Design And Optimization Of The Green Production Technology For Tartaric Acid

Tartaric acid (chemical formula, C4H6O6), which is one of the most common organic acids, was first discovered from the deposit sediment of wine making procedure. And because of its unique physical and chemical properties, it is widely used in many fields, such as food industry, pharmaceutical industry and so on. Especially in the food industry, tartaric acid, whose acidity is1.2-1.3times of citric acid, is often used as sour agent in beverages and candies. And it can also be used as antioxidant. Currently, the yield coefficient of tartaric acid production process is low and may cause severe environment problems. And in the meantime, the production cost is relatively high. Therefore, it is of great practical significance to design a new and high-performance procedure for tartaric acid production.A new process for tartaric acid production is designed on the basis of abundant literature reviews. Maleic anhydride is used as the raw material, heteropolyacid is applied as the new high-efficiency catalyst, and hydrogen peroxide is employed as the "green" oxidant in the synthesis procedure for tartaric acid. Then the potassium hydroxide solution is used to adjust the pH value after the tartaric acid crystal is removed in order to obtain the main by-product potassium bitartrate. Then recycle the mother liquor for several times to improve the total molar yield. And the highest molar yield can reach93.1%. At last, the catalyst recovery process is conducted in order to protect the environment. In addition, tartaric acid obtained from the laboratory experiment was characterized by Fourier Transform Infrared Spectroscopy(FTIR) and Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS), the content of tartaric acid was measured according to national standard(GB15358-2008), and the concentrations of Pb, Fe, W ions were determined. Finally, after the industrialization study was successfully conducted, tartaric acid products, including tartaric acid and potassium bitartrate, were determined comprehensively and results show that all the items conform the national standard.The specific process conditions are as follows:1) Synthesis of tartaric acid. First, Maleic anhydride was mixed with30%hydrogen peroxide and distilled water at a specific temperature to hydrolyze, and then heteropolyacid is added as the catalyst. Then raise the temperature to65℃, and react for another16hours. Finally, raise the temperature to102℃until the product is hydrolyzed extensively. Then the solution is cooled to form tartaric acid crystal, which is filtrated to get the pure tartaric acid. Then the potassium hydroxide solution is applied to adjust the pH value, and the potassium bitartrate is obtained. And the highest one-off molar yield can reach78.6%.2) Efficient evaporation process research. Self-made film evaporator is applied to concentrate the mother solution in the temperature range of70-72℃, at the vacuum degree of0.07. And the highest molar yield can reach92.7%.3) Catalyst recovery. The adsorption and desorption properties of self-made chelating anion resin is discussed via batch and column studies. Results show that the adsorption capacity (Q) of self-made chelating anion resin for W can achieve221.5mg/g resin. Kinetic study shows that the adsorption process fitted well with the Lagergren-first-order model and Intraparticle diffusion model;99.1%W which is loaded on the self-made chelating anion resin can be eluted efficiently. And after5times adsorption-desorption cycle,96.1%of the catalyst can be recovered. The results of column study show that this recover method is suitable to be applied in practical use, and after the dynamic elution procedure, above95%catalyst can be recovered.In this article, several breakthroughs were achieved:a) A new process is designed based on the traditional procedure. The co-production of potassium hydrogen tartrate is achieved, the mother solution is reused, and the catalyst is recovered. The production cost is cut efficiently, while the contamination brought by the wastewater is eliminated.b) The newly discovered heteropolyacid catalyst is applied, hence the highest one-off molar yield can increase for about10%.c) Self-made film evaporator is applied to concentrate the mother solution to achieve efficient evaporation process. Therefore, the total molar yield can increase for about another15%.d) The self-made chelating anion resin is employed to remove W, and above95%catalyst is recovered.