Method and model for estimating the risk of a substitution chlorination reaction

Abstract

The present application relates to the technical field of regulation system, specifically, a method and model for estimating the thermal risk of substitution chlorination reaction, comprising the following steps: step 1, classifying and sorting different types of substitution chlorination reaction, obtaining thermal risk data and key parameters of various reactions, the key parameters including reaction temperature T, reaction pressure P, reactant molecular weight M, and the distance D between special atoms and reaction site; step 2, analyzing the influence weight of key parameters on the thermal risk of substitution chlorination reaction, and determining the proportion of each parameter in the thermal risk calculation; step 3, based on the parameter influence weight, constructing the calculation formula of the thermal risk value R by weighted summation according to the scene; step 4, determining the reaction thermal risk grade according to the thermal risk value R. The present application can greatly reduce the thermal risk test of some unnecessary substitution chlorination reaction, reduce the waste of scientific research funds, and also reduce the risk in the test process.

Description

Technical Field

[0001] This invention relates to the field of regulation system technology, and more specifically, to a method and model for predicting the heat risk of chlorination reaction. Background Technology

[0002] The substitution chlorination reaction, as a typical hazardous process, is characterized by its rapid reaction rate, large heat release, and the potential for explosive mixtures to form in the tail gas. Therefore, its thermal risk assessment is crucial for safe chemical production. Currently, related research and technical methods have significant limitations, failing to meet the demand for efficient and low-cost risk prediction. Traditional experimental methods, such as differential scanning calorimetry (DSC), while providing reliable results, suffer from high costs, long processing times, and operational hazards, making them unsuitable for the practical needs of chemical enterprises for rapid assessment of reaction thermal risks. There is a lack of a universally applicable method for predicting the thermal risks of substitution chlorination reactions that requires no experimental testing, integrates multiple key parameters, and is suitable for all situations. A new model is urgently needed to fill this technological gap.

[0003] The QSPR model proposed in the literature "Pan Yong, Jiang Juncheng, Wang Rui, et al. Research on prediction of lower explosive limit of hydrocarbons based on quantitative structure-property correlation [C]. Chemical Industry and Engineering Society of China; Guangdong Chemical Industry and Engineering Society, 2008." can predict the physicochemical properties of substances based on molecular structure, without the need for complex experiments and with low computational cost, but it has three major drawbacks: First, the accuracy of the model is highly dependent on the quality of the data, and data deviation will directly affect the prediction results; second, the nonlinear relationship between molecular structure and properties and the comprehensive influence of multiple factors lead to the limited applicability of the model; third, the prediction results are based on complex machine learning algorithms, lack physical interpretation, and it is difficult to trace the root cause of risks in industrial applications. The ISM model used in the literature "Ma,Y.,Zhang,M.,&Wang,M.(2023). Analysis of chemical accident risk factors based on ISM-BN. Proceedings of the Institution of Mechanical Engineers Part O - Journal of Risk and Reliability, 111,0." relies on experimentally obtained reaction heat data and is mostly used for risk analysis of specific chemical reactions. It cannot establish a universal correlation model between key parameters such as reaction temperature and pressure and thermal risk. Summary of the Invention

[0004] The first aspect of this invention provides a method for predicting the heat risk of chlorination reaction, comprising the following steps:

[0005] Step 1: Classify and organize different types of substitution chlorination reactions, and obtain thermal risk data and key parameters for each type of reaction. The key parameters include reaction temperature T (°C), reaction pressure P (MPa), reactant molecular weight M (g / mol), and the distance D of special atoms from the reaction site (the distance is characterized by the number of carbon atoms between them).

[0006] Step 2: Analyze the influence weight of key parameters on the thermal risk of the substitution chlorination reaction, and determine the proportion of each parameter in the thermal risk calculation;

[0007] Step 3: Based on the parameter influence weights, construct the calculation formula for the thermal risk value R by weighted summation for different scenarios. The scenarios include the following four types: reactants have no special atoms, reactants have special atoms and the number of carbon atoms between the special atoms and the reaction site is less than 5, reactants have special atoms and the number of carbon atoms between the special atoms and the reaction site is greater than 5, and special atoms form hydrogen bonds or conjugate with the benzene ring.

[0008] Step 4: Determine the reaction heat risk level based on the heat risk value R. When R > 70, the risk level is level 3; when 40 ≤ R ≤ 70, the risk level is level 2; when R < 40, the risk level is level 1.

[0009] The substitution chlorination reaction includes reactants and a compound containing chlorine atoms, wherein the reactants include one of the compounds of formulas R1-R9;

[0010] The compounds containing chlorine atoms include one of the following: chlorine, thionyl chloride, 3-chloropropionyl chloride, and phosphorus pentachloride.

[0011] The special atom includes at least one of F, N, and Cl.

