作　　者： ; ;

机构地区： 华南理工大学轻工与食品学院

出　　处： 《华南理工大学学报（自然科学版）》 2011年第12期127-131,共5页

摘　　要： 引入脉冲电场(PEF)强化乳酸乙醇酯化反应,分析了脉冲电场强度、体系温度以及体系是否含水对酯化反应的影响,并探讨了反应活化能的变化.结果显示:温度为30℃、流速为50mL/min、反应时间一定时,PEF对乳酸乙醇酯化反应的促进作用随着场强的增加而增强;施加25kV/cm的PEF反应10h,乳酸乙酯的生成量是不施加PEF时的2.1倍;施加20kV/cm的PEF,反应时间为10h,反应温度分别为25、30、35℃时,所生成的乳酸乙酯的量分别是未施加电场时的1.7、1.8、1.4倍;与乳酸和乙醇的纯反应物体系反应相比,PEF对含水体系反应的促进效果更为明显;实验条件下乳酸乙醇阶段性酯化反应为零级反应,20kV/cm的PEF处理使反应的活化能从43.43kJ/mol降至25.05kJ/mol.上述结果说明,在常温非催化状态下PEF对反应有明显的促进作用. Pulsed electric field(PEF) was used to enhance the esterification of lactic acid and ethanol,and the influences of electric field strength,temperature and system moisture on the esterification were analyzed.Then,the variation of activation energy during the esterification was explored.The results indicate that(1) when the reaction performs with a flowrate of 50 mL/min at 30 ℃,the enhancement by PEF in a certain duration becomes stronger with the increase in electric field strength;(2) by applying 25 kV/cm PEF to the system for 10 h,the production of ethyl lactate is 2.1 times that of the production without PEF irradiation;(3) by applying 20 kV/cm PEF for 10 h at 25,30 and 35 ℃,the productions of ethyl lactate are respectively 1.7,1.8 and 1.4 times that of the productions without PEF irradiation;(4) PEF treatment is more effective for the system containing water;and(5) by applying 20kV/cm PEF to the esterification system,the activation energy significantly decreases from the original 43.43 kJ/mol to 25.05 kJ/mol and the stage esterification is a zero-order reaction.The above-mentioned findings indicate that PEF treatment is a promising technique to enhance chemical reaction under non-catalytic condition at room temperature.

关 键 词： 脉冲电场 乳酸 乙醇 酯化反应 乳酸乙酯 活化能

领　　域： [轻工技术与工程] [轻工技术与工程]