenation products were sorted into four kinds based on lumping principle.To gain SA product as the separation target,the optimum separation process was elected.Adopting UNIQUAC equation,SA-γ-butyrolactone VLE data was estimated by UNIFAC group-contribution method.The continuous distillation separation process was simulated and optimized by Aspen Plus.Suitable separation process condition was identified.For de-light component distillation tower the bottom pressure of the tower:20k Pa(A);the number of the theoretical plate :18;the number of the feeding tray:14;the reflux ratio :0.35.For de-heavy component distillation tower,the bottom pressure of the tower:5k Pa(A):the number of the theoretical plate :26;the number of the feeding tray:7;the reflux ratio :0.55.Through tests,the purity of the product ofγ-butyrolactone was 99.73%,succinic anhydride was 99.95%.The simulation data is highly matched with the experimental results.Based on the simulation optimization parameters,In the form of packing column.The diameters of the de-light component and de-heavy distillation column were determined.Hydraulic calculation were performed for the de-light component and de-heavy distillation column.The hydraulic calculation result indicated that the de-light component and de-heavy distillation column were qualified for the verification criteria.The operation was flexibility.