The Synthesis Of Glycolic Acid By Hydrolysis Of Chloroactic Acid

glycolic acid (Hydroxyacetic acid, 2-hydroxyethanoic acid) is a chemical industry material. It is applied in a lot of fields including organic synthesis, cleanout, plating, spinning, leather and sterilization, etc. It was found that its polymer had biological degradability which the traditional plastic hadn't, so, it can be used in medicine, packing and other fields. The preparation of polymer is required for high purity of glycolic acid, if not, low-weight polymer is obtained, therefore, high purity glycolic acid is scarce in the market. So, the research for the synthesis of glycolic acid is essential. In domestic and overseas, there are many methods for preparation of glycolic acid, including glycin oxidation, cyanogenesis, aldehyde oxidation, coupling of maldehyde and methyl formate, oxalic acid electrolysis, chloroactic acid hydrolysis and so on. The productions of glycin oxidation are complicated and the cost is high. The cyanogenesis is poisonous and unsafe. Formaldehyde oxidation requires for rigorous reaction conditions, the products are complicated, the equipment is eroded hard. The cost of raw material is high for diacetaldehyde oxidation. The yield of coupling of maldehyde and methyl formate is low, the separation of catalyzer is difficult. The yield is low for oxalic acid electrolysis. By comparison we adopt means of chloroactic acid hydrolysis to synthesize glycolic acid. This technical route has many merits such as low cost of materials, low requirement for reaction condition, little environmental pollution. The difficulty of route is the refinement of products. There is a lot of sodium chloride in solution. In order to refine the glycolic acid, the methods of vacuum distillation and organic solvent extraction are adopted. The yield of glycolic acid was mensurated by HPLC, the content of NaCl was mensurated by Moor, the qualitative analysis of glycolic acid was carried by infrared spectrometer and element analysis. Firstly, the factors that can affect the reaction were studied, these factors include reaction temperature, reaction time, the ratio of raw materials and the weight percent of NaOH. The optimum reaction conditions were achieved, n(NaOH)/n(chloroactic acid) was 1.2/1, reaction temperature was 110℃, reaction time was 10h, the weight percent of NaOH was 45%. Secondly, the solution of glycolic acid was purify by vacuum distillation and organic solvent extraction, the solid of glycolic acid was achieved which purity was over 97% and yield of product was over 73%. Lastly, we took kinetic study of reaction, the relation between reaction speed and concentration of raw materials was obtained by nonlinear simulation and linear regression, the equation was r = 2 .91C2.