Modeling Method and Modeling System for Runaway Mechanism Model of Benzene Nitration Reaction

Abstract

The present invention discloses a modeling method for a runaway mechanism model of benzene nitration reaction, comprising the following steps: performing a programmed temperature rise calorimetry test on a target benzene nitration reaction system to obtain all exothermic temperature ranges, heat release amounts during the runaway process of the benzene nitration reaction, as well as the reactant, intermediate and product information in each exothermic temperature range; according to the reactant, intermediate and product information in each exothermic temperature range, using reactive molecular dynamics simulation to obtain the reaction runaway path set and reaction mechanism in each exothermic temperature range; and adopting quantum chemical density functional theory calculation to analyze the reaction mechanism in each exothermic temperature range, determine the order of the runaway paths in the reaction runaway path set in each exothermic temperature range, and construct a reaction runaway mechanism model of the target benzene nitration reaction system. The present invention also discloses a modeling system for a runaway mechanism model of benzene nitration reaction. The present invention realizes the modeling of the runaway process of the target benzene nitration reaction system.

Description

Technical Field

[0001] The present invention relates to the technical field of diagnosis and control of safety runaway in chemical reaction processes, and particularly relates to a modeling method and a modeling system for a benzene nitration reaction runaway mechanism model. Background Art

[0002] The nitration reaction system plays an important role in chemical production. Nitrobenzene is an important chemical raw material and intermediate, which is widely used in the production of pharmaceuticals, dyes, pesticides, explosives, polyurethane foam plastics, etc. The benzene nitration process is an important production process in the chemical industry. The benzene nitration reaction has a large heat release and a fast reaction rate, which is likely to cause local heat accumulation in the reaction kettle. In addition, the benzene nitration reaction materials have high oxidizing and reactive properties. Slight control errors will lead to violent side reactions. Moreover, the nitration products and by-products also have significant combustion and explosion hazards. Therefore, the benzene nitration process is a typical dangerous process with frequent accidents, and there is an urgent need to establish a safety monitoring and early warning technology for the benzene nitration process. A comprehensive and accurate benzene nitration reaction mechanism model is the basis for developing an effective monitoring and early warning technology. However, for the current benzene nitration reaction process, only the main reaction and a small number of side reactions have been modeled. During the reaction runaway process, secondary side reactions and exothermic reactions of material secondary decomposition will occur successively as the runaway temperature rises, which often play a major role in the rate and consequences of the reaction runaway. There is still a lack of understanding of the reaction runaway mechanism models such as secondary side reactions and exothermic reactions of material secondary decomposition.

[0003] In the prior art, the patent document CN101251747A discloses a modeling method for a p-xylene oxidation reaction industrial device model. By using multiple linear regression technology, a correlation model between each reaction factor and the rate constants of each step of consecutive reactions is established, and directly based on the production data of the industrial device, the regression coefficients of the rate constant correlation model are obtained by optimization, and a model that can well describe the characteristics of the industrial device is established. The patent document CN1417192A discloses a modeling method for the kinetic model of the p-xylene liquid-phase catalytic oxidation reaction, and establishes a modeling method for the kinetic model of the PX liquid-phase catalytic oxidation reaction. The rate constant model can describe the influence of each factor on the reaction process in the industrial reactor, and solves the problem that the expression of the rate constant model is difficult to describe the influence of each factor on the reaction process in the industrial reactor. However, none of the above existing solutions establish a model for the reaction runaway process.

[0004] Therefore, there is an urgent need for a modeling method and a modeling system for a benzene nitration reaction runaway mechanism model.

[0005] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0006] One of the objectives of the present invention is to provide a modeling method and a modeling system for the runaway mechanism model of the benzene nitration reaction, so as to improve the problem that there is a lack of a runaway mechanism model for the benzene nitration reaction in the prior art.

[0007] Another objective of the present invention is to provide a modeling method and a modeling system for the runaway mechanism model of the benzene nitration reaction, so as to provide data support for the monitoring and early warning of the runaway reaction of the benzene nitration process.

[0008] To achieve the above objectives, according to the first aspect of the present invention, the present invention provides a modeling method for the runaway mechanism model of the benzene nitration reaction, including the following steps: performing a programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges, heat release amounts, and reactant, intermediate, and product information in each exothermic temperature range during the runaway process of the benzene nitration reaction; according to the reactant, intermediate, and product information in each exothermic temperature range, using reactive molecular dynamics simulation to obtain the set of runaway reaction paths and the reaction mechanism in each exothermic temperature range; and using quantum chemical density functional theory calculation to analyze the reaction mechanism in each exothermic temperature range, determine the order of the runaway paths in the set of runaway reaction paths in each exothermic temperature range, and construct the runaway reaction mechanism model of the target benzene nitration reaction system.

[0009] Further, in the above technical solution, the reaction mechanism in each exothermic temperature range includes microscopic reaction steps.

[0010] Further, in the above technical solution, using quantum chemical density functional theory calculation to analyze the reaction mechanism in each exothermic temperature range includes performing kinetic and thermodynamic calculations on the microscopic reaction steps to obtain microscopic thermokinetic data.

[0011] Further, in the above technical solution, determine the order of the runaway paths in the set of runaway reaction paths in each exothermic temperature range according to the microscopic thermokinetic data.

[0012] Further, in the above technical solution, using reactive molecular dynamics simulation includes establishing a set of kinetic equations for each exothermic temperature range.

[0013] Further, in the above technical solution, performing a programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges, heat release amounts, and reactant, intermediate, and product information in each exothermic temperature range during the runaway process of the benzene nitration reaction includes: performing a mg-level programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges and heat release amounts during the runaway process of the benzene nitration reaction; and performing a g-level programmed temperature calorimetry test on the target benzene nitration reaction system, collecting gas-phase and liquid-phase samples in each exothermic temperature range, analyzing the samples, and obtaining reactant, intermediate, and product information in each exothermic temperature range.

[0014] Furthermore, in the above technical solution, the sampling temperature interval for collecting gas-phase and liquid-phase samples in each exothermic temperature range is 10°C to 50°C.

[0015] Furthermore, in the above technical solution, obtaining the reaction runaway path set and reaction mechanism for each exothermic temperature range includes: constructing a three-dimensional molecular simulation system for a closed space based on the reactant and product information for each exothermic temperature range; obtaining the initial state of the three-dimensional molecular simulation system through energy minimization and kinetic equilibrium calculations; performing molecular dynamics simulations using ReaxFF to obtain simulation data; and performing molecular recognition searches on the simulation data based on the intermediate and product information for the exothermic temperature range, and tracking the evolution of the reactant molecular structures corresponding to the intermediates and products to obtain the reaction runaway path set and reaction mechanism for each exothermic temperature range.

[0016] Furthermore, in the above technical solution, the temperature increase interval for the programmed temperature rise calorimetry test is 0.1°C to 2°C.

