Study On Preparation Of Glycolic Acid By Hydrolysis Of Methyl Glycolate

Glycolic acid is an important kind of organic synthesis intermediates and chemical products, and has a wide range of applications; By comparing and analyzing the different ways of preparing glycolic acid, the economy and feasibility of the preparation of glycolic acid crystals through the hydrolysis of methyl alcohol are confirmed; The further study of catalytic activity and the reuse of condensate is proceeded under optimal conditions of lab research. In the amplification reaction (5L), the effect of pressure and ratio of raw materials on the hydrolysis reaction of methyl alcohol is studied. The experimental results show that the001*7catalyst can be applied repeatedly over six times, and appropriate ratio of water and ester is10:1, the hydrolysis reaction can be carried out under the constant pressure of30kPa, making the operation more convenient. At the same time, a qualitative analysis of impurities of the methyl alcohol hydrolysis reaction system is established.In this paper the temperature effect on the solubility of glycolic acid, and the stirring speed, cooling rate effect on metastable zone width are also studied. The dates of solubility are fitted by classical equation and Apellblat solubility model. It is found that GA’s solubility decreases when temperature lowed, and the metastable zone of80%glycolic acid solution is very wide. Therefore, the glycolic acid solution can be purified by crystallization. By studying the factors of crystallization time, the end temperature, the amount of seed crystals, cooling rate, and seed crystal adding temperature, stirring speed, the relative optimum process is obtained, getting the glycolic acid crystals with high purity(>99%). The analytical methods of translucent reflective microscope and Malvern particle size analyzer are used to study the morphology and particle size of the final products.