Insight into the synthesis of isosorbide diester plasticizer using immobilized lipases

A bio-plasticizer isosorbide diester was synthesized using three immobilized lipases to select a suitable catalyst. These three immobilized lipases demonstrated an (R)-enantio-preference for synthesizing isosorbide monoesters with different MS : MR values. The S-monoester content was close to zero when the reaction was catalyzed by Yarrowia lipolytica lipase lip2 (Ylip2) or RM IM. Thus, the MS synthesis rate was the limiting step for diester production. To overcome this constraint, the catalysis condition was optimized by using mixture of Novo 435 & Ylip2, or Novo 435 & RM IM, or Ylip2 and Novo 435 sequentially, respectively. When the reaction was sequentially catalyzed by Ylip2 and Novo 435, the highest diester content was obtained (77.4%), which was 2.1- and 1.7-fold greater than the content obtained using either Ylip2 or Novo 435 alone, respectively.