[0017] Furthermore, in the above technical solution, the temperature range for the programmed temperature rise calorimetry test is 25°C to 500°C.

[0018] According to the second aspect of the present invention, the present invention provides a modeling system for a benzene nitration reaction runaway mechanism model, which includes: a reaction calorimeter for obtaining all exothermic temperature ranges and heat release amounts during the benzene nitration reaction runaway process; a sample analyzer for obtaining reactant, intermediate, and product information for each exothermic temperature range; a simulation analysis unit for obtaining the reaction runaway path set for each exothermic temperature range using reactive molecular dynamics simulations based on the reactant and product information obtained for each exothermic temperature range, and obtaining the reaction mechanism for each exothermic temperature range in combination with the intermediate and product information for each exothermic temperature range; and a modeling unit for analyzing the reaction mechanism for each exothermic temperature range using quantum chemical density functional theory calculations, determining the order of the runaway paths in the reaction runaway path set for each exothermic temperature range, and constructing a benzene nitration reaction runaway mechanism model.

[0019] Furthermore, in the above technical solution, the sample analyzer is a gas chromatography / mass spectrometry instrument and a Fourier transform infrared spectrometer.

[0020] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0021] 1. The present invention combines programmed temperature calorimetry testing and reactive molecular dynamics simulation to obtain the reaction mechanisms in each exothermic temperature range, and analyzes and determines the order of the runaway paths in the set of runaway paths for the target benzene nitration reaction system through quantum chemical density functional theory calculations, thereby constructing a reaction runaway mechanism model to realize the modeling of the reaction runaway process of the target benzene nitration reaction system.

[0022] 2. The present invention models the runaway process of the benzene nitration reaction system, thereby being able to provide data support for the monitoring and early warning of the reaction runaway of the benzene nitration process.

[0023] 3. Through mg-level programmed temperature calorimetry testing, the influence of phase interface transfer can be eliminated, and the true reaction process of the target benzene nitration reaction system can be restored to the greatest extent, accurately obtaining all exothermic temperature ranges of the benzene nitration reaction runaway process; through g-level programmed temperature calorimetry testing, sample collection is carried out to facilitate the analysis of reactants, intermediates, and products at different stages in each exothermic temperature range.

[0024] The above description is only an overview of the technical solution of the present invention. In order to be able to more clearly understand the technical means of the present invention and implement it according to the content of the specification, and at the same time to make the above and other purposes, technical features, and advantages of the present invention more understandable, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings as follows. Description of the Drawings

[0025] Figure 1 is a schematic flow chart of a method for modeling a reaction runaway mechanism model of a benzene nitration reaction according to an embodiment of the present invention.

[0026] Figure 2 is a schematic block diagram of a modeling system of a reaction runaway mechanism model of a benzene nitration reaction according to an embodiment of the present invention. Detailed Embodiments

[0027] The following combines the accompanying drawings to describe in detail the specific embodiments of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0028] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0029] In this text, for convenience of description, spatial relative terms such as "below", "beneath", "under", "above", "over", "on" etc. may be used to describe the relationship of one element or feature with another element or feature in the drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the figures. For example, if an object in the figure is flipped, an element described as "below" or "under" another element or feature will be oriented "above" the element or feature. Thus, the exemplary term "below" can encompass both the below and above directions. The object may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used herein should be interpreted accordingly.

[0030] In this text, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to define a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. may also be interchanged with each other.

[0031] As Figure 1 shown, a method for modeling a runaway mechanism model of a benzene nitration reaction according to a specific embodiment of the present invention includes the following steps:

[0032] S110 Perform a programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges, heat release amounts during the runaway process of the benzene nitration reaction, and information on reactants, intermediates, and products in each exothermic temperature range.

[0033] Further, in one or more exemplary embodiments of the present invention, step S110 includes a two-stage programmed temperature calorimetry test:

[0034] S111 Perform a mg-level programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges and heat release amounts during the runaway process of the benzene nitration reaction. The mg-level programmed temperature calorimetry test can approximately eliminate the influence of phase interface transfer and more accurately determine all exothermic temperature ranges.

[0035] S112 Perform a g-level programmed temperature calorimetry test on the target benzene nitration reaction system, collect gas-phase and liquid-phase samples in each exothermic temperature range, analyze the samples, and obtain information on reactants, intermediates, and products in each exothermic temperature range. The g-level programmed temperature calorimetry test can collect an appropriate amount of gas-phase and liquid-phase samples to analyze the information on reactants, intermediates, and products in each exothermic temperature range. It should be understood that the reactants, intermediates, and products in each exothermic temperature range refer to the gas-phase and liquid-phase components at the lowest temperature, the gas-phase and liquid-phase components at the intermediate temperature, and the gas-phase and liquid-phase components at the highest temperature within a certain exothermic temperature range.

[0036] Further, in one or more exemplary embodiments of the present invention, the sampling temperature interval for collecting gas-phase and liquid-phase samples in each exothermic temperature range is 10°C to 50°C. It is difficult to achieve control operations when the sampling interval is less than 10°C, and intermediate product information may not be obtained if the sampling interval exceeds 50°C.

[0037] Further, in one or more exemplary embodiments of the present invention, the temperature increase interval for the programmed temperature rise calorimetry test is 0.1°C to 2°C. Further, in one or more exemplary embodiments of the present invention, the temperature range for the programmed temperature rise calorimetry test is 25°C to 500°C.

[0038] Exemplarily, there are four exothermic temperature ranges, namely the main benzene nitration reaction range, the exothermic temperature range of secondary side reactions, the first thermal runaway range, and the second thermal runaway range. It should be understood that the present invention is not limited thereto, and different numbers of exothermic temperature ranges can be obtained through programmed temperature rise calorimetry tests according to different target benzene nitration reaction systems.

[0039] S120 obtains the reaction runaway path sets and reaction mechanisms for each exothermic temperature range by using reactive molecular dynamics simulation based on the reactant, intermediate product, and product information for each exothermic temperature range.

[0040] Further, in one or more exemplary embodiments of the present invention, using reactive molecular dynamics simulation includes establishing a set of kinetic equations for each exothermic temperature range.

[0041] Further, in one or more exemplary embodiments of the present invention, obtaining the reaction runaway path sets and reaction mechanisms for each exothermic temperature range includes: constructing a three-dimensional molecular simulation system in a closed space based on the reactant and product information for each exothermic temperature range; obtaining the initial state of the three-dimensional molecular simulation system through energy minimization and kinetic equilibrium calculations; and performing molecular dynamics simulation using ReaxFF to obtain simulation data; performing molecular recognition search on the simulation data according to the intermediate product and product information for the exothermic temperature range, and tracking the structural evolution of the reactant molecules corresponding to the intermediate products and products to obtain the reaction runaway path sets and reaction mechanisms for each exothermic temperature range.

