Catalytic Synthesis of Hydroxymethyl-2-oxazolidinones from Glycerol or Glycerol Carbonate and Urea
作者:Angela Dibenedetto、Francesco Nocito、Antonella Angelini、Imre Papai、Michele Aresta、Raffaella Mancuso
DOI:10.1002/cssc.201200524
日期:2013.2
difficult. Starting from glycerol carbonate, two isomers, 6 and 6′, are formed with a quasi 1:1 molar ratio because urea can attack the carbonate moiety on both sides of the carboxylic CO moiety. From glycerol the formation of the 6′ isomer is preferred: the ratio of 6′/6 is close to 7. The oxazolidinones formed act as templates because they interact through hydrogen bonding with glycerol. The intensity
恶唑烷酮是通过在γ-Zr磷酸盐作为催化剂的情况下使碳酸甘油酯或甘油与尿素反应而合成的。多元醇或其碳酸盐的转化率取决于温度。低于408 K时,选择性为100%,转化率最高为25%,而提高温度意味着转化率提高,但选择性降低,这使分离过程更加困难。从碳酸甘油酯开始,以大约1:1的摩尔比形成两个异构体6和6',这是因为尿素会侵蚀羧基CO部分两侧的碳酸酯部分。从甘油中优选形成6 '异构体:6' / 6的比例接近7。形成的恶唑烷酮起模板的作用,因为它们通过与甘油的氢键相互作用。相互作用的强度依赖于6或6'异构体:DFT计算表明,能量为22.6千卡摩尔-1为6 -oxazolidinone和25.7千卡摩尔-1为6' -oxazolidinone。