甲苯一步催化硝化制备二硝基甲苯反应过程及危险性

Trimetallic spinel CuMnCoO₄ was prepared by the freezing-assisted sol-gel method, characterized by XRD, BET, FTIR, Raman and XPS, and its catalytic performance for solvent-free toluene nitration with nitric acid as nitration agent in the absence of sulfuric acid was investigated. The findings indicated that the toluene nitration system catalyzed by CuMnCoO₄ spinel had a preference for the generation of dinitrotoluene (DNT) with the selectivity of DNT being 1.6 times higher than that of the toluene nitration system without spinel. On this basis, in accordance with the fundamental principle of “substitution, mitigation and simplification” for intrinsic safety, this study optimized the conventional production process of two-stage nitrous-sulfur mixed acid nitrification of DNT and obtained the optimal process conditions as follows. With molar ratio of 95% HNO₃, toluene, CuMnCoO₄ spinel catalyst is 4∶1∶0.15, the toluene was dosed at room temperture and then the reaction was kept at 50℃ for 6h, and the DNT can be prepared by the one-step nitration of toluene (the selectivity can be up to 67.44%). In the meantime, this study tested the thermal hazard parameters of CuMnCoO₄ spinel-catalyzed toluene nitration process under semi-intermittent reaction by the reaction calorimeter(RC1e), and investigated the dangerousness of the reaction process. The calculations showed that this new heterogeneous catalytic system could improve DNT selectivity and decrease the maximum temperature which can be reached by a failure control system (MTSR), thereby enhancing the safety of the reaction system.