[0042] Further, in one or more exemplary embodiments of the present invention, the reaction mechanism for each exothermic temperature range includes microscopic reaction steps.

[0043] Further, in one or more exemplary embodiments of the present invention, step 120 includes matching and screening the reaction paths in the set of reaction runaway paths obtained by reaction molecular dynamics simulation based on the reactant, intermediate, and product information of each exothermic temperature range obtained from the programmed temperature calorimetry test, so as to obtain the microscopic reaction mechanism of each exothermic temperature range.

[0044] S130 uses quantum chemistry density functional theory calculation to analyze the reaction mechanism of each exothermic temperature range, determine the order of the runaway paths in the set of reaction runaway paths of each exothermic temperature range, and construct a reaction runaway mechanism model for the target benzene nitration reaction system.

[0045] Further, in one or more exemplary embodiments of the present invention, using quantum chemistry density functional theory calculation to analyze the reaction mechanism of each exothermic temperature range includes performing kinetic and thermodynamic calculations on the microscopic reaction steps to obtain microscopic thermokinetic data. Further, in one or more exemplary embodiments of the present invention, the order of the runaway paths in the set of reaction runaway paths of each exothermic temperature range is determined according to the microscopic thermokinetic data.

[0046] Combined with Figure 2 As shown, the modeling system of the reaction runaway mechanism model of benzene nitration according to the specific embodiment of the present invention includes: a reaction calorimeter 10, which is used to obtain all exothermic temperature ranges and heat release amounts during the reaction runaway process of benzene nitration; a sample analyzer 20, which is used to obtain the reactant, intermediate, and product information of each exothermic temperature range; a simulation analysis unit 30, which is used to obtain the set of reaction runaway paths of each exothermic temperature range by using reaction molecular dynamics simulation according to the reactant and product information of each exothermic temperature range obtained, and combine the reactant, intermediate, and product information of each exothermic temperature range to obtain the reaction mechanism of each exothermic temperature range; and a modeling unit 40, which is used to use quantum chemistry density functional theory calculation to analyze the reaction mechanism of each exothermic temperature range, determine the order of the runaway paths in the set of reaction runaway paths of each exothermic temperature range, and construct a reaction runaway mechanism model for the target benzene nitration reaction system.

[0047] Further, in one or more exemplary embodiments of the present invention, the sample analyzer 20 is a gas chromatography / mass spectrometry combined instrument and a Fourier transform infrared spectrometer. It should be understood that the present invention is not limited thereto.

[0048] The modeling method and modeling system of the reaction runaway mechanism model of benzene nitration of the present invention will be described in more detail below by way of specific embodiments. It should be understood that the present invention is not limited thereto.

[0049] Example 1

[0050] According to the composition of the benzene and mixed acid reaction system in the target benzene nitration process, first prepare the mixed acid, where the molar ratio of sulfuric acid to nitric acid is 2:1. Add benzene and the mixed acid dropwise to the sample cell of the reaction calorimeter according to the molar ratio of benzene to nitric acid of 1:1.

[0051] Perform mg-level programmed temperature rise calorimetry tests on the benzene-mixed acid system, rising from room temperature (25 °C) to high temperature (500 °C) at a heating rate of 0.5 °C / min. Record the test results during the programmed temperature rise process to obtain all exothermic temperature ranges and heat release amounts during the out-of-control process of the benzene nitration reaction. In this example, there are four exothermic temperature ranges obtained through mg-level programmed temperature rise calorimetry tests. The exothermic temperature range of the main reaction is 25 °C to 150 °C, and the heat release amount is 328.92 J / g; the exothermic temperature range of the secondary side reaction is 150 °C to 190 °C, and the heat release amount is 40 J / g; the exothermic temperature range of the first-stage thermal runaway is 190 °C to 250 °C, and the heat release amount is 325.4 J / g; the exothermic temperature range of the second-stage thermal runaway is 270 °C to 355 °C, and the heat release amount is 112.9 J / g. Among them, the heat release amounts in the exothermic temperature ranges of the first-stage thermal runaway and the second-stage thermal runaway are relatively large, which are the main out-of-control reactions of benzene nitration.

[0052] According to the exothermic temperature ranges obtained from the mg-level programmed temperature rise calorimetry tests, perform g-level programmed temperature rise calorimetry tests according to the same composition of the benzene and mixed acid reaction system. Take gas-phase and liquid-phase samples at a series of exothermic interval temperatures for analysis, and use chromatograph / mass spectrometer (GC / MS) and Fourier transform infrared spectroscopy (FTIR) analysis and detection techniques to determine the composition and structure of the samples. More than 95% of the products in the exothermic temperature range of the main reaction are nitrobenzene; more than 50% of the products in the exothermic temperature range of the secondary side reaction are nitrobenzenesulfonic acid; coking occurs in the products in the exothermic temperature range of the first-stage thermal runaway, and the main functional groups are phenol, thiol, and nitro, and the gas products are NO and SO2; the coking of the products in the exothermic temperature range of the second-stage thermal runaway is serious, and the main functional groups are phenol and hydroxyl, and the gas products are NO and N2.

[0053] By using reactive molecular dynamics simulation, the reaction runaway path sets in each exothermic temperature range and the reaction mechanisms in each exothermic temperature range are obtained. Specifically, first, a three-dimensional molecular simulation system of a closed space is constructed based on the reactant and product components, and the composition and number of molecules of the simulation system are set and adjusted according to the actual situation; the molecular simulation system reaches equilibrium through energy minimization and kinetic equilibrium calculations to obtain the initial simulation state; then, the ReaxFF reactive molecular dynamics is used to simulate and calculate the reaction process of the three-dimensional molecular simulation system; according to the structures of intermediates and products in each exothermic temperature range obtained from the g-level programmed temperature calorimetry test, the simulation data is searched for molecular recognition through a python program, and the structural evolution of the reactant molecules corresponding to the intermediates and products is traced to obtain the reaction runaway path sets in each exothermic temperature range. Combining the changes of intermediates and products in each exothermic temperature range of the calorimetry test, the microscopic reaction mechanisms in each exothermic temperature range are obtained. Through quantum chemical density functional theory, kinetic and thermodynamic calculations are carried out on each microscopic reaction step to obtain microscopic thermokinetic data, and the order of the runaway paths in the reaction runaway path sets in each exothermic temperature range is analyzed to construct a reaction runaway mechanism model for the target benzene nitration reaction system.

[0054] The reaction mechanisms in each exothermic temperature range in this embodiment are as follows:

[0055] The reaction mechanism in the main reaction exothermic temperature range includes the reaction of benzene and nitric acid to form nitrobenzene.

