化学工业与工程

芳烃硝化反应由于其快速反应且剧烈放热特性，制约了传统间歇合成工艺的可持续发展，而微通道连续流技术为这类典型强放热反应的安全、高效、绿色合成提供了重要保障。以环隙式套管微通道连续流技术为核心，系统研究了苯和氯苯连续硝化控制步骤及过程强化策略，为高通量放大提供技术支持。对于一硝化反应，在混酸含水量13%、n(硝酸)∶n(苯)为1.05∶1.00、反应温度50℃、停留时间3 s下苯的转化率>99.5%，硝基苯(NB)收率达99%;在n(硝酸)∶n(氯苯)为1.2∶1.0、反应温度40℃下氯苯的转化率> 99.5%，硝基氯苯(NCB)收率99.2%。对于二硝化反应，在混酸含水量3.5%、反应温度90℃、停留时间156 s条件下，二硝基苯(DNB)总收率98.5%(间二硝基苯占比82.5%);在n(硝酸)∶n(氯苯)为2.2∶1.0，二硝基氯苯(DNCB)收率98.6%(2,4-DNCB占比>95%)。在高通量(150～750 m L·min^-1)放大过程中，苯与氯苯的一硝化产物收率分别达99.3%与99.6%，二硝化产率可达96.4%与96.5%，未出现显著放大效应。

Aromatic nitration reaction poses challenges to the sustainable development of traditional batch synthesis process due to its rapid kinetics and significant exothermic nature. In contrast,microchannel flow technology offers crucial technical support for the safe,efficient,and environmentally friendly synthesis of such typical strong exothermic reactions. This work systematically investigated the control steps and process intensification strategies of high-throughput continuous nitration of benzene and chlorobenzene by utilizing annular tube-in-tube microchannel continuous flow technology. For the mononitration reaction,the conversion of benzene exceeds 99. 5%,yielding nitrobenzene( NB) at an impressive rate of99% under the conditions comprising of mixed acid water content of 13%,nitric acid/benzene molar ratio of 1. 05 ∶1. 00,reaction temperature of 50 ℃ and residence time of 3 s. Similarly,chlorobenzene exhibits over 99. 5% conversion with a nitrochlorobenzene( NCB) yield reaching 99. 2% when subjects to a nitric acid/chlorobenzene molar ratio of 1. 2 ∶ 1. 0 at a reaction temperature of 40 ℃ ． For the dinitration reaction,under the conditions featuring a 3. 5% water content of mixed acid,a 90 ℃ reaction temperature and 156 s residence time,the total yield of dinitrobenzene( DNB) reaches up to 98. 5%,with m-isomers constituting 82. 5% thereof. At a nitric acid/chlorobenzene molar ratio of 2. 2 ∶1. 0,the yield of dinitrochlorobenzene( DNCB) is 98. 6%( 2,4-DNCB accounted for > 95%). In the high-throughput( 150 ～750 m L·min^-1) scale-up process,the yields of mononitration products of benzene and chlorobenzene are99. 3% and 99. 6%,respectively,and the yields of dinitration are 96. 4% and 96. 5%,respectively. Notably,no significant amplification effect was observed throughout these experiments.