苯酐选择性加氢制苯酞催化剂的研究

本文对苯酐选择性加氢制苯酞的催化剂进行了详细研究．研究结果表明，采用共沉淀法制备的Ｎｉ－Ｃｒ－Ｏ／Ａｌ２Ｏ３催化剂具有较高活性和选择性．ＸＲＤ研究表明，Ｈ２还原前催化剂呈晶体结构，还原后出现弥散峰．由ＸＲＤ，ＸＰＳ，ＳＥＭＳ研究表明Ｎｉ２．５＋～２．６＋是活性物种，失活原因是由于在反应中镍还原为低价和零价，物理上是由于活性组分颗粒的聚集，颗粒变大，比表面下降．ＴＰＤ研究表明Ｃｒ的作用是使Ｔｍ升高，吸附量降低，从而提高了活性和选择性．

STUDY ON CATALYST FOR SELECTIVE HYDROGENATION OF PHTHALIC ANHYDRIDE TO PHTHALIDE

he catalyst for selective hydrogenation of phthalic anhydride tophthalide has been studied in details. It has been shown that Ni-Cr-O/Al2O3 catalyst prepared by coprecipitation is of high activity and selectivity. The XRD study shows that the crystal structure exists in the catalyst before reduced with hydrogen, and the spread peaks appear afterreduced. XRD, XPS and SEMS results show that the Ni2.5+-2.6+ is anactive species, the activity of catalyst decrease is due to the reduction ofNiO. The congregate of particulate and decrease in surface area are thephysical reasons for the deactivation of catalyst. TPD study shows thatthe action of Cr is to increase the Tm and to decrease the adsorption volume, and thus increasing the activity and selectivity of catalyst.