[0056] The reaction mechanisms in the secondary side reaction exothermic temperature range include the further nitration of nitrobenzene and nitric acid to form dinitrobenzene; the sulfonation of nitrobenzene and sulfuric acid to form nitrobenzenesulfonic acid; the sulfonation of nitrobenzenesulfonic acid and sulfuric acid to form nitrobenzene disulfonic acid.

[0057] The reaction mechanism in the first-stage thermal runaway exothermic temperature range includes the decomposition of nitrobenzenesulfonic acid to form nitrophenol radicals and sulfur dioxide; the decomposition and coking of nitrophenol radicals to form coke and nitric oxide.

[0058] The second-stage thermal runaway exothermic temperature range includes the decomposition of nitrobenzene to form phenol radicals and NO, the hydrogen abstraction of NO to form HNO, and the further decomposition to form OH radicals and N2; the oxidation of phenol radicals by OH radicals to form CO and CO2, and the coking of the benzene ring at high temperature to form coke.

[0059] Based on reactive molecular dynamics simulation and microscopic thermokinetic calculations, the thermokinetic mechanisms in each exothermic temperature range are obtained as follows:

[0060] The reaction order n in the exothermic temperature range of the main reaction is 1.0, the pre-exponential factor A is 2522.1, and the activation energy E is 44.9 kJ / mol; the reaction order n in the exothermic temperature range of the first-stage thermal runaway is 5.75, the pre-exponential factor A is 5×10^116, and the activation energy E is 1125.38 kJ / mol; the reaction order n in the exothermic temperature range of the second-stage thermal runaway is 3.1, the pre-exponential factor A is 2.99×10^22, and the activation energy E is 275.7 kJ / mol. The heat release in the exothermic temperature range of the secondary side reaction is small and is ignored here.

[0061] According to the reaction mechanism (including thermokinetic mechanism) in each exothermic temperature range, a runaway mechanism model for benzene nitration reaction is constructed.

[0062] Example 2

[0063] According to the composition of the benzene and mixed acid reaction system of the target benzene nitration process, first prepare the mixed acid, in which the molar ratio of sulfuric acid to nitric acid is 5:1. Add benzene and the mixed acid dropwise to the sample cell of the reaction calorimeter according to the molar ratio of benzene to nitric acid of 1:1.

[0064] Perform mg-level programmed temperature calorimetry test on the benzene-mixed acid system, heat up from room temperature (25°C) to high temperature (500°C) at a heating rate of 0.5°C / min, record the test results during the programmed temperature rise process, and obtain all exothermic temperature ranges and heat releases during the runaway process of the benzene nitration reaction. In this example, there are four exothermic temperature ranges obtained by the mg-level programmed temperature calorimetry test. The exothermic temperature range of the main reaction is 25°C to 125°C, and the heat release is 297.7 J / g; the exothermic temperature range of the secondary side reaction is 130°C to 180°C, and the heat release is 35 J / g; the exothermic temperature range of the first-stage thermal runaway is 180°C to 255°C, and the heat release is 332.1 J / g; the exothermic temperature range of the second-stage thermal runaway is 270°C to 355°C, and the heat release is 100.3 J / g. Among them, the heat releases in the first-stage thermal runaway and the second-stage thermal runaway ranges are relatively large, which are the main runaway reactions of benzene nitration.

[0065] According to the exothermic temperature ranges obtained by the mg-level programmed temperature calorimetry test, perform g-level programmed temperature calorimetry test according to the same benzene and mixed acid reaction system composition. Take gas-phase and liquid-phase samples at a series of exothermic interval temperatures for product analysis, and use chromatograph / mass spectrometry (GC / MS) and Fourier transform infrared spectroscopy (FTIR) analysis and detection techniques to determine the composition and structure of the products. More than 90% of the products in the exothermic temperature range of the main reaction are nitrobenzene; more than 40% of the products in the exothermic temperature range of the secondary side reaction are nitrobenzene disulfonic acid; coking occurs in the products in the exothermic temperature range of the first-stage thermal runaway, and the main functional groups are benzenediol, mercaptan, and nitro, and the gas products are NO and SO2; the coking of the products in the exothermic temperature range of the second-stage thermal runaway is serious, and the main functional groups are phenol and hydroxyl, and the gas products are NO and N2.

[0066] Reactive molecular dynamics simulation is used to obtain the reaction runaway path sets in each exothermic temperature range and the reaction mechanisms in each exothermic temperature range. Specifically, first, a three-dimensional molecular simulation system of a closed space is constructed based on the reactant and product components, and the composition and number of molecules of the simulation system are set and adjusted according to the actual situation; the molecular simulation system undergoes energy minimization and kinetic equilibrium calculations to make the molecular system reach equilibrium and obtain the initial simulation state; then, the ReaxFF reactive molecular dynamics is used to perform reaction process simulation calculations on the three-dimensional molecular simulation system; according to the structures of intermediates and products in each exothermic temperature range obtained from the g-level programmed heating calorimetry test, the simulation data is searched for molecular recognition through a python program, and the structural evolution of the reactant molecules corresponding to the intermediates and products is traced to obtain the reaction runaway path sets in each exothermic temperature range. Combining the changes in intermediates and products in each exothermic temperature range of the calorimetry test, the microscopic reaction mechanisms in each exothermic temperature range are obtained. The kinetic and thermodynamic calculations are performed on each microscopic reaction step through quantum chemical density functional theory to obtain microscopic thermokinetic data, and the order of the runaway paths in the reaction runaway path sets in each exothermic temperature range is analyzed to construct a reaction runaway mechanism model for the target benzene nitration reaction system.

[0067] The reaction mechanisms in each exothermic temperature range in this embodiment are as follows:

[0068] The reaction mechanism in the main reaction exothermic temperature range includes the reaction of benzene and nitric acid to form nitrobenzene.

[0069] The reaction mechanisms in the secondary side reaction exothermic temperature range include the further nitration of nitrobenzene and nitric acid to form dinitrobenzene; the sulfonation of nitrobenzene and sulfuric acid to form nitrobenzenesulfonic acid; the sulfonation of nitrobenzenesulfonic acid and sulfuric acid to form nitrobenzene disulfonic acid; the sulfonation of nitrobenzene disulfonic acid and sulfuric acid to form nitrobenzene trisulfonic acid.

[0070] The reaction mechanism in the first-stage thermal runaway exothermic temperature range includes the decomposition of nitrobenzene disulfonic acid to form nitrobenzene diol radicals and sulfur dioxide; the decomposition and coking of nitrobenzene diol radicals to form coke and nitric oxide.

[0071] The second-stage thermal runaway exothermic temperature range includes the decomposition of nitrobenzene to form phenol radicals and NO, the hydrogen abstraction of NO to form HNO, and the further decomposition to form OH radicals and N2; the oxidation of phenol radicals by OH radicals to form CO and CO2, and the coking of the benzene ring at high temperature to form coke.