[0012] The reaction mechanism of the reactants and chlorine is a typical free radical substitution reaction. First, liquid chlorine decomposes into two chlorine free radicals under light irradiation. Then, these chlorine free radicals abstract hydrogen atoms from reactant R, generating hydrogen chloride and R free radicals. Finally, the R free radicals continue to abstract chlorine atoms from liquid chlorine, ultimately forming the chlorinated product. The inventors studied the reactions of R1-R4 with chlorine. Compared to R2 and R4, R1 and R3 are smaller molecules. Under the same volume of reactor and time conditions, smaller molecules have a larger effective contact area with chlorine during the reaction, resulting in a relatively faster reaction rate, higher reactivity, and a higher reaction risk. Compared to R1 and R3, R2 and R4 are larger molecular weight compounds, with less effective contact area with chlorine, resulting in a relatively lower reaction rate and a lower reaction risk. The molecular weight of the reactants has a certain influence on the reaction risk. Comparing R4 and R2, it was found that the reaction process hazard level of R4 is higher than that of R2. From the selection of the reaction site, it was found that R4 is adjacent to the carbonyl group. CH2 In the reaction, R2 is adjacent to the benzene ring. The CH3 reaction. Analysis revealed that the carboxyl group is an electron-withdrawing group, which has an inductive effect, causing the hydrogen atom on the adjacent methylene group to be electron-deficient. The electron-deficient hydrogen atom is easily ionized and replaced by other groups, thus making it more likely to react with chlorine. In R2, the left side is a benzene ring. Although it also contains a carbonyl group, the carbonyl oxygen can return a pair of p electrons to form p-π conjugation with the benzene ring, increasing the overall uniformity of electron distribution. Because this conjugation effect is greater than the electron-withdrawing inductive effect of the carbonyl group, when connected to the π bond, it acts as an electron-donating group, resulting in a certain degree of reduced reactivity. Both the carbonyl group and the benzene ring have a certain influence on the heat of reaction; their relative strengths must be compared under different conditions. It was also found that the reaction temperature of R3 is lower than that of R1 (110℃ and 150℃). This may be because the fluorine atom has 7 electrons in its outermost shell, which is not a typical octet stable structure. Therefore, it tends to gain one electron to achieve an octet stable structure. Compared to the hydrogen atom, it exhibits a certain oxidizing property, thus reacting more easily with chlorine, and the reaction temperature required is relatively lower. In cases of similar structures, specific atoms can have a certain impact on the reaction.

[0013] The reactants react with thionyl chloride. First, the oxygen atom in the hydroxyl group of reactant R attacks the sulfur atom in thionyl chloride, breaking the carbon-sulfur bond and forming an intermediate. Then, the hydrogen ion bonded to oxygen and the chlorine atom bonded to sulfur are released to form hydrogen chloride. Finally, one molecule of sulfur dioxide is removed to form the final product. Analysis of the reactions of three different reactants with thionyl chloride revealed that R5 and R6 are similar. In R5, the carboxyl group is adjacent to a large functional group. Although it also contains fluorine atoms, they are not adjacent, resulting in less pronounced oxidizing power. The large functional group plays a dominant role, thus reducing the reaction's hazard level. In contrast, R6 has a nitrogen-doped benzene ring structure next to the carboxyl group. Both the amino and hydroxyl groups can influence the electron density distribution of the benzene ring through hydrogen bonding, thus increasing the reaction's hazard level. Comparing R6 and R7, both contain complex benzene ring structures, but R7's reaction process has a hazard level of 2. This is because R6 involves the reaction of thionyl chloride with the carboxyl group, while R7 is a typical benzene ring substitution reaction, where substitution occurs within an existing functional group of the benzene ring. At the para position of NHCOCH3, compared to the reaction with the carboxyl group, the chlorination reaction of the benzene ring substitution is more likely to occur and the risk level is relatively low.

[0014] The reaction between the reactant and 3-chloropropionyl chloride mainly involves a hydroxyl group attacking the carbon atom in 3-chloropropionyl chloride, followed by the release of a hydrogen ion and a chloride ion, ultimately forming HCl and the final product. Although the reactant also contains a benzene ring structure, it has a long-chain alkyl chain. The long-chain alkyl chain and the benzene ring together form a large functional group, similar to the R2 and R4 cases mentioned above. Therefore, it weakens the influence of the benzene ring on the reaction to some extent. During the reaction, the chains tend to entangle with each other, reducing the reactivity of the reaction. This reaction shows that although the structure contains a benzene ring, the influence of the benzene ring on the reaction's hazard can be reduced by introducing a long-chain alkyl chain.

