环己酮肟气相重排固体酸催化剂的研究进展

Research progress on solid acid catalysts for cyclohexanone oxime vapor-phase rearrangement

介绍了传统液体催化剂浓硫酸或发烟硫酸催化环己酮肟贝克曼重排反应制己内酰胺存在的问题,以及替代传统液体催化剂的气相贝克曼重排固体酸催化剂的种类和催化效果。固体酸催化剂主要有沸石分子筛、金属氧化物两类,其中Silicalite-1全硅分子筛在高温下催化环己酮肟气相重排,环己酮肟转化率和己内酰胺选择性均较高。固体酸催化剂应用于环己酮肟气相贝克曼重排反应,无副产物硫酸铵、对设备腐蚀小,且环己酮肟转化率与己内酰胺的选择性较高,但使用寿命受到较大限制。建议加强对催化剂失活机理,以及适用于环己酮肟气相重排的固体酸催化剂的制备和筛选的研究,在确保己内酰胺高收率的同时,进一步提高催化剂的寿命。

The problems in the production of caprolactam by Beckmann rearrangement of cyclohexanone oxime over the traditional liquid catalysts of concentrated sulfuric acid or fuming sulfuric acid were analyzed. The types and catalytic effects of solid acid catalysts for vapor-phase Beckmann rearrangement instead of traditional liquid catalysts were introduced. There are mainly two types of solid acid catalysts, i.e. zeolite molecular sieves and metal oxides. Among them, Silicalite-1 silica zeolite molecular sieves contribute relatively high cyclohexanone oxime conversion rate and caprolactam selectivity in cyclohexanone oxime vapor-phase rearrangement at high temperature. Solid acid catalysts have the advantages of no by-product ammonium sulfate, light equipment corrosion and high cyclohexanone oxime conversion rate and caprolactam selectivity in the vapor-phase Beckmann rearrangement of cyclohexanone oxime, but the service life of the catalysts will be greatly limited. It was suggested that the research of the deactivation mechanism of the catalysts and the preparation and selection of solid acid catalysts for cyclohexanone oxime vapor-phase rearrangement be strengthened so as to further improve the catalyst life at high caprolactam yield.