[0072] Based on reactive molecular dynamics simulation and microscopic thermokinetic calculations, the thermokinetic mechanisms in each exothermic temperature range are obtained as follows:

[0073] The reaction order n in the exothermic temperature range of the main reaction is 1.0, the pre-exponential factor A is 1530.2, and the activation energy E is 37.9 kJ / mol; the reaction order n in the exothermic temperature range of the first-stage thermal runaway is 5.55, the pre-exponential factor A is 4×10^113, and the activation energy E is 1100.1 kJ / mol; the reaction order n in the exothermic temperature range of the second-stage thermal runaway is 3.03, the pre-exponential factor A is 3.2×10^25, and the activation energy E is 275.7 kJ / mol. The heat release in the exothermic temperature range of the secondary side reaction is small and is ignored here.

[0074] According to the reaction mechanism (including thermokinetic mechanism) in each exothermic temperature range, a runaway mechanism model for benzene nitration reaction is constructed.

[0075] Example 3

[0076] According to the composition of the benzene and mixed acid reaction system of the target benzene nitration process, first prepare the mixed acid, in which the molar ratio of sulfuric acid to nitric acid is 2:1. Drop benzene and the mixed acid into the sample cell of the reaction calorimeter according to the molar ratio of benzene to nitric acid of 1:2.

[0077] Perform mg-level programmed temperature calorimetry test on the benzene-mixed acid system, heat up from room temperature (25°C) to high temperature (500°C) at a heating rate of 0.5°C / min, record the test results during the programmed temperature rise process, and obtain all exothermic temperature ranges and heat releases during the runaway process of the benzene nitration reaction. In this example, four exothermic temperature ranges are obtained through the mg-level programmed temperature calorimetry test. The exothermic temperature range of the main reaction is 25°C to 150°C, and the heat release is 405.3 J / g; the exothermic temperature range of the secondary side reaction is 150°C to 190°C, and the heat release is 35 J / g; the exothermic temperature range of the first-stage thermal runaway is 190°C to 260°C, and the heat release is 287.5 J / g; the exothermic temperature range of the second-stage thermal runaway is 260°C to 355°C, and the heat release is 155.2 J / g. Among them, the heat releases in the first-stage thermal runaway and the second-stage thermal runaway ranges are relatively large, which are the main runaway reactions of benzene nitration.

[0078] According to the exothermic temperature ranges obtained from the mg-level programmed temperature calorimetry test, perform g-level programmed temperature calorimetry test according to the same benzene and mixed acid reaction system composition. Take gas-phase and liquid-phase samples at a series of exothermic interval temperatures for product analysis, and use chromatograph / mass spectrometry (GC / MS) and Fourier transform infrared spectroscopy (FTIR) analysis and detection techniques to determine the composition and structure of the products. More than 85% of the products in the exothermic temperature range of the main reaction are dinitrobenzene; more than 45% of the products in the exothermic temperature range of the secondary side reaction are dinitrobenzenesulfonic acid; coking occurs in the products in the exothermic temperature range of the first-stage thermal runaway, and the main functional groups are phenol, mercaptan, and nitro, and the gas products are NO and SO2; the coking of the products in the exothermic temperature range of the second-stage thermal runaway is serious, and the main functional groups are benzenediol and hydroxyl, and the gas products are NO and N2.

[0079] By using reactive molecular dynamics simulation, the reaction runaway path sets in each exothermic temperature range and the reaction mechanisms in each exothermic temperature range are obtained. Specifically, first, a three-dimensional molecular simulation system of a closed space is constructed according to the reactant and product components, and the composition and number of molecules of the simulation system are set and adjusted according to the actual situation; the molecular simulation system undergoes energy minimization and kinetic equilibrium calculations to make the molecular system reach equilibrium, and the initial simulation state is obtained; then, the ReaxFF reactive molecular dynamics is used to perform reaction process simulation calculations on the three-dimensional molecular simulation system; according to the structures of intermediates and products in each exothermic temperature range obtained from the g-level programmed temperature calorimetry test, the simulation data is searched for molecular recognition through a python program, and the structural evolution of the reactant molecules corresponding to the intermediates and products is traced to obtain the reaction runaway path sets in each exothermic temperature range. Combining the changes of intermediates and products in each exothermic temperature range of the calorimetry test, the microscopic reaction mechanisms in each exothermic temperature range are obtained. Through quantum chemical density functional theory, kinetic and thermodynamic calculations are performed on each microscopic reaction step to obtain microscopic thermokinetic data, and the order of the runaway paths in the reaction runaway path sets in each exothermic temperature range is analyzed, and a reaction runaway mechanism model of the target benzene nitration reaction system is constructed.

[0080] The reaction mechanisms in each exothermic temperature range in this embodiment are as follows:

[0081] The reaction mechanism in the exothermic temperature range of the main reaction includes the reaction of benzene and nitric acid to form dinitrobenzene.

[0082] The reaction mechanisms in the exothermic temperature range of the secondary side reactions include the further nitration of dinitrobenzene and nitric acid to form trinitrobenzene; the sulfonation of dinitrobenzene and sulfuric acid to form dinitrobenzenesulfonic acid; the sulfonation of dinitrobenzenesulfonic acid and sulfuric acid to form dinitrobenzene disulfonic acid.

[0083] The reaction mechanism in the exothermic temperature range of the first-stage thermal runaway includes the decomposition of dinitrobenzenesulfonic acid to form dinitrophenol radicals and sulfur dioxide; the decomposition and coking of dinitrophenol radicals to form coke and nitric oxide.

[0084] The second-stage thermal runaway exothermic temperature range includes the decomposition of dinitrobenzene to form benzenediol radicals and NO, the hydrogen abstraction of NO to form HNO, and further decomposition to form OH radicals and N2; the oxidation of benzenediol radicals by OH radicals to form CO and CO2, and the coking of the benzene ring at high temperature to form coke.

[0085] Based on the reactive molecular dynamics simulation and microscopic thermokinetic calculations, the thermokinetic mechanisms in each exothermic temperature range are obtained as follows:

[0086] The reaction order n in the exothermic temperature range of the main reaction is 1.0, the pre-exponential factor A is 2530.7, and the activation energy E is 60.9 kJ / mol; the reaction order n in the exothermic temperature range of the first-stage thermal runaway is 5.24, the pre-exponential factor A is 1×10^110, and the activation energy E is 998.2 kJ / mol; the reaction order n in the exothermic temperature range of the second-stage thermal runaway is 3.25, the pre-exponential factor A is 3.7×10^28, and the activation energy E is 285.2 kJ / mol. The heat release in the exothermic temperature range of the secondary side reaction is small and is ignored here.

[0087] According to the reaction mechanism (including thermokinetic mechanism) in each exothermic temperature range, a runaway mechanism model for benzene nitration reaction is constructed.

