【摘要】 采用硝硫混酸作催化剂 ,乙醛酸 (乙二醛硝酸氧化法 ,未分离 )和尿素为原料缩合反应合成了尿囊素。考察了原料配比、反应温度和反应时间以及催化剂的组成和用量对尿囊素产率的影响。得到适宜的工艺条件为 :尿素与乙醛酸物质的量比为5∶1,硫酸与硝酸物质的量比为 8∶1,混酸与乙醛酸物质的量比为 0 5∶1,反应温度为 75℃ ,反应时间为 3h。在上述工艺条件下 ,尿囊素的产率达到 5 9 3 % ,产品纯度达到 98 5 %以上。并通过熔点测定、元素分析和IR光谱对产品进行了验更多还原

【Abstract】 Allantoin acid was produced by condensating glyoxylic acid (prepared by means of oxidation glyoxal with nitric acid, without separation) with urea in the presence of nitro-sulfuric acid catalyst. The influences of the molar ratio of urea to glyoxylic acid ,reaction temperature,reaction time , the quantity and composition of catalyst on the yield of product were investigated. The optimum synthetic conditions were urea/glyoxylic acid molar ratio 5∶1,sulfuric acid/nitric acid molar ratio 8∶1,nitro-sulfuric acid catalyst/glyoxylic acid molar ratio 0 5∶1,reaction time 3h and reaction temperature 75℃.Under the optimum conditions,the yield of allantoin was 59 3%,the purity of allantoin over 98 5%.Through melting test,elementary analysis and spectrum of IR, the constitutional formula of allantoin was proved.更多还原