Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface te...Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface tensions were calculated from crystallization induction times using classic homogeneous nucleation theory. Induction time and surface tension decreased at higher temperature.展开更多
以L-色氨酸为起始原料,经过甲酯化、Pictet-Spengler反应、结晶诱导非对称转化(CIAT)、脱盐酸化等步骤,得到5个1-芳基四氢-β-咔啉-3-羧酸甲酯化合物。目标产物通过重结晶、柱层析等方法纯化,其结构经元素分析、IR、1 H NMR、13C NMR、...以L-色氨酸为起始原料,经过甲酯化、Pictet-Spengler反应、结晶诱导非对称转化(CIAT)、脱盐酸化等步骤,得到5个1-芳基四氢-β-咔啉-3-羧酸甲酯化合物。目标产物通过重结晶、柱层析等方法纯化,其结构经元素分析、IR、1 H NMR、13C NMR、NOE等进行表征。展开更多
文摘Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface tensions were calculated from crystallization induction times using classic homogeneous nucleation theory. Induction time and surface tension decreased at higher temperature.