共查询到18条相似文献,搜索用时 207 毫秒
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为了对2,4-二硝基氯苯生产进行连续自动化提升改造,检测并分析了邻硝基氯苯硝化生产2,4-二硝基氯苯合成过程的热危险性,以邻硝基氯苯为原料,经硝化反应制备得到2,4-二硝基氯苯,采用反应量热仪(RC1)测定了该硝化反应热稳定性数据,采用差示扫描量热仪和绝热仪分别对邻硝基氯苯、硝化反应液热和2,4-二硝基氯苯成品的热分解过程进行了测试,结果表明:邻硝基氯苯起始分解温度为376℃,2,4-二硝基氯苯起始分解温度为371℃,该反应的绝热温升约为253.7 K,失控反应严重度等级为3级,该反应MTSR为94.1℃,TP为70℃,TD24约为142℃,MTT为327℃,TP 相似文献
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连续绝热硝化法制备硝基氯苯的研究 总被引:2,自引:0,他引:2
本文介绍了氯苯连续绝热硝化制箅硝基氯苯的方法,对绝热硝化过程中的混酸组成,反应温度、停留时间等影响因素进行了较系统的研究,获得了较佳的结果。本研究为硝基氯茉生产技术的开发提供了实验依据。 相似文献
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对分别以氯苯和对硝基氯苯为原料,间歇式硝化法生产2,4-二硝基氯苯的工业生产工艺进行了对比分析。分析表明,乙硝基氯苯为原料生产2,4-二硝基氯苯,反应平和,反应放热速度慢,放热量少,产品纯度高。 相似文献
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绿色硝化技术在硝基氯苯合成中的应用 总被引:14,自引:2,他引:12
将绿色硝化方法应用于一硝基氯苯的制备 ,获得了氧气流量、二氧化氮的初始浓度及氯苯的初始浓度对一硝基氯苯产量的影响。实验结果表明该硝化过程具有一个明显的诱导期 ,反应时间过长将导致一硝基氯苯的收率下降 相似文献
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本文综述了氯苯液相硝化及气相催化硝化制硝基氯苯的专利文献,对分离硝化产物异构体的工艺也作了介绍,认为氯苯液相硝化工业化较容易。 相似文献
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芳香族化合物的硝化是快速、强放热反应,采用连续硝化工艺可降低间歇操作可能引起的潜在风险。本文采用可视化方法和计算流体力学(CFD)模拟研究微管内流动状况的基础上,在体积为10mL的微管反应器中进行了氯苯连续硝化反应,探究了停留时间、温度、混酸比(硝酸与硫酸的摩尔比)、相比(硝酸与氯苯的摩尔比)对反应转化率、收率、产物邻对比和选择性的影响。结果表明,氯苯和混酸两相在内径为1mm的微通道内呈现出的Taylor流流型可以强化传质传热的效率,提高宏观反应速率。在停留时间为8min、温度80℃、混酸比=1∶1.5、相比=1∶1时,产物中邻对比在0.7~0.8之间,氯苯单程转化率为81.24%,一硝基氯苯的选择性为93.77%。采用连续硝化后,反应停留时间大幅降低,一硝基氯苯的邻对比明显提高。相比于传统釜式工艺,微管反应器内连续硝化更加安全、高效。 相似文献
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Yongjin Cui Jing Song Chencan Du Jian Deng Guangsheng Luo 《American Institute of Chemical Engineers》2022,68(4):e17564
The nitration of chlorobenzene with concentrated mixed acids is a fast and highly exothermic process, which suffers from considerable mass transfer resistance and poor heat transfer rates. The reaction kinetics has not been thoroughly reported before. In this work, a continuous-flow microreactor system and a homogeneous reaction condition were proposed to obtain accurate chlorobenzene nitration kinetics parameters at high mixed acid concentrations. A general model for predicting the observed reaction rate constants was established. With a new method for estimating the equilibria associated with HNO3 in aqueous sulfuric acid, the rate constants based on nitronium ion and activation energies were obtained. Compared with batch reactors, the continuous-flow microreactor system allows for a sufficient heat transfer efficiency and accurate residence time control, making it possible to study the reaction performance more quickly and sensitively. This work may provide a reliable reference for the kinetic study of similar processes. 相似文献
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硝基苯生产工艺评述与技术进展 总被引:4,自引:0,他引:4
