摘要
苯甲酸硝化制备3,5-二硝基苯甲酸是强放热反应,反应热为-278.96 kJ/mol,传统间歇硝化反应器存在传热、传质效率差,物料蓄积易引发爆炸事故等安全问题。针对以上不足,提出了在脉冲微通道反应器中采用连续法合成3,5-二硝基苯甲酸的新工艺。选择苯甲酸为原料,发烟硫酸为溶剂,浓硝酸为硝化剂,考察了发烟硫酸用量、物料配比、温度、停留时间等条件对苯甲酸硝化反应的影响,优化了工艺条件。结果表明,当n(苯甲酸):n(浓硝酸):n(发烟硫酸)=1:2.8:7,反应温度为75℃,停留时间为4 min时,苯甲酸转化率为100%,3,5-二硝基苯甲酸的选择性达97.2%。微通道反应器良好的热交换性能在保证工艺体系安全的前提下大幅度缩短了停留时间、提高了生产效率。
Nitration of benzoic acid to 3,5-dinitrobenzoic acid is a strong exothermic reaction and the reaction enthalpy is-278.96 kJ/mol.The traditional batch nitrification reactor has some safety problems,such as poor efficiency of heat and mass transfer,explosive accident caused by material accumulation.In view of the above shortcomings,a new process of continuous synthesis of 3,5-dinitrobenzoic acid in pulse microchannel reactor was proposed.Taking benzoic acid as raw material,fuming sulfuric acid as solvent and concentrated nitric acid as nitrating agent,the effects of the amount of fuming sulfuric acid,material ratio,temperature and residence time on the nitration of benzoic acid were investigated,and the process conditions were accordingly optimized.The results show that when n(benzoic acid):n(concentrated nitric acid):n(fuming sulfuric acid)=1:2.8:7,reaction temperature is 75℃and residence time is 4 min,the conversion of benzoic acid is 100%and the selectivity of 3,5-dinitrobenzoic acid is 97.2%.The good heat exchange performance of the microchannel reactor can greatly shorten the residence time and improve the production efficiency on the premise of ensuring the safety of the process system.
作者
郭冰蒙
张跃
严生虎
刘建武
陈代祥
沈介发
马晓明
辜顺林
GUO Bing-meng;ZHANG Yue;YAN Sheng-hu;LIU Jian-wu;CHEN Dai-xiang;SHEN Jie-fa;MA Xiao-ming;GU Shun-lin(School of Petrochemical Engineering,Changzhou University,Changzhou 213164,Jiangsu,China;Continuous Flow Technical Engineering Laboratory for Petroleum and Chemical Industry,Changzhou 213164,Jiangsu,China)
出处
《天然气化工—C1化学与化工》
CAS
北大核心
2021年第2期76-80,共5页
Natural Gas Chemical Industry
基金
江苏省产学研前瞻性联合研究项目(BY2014037-19)。
关键词
3
5-二硝基苯甲酸
硝化
微通道反应器
连续工艺
3,5-dinitrobenzoic acid
nitrification
microchannel reactor
continuous process
