针对萘硝化间歇式反应存在反应时间长、收率低和风险高等问题,以萘为原料、浓硝酸为硝化剂、二氯乙烷为溶剂,提出了微通道反应器内合成一硝基萘的连续流工艺。考察了硝酸与萘摩尔比、反应温度、硝酸质量分数、反应停留时间4个因素对微通道连续反应的影响,验证了最佳工艺条件下微通道连续反应转化率和收率的稳定性,并对比分析了间歇式反应与微通道连续流反应的反应严重度。结果表明,硝酸与萘摩尔比为2∶1、反应温度为40℃、硝酸质量分数为85%、停留时间为96 s时微通道连续流反应效果最佳;最佳工艺条件下,微通道连续反应稳定,萘的转化率达到99.1%,一硝基萘的收率达到96.3%;间歇反应、微通道连续反应绝热温升分别为103.25℃和1.5℃,表明微通道连续流的萘一段硝化反应风险更低。

To address the problems of long reaction time,low yield,and high risk in the intermittent nitration reaction of naphthalene,a continuous flow process for the synthesis of mononitronaphthalene in a microchannel reactor is proposed with naphthalene as raw material,concentrated nitric acid as nitrating agent,and dichloroethane as solvent.The influences of four factors,including the molar ratio of nitric acid to naphthalene,reaction temperature,nitric acid concentration,and reaction residence time,on the continuous microchannel reaction are evaluated.The stability of the conversion rate and yield of microchannel continuous reaction is verified under the optimal process conditions,and the reaction severity of intermittent reaction and microchannel continuous flow reaction is compared and analyzed.The results indicate that the microchannel continuous flow reaction presents the best effect when the molar ratio of nitric acid to naphthalene is 2∶1,reaction temperature is 40℃,nitric acid concentration is 85%,and residence time is 96 seconds;Under the optimal process conditions,the microchannel continuous reaction remains stable,with a naphthalene conversion rate of 99.1% and a mononitronaphthalene yield of 96.3%;The adiabatic temperature rise of intermittent reaction and microchannel continuous reaction is 103.25℃ and 1.5℃,respectively,indicating that the naphthalene one-stage nitrification reaction in microchannel continuous flow has lower risk.

刘祥(1997-),男,硕士生,研究方向为连续流合成工艺,599982408@qq.com;张跃(1964-),男,博士,研究员,研究方向为连续流化工工艺开发,通讯联系人,zyjs@cczu.edu.cn。