The Process Research Of Wax Ester Synthesized By Immobilized Lipase

High-molecular weight esters from long-chain alcohols and long-chain acids are typically referred to as wax esters.The novel characteristics,such as excellent emollient behavior of wax esters have maximized their usage in various industries.They are used in foods, personal care,metal working fluids,rolling oils and synthetic lubricants. However,the main obstacle to large-scale use of natural wax ester is its cost and availability.Thus,attempts to synthesize wax esters with cheaper starting materials and shorter time have become very important. Interest in lipase-catalyzed preparations of wax esters has grown due to the possibility of obtaining a wide variety of high-quality products under mild reaction conditions utilizing the substrate selectivity of such biocatalysts.Furthermore,the growing demand for the environmentally friendly processes,has widened the use of enzymes as biocatalysts. In this paper,wax ester was synthesized from soybean oil and cetyl alcohol in a packed-bed reactor with petroleum ether as solvent and immobilized lipase Candida sp.99-125 as catalyst.The effects of the height of packed-bed,flow rate of reactant,dosage of immobilized lipase,molar ratio of substrate were investigated.The optimum conditions were as follows:immobilized lipase 47g,the height of packed bed was 40cm(diameter 3.5cm),the molar ratio of oil to cetyl alcohol was 1:2.4,the flow rate of reactant was 4mL/min and the retention time was 4h,the yield of wax ester reached 83%.The stability of the immobilized lipase was also studied,and the yield remained above 70% after 16 batches.The packed mode of the immobilized lipase in reactor was discussed.Wax ester was synthesized in a stirred tank reactor in solvent-free system.The effects of the molar ratio of substrate,dosage of immobilized lipase,stirring speed were investigated.The optimum conditions were as follows:immobilized lipase 2.5%W oil,the molar ratio of oil to cetyl alcohol was 1:2.25,the stirring speed was 150-200rpm(Corresponding Reynolds number was 294-392),the yield of wax ester reached 74%.The yield increased by adding cetyl alcohol and immobilized lipase in 4 batches.Immobilized lipase could reused that can reduce the cost.The purification of crude product was also investigated.The processing conditions of removal alcohol and acid was confirmed.The purity of products reached 95%,the yield of purification was 92%. Tested some performance indexes of products,the result showed that the product from experiment has high viscosity,high flash point,good thermal stability and moisture retention which can be used in lubricant and cosmetic.The composing and performance of products was similar to natural wax ester,could used as substitute of natural wax ester.