手性修饰的介孔树脂材料负载铂催化剂上丙酮酸乙酯的不对称氢化反应

采用氯铂酸和二氯四氨合铂为前体通过浸渍法分别制备了介孔树脂材料FDU-14负载的质量分数为5%的铂催化剂Pt/FDU-14, 并利用XRD, TEM, N₂气吸附和CO化学吸附等手段对催化剂进行了表征. 考察了经过手性分子辛可尼定修饰后的Pt/FDU-14催化剂在丙酮酸乙酯不对称氢化反应中的催化性能. 以氯铂酸为前体制备的Pt/FDU-14催化剂因其具有较小的铂粒子和较高的分散度而表现出较高的活性, 乙酸溶剂中的初始活性(TOF)可以达到21902 mol/(mol?h); 而以二氯四氨合铂为前体制备的Pt/FDU-14催化剂则具有较强的手性诱导能力, 乙酸溶剂中(R)-(+)-乳酸乙酯的光学选择性可以达到81.4% e.e.. 更重要的是, 由于FDU-14具有较强的疏水性, Pt/FDU-14催化剂在水溶剂中也表现出较高的催化性能, 并且还可以重复使用10次以上.     

Energitics of micellizaion of sodium n-dodecyl sulfate at physiological conditions using isothermal titration calorimetry

The curing kinetics of nanocomposites based on phenolic resol cured with triethylamine (TEA) containing different amounts of organic montmorillonite was analyzed by differential scanning calorimetry. Kissinger-Akahira-Sunose (KAS) model-free kinetics has been applied to correlate the dynamic cure behaviour in the presence of modified montmorillonite. The effect in the curing of the use of different clay modifiers has also been studied. A commercial clay with hydroxyl groups (Cloisite 30B) and a customized montmorillonite (PheMMT) whose reactive groups induce condensation reactions with the resol matrix have been used. Strong dependency of activation energy on apparent conversion has been observed for all compounds.