Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical metho...Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical methods, such as XRF, XRD, low-temperature N2 adsorption/desorption, TEM, FT-IR, UV-Vis, 29Si MAS NIVIR, and XPS techniques. The characterization results suggest that HTS zeolite has a special hollow crystal structure and its mesopore volume is larger than that of TS-1 zeolite. The titanium species in this zeolite are composed of the framework tetrahedral Ti （IV） ions and extra-framework octahedral Ti （IV） ions, which tend to disperse into its bulk phase. This zeolite material also has been applied to catalyze the cyclohexanone oxidation process, and the products are not completely consistent with those results obtained by using TS-1 zeolite, which might be caused by their difference in pore structure and pore volume, especially the mesopore volume. Cy- clohexanone oxidation catalyzed by HTS zeolite is a representative consecutive reaction, the main target products of which are e-caprolactone, 6-hydroxyhexanoic acid and adipic acid. The effect of H202/cyclohexanone mole ratio on the cyclohexa- none conversion, the total target product selectivity, the distribution of three target products selectivity and their variations along with reaction time is also researched and analyzed, which indicate that HTS zeolite shows a high performance for the Baeyer-Villiger reaction of cyclohexanone and catalytic oxidation of 6-hydroxyhexanoic acid under mild conditions, and the quantity of active surface titanium species as well as the pore structure and mesopore volume controlling the mass diffusion rate are the key factors determining the catalytic activity of HTS zeolite and product selectivity.展开更多
文摘二苯甲酮在过氧酸的氧化作用下,可以发生Baeyer-Villiger重排反应生成苯甲酸苯酯.研究了Baeyer-Villiger反应的安全、简易的方法,即利用过硫酸钾将有机羧酸氧化为过氧酸.考察了影响反应的因素,得出最佳实验条件,即反应在室温下进行,苯甲酸苯酯制备的最佳比例为:浓硫酸20 mL;冰乙酸40 mL;过硫酸钾25 g;二苯甲酮9.1 g.
基金the financial support of the State Basic Research Project ‘‘973’’ by the Ministry of Science and Technology of People’s Republic of China (2006CB202508)
文摘Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical methods, such as XRF, XRD, low-temperature N2 adsorption/desorption, TEM, FT-IR, UV-Vis, 29Si MAS NIVIR, and XPS techniques. The characterization results suggest that HTS zeolite has a special hollow crystal structure and its mesopore volume is larger than that of TS-1 zeolite. The titanium species in this zeolite are composed of the framework tetrahedral Ti （IV） ions and extra-framework octahedral Ti （IV） ions, which tend to disperse into its bulk phase. This zeolite material also has been applied to catalyze the cyclohexanone oxidation process, and the products are not completely consistent with those results obtained by using TS-1 zeolite, which might be caused by their difference in pore structure and pore volume, especially the mesopore volume. Cy- clohexanone oxidation catalyzed by HTS zeolite is a representative consecutive reaction, the main target products of which are e-caprolactone, 6-hydroxyhexanoic acid and adipic acid. The effect of H202/cyclohexanone mole ratio on the cyclohexa- none conversion, the total target product selectivity, the distribution of three target products selectivity and their variations along with reaction time is also researched and analyzed, which indicate that HTS zeolite shows a high performance for the Baeyer-Villiger reaction of cyclohexanone and catalytic oxidation of 6-hydroxyhexanoic acid under mild conditions, and the quantity of active surface titanium species as well as the pore structure and mesopore volume controlling the mass diffusion rate are the key factors determining the catalytic activity of HTS zeolite and product selectivity.
