Construction of 2-(2鈥?Hydroxy-5鈥?methylphenyl)benzotriazole over Pd/纬-Al2O3 by a Continuous Process

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• 作者：Bowei Wang ; Wangwang Fang ; Leilei Si ; Yang Li ; Xilong Yan ; Ligong Chen ; Shutao Wang
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2015
• 出版时间：August 3, 2015
• 年：2015
• 卷：3
• 期：8
• 页码：1890-1896
• 全文大小：478K
• ISSN：2168-0485

文摘

The synthesis of 2-(2鈥?hydroxy-5鈥?methylphenyl)benzotriazole from 2-nitro-2鈥?hydroxy-5鈥?methylazobenzene over Pd/纬-Al₂O₃ in a fixed-bed reactor was investigated. Pd/纬-Al₂O₃ catalysts were prepared by two methods and characterized by XRD, TEM, H₂-TPR, and N₂ adsorption鈥揹esorption. Employed in the above reaction, the palladium catalyst impregnated in hydrochloric acid exhibited much better catalytic performance than that impregnated in ammonia鈥搘ater, which was possibly attributed to the better dispersion of palladium crystals on 纬-Al₂O₃. This result demonstrated that the preparation process of the catalyst was very important. Furthermore, the reaction parameters were optimized. Under the optimized conditions (toluene, NAB/triethylamine molar ratio 1:2, 60 掳C, 2.5 MPa hydrogen pressure, 0.23 h^鈥? liquid hourly space velocity), about 90% yield of 2-(2鈥?hydroxy-5鈥?methylphenyl)benzotriazole was obtained. Finally, the time on stream performance of the catalyst was evaluated, and the reaction could proceed effectively over 200 h without deactivation of the catalyst.