Synthesis of dioctyl sebacate catalysed by cellulose-immobilized lipase

Abstract

Dioctyl sebacate is a long carbon chain dibasic acid ester with methylene as the main body. It is widely used in plasticizers because of its good cold resistance and high viscosity. And it has excellent properties of non-toxicity and easy biodegradation, so it can be used as a potential new green bio-based plasticizer. At present, most of the preparation methods of dioctyl sebacate are chemical methods, which have many by-products and cause environmental pollution. In this article, cellulose microspheres were used as a carrier to immobilize Candida antarctica lipase B (CALB) to catalyse the esterification of sebacic acid and n-octanol to prepare dioctyl sebacate. Through single factor experiments, the lipase immobilized on cellulose microspheres was optimized to determine the best process conditions: add 500 µL CALB to the erlenmeyer flask, and then add 0.02 mol/L PBS buffer (pH 8.0). After being prepared into a 5 mL system, 0.1 g of cellulose microspheres were added as a carrier and reacted for 3 h at 35 °C and 180 r/min. Added 0.5 vt% polyethylene glycol diglycidyl ether (PEGDEG) to the system for crosslinking. The final immobilization rate of lipase immobilized on cellulose microspheres was 80.06%, and the enzyme activity was 288.07 U/g. Using the cellulose-immobilized lipase as a catalyst, in the toluene system, the molar ratio of n (sebacic acid)/n (n-octanol) substrate was 1:3.5, the amount of immobilized enzyme was 0.04 g, 4 Å molecular sieve 1.5 g, 40 °C, and 150 r/min for 30 h, the conversion rate of dioctyl sebacate was 76.45%.