Novozym® 435-catalyzed production of ascorbyl oleate in organic solvent ultrasound-assisted system

Ultrasound-assisted system is promising for chemical synthesis. This study aimed the production of ascorbyl oleate catalyzed by lipase Novozym® 435 in organic solvent using ultrasound-assisted system. Different organic solvents and solvent concentration were tested at 70 °C using 1:9 M ratio ascorbic acid:oleic acid. The solubility was evaluated by visual analysis after 40 min of stirring substrates and solvent. By this procedure, 20 mL of tert-butanol was defined as the best solvent for the reaction. The maximized conditions for ascorbyl oleate production in the ultrasound-assisted system were determined by evaluating the temperature, enzyme concentration and molecular sieves influence in the kinetics reaction. At the end of reaction the best conditions obtained for the maximal ascorbyl oleate conversion was molar ratio ascorbic acid:oleic acid, 1:9, 20 mL tert-butanol, 70 °C, 5 wt% Novozym® 435, 20 wt% molecular sieve, 100% ultrasound power and 12 h reaction, resulting in 87% of ascorbyl oleate conversion. Without the use of molecular sieve, the kinetic study pointed the maximized experimental condition conversions of 66% after 3 h of reaction.