Institute of Technical Biochemistry, Universitaet Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
Enzyme Microb Technol. 2012 Jun 10;51(1):9-15. doi: 10.1016/j.enzmictec.2012.03.007. Epub 2012 Apr 3.
Immobilized cutinase HiC from the ascomycete Humicola insolens was applied as a novel biocatalyst for the synthesis of functionalized acryclic esters by transesterification. As a model reaction, transesterification of methyl acrylate with 6-mercapto-1-hexanol at a high molar ratio in a solvent free system was chosen. Besides two minor Michael-addition by-products, 6-mercaptohexyl acrylic ester was identified as the main product with the thiol as the functional end group. Reaction conditions were optimized regarding the influence of water (0-1.72 M), temperature (22-50 °C), product inhibition and addition of the radical inhibitor butylated hydroxytoluol (BHT; 0.14-0.71 M) on conversion and by-product formation. Highest conversion of 6-mercapto-1-hexanol to 6-mercaptohexyl acrylic ester (95.4 ± 0.3%) was achieved after 6h at 40 °C in the presence of 0.025% (w/w) water without formation of by-products in a solvent free system. Applying methyl methacrylate, transesterification with 6-mercapto-1-hexanol was significantly lower (43.6 ± 0.1%) compared to transesterification of methyl acrylate with 6-mercapto-1-hexanol.
固定化角鲨烯酶 HiC 来源于子囊菌嗜热毁丝霉，可用作通过酯交换反应合成功能化丙烯酸酯的新型生物催化剂。选择甲酯与 6-巯基-1-己醇在无溶剂体系中高摩尔比进行转酯化反应作为模型反应。除了两种次要的迈克尔加成副产物外，还鉴定出具有巯基官能端基的 6-巯基己基丙烯酸酯为主要产物。研究了水（0-1.72M）、温度（22-50°C）、产物抑制以及自由基抑制剂丁基羟基甲苯（BHT；0.14-0.71M）的添加对转化率和副产物形成的影响，优化了反应条件。在无溶剂体系中，添加 0.025%（w/w）的水，40°C 下反应 6h，6-巯基-1-己醇的转化率最高（95.4±0.3%），没有副产物生成。而用甲基丙烯酸甲酯进行转酯化反应，与 6-巯基-1-己醇的转酯化反应相比，转化率明显较低（43.6±0.1%）。
