Lever Sarah D, Papadaki Maria
Chemical Engineering Department, School of Process Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT, UK.
J Hazard Mater. 2004 Nov 11;115(1-3):91-100. doi: 10.1016/j.jhazmat.2004.05.026.
The risks associated with batch processing in the manufacture of chemicals and pharmaceuticals via highly exothermic reactions are of special interest due to the possibility of runaway reactions. o-Nitrated benzoyl chlorides are intermediates in the production of agrochemicals and are produced via the reaction of o-nitrated carboxylic acids with thionyl chloride in a solvent mixture. ortho-Nitrated acyl chlorides have exploded violently on attempted distillation on numerous occasions. An inadequate investigation of the process prior to large-scale operation is the most likely cause. Here we present preliminary results of studies on the decomposition of 2-nitrobenzoyl chloride. This study has revealed that the decomposition reaction is strongly condition dependent. The heating rate of the sample plays a preponderant role in the course of the decomposition reaction. That renders the interpretation of differential scanning calorimetry (DSC) or adiabatic calorimetry measurements, which are routinely used to assess the thermochemistry and safety of the large-scale reactions, problematic. Following this on-going study, we report here key features of the system that have been identified.
由于存在反应失控的可能性，通过高度放热反应制造化学品和药品时，与间歇式加工相关的风险备受关注。邻硝基苯甲酰氯是农用化学品生产中的中间体，通过邻硝基羧酸与亚硫酰氯在混合溶剂中反应制得。邻硝基酰氯在多次蒸馏尝试中发生剧烈爆炸。大规模操作前对工艺的调查不足很可能是原因所在。在此，我们展示了关于2-硝基苯甲酰氯分解研究的初步结果。该研究表明，分解反应强烈依赖于条件。样品的加热速率在分解反应过程中起主要作用。这使得常规用于评估大规模反应热化学和安全性的差示扫描量热法（DSC）或绝热量热法测量的解释变得困难。在这项正在进行的研究之后，我们在此报告已确定的该系统的关键特征。