对工业上使用的混酸硝化法、绝热硝化法等硝基苯生产工艺进行了评述。综述了采用固体酸催化剂取代硫酸用于制备硝基苯的研究进展 ,指出以固体酸催化苯的气相硝化工艺是未来硝基苯生产工艺的发展方向 相似文献
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J. M. Zaldivar E. Molga M. A. Al s H. Hern ndez K. R. Westerterp 《Chemical Engineering and Processing: Process Intensification》1995,34(6):543-559
Aromatic nitrations by mixed acid have been selected as a specific case of a heterogeneous liquid-liquid reaction. An extensive experimental programme has been followed using adiabatic and heat-flow calorimetry and pilot reactor experiments, supported by chemical analysis. A series of nitration experiments has been carried out to study the influences of different initial and operating conditions such as temperature, stirring speed and sulphuric acid concentration. In parallel, a mathematical model to predict the overall conversion rate has been developed. In this paper the mathematical modelling and the implementation and experimental validation for benzene, toluene and chlorobenzene mononitration in the kinetic control regime (slow liquid-liquid reaction) are presented and discussed. 相似文献
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Jun Liang Lei Ni Peihong Wu Hang Yao Qiang Chen Gang Fu Juncheng Jiang 《American Institute of Chemical Engineers》2022,68(7):e17679
In this study, different calorimetric and analytical techniques were used to evaluate the thermal behavior of the preparation of 1-nitronaphthalene through the nitration of naphthalene with mixed acid. Differential scanning calorimetry and adiabatic calorimetry revealed that 1-nitronaphthalene lacks thermal decomposition characteristics. The results of reaction calorimetry, high-performance liquid chromatography, and the density function theory method were combined to analyze the reaction mechanism. An expanded Stoessel criticality diagram was developed to evaluate the process safety of the semibatch nitration reaction. The results revealed a higher degree of risk than that obtained when using the traditional Stoessel criticality diagram. Kinetics parameters of the reaction were investigated. 相似文献
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三硝基间苯三酚(TNPG)是重要的医药中间体,通常以间苯三酚(PG)为原料,在间歇反应釜中经硝化合成。该工艺存在反应时间长、能耗高、安全性差等问题,亟需开展新型连续合成工艺研究。在超声微反应器中开展了PG混酸硝化过程研究,通过引入超声解决微通道中高黏流体混合差和固体产物易造成通道堵塞的难题,实现TNPG连续合成并大幅缩短了反应时间。此外,基于对原料和产物的质谱等分析,初步探讨了反应路径和行为特征。在优化工艺条件下(PG浓度:1.0 mol/L;硝酸与PG摩尔比:4;反应温度:40℃;停留时间6~10 min),TNPG收率可达80%,固体纯度大于98%。 相似文献
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三硝基间苯三酚(TNPG)是重要的医药中间体,通常以间苯三酚(PG)为原料,在间歇反应釜中经硝化合成。该工艺存在反应时间长、能耗高、安全性差等问题,亟需开展新型连续合成工艺研究。在超声微反应器中开展了PG混酸硝化过程研究,通过引入超声解决微通道中高黏流体混合差和固体产物易造成通道堵塞的难题,实现TNPG连续合成并大幅缩短了反应时间。此外,基于对原料和产物的质谱等分析,初步探讨了反应路径和行为特征。在优化工艺条件下(PG浓度:1.0 mol/L;硝酸与PG摩尔比:4;反应温度:40℃;停留时间6~10 min),TNPG收率可达80%,固体纯度大于98%。 相似文献