Control Of Fumaric Acid Content In Electrochemical Synthesis Of Succinic Acid

There is an increasing emphasis on electromechanical synthesis as a new technology for green organic synthesis.The organic electrochemical synthesis of succinic acid is relatively competitive with traditional methods.At present,the application of succinic acid is no longer limited to intermediates,chemical raw materials,food additives,etc.,but biodegradable plastics-the main raw material of polybutylene succinate(PBS),and its market demand is also dramatic increased market potential.The method for producing succinic acid by electrolytic synthesis is based on maleic anhydride as the main raw material,and the yield is improved by the mother liquor circulating application.However,it has also led to the problem of the accumulation of fumaric acid as a by-product of the current electrolytic synthesis of succinic acid.Existing solutions such as the post-processing method are ineffective and increase the cost;the over-power electrolysis method is not applicable for the original equipment,and in order to avoid a large amount of hydrogen evolution and requires a small current to consume a large amount of time to remove the fumaric acid,a new one is sought.The electrolytic process to solve the problem of excessive fumaric acid is imminent.This article explores the possible causes of fumaric acid production and targets the inhibition of plate heating so as not to promote the production of by-products.According to this idea,this paper uses the existing plate and frame type electrolyzers,and a set of overflow electrochemical reactors capable of cooling plates is designed and modified.Based on this,the technological conditions of electrolytic synthesis of succinic acid by cooling plate method are optimized.Experimental results:(1)the cooling plate method can inhibit the production of fumaric acid.In the electrolytic process of most cooling plate methods in the experiment,the content of fumaric acid in the electrolysis terminating liquidwas lower than that in the case of no cooling;(2)When the electrolysis temperature For 50°C,cooling circulating water temperature40°C,maleic anhydride mass fraction 9.8%,mass fraction of sulfuric acid 5%,electrode current density 1000 A/m~2,electric current 100%Q,the best experimental results are obtained.The content of fumaric acid in the initial electrolytic product is lower than 0.02%,which is 42.7%lower than when the plate is not cooled.The content of succinic acid was 99.69%.The yield was 59.5%.(3)Under the optimized electrolytic process conditions,the circulatory electrolysis of original liquid was used.After 10 times circulatory electrolysis of original liquid,the synthesis yield of succinic acid can reach 84.1%,the average yield of electrolysis can be increased to about 76.2%,the electrolysis voltage can be maintained at 4.4-4.8V.The content of fumaric acid is still not excessive,and at a lower value.This shows that the electrolytic synthesis of succinic acid by the cooling plate method does not require the use of over-power electrolysis to reduce the content of fumaric acid in the product or in the longer production period,which has a preliminary application prospect.