[0015] The reactant reacts with phosphorus pentachloride, where two chlorine atoms simultaneously attack the carbonyl group, subsequently releasing one molecule of phosphorus oxychloride to form the final product. Reactions R1-R8 all involve chlorine atoms replacing hydrogen atoms on methyl, hydroxyl, carboxyl, or benzene rings. However, this reaction proceeds through a process similar to an addition carbonyl reaction, making it much faster and more vigorous than the reactions described above, thus posing a higher thermal risk.

[0016] Therefore, the inventors discovered that the main factors affecting chlorination reactions include reaction temperature, pressure, molecular weight of reactants, and specific atoms contained in the reactants. By further subdividing and comparing reactions of the same type, the influence of each factor on the reaction was further explored.

[0017] In the scenario described above, when the reactants have no special atoms or the number of carbon atoms at the reaction site is greater than 5, the reaction temperature T and reaction pressure P each account for 33-37%, and the reactant molecular weight M accounts for 28-32%. In the scenario described above, when the reactants have special atoms and the number of carbon atoms at the reaction site is less than 5, or when the special atoms form hydrogen bonds or conjugate with the benzene ring, the reaction temperature T and reaction pressure P each account for 26-30%, the reactant molecular weight M accounts for 18-22%, and the distance D of the special atoms from the reaction site accounts for 22-26%.

[0018] Optionally, in the scenario where the reactant has no special atoms or the number of carbon atoms of the special atom at the reaction site is greater than 5, the reaction temperature T and reaction pressure P each account for 35%, and the reactant molecular weight M accounts for 30%; in the scenario where the reactant has special atoms and the number of carbon atoms of the special atom at the reaction site is less than 5, and the special atom forms a hydrogen bond or conjugate with the benzene ring, the reaction temperature T and reaction pressure P each account for 28%, the reactant molecular weight M accounts for 20%, and the distance D of the special atom from the reaction site accounts for 24%.

[0019] The scenario described above refers to a situation where the reactants have no special atoms. The formula for calculating the thermal risk value R is: R = T × 35% + P × 35% × 100 + (1 + 1 / M) × 30% × 10.

[0020] The scenario described is when the reactant has special atoms and the number of carbon atoms between the special atoms and the reaction site is less than 5. The formula for calculating the thermal risk value R is: R = T × 28% + P × 28% × 100 + (1 + 1 / M) × 20% × 10 + (1 + 1 / D) × 24% × 100.

[0021] The scenario described is when the reactant has special atoms and the number of carbon atoms between the special atoms and the reaction site is greater than 5. The formula for calculating the thermal risk value R is: R = T × 35% + P × 35% × 100 + (1 + 1 / M) × 30% × 10.

[0022] The scenario described is when a special atom forms a hydrogen bond or conjugate with a benzene ring. The formula for calculating the thermal risk value R is: R = T × 28% + P × 28% × 100 + (1 + 1 / M) × 20% × 10 + (1 + 1 / D) × 24% × 200.

[0023] The second aspect of the present invention provides a thermal risk prediction model for substitution chlorination reactions. The model can take into account the following parameters: reaction temperature T, reaction pressure P, reactant molecular weight M, and the distance D of special atoms from the reaction site, and automatically calculate the thermal risk value R based on the input parameters and output the corresponding thermal risk level.

[0024] Beneficial effects

[0025] 1. The method for predicting thermal risk of the present invention can accurately predict the thermal risk value of the substitution chlorination reaction by taking into account the temperature, pressure, molecular weight of the reactants, and distance between specific atoms and the reaction point, and thus obtain the thermal risk level of the reaction.

[0026] 2. The thermal risk prediction model of this invention can predict the risk of substitution chlorination reaction without actual experimental measurement of thermal risk. This can significantly reduce some unnecessary thermal risk tests for substitution chlorination reaction, reduce the waste of scientific research funds, and also reduce the risk of the testing process. Attached Figure Description

[0027] Figure 1 This is the model interface for Example 1. Detailed Implementation

[0028] Examples 1-8

[0029] A method for predicting the heat risk of chlorination reactions, comprising the following steps:

[0030] Step 1: Classify and organize different types of substitution chlorination reactions, and obtain thermal risk data and key parameters for each type of reaction. The key parameters include reaction temperature T, reaction pressure P, reactant molecular weight M, and the distance D of special atoms from the reaction site.

[0031] Step 2: Analyze the influence weight of key parameters on the thermal risk of the substitution chlorination reaction, and determine the proportion of each parameter in the thermal risk calculation;

[0032] Step 3: Based on the parameter influence weights, construct the calculation formula for the thermal risk value R by weighted summation for different scenarios. The scenarios include the following four types: reactants have no special atoms, reactants have special atoms and the number of carbon atoms between the special atoms and the reaction site is less than 5, reactants have special atoms and the number of carbon atoms between the special atoms and the reaction site is greater than 5, and special atoms form hydrogen bonds or conjugate with the benzene ring.

