戊内酰胺合成新工艺探索

Exploration of new synthesis process of pentalactam

以环戊酮与反应助剂环己酮为原料,按照一定比例混合,经过氨肟化反应、氨肟化产物分离、贝克曼重排反应、水解中和反应、分离精制制得戊内酰胺,采用单因素实验考察了戊内酰胺的合成工艺条件。结果表明:通过在环戊酮中添加反应助剂环己酮,当环己酮/环戊酮摩尔比大于4.0时,氨肟化分离单元分离后的氨肟化废水中肟的质量分数降至0.1%以下,采用苯萃取水解中和产生的己内酰胺和戊内酰胺油相,可得到苯中内酰胺质量分数大于30%的溶液;环戊酮与环己酮的混合物氨肟化反应较佳的反应工艺条件为反应温度80~85℃,双氧水/酮摩尔比1.08~1.12,氨/酮摩尔比1.4~1.6,体系中催化剂质量分数3.0%~4.0%,反应停留时间90 min,在此条件下酮的转化率、肟的选择性均大于99.8%;贝克曼重排和水解中和反应较佳的反应工艺条件为重排反应温度90~110℃、酸肟摩尔比1.12~1.20,水解中和反应温度40~50℃、pH值5,在此条件下肟的转化率、产物的选择性均大于99.8%;该戊内酰胺合成新工艺不仅具有高的转化率和选择性,而且可以降低氨肟化废水中肟的含量,减少肟的损失,同时解决了苯萃取戊内酰胺效率低的问题。

Pentanolactam was prepared by mixing cyclopentanone and reaction auxiliary cyclohexanone in a certain proportion as raw materials,followed by aminooximation reaction,separation of oxime products,Beckmann rearrangement reaction,hydrolysis neutralization reaction,separation and purification.The synthesis process conditions of pentanolactam were investigated through single factor experiments.The results showed that the mass fraction of oxime in the separated ammonia oxime wastewater from aminooximation separation unit could decrease to below 0.1%by adding the reaction auxiliary cyclohexanone to cyclopentanone at a molar ratio of above 4.0,and a solution with a mass fraction of lactam higher than 30%in benzene could be obtained by using benzene to extract the oil phase of caprolactam and pentalactam produced during hydrolysis neutralization;the conversion rate of ketone and the selectivity of oxime were both higher than 99.8%when the aminooximation reaction conditions of cyclopentanone and cyclohexanone mixture were optimized as followed:reaction temperature of 80-85℃,hydrogen peroxide-to-ketone molar ratio of 1.08-1.12,ammonia-to-ketone molar ratio of 1.4-1.6,3.0%-4.0%catalyst in reaction system by mass fraction and reaction residence time of 90 min;the conversion rate of oxime and the selectivity of the product were both above 99.8%when the reaction conditions for Beckman rearrangement and hydrolysis neutralization reaction were optimized as followed:rearrangement reaction temperature of 90-110℃,acid-to-oxime molar ratio of 1.12-1.20,hydrolysis neutralization reaction temperature of 40-50℃and pH value of 5;and the new process for synthesizing pentanolactam not only can provide high conversion rate and selectivity,but also can reduce the oxime content of ammonia oxime wastewater,depress the loss of oxime,and solve the problem of low extraction efficiency of pentalactam with benzene.