Synthesis Of 2-ethylhexyl Palmitate Catalyzed By Immobilized Lipase Under Microwave

Isooctyl palmitate is an excellent skin emollient and has often been used in various skin creams,cosmetics and shower gels.However,there are loads of shortcomings in the producing progress,such as too many by-products,low yield,and high energy consumption.In order to lower the energy consumption and shorten the reaction time,we consider the application of immobilization.Immobilized enzyme is widely used to improve enzyme activity,which can shorten the time course and at the same time improve the stability of the enzyme.Moreover,studies have found microwaves can induce water evaporation and change the reaction balance,thereby increase the initial speed and yield in non-aqueous enzyme-catalyzed reactions.This article focuses on the synthesis of 2-ethylhexyl palmitate(IOP)catalyzed by lipase QLM in organic solvents,at the same time studied the effects of immobilization technology and microwave on the reaction.We first found out the optimal reaction conditions for preparing IOP under conventional heating.The effects of p H and ionic strength of buffer for dry-freezing,organic media,temperature and water activity were investigated.Under the optimal conditions(buffer for dry-freezing,300 m M,p H 7.4;reaction media,n-heptane;water activity,0.79;reaction temperature,65 ?),the enzyme activity is 7.29 mmol/h/g.On the base of the above research,we immobilized QLM on SBA-15 and optimized its reaction conditions.Under the optimal conditions,the enzyme activity(19.76 mmol/h/g)was increased by nearly three times.Also,the immobilized enzyme activity remained almost unchanged after 10 repeated reactions.Therefore,the immobilization technology improves the catalytic performance of QLM to a certain extent,and greatly improves the reusability of the enzyme.Finally,microwave irradiation was used to further improve the catalytic activity and shorten the reaction time.After optimizing the microwave power(640 W)and microwave temperature(70 ?),microwave irradiation had improved the immobilized QLM activity to 69.52 mmol/h/g,and enhanced the conversion rate to 99% in 3 hours.We also found that microwave-assisted catalysis technology hardly affected the reusability of immobilized QLM.In summary,we succeed in using microwave to improve the synthesis of IOP catalyzed by the immobilized QLM,which greatly shortens the reaction time,increases the reaction yield and reduces the by-products.Simultaneously,thanks to immobilization technology,the stability of the enzyme is improved and at the same time made the enzyme recyclable.All in all,this study proved that immobilization technology and microwave-assisted catalysis technology both do good to IOP synthesis so as can be applied to industrial production.