三氟甲磺酸锡酯的晶体结构和催化性能

摘要

以甲苯为溶剂,通过回流反应n-Bu2 SnO和TfOH得到了三氟甲磺酸锡酯,并采用红外光谱和X-射线单晶衍射对其进行了表征.结果表明:化合物属三斜晶系,空间群为Pi,晶胞参数a=0.808 3(1)nm,b=0.868 5(1)nm,c=1.163 6(2)nm,a=90.45(2)°,β=94.24(1)°,y=101.08(1)°,V=0.799 29(20) nm-3,Z=2；化合物中的锡原子为严重畸变的八面体构型,且三氟甲磺基的强吸电子效应使Sn-O(磺基氧)键中Sn原子的Lewis酸性较强.当其催化碳酸二甲酯与苯酚酯交换合成碳酸二苯酯时,催化剂的强Lewis酸性有利于碳酸二甲酯转化率的提高,但过强的Lewis酸性易致中间体甲基苯基碳酸酯分解；降低强Lewis酸浓度可以显著抑制甲基苯基碳酸酯分解,提高酯交换选择性.%The organotin triflate was synthesized by the reflux reaction of n-Bu2SnO with TfOH in toluene and determined by elemental analysis, IR and X-ray diffraction single crystal structure analysis. The results show that the crystal belongs to triclinic, space group Pi with a = 0. 808 3(l)nm,b = 0.868 5(l)nm,c=l. 163 6(2) nm,a = 90. 45(2)°,β= 94. 24(1)°,r= 101. 08(1)°,V=0. 799 29(20) nm-3,Z=2. The tin atom was six-coordinated in a severely distorted octahedron configuration,and exhibited the strong Lewis acidity under the influence of the strong electron-withdrawing effect of the sulfonic group. When the compound catalyzed the transesterification of dimethyl carbonate(DMC) and phenol to diphenyl carbonate, its strong Lewis acidity was of benefit to the enhancement of the DMC conversion, but the intermediate methyl phenyl carbonate was easily decomposed on the basis of the excessively strong Lewis acidity. Decreasing the concentration of the strong Lewis acid could observably restrain the decomposition of methyl phenyl carbonate, and improve the transesterification selectivity.