[0033] Step 4: Determine the reaction heat risk level based on the heat risk value R. When R > 70, the risk level is level 3; when 40 ≤ R ≤ 70, the risk level is level 2; when R < 40, the risk level is level 1.

[0034] The scenario described above refers to a situation where the reactants have no special atoms. The formula for calculating the thermal risk value R is: R = T × 35% + P × 35% × 100 + (1 + 1 / M) × 30% × 10.

[0035] The scenario described is when the reactant has special atoms and the number of carbon atoms between the special atoms and the reaction site is less than 5. The formula for calculating the thermal risk value R is: R = T × 28% + P × 28% × 100 + (1 + 1 / M) × 20% × 10 + (1 + 1 / D) × 24% × 100.

[0036] The scenario described is when the reactant has special atoms and the number of carbon atoms between the special atoms and the reaction site is greater than 5. The formula for calculating the thermal risk value R is: R = T × 35% + P × 35% × 100 + (1 + 1 / M) × 30% × 10.

[0037] The scenario described is when a special atom forms a hydrogen bond or conjugate with a benzene ring. The formula for calculating the thermal risk value R is: R = T × 28% + P × 28% × 100 + (1 + 1 / M) × 20% × 10 + (1 + 1 / D) × 24% × 200.

[0038] Input the data from Table 1 Figure 1 The calculation is performed in the interface shown (the result is an integer). The blank spaces in Table 1 indicate that the value is not present or has not been added. R1-R9 are shown in the following formulas. .

[0039] Example 1 calculated R=73, and the risk level is level 3;

[0040] Example 2 calculated R=37, and the risk level is level 1;

[0041] Example 3 calculated R=85, and the risk level is level 3;

[0042] Example 4 calculated R=50, and the risk level is level 2;

[0043] Example 5 calculated R=12, and the risk level is level 1;

[0044] Example 6 calculated R=83, and the risk level is level 3;

[0045] Example 7 calculated R=21, and the risk level is level 1;

[0046] Example 8 calculated R=29, and the risk level is level 1;

[0047] Example 9 calculated R=81, with a risk level of 3;

[0048] Table 1

[0049]

[0050] Performance testing methods

[0051] The risk level calculated from the examples was compared with the test risk level (obtained through experimental testing according to the methods in the following documents: Anjian Zongguan San

[2017] No. 1 - Guiding Opinions of the State Administration of Work Safety on Strengthening the Safety Risk Assessment of Fine Chemical Reactions, Appendix 6.1-6.6), and the test data are listed in Table 2.

[0052] Performance test data

[0053] Table 2

[0054]

[0055] As shown in Table 2, the risk level obtained by the model established by the specific thermal risk prediction method in this application corresponds to the risk level obtained by experiment, indicating that the model of this application has high accuracy and can greatly reduce unnecessary thermal risk testing of substitution chlorination reaction in industrial production.

Claims

1. A method of estimating a risk of a hot reaction in a substitution chlorination, characterized by, The method comprises the following steps: Step 1, classifying different types of substitution chlorination reactions, obtaining thermal risk data and key parameters of various reactions, wherein the key parameters include reaction temperature T, reaction pressure P, reactant molecular weight M, and special atom distance from the reaction site D; Step 2, analyzing the influence weight of the key parameters on the thermal risk of substitution chlorination reaction, and determining the proportion of each parameter in the thermal risk calculation; Step 3, based on the parameter influence weight, weighted summation is performed according to the scene to construct the calculation formula of the thermal risk value R, wherein the scene includes the following four kinds: no special atom in the reactant, special atom in the reactant and the number of carbon atoms between the special atom and the reaction site is less than 5, special atom in the reactant and the number of carbon atoms between the special atom and the reaction site is greater than 5, and the special atom forms a hydrogen bond or a conjugate with the benzene ring; Step 4, determining the reaction thermal risk level according to the thermal risk value R, when R>70, the risk level is level 3; when 40≤R≤70, the risk level is level 2; and when R<40, the risk level is level 1. The substitution chlorination reaction comprises a reactant and a substance containing a chlorine atom, and the reactant comprises one of the compounds in the formula R1-R9. ; the substance containing a chlorine atom is one of the following: chlorine, thionyl chloride, 3-chloropropionyl chloride, phosphorus pentachloride; The special atom comprises at least one of F, N and Cl.

2. The method of claim 1, wherein the method further comprises: When the scene is that the reactant has no special atom or the number of carbon atoms between the special atom and the reaction site is greater than 5, the proportion of the reaction temperature T and the reaction pressure P is 33-37%, and the proportion of the reactant molecular weight M is 28-32%; when the scene is that the reactant has a special atom and the number of carbon atoms between the special atom and the reