Novozyme 435,which is the commercially available immobilized form of Candida antarctica lipase B,has been successfully conducted ring opening polymerization of lactones in organic solvents.In this paper,it was aimed t...Novozyme 435,which is the commercially available immobilized form of Candida antarctica lipase B,has been successfully conducted ring opening polymerization of lactones in organic solvents.In this paper,it was aimed to introduce an alternative biocatalyst for Novozyme 435.Candida antarctica lipase B immobilized onto rice husk ashes via physical adsorption(with a specific activity of 4.4 U/mg)was prepared in previous studies and used as a biocatalyst for poly(δ-valerolactone)synthesis in the present work.Polymerization reactions were proceeded at various reaction temperatures and periods via both two immobilized enzyme preparations.The resulting products were characterized spectroscopically and thermally.The highest molecular weight(Mn=9010 g/mol)was obtained via Novozyme 435 catalysis at 40℃and 24 hours.The performance of home-made lipase,which resulted in a molecular weight of 8040 g/mol,was close to commercial one.展开更多
Chiral 2-octanol is one of the key intermediates for preparation of liquid crystal materials, as well as many optically active pharmaceuticals. Lipase catalyzed kinetic resolution has proved to be an efficient techniq...Chiral 2-octanol is one of the key intermediates for preparation of liquid crystal materials, as well as many optically active pharmaceuticals. Lipase catalyzed kinetic resolution has proved to be an efficient technique for synthesis of enantiomerically enriched compounds. In the present study, optimization and kinetic modeling of kinetic resolution of (±)-2-octanol was done by using vinyl acetate as an acyl donor in n-heptane as a solvent. Response surface methodology (RSM) and four-factor-five-level Centre Composite Rotatable Design (CCRD) were employed to evaluate the effect of various parameters such as speed of agitation, enzyme loading, temperature and acyl donor/alcohol molar ratio on conversion, enantiomeric excess (ee), enantioselectivity and initial rate of reaction. Acylation of 2-octanol with vinyl acetate catalyzed by Novozyme 435 follows the ternary complex mechanism (ordered bi-bi mechanism) with inhibition by 2-octanol.展开更多
文摘Novozyme 435,which is the commercially available immobilized form of Candida antarctica lipase B,has been successfully conducted ring opening polymerization of lactones in organic solvents.In this paper,it was aimed to introduce an alternative biocatalyst for Novozyme 435.Candida antarctica lipase B immobilized onto rice husk ashes via physical adsorption(with a specific activity of 4.4 U/mg)was prepared in previous studies and used as a biocatalyst for poly(δ-valerolactone)synthesis in the present work.Polymerization reactions were proceeded at various reaction temperatures and periods via both two immobilized enzyme preparations.The resulting products were characterized spectroscopically and thermally.The highest molecular weight(Mn=9010 g/mol)was obtained via Novozyme 435 catalysis at 40℃and 24 hours.The performance of home-made lipase,which resulted in a molecular weight of 8040 g/mol,was close to commercial one.
文摘Chiral 2-octanol is one of the key intermediates for preparation of liquid crystal materials, as well as many optically active pharmaceuticals. Lipase catalyzed kinetic resolution has proved to be an efficient technique for synthesis of enantiomerically enriched compounds. In the present study, optimization and kinetic modeling of kinetic resolution of (±)-2-octanol was done by using vinyl acetate as an acyl donor in n-heptane as a solvent. Response surface methodology (RSM) and four-factor-five-level Centre Composite Rotatable Design (CCRD) were employed to evaluate the effect of various parameters such as speed of agitation, enzyme loading, temperature and acyl donor/alcohol molar ratio on conversion, enantiomeric excess (ee), enantioselectivity and initial rate of reaction. Acylation of 2-octanol with vinyl acetate catalyzed by Novozyme 435 follows the ternary complex mechanism (ordered bi-bi mechanism) with inhibition by 2-octanol.
