Study On Green Sythesis Of Fumaric Acid

In this paper,maleic anhydride and water as raw materials,a green chemical method for preparing fumaric acid without using catalyst was studied.In the process of the reaction,which solved the problems of the serious corrosion of equipment,wastewater discharge,difficult to recycle and increase the cost with strong acid and thiourea and other catalysts in the solutions.At the same time,the yield was guaranteed.(This article only considered the temperature conditions because it is an aqueous system and the temperature and pressure were associated)The effects of different concentrations of maleic anhydride aqueous solution under a certain temperature and pressure as well as a certain period of time were studied in a closed hydrothermal reactor.Using the single factor experiment and maintaining the other several factors remain unchanged,only change one of these three variables,the reaction is completed,continue stirring until cooled to room temperature,further purification,drying to obtain high purity fumarate Crystal or powder.The mass of fumaric acid solid powder was weighed to calculate the yield,and the properties of the maleic acid solid powder were analyzed by 1H nuclear magnetic resonance spectroscopy,high performance liquid chromatography and infrared detection.According to the yield of fumaric acid product and the change of each index,the optimal reaction conditions for fumaric acid production can be explored,including the optimal concentration,the optimal reaction temperature and the optimum reaction time.In the fumaric acid filtrate cycle experiment,the fumaric acid product filtrate was used as the solvent for further experiments.The content of each substance in the filtrate was analyzed by high performance liquid chromatography(HPLC).The cycle times of fumaric acid filtrate were determined in the filtrate circulation experiment.The purity and the change in pH of the filtrate filtrate cycle detennined by nuclear magnetic resonance of the products.The results show that the optimal reaction temperature is 200 ?(pressure 1.6MP),the best reaction time is 1 hour.The optimal reaction concentration of this experiment was 80%maleic acid,and the yield of fumaric acid reached 86%.At the filtrate circulation experiment,the yield of fumaric acid reached over 90%and the pH value of the filtrate was 1.01 when six times.The purity of fumaric acid product and it's products were determined by NMR and FTIR spectroscopy.The purity of fumaric acid product was not affected by the number of cycles and the green production of fumaric acid filtrate was achieved.The isomerization of maleic acid was determined by high performance liquid chromatography(HPLC).The formation of malic acid,a byproduct,and the reaction pathway of maleic anhydride with water to form maleic acid were studied in this paper.The maleic acid was isomerized to generate fumaric acid under high temperature and high pressure,and the content of several organic acids in maleic acid,fumaric acid and byproduct malic acid were measured and a new method for the determination of organic acids in fumaric acid was established.