"MOOC"(Massive Open Online Course,大规模在线开放课程)在全球的兴起给传统的课堂教学带来了前所未有的竞争与挑战。本文分析了MOOC对生物化学传统课堂教学的影响,如MOOC考验传统教学的吸引力和教学模式;探析了MOOC时代下生物化学课堂教学改革的具体方法,如修订生物化学教学大纲,改进生物化学教学课件,充分利用网络资源促进师生沟通;并提出了目前存在的阶段性问题,供生物化学教学改革参考。
Toluene dicarbamate(TDC)is an important precursor for preparing toluene diisocyanate(TDI). The biological enzyme catalyst for the synthesis of TDC from toluene diamine(TDA) and dimethyl carbonate(DMC) is investigated. It is found that papain exhibits the best catalgtic activity and the most suitable solvent is tetrahydrofuran. The optimal reaction conditions over papain are as follows: reaction temperature, 40 ℃; reaction time, 40 minutes; n(TDA)/n(DMC)=1/20, the enzyme concentration, 17.4mg/mL; the yield of TDC is 3.94%.
