One-step enzymatic synthesis of bio-based plasticizer isosorbide hexanoate diester
Isosorbide dihexanoate was prepared from the esterification reaction of isosorbide and hexanoic acid under the catalysis of immobilized lipase Novozym 435 in the presence of 4A molecular sieve using toluene as solvent.Response surface analysis was then conducted with four factors(reaction time,reaction temperature,enzyme addition amount,4A molecular sieve dosage)selected via single factor experiment.The results showed that the yield of isosorbide dihexanoate reached 93.77%under the optimal conditions of toluene 10 mL,isosorbide 3 mmol,n(isosorbide)∶n(caproic acid)=1∶6,reaction time 43 h,reaction temperature 40℃,Novozym 435 0.10 g and 4A molecular sieve 2.00 g.