有机相脂肪酶催化合成柠檬酸甘油酯

以脂肪酶为催化剂,在有机介质中合成柠檬酸甘油酯。对催化合成反应的脂肪酶和反应介质进行了筛选,最佳溶剂为叔丁醇,固定化于大孔丙烯酸树脂的Candida antarctica脂肪酶B(Novozym 435)的催化活性最好。同时对底物浓度、底物摩尔比、脂肪酶用量、吸水剂用量、反应温度和反应时间等条件进行了优化,确定最佳工艺参数为:酸浓度0.12mol/L,单甘酯和柠檬酸摩尔比2∶1,脂肪酶用量为质量分数8%,吸水剂用量0.12g/mL,50℃反应48h,柠檬酸转化率可达70.97%。经电喷雾质谱和红外光谱分析,反应产物主要是α-柠檬酸单硬脂酸甘油酯。

Lipase Catalyzed Synthesis of Monoglyceride Citrates in Organic Medium

The synthesis of monoglyceride citrates catalyzed by lipase in organic medium was investigated. Novozym435 (Candida antarctica lipase immobilized on a macroporous acrylic resin) was found to be the best lipase to convert citric acid to monoglyceride citrates in t-butyl alcohol. The conditions of reaction were optimized: lipase Novozym 435 dosage 8% (w/w) in anhydrous t-butyl alcohol, citric acid concentration 0.12 mol/L, ratio of monoglyceride to citric acid 2 ∶1, 4 molecular sieves concentration 0.12 g/mL, temperature 50℃, and incubation time 48 h. Using these conditions, the conversion rate of citric acid reached 70.97%. The main product as characterized by electron spray ionization-mass spectrum and infrared spectrum was α-citric acid esters of glycerol monostearate.