脂肪酶粉催化酯化合成三羟甲基丙烷酯

Synthesis of trimethylolpropane esters by powdered lipase-catalyzed esterification

以辛酸、癸酸和三羟甲基丙烷作为反应底物,利用Candida sp.99-125脂肪酶粉催化反应,研究了反应条件对酶法合成三羟甲基丙烷三辛癸酸酯的影响,并在实验中找到一种可以提高酶粉稳定性的添加剂β-环糊精。结果表明,加入0.01 mol三羟甲基丙烷(TMP)(1.34 g),n三羟甲基丙烷/n(癸酸+辛酸)=1∶4,其中n癸酸∶n辛酸=1∶1,添加水的质量分数为0.05%(以底物总质量为基准)、脂肪酶粉的质量分数为12%(以底物总质量为基准)、β-环糊精的质量为酶粉质量的1.5倍,40℃下在恒温摇床中,振荡反应130 h,转速130 r/min。在此条件下,反应产物三羟甲基丙烷三辛癸酸酯(三羟基酯)的质量分数可达到80%左右,酸与酯分离后收率可达96%;连续使用6批添加了β-环糊精的脂肪酶粉,三羟基酯的质量分数可保持在60%以上,与固定化酶的使用寿命相当。

The enzymatic production of trimethylolpropane（TMP） esters from the reaction of octanoic acid and decanoic acid with TMP in the presence of powdered lipase Candida sp.99-125 in a solvent-free system has been studied.The effects of varying the experimental conditions were studied in order to optimize the process.A maximum mass fraction of 80% of triesters was obtained after 130h under the following optimized conditions： 0.01 mol TMP,nTMP/n（octanoic acid＋decanoic acid）=1∶4,noctanoic acid/ndecanoic acid=1∶1,0.05%（mass fraction） of added water（based on the weight of total substrate）,12%（mass fraction） of powdered lipase（based on the weight of total substrate）,with added β-cyclodextrin（1.5 times the mass of powdered lipase）,at 40 ℃.After separating the products,the yield of triester reached 96%.Moreover,the powdered lipase with added β-cyclodextrin could be used continuously in six batches with the final mass fraction of triester remaining over 60%.