纳米TiO_2催化α-蒎烯空气环氧化反应

α-Pinene Epoxidation with Air Catalyzed by Nanosized TiO_2

采用硫酸钛和氢氧化钠等无机试剂为原料,经过简单步骤制备出纳米Ti O2前驱体,用高压釜在270℃和7·07MPa下进行乙醇热处理,得到锐钛矿型纳米Ti O2催化剂,并考察了该催化剂对α-蒎烯空气环氧化反应的催化性能.结果表明,乙醇高压热处理明显地提高了纳米Ti O2的催化活性.在常压、70℃和6h条件下,α-蒎烯转化率可达17·02%,环氧化物选择性为53·47%;当压力增大到1·01MPa时,转化率提高到35·24%,选择性下降到41·20%.对反应机理进行了探讨.

The anatase TiO2 nanoparticles were prepared by heat treating TiO2 precursor, which was made from Ti（SO4）2 and washed with ethanol, in an autoclave under the conditions of 270 ℃ and 7.07 MPa. The catalyst was used to catalyze α-pinene epoxidation with air. The results showed that the catalyst activity increased markedly after heat treating with ethanol under high pressure. Under the conditions of 101. 325 kPa, 70 ℃ and 6 h, the α-pinene conversion reached 17.02% and the selectivity for epoxides was 53.47%. When the system pressure increased to 1.01 MPa, the conversion increased to 35.24 % and the epoxide selectivity decreased to 41 .20%. The possible reaction mechanism has also been investigated.