钛硅分子筛催化环己酮液相氨肟化固定床工艺

采用固定床模式,研究了钛硅分子筛催化环己酮制环己酮肟液相氨肟化反应.结果表明,该工艺模式具有可行性与普适性.优化的反应条件为:温度333K,体系氨浓度>2%,酮/H₂O₂摩尔比=5,H₂O₂空速0.083h^-1.此时环己酮转化率、环己酮肟选择性、H₂O₂转化率及其有效利用率分别达18.7%,99.5%,94.7%和98.7%.进一步研究了H₂O₂在该过程中的反应行为,发现固定床工艺模式能有效提高H₂O₂的有效利用率,其主要原因是该模式有利于羟胺的生成及其进一步与酮反应生成肟.适当的空速与氨和酮的浓度是实现H₂O₂高效利用的关键因素.

Fixed-bed process of liquid-phase ammoximation of cyclohexanone over titanosilicates

Liquid-phase ammoximation of cyclohexanone to the corresponding oxime was conducted in a fixed-bed reactor over titanium silicalite (TS-1), which was proved to be a feasible and universal process. The primary rules of ammoximation were explored in the fixed-bed reactor system.The initial results indicated that the utilization of H₂O₂ was enhanced obviously through this mode, which is attributed to successful hydroxylamine generation and smooth contact with ketones. Further investigations of H₂O₂ reaction behavior showed that the proper weight hourly space velocity of H₂O₂ and the concentrations of ammonia and ketone both play a key role in highly efficient utilization of H₂O₂. The cyclohexanone and H₂O₂ conversion, cyclohexanone-oxime selectivity, and H₂O₂ efficiency reached 18.7%, 94.7%, 99.5%, and 98.7%, respectively, under the optimum reaction conditions of temperature of 333 K, ammonia concentration higher than 2%, cyclohexanone/H₂O₂ molar ratio of 5, and WHSV (H₂O₂)of 0.083h^-1 with 85% t-BuOH as solvent.