乙醇酸甲酯法制备乙醛酸

以乙醇酸甲酯为原料，经空气催化氧化、水解得乙醛酸。研究了氧化催化剂种类、氧化反应温度、物料空速、水解酯水比、甲醇分离方法等条件对反应的影响，优化了两步反应的工艺条件。在氧化反应中，用自制的催化剂C-3，反应温度为320 ℃，空气空速为42 h^－1，乙醇酸甲酯空速为1.8 h^－1；在水解反应中，用环己烷共沸分离甲醇，水酯比为5︰1。在优化条件下，氧化反应选择性达98.8%，收率达97.7%；水解反应收率92.6%，总收率达90.5％，产品质量达到Q/320902YYH005-2000要求。

Preparation of glyoxylic acid from methyl glycolate

Glyoxylic acid has been synthesized from methyl glycolate by oxidation and hydrolysis reactions. The oxidation condition of methyl glycolate is investigated，which includes catalyst，temperature，the ratio of H₂O to methyl glyoxylate，space velocity of methyl glycolate and air. The method for methol removing in the hydrolysis reaction has also been studied. The optimized condition for the oxidation of methyl glycolate using C-3 catalyst is obtained when temperature is 320 ℃，the GHSV of air is 42 h^?1，the LHSV of methyl glyoxylate is 1.8 h^?1. And the condition for hydrolysis is optimal when cyclohexane is used as the water-entrainer，the mol ratio of H₂O to methyl glyoxylate is 5︰1. Under the optimized condition，the selectivity of oxidation is 98.8%. The yield of oxidation and hydrolysis reach 97.7% and 92.6% respectively. The total yield of glyoxylic acid is 90.5%. The quality meets the standard of Q/320902YYH005-2000.