[0088] Example 4

[0089] According to the composition of the benzene and mixed acid reaction system of the target benzene nitration process, first prepare the mixed acid, in which the molar ratio of sulfuric acid to nitric acid is 5:1. Add benzene and the mixed acid dropwise to the sample cell of the reaction calorimeter according to the molar ratio of benzene to nitric acid of 1:2.

[0090] Perform mg-level programmed temperature calorimetry test on the benzene-mixed acid system, heat up from room temperature (25°C) to high temperature (500°C) at a heating rate of 0.5°C / min, record the test results during the programmed temperature rise process, and obtain all exothermic temperature ranges and heat releases during the runaway process of the benzene nitration reaction. In this example, four exothermic temperature ranges are obtained through the mg-level programmed temperature calorimetry test. The exothermic temperature range of the main reaction is 25°C to 130°C, and the heat release is 326.8 J / g; the exothermic temperature range of the secondary side reaction is 130°C to 175°C, and the heat release is 30 J / g; the exothermic temperature range of the first-stage thermal runaway is 175°C to 250°C, and the heat release is 287.5 J / g; the exothermic temperature range of the second-stage thermal runaway is 270°C to 350°C, and the heat release is 157.5 J / g. Among them, the heat releases in the first-stage thermal runaway and the second-stage thermal runaway ranges are relatively large, and they are the main runaway reactions of benzene nitration.

[0091] According to the exothermic temperature ranges obtained from the mg-level programmed temperature calorimetry test, perform g-level programmed temperature calorimetry test according to the same composition of the benzene and mixed acid reaction system. Take gas-phase and liquid-phase samples at a series of exothermic interval temperatures for product analysis, and use chromatograph / mass spectrometer (GC / MS), Fourier transform infrared spectroscopy (FTIR) analysis and detection techniques to determine the composition and structure of the products. More than 90% of the products in the exothermic temperature range of the main reaction are dinitrobenzene; more than 40% of the products in the exothermic temperature range of the secondary side reaction are dinitrobenzenedisulfonic acid; coking occurs in the products in the exothermic temperature range of the first-stage thermal runaway, and the main functional groups are benzenediol, mercaptan, nitro, and the gas products are NO and SO2; the coking of the products in the exothermic temperature range of the second-stage thermal runaway is serious, and the main functional groups are benzenediol and hydroxyl, and the gas products are NO and N2.

[0092] By using reactive molecular dynamics simulation, the reaction runaway path sets in each exothermic temperature range and the reaction mechanisms in each exothermic temperature range are obtained. Specifically, first, a three-dimensional molecular simulation system of a closed space is constructed according to the reactant and product components, and the composition and number of molecules of the simulation system are set and adjusted according to the actual situation; the molecular simulation system reaches equilibrium through energy minimization and kinetic equilibrium calculations to obtain the initial simulation state; then, the ReaxFF reactive molecular dynamics is used to perform reaction process simulation calculations on the three-dimensional molecular simulation system; according to the structures of intermediates and products in each exothermic temperature range obtained from the g-level programmed heating calorimetry test, molecular recognition search is performed on the simulation data through a python program, and the structural evolution of the reactant molecules corresponding to the intermediates and products is traced to obtain the reaction runaway path sets in each exothermic temperature range. Combining the changes of intermediates and products in each exothermic temperature range of the calorimetry test, the microscopic reaction mechanisms in each exothermic temperature range are obtained. Through quantum chemical density functional theory, kinetic and thermodynamic calculations are performed on each microscopic reaction step to obtain microscopic thermokinetic data, and the order of the runaway paths in the reaction runaway path sets in each exothermic temperature range is analyzed to construct a reaction runaway mechanism model for the target benzene nitration reaction system.

[0093] The reaction mechanisms in each exothermic temperature range in this embodiment are as follows:

[0094] The reaction mechanism in the exothermic temperature range of the main reaction includes the reaction of benzene and nitric acid to form dinitrobenzene.

[0095] The reaction mechanisms in the exothermic temperature range of the secondary side reactions include the further nitration of dinitrobenzene and nitric acid to form trinitrobenzene; the sulfonation of dinitrobenzene and sulfuric acid to form dinitrobenzenesulfonic acid; the sulfonation of dinitrobenzenesulfonic acid and sulfuric acid to form dinitrobenzene disulfonic acid; the sulfonation of dinitrobenzene disulfonic acid and sulfuric acid to form dinitrobenzene trisulfonic acid.

[0096] The reaction mechanism in the exothermic temperature range of the first-stage thermal runaway includes the decomposition of dinitrobenzene disulfonic acid to form dinitrobenzene diol radicals and sulfur dioxide; the decomposition and coking of dinitrobenzene diol radicals to form coke and nitric oxide.

[0097] The second-stage thermal runaway exothermic temperature range includes the decomposition of dinitrobenzene to form benzenediol radicals and NO, the hydrogen abstraction of NO to form HNO, and further decomposition to form OH radicals and N2; the oxidation of benzenediol radicals by OH radicals to form CO and CO2, and the coking of the benzene ring at high temperature to form coke.

[0098] Based on the reactive molecular dynamics simulation and microscopic thermokinetic calculations, the thermokinetic mechanisms in each exothermic temperature range are obtained as follows:

[0099] The reaction order n in the exothermic temperature range of the main reaction is 1.0, the pre-exponential factor A is 1930.5, and the activation energy E is 45.7 kJ / mol; the reaction order n in the exothermic temperature range of the first-stage thermal runaway is 5.68, the pre-exponential factor A is 8×10^114, and the activation energy E is 1200.1 kJ / mol; the reaction order n in the exothermic temperature range of the second-stage thermal runaway is 3.23, the pre-exponential factor A is 2.3×10^20, and the activation energy E is 235.4 kJ / mol. The heat release in the exothermic temperature range of the secondary side reaction is small and is ignored here.

[0100] According to the reaction mechanisms (including thermokinetic mechanisms) in each exothermic temperature range, a runaway mechanism model for benzene nitration reaction is constructed.

[0101] Example 5

[0102] According to the composition of the benzene and mixed acid reaction system of the target benzene nitration process, first prepare the mixed acid, in which the molar ratio of sulfuric acid to nitric acid is 5:1. Add benzene and the mixed acid dropwise to the sample cell of the reaction calorimeter according to the molar ratio of benzene to nitric acid of 1:3.

