Enzymatic synthesis of surfactants based on polyethylene glycol and stearic or 12-hydroxystearic acid

High-purity mono- and di-esters of polyethylene glycol (molecular weight: 600) with stearic acid or 12-hydroxystearic acid was afforded using enzymatic catalysis with immobilized Candida antarctica lipase B. The reactions were performed without solvent and the formed water was removed with vacuum, driving the reactions to completion. Isolated yields varied between 77 and 87%.