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制备了表面修饰多壁碳纳米管负载TiO2的催化剂,并将其应用于碳酸二甲酯与苯酚的酯交换反应.采用X射线电子能谱、透射电子显微镜、低温N2吸附-脱附和X射线衍射等对催化剂进行了表征.结果表明,以低浓度的氨水(0.4%)代替去离子水作为沉淀剂时,制备的催化剂显示出更好的催化活性、分离性与重复使用性.考察了TiO2负载量、催化剂用量及反应时间对反应性能的影响.在最佳反应条件下,苯酚转化率为42.5%,碳酸甲苯酯与碳酸二苯酯的总选择性达到99.9%以上.经过4次重复使用后,催化剂的活性略有下降.
The surface-modified multi-walled carbon nanotubes supported TiO2 catalysts were prepared and applied to the transesterification of dimethyl carbonate with phenol.The structures of the catalysts were characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, N2 adsorption-desorption and X-ray diffraction Were used to characterize the catalyst.The results showed that the prepared catalyst showed better catalytic activity, separability and reusability when substituted deionized water was used as precipitant at a low concentration of ammonia water (0.4%). The effects of TiO2 loading The amount of catalyst and the reaction time on the reaction performance under the best reaction conditions, the conversion of phenol was 42.5%, the total selectivity of cresyl carbonate and diphenyl carbonate reached 99.9%. After 4 times repeated use , The activity of the catalyst decreased slightly.