[0103] Perform mg-level programmed temperature calorimetry tests on the benzene-mixed acid system, and increase the temperature from room temperature (25°C) to high temperature (500°C) at a heating rate of 0.5°C / min. Record the test results during the programmed temperature increase process to obtain all exothermic temperature ranges and heat releases during the runaway process of the benzene nitration reaction. In this example, four exothermic temperature ranges are obtained through mg-level programmed temperature calorimetry tests. The exothermic temperature range of the main reaction is 25°C to 140°C, and the heat release is 384.3 J / g; the exothermic temperature range of the secondary side reaction is 140°C to 170°C, and the heat release is 20 J / g; the exothermic temperature range of the first-stage thermal runaway is 195°C to 255°C, and the heat release is 135.3 J / g; the exothermic temperature range of the second-stage thermal runaway is 260°C to 340°C, and the heat release is 287.3 J / g. Among them, the heat releases in the first-stage thermal runaway and the second-stage thermal runaway ranges are relatively large, and they are the main runaway reactions of benzene nitration.

[0104] According to the exothermic temperature ranges obtained from the mg-level programmed temperature calorimetry tests, perform g-level programmed temperature calorimetry tests according to the same composition of the benzene and mixed acid reaction system. Take gas-phase and liquid-phase samples at a series of exothermic interval temperatures for product analysis, and use chromatograph / mass spectrometry (GC / MS) and Fourier transform infrared spectroscopy (FTIR) analysis and detection techniques to determine the composition and structure of the products. More than 90% of the products in the exothermic temperature range of the main reaction are trinitrobenzene; more than 40% of the products in the exothermic temperature range of the secondary side reaction are trinitrobenzenedisulfonic acid; coking occurs in the products in the exothermic temperature range of the first-stage thermal runaway, and the main functional groups are benzenediol, mercaptan, and nitro, and the gas products are NO and SO2; the coking of the products in the exothermic temperature range of the second-stage thermal runaway is serious, and the main functional groups are benzene triol and hydroxyl, and the gas products are NO and N2.

[0105] Reactive molecular dynamics simulation is adopted to obtain the reaction runaway path sets in each exothermic temperature range and the reaction mechanisms in each exothermic temperature range. Specifically, first, a three-dimensional molecular simulation system of a closed space is constructed according to the reactant and product components, and the composition and number of molecules of the simulation system are set and adjusted according to the actual situation; the molecular simulation system undergoes energy minimization and kinetic equilibrium calculations to make the molecular system reach equilibrium and obtain the initial simulation state; then, the ReaxFF reactive molecular dynamics is used to perform reaction process simulation calculations on the three-dimensional molecular simulation system; according to the structures of intermediates and products in each exothermic temperature range obtained from the g-level programmed heating calorimetry test, the simulation data is searched for molecular recognition through a python program, and the structural evolution of the reactant molecules corresponding to the intermediates and products is traced to obtain the reaction runaway path sets in each exothermic temperature range. Combining the changes of intermediates and products in each exothermic temperature range of the calorimetry test, the microscopic reaction mechanisms in each exothermic temperature range are obtained. Through quantum chemical density functional theory, kinetic and thermodynamic calculations are performed on each microscopic reaction step to obtain microscopic thermokinetic data, and the order of the runaway paths in the reaction runaway path sets in each exothermic temperature range is analyzed to construct a reaction runaway mechanism model for the target benzene nitration reaction system.

[0106] The reaction mechanisms in each exothermic temperature range in this embodiment are as follows:

[0107] The reaction mechanism in the main reaction exothermic temperature range includes the reaction of benzene and nitric acid to form trinitrobenzene.

[0108] The reaction mechanisms in the secondary side reaction exothermic temperature range include the further nitration of trinitrobenzene and nitric acid to form trinitrophenol; the sulfonation of trinitrobenzene and sulfuric acid to form trinitrobenzenesulfonic acid; the sulfonation of trinitrobenzenesulfonic acid and sulfuric acid to form trinitrobenzene disulfonic acid.

[0109] The reaction mechanism in the first-stage thermal runaway exothermic temperature range includes the decomposition of trinitrobenzene disulfonic acid to form nitrobenzene diol radicals and sulfur dioxide; the decomposition and coking of nitrobenzene diol radicals to form coke and nitric oxide.

[0110] The second-stage thermal runaway exothermic temperature range includes the decomposition of trinitrobenzene to form benzene triol radicals and NO, the hydrogen abstraction of NO to form HNO, and further decomposition to form OH radicals and N2; the oxidation of benzene triol radicals by OH radicals to form CO and CO2, and the coking of the benzene ring at high temperature to form coke.

[0111] Based on reactive molecular dynamics simulation and microscopic thermokinetic calculations, the thermokinetic mechanisms in each exothermic temperature range are obtained as follows:

[0112] The reaction order n in the exothermic temperature range of the main reaction is 1.0, the pre-exponential factor A is 3780.7, and the activation energy E is 76.5 kJ / mol; the reaction order n in the exothermic temperature range of the first-stage thermal runaway is 4.81, the pre-exponential factor A is 6×10^68, and the activation energy E is 886.5 kJ / mol; the reaction order n in the exothermic temperature range of the second-stage thermal runaway is 3.02, the pre-exponential factor A is 1.6×10^16, and the activation energy E is 200.3 kJ / mol. The heat release in the exothermic temperature range of the secondary side reaction is small and is ignored here.

[0113] According to the reaction mechanism (including thermokinetic mechanism) in each exothermic temperature range, a runaway mechanism model for benzene nitration reaction is constructed.

[0114] Example 6

[0115] According to the composition of the benzene and nitric acid reaction system of the target benzene nitration process, benzene and mixed acid are added dropwise to the sample cell of the reaction calorimeter according to the molar ratio of benzene to nitric acid of 1:1.

[0116] Perform mg-level programmed temperature calorimetry test on the benzene-mixed acid system, heat up from room temperature (25°C) to high temperature (500°C) at a heating rate of 0.5°C / min, record the test results during the programmed temperature rise process, and obtain all exothermic temperature ranges and heat releases during the runaway process of benzene nitration reaction. In this example, two exothermic temperature ranges are obtained through mg-level programmed temperature calorimetry test. The exothermic temperature range of the main reaction is 25°C to 150°C, and the heat release is 567.8 J / g; the exothermic temperature range of the thermal runaway is 255°C to 380°C, and the heat release is 680.3 J / g.

[0117] According to the exothermic temperature ranges obtained from the mg-level programmed temperature calorimetry test, perform g-level programmed temperature calorimetry test according to the same composition of the benzene and mixed acid reaction system. Take gas-phase and liquid-phase samples at a series of exothermic interval temperatures for product analysis, and use chromatograph / mass spectrometry (GC / MS) and Fourier transform infrared spectroscopy (FTIR) analysis and detection techniques to determine the composition and structure of the products. More than 90% of the products in the exothermic temperature range of the main reaction are nitrobenzene; the products in the exothermic temperature range of the thermal runaway are severely coked, the main functional groups are phenol and hydroxyl group, and the gas products are NO and N2.

[0118] By using reactive molecular dynamics simulation, the reaction runaway path sets in each exothermic temperature range and the reaction mechanisms in each exothermic temperature range are obtained. Specifically, first, a three-dimensional molecular simulation system of a closed space is constructed based on the reactant and product components, and the composition and number of molecules of the simulation system are set and adjusted according to the actual situation; the molecular simulation system undergoes energy minimization and kinetic equilibrium calculations to make the molecular system reach equilibrium and obtain the initial simulation state; then, the reaction process simulation calculation is carried out on the three-dimensional molecular simulation system using ReaxFF reactive molecular dynamics; according to the structures of intermediates and products in each exothermic temperature range obtained from the g-level programmed heating calorimetry test, the simulation data is searched for molecular recognition through a python program, and the structural evolution of the reactant molecules corresponding to the intermediates and products is traced to obtain the reaction runaway path sets in each exothermic temperature range. Combining the changes of intermediates and products in each exothermic temperature range of the calorimetry test, the microscopic reaction mechanisms in each exothermic temperature range are obtained. Through quantum chemical density functional theory, kinetic and thermodynamic calculations are carried out on each microscopic reaction step to obtain microscopic thermokinetic data, and the order of the runaway paths in the reaction runaway path sets in each exothermic temperature range is analyzed, and a reaction runaway mechanism model of the target benzene nitration reaction system is constructed.

[0119] The reaction mechanisms in each exothermic temperature range in this embodiment are as follows:

[0120] The reaction mechanism in the main reaction exothermic temperature range includes the reaction of benzene and nitric acid to form nitrobenzene.

[0121] The thermal runaway exothermic temperature range includes the decomposition of nitrobenzene to form phenol radicals and NO, the hydrogen abstraction of NO to form HNO, and further decomposition to form OH radicals and N2; the oxidation of phenol radicals by OH radicals to form CO and CO2, and the coking of the benzene ring at high temperature to form coke.

[0122] Based on reactive molecular dynamics simulation and microscopic thermokinetic calculations, the thermokinetic mechanisms in each exothermic temperature range are obtained as follows:

[0123] The reaction order n = 1.00 in the main reaction exothermic temperature range, the pre-exponential factor A = 4734.2, and the activation energy E = 65.4 kJ / mol; the reaction order n = 1.01 in the thermal runaway exothermic temperature range, the pre-exponential factor A = 7.1*10^12, and the activation energy E = 189.6 kJ / mol.

[0124] According to the reaction mechanisms (including thermokinetic mechanisms) in each exothermic temperature range, a reaction runaway mechanism model of benzene nitration is constructed.

[0125] The foregoing description of specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that, according to the above teachings, many changes and variations are possible. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the invention, as well as various different selections and changes. Any simple modifications, equivalent variations, and embellishments made to the above exemplary embodiments shall fall within the protection scope of the present invention.

Claims

1. A modeling method for the runaway mechanism model of benzene nitration reaction, characterized in that, It includes the following steps: Perform a programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges, heat release amounts during the out-of-control process of the benzene nitration reaction, as well as the reactant, intermediate, and product information for each exothermic temperature range; Based on the reactant, intermediate, and product information for each exothermic temperature range, use reactive molecular dynamics simulation to obtain the set of out-of-control reaction paths for each exothermic temperature range and the reaction mechanism for each exothermic temperature range; and Adopt quantum chemical density functional theory calculation to analyze the reaction mechanism for each exothermic temperature range, determine the order of the out-of-control paths in the set of out-of-control reaction paths for each exothermic temperature range, and construct a reaction out-of-control mechanism model for the target benzene nitration reaction system.

2. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, The reaction mechanism for each exothermic temperature range includes microscopic reaction steps.

3. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 2, characterized in that, The adoption of quantum chemical density functional theory calculation to analyze the reaction mechanism for each exothermic temperature range includes performing kinetic and thermodynamic calculations on the microscopic reaction steps to obtain microscopic thermokinetic data.

4. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 3, characterized in that, Determine the order of the out-of-control paths in the set of out-of-control reaction paths for each exothermic temperature range according to the microscopic thermokinetic data.

5. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, Using reactive molecular dynamics simulation includes establishing a set of kinetic equations for each exothermic temperature range.

6. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, Performing a programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges, heat release amounts during the out-of-control process of the benzene nitration reaction, as well as the reactant, intermediate, and product information for each exothermic temperature range includes: Perform an mg-level programmed temperature calorimetry test on the target benzene nitration reaction system to obtain all exothermic temperature ranges and heat release amounts during the out-of-control process of the benzene nitration reaction; and Perform a g-level programmed temperature calorimetry test on the target benzene nitration reaction system, collect gas-phase and liquid-phase samples for each exothermic temperature range, analyze the samples, and obtain the reactant, intermediate, and product information for each exothermic temperature range.

7. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, The sampling temperature interval for collecting gas-phase and liquid-phase samples for each exothermic temperature range is 10°C to 50°C.

8. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, Obtaining the set of out-of-control reaction paths for each exothermic temperature range and the reaction mechanism for each exothermic temperature range includes: Based on the reactant and product information for each exothermic temperature range, construct a three-dimensional molecular simulation system in a closed space; Through energy minimization and kinetic equilibrium calculations, obtain the initial state of the three-dimensional molecular simulation system; Perform molecular dynamics simulation using ReaxFF to obtain simulation data; and According to the intermediate and product information for the exothermic temperature range, perform molecular recognition search on the simulation data, and track the structural evolution of the reactant molecules corresponding to the intermediate and product, to obtain the set of out-of-control reaction paths for each exothermic temperature range and the reaction mechanism for each exothermic temperature range.

9. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, The temperature increase interval for the programmed temperature calorimetry test is 0.1°C to 2°C.

10. The modeling method of the runaway mechanism model for benzene nitration reaction according to claim 1, characterized in that, The temperature range for the programmed temperature calorimetry test is 25°C to 500°C.

11. A modeling system for the runaway mechanism model of benzene nitration reaction, characterized in that, It includes: A reaction calorimeter, which is used to obtain all exothermic temperature ranges and heat release amounts during the out-of-control process of the benzene nitration reaction; A sample analyzer, which is used to obtain the reactant, intermediate, and product information for each exothermic temperature range; A simulation analysis unit, which is used to obtain a set of reaction runaway paths for each exothermic temperature range by using reactive molecular dynamics simulation based on the reactant and product information of each exothermic temperature range obtained, and to obtain the reaction mechanism of each exothermic temperature range in combination with the intermediate and product information of each exothermic temperature range; and A modeling unit, which is used to analyze the reaction mechanism of each exothermic temperature range by using quantum chemical density functional theory calculation, determine the order of the runaway paths in the set of reaction runaway paths for each exothermic temperature range, and construct a benzene nitration reaction runaway mechanism model.

12. The modeling system of the runaway mechanism model for benzene nitration reaction according to claim 11, characterized in that, The sample analyzer is a gas chromatography / mass spectrometry instrument and a Fourier transform infrared spectrometer.

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