以乙酰丙酸为原料合成5-羟基乙酰丙酸的研究

对新型聚酯单体5 羟基乙酰丙酸（5-HLA）的合成工艺进行了改进和优化.以来源于生物质资源的乙酰丙酸(LA)为原料，通过改进的溴化和水解反应合成了5-HLA.优化溴化反应温度、液溴滴加速率、反应介质用量等溴化反应条件；同时利用3 溴乙酰丙酸甲酯等溴化物的分子内重排和歧化反应，对溴化反应生成的副产物回收再利用，将中间产物5 溴乙酰丙酸甲酯的产率从文献值30%提高到45%.5-溴乙酰丙酸甲酯经一步水解、乙醚连续萃取和重结晶得到5-HLA.改进后的工艺基于乙酰丙酸的产率为30%，与二步法相比，操作时间短，产率大大提高.

Synthesis of 5-hydroxylevulinic acid from levulinic acid

The synthetic method of polyester monomer 5-hydroxylevulinic acid(5-HLA) was improved and simplified.Using levulinic acid(LA) derived from biomass as raw material,5-HLA was synthesized via modified bromination and hydrolysis processes.In the bromization reaction of LA,the reaction conditions such as reaction temperature,drop time of Br_2 and reaction medium were optimized.The side product was reused via rearrangement of methyl 3-bromolevulinate to methyl 5-bromolevulinate(5-MBL) and the yield of 5-MBL was thus improved to 45% from an earlier reported value of 30%.Then pure 5-HLA in 30% yield was obtained via a simplified one-step hydrolysis of 5-MBL followed by concentration of the hydrolysate,extraction of 5-HLA in a continuous manner with stirring,and recrystallization in chloroform.Compared with the two-step method,the processing time was shortened and the yield of 5-HLA was improved.