The Green Process For Preparation Of Folic Acid

Folic acid is an essential nutrient for body growth, which is widely used in feed, food, medicines and health products. Although there is a relatively mature synthesis method, there are some disadvantages such as low yield and large amount of waste water. According to the current status of folic acid production in China, there are some improvements to increase the purity and yield.In this dissertation, a method for the production of folic acid was investigated from N-(P-amino-benzoyl)-L-glutamic acid,2,4,5-triamino-6-hydroxypyrimidine-sulfate, and trichloroacetone. Green production of folic acid technology was mainly carried on synthesis process and production refining process. Specifically, the work was mainly carried out in the following three aspects. The first was the synthesis of folic acid. The process was optimized from the aspects like charging sequence, reaction temperature and raw material to have a yield 65.34% and purity of 62.14%. And the filtration solutions (synthesis, acid refining and alkali refining) could be recycled three times in the synthesis process. Secondly, we investigated the effect of different acids and concentration in acid refining process, which improved the yield over 88.92%, with the purity of 89.24%. The last, alkali refining methods were carried on from different bases, the pH value in the dissolution process, solvent and the reaction temperature to obtain the optimal process conditions for preparing folic acid, yield 92.87%, purity of 98.66%. And through the work above, the totally yield of folic acid was 53.96% and purity 98.66%.In this paper, synthesis route of 2,4,5-triamino-6-hydroxypyrimidine-sulfate were also studied. The optimum technological conditions on reaction time and catalyst were studied in the synthesis of ethyl cyanoglyoxyIate-2-oxime, and the conversion rate was up to 94.67%. By adjusting the charging ratio of raw materials, the yield of 2,4-diamino-6-hydroxy-5-nitroso-pyrimidine was up to 92.51%. The 2,4,5-triamino-6-hydroxypyrimidine-sulfate was studied from solvent, pressure, temperature, time and catalyst, and the conversion rate can be up to 92.18%. And the total yield of 2,4,5-triamino-6-hydroxypyrimidine-sulfate from ethyl cyanoglyoxylate-2-oxime could up to 80.73%.