Enzymatic Synthesis Of Vitamin A Palmitate And Its Process Design Of 200 T/a Scale

Vitamin A palmitate,functioning as vitamin A,is one of commercially available vitamin A forms and widely used in health care and feed additives because of its better stability.At present,the production of vitamin A palmitate is still produced by chemical method which needs complex reaction processes and harsh conditions.Besides,isomers are easily produced,which would result in great difficulties in the separation and extraction of products.Therefore,it has significant researching meanings and application values to carry in green manufacturing process.In order to meet the requirement for the industrial production of vitamin A palmitate,reasonable esterification synthesis and separation routes have been designed in this study.The conditions of alcoholysis reaction of vitamin A acetate were researched.The optimum conditions were 240 g vitamin A acetate and200 m L 270 g/L KOH at 21°C,300 rpm for 1 h to hydorlyze vitamin A acetate completely.Meanwhile,the conditions of vitamin A palmitate synthesized by immobilized lipase in 1L pilot scale were further studied.The optimal esterification conditions:molar ratio of vitamin A acetate and the palmitic was 1:1.1,immobilized enzyme was 25 g/L,the reaction temperature was 32°C,anhydrous Na₂SO₄ was 15 g/L and reaction time was 2 h.In this study,we realized the separation and extraction of vitamin A palmitate in two steps.In the first step,primary product was diluted with n-hexane and palmitic acid will be crystallized at-5°C for 12 h to be mostly removed by filtration,and the crude product was obtained.In the second step,the crude product was diluted with acetone in the ratio of1:4.5 and stirred lightly at-8°C to remove retinol and other impurities,and the vitamin A palmitate was recovered with>99%purity.Ultimately,the biosynthetic routes and isolation of vitamin A palmitate were designed,and the technological design from material balance,equipment selection and cost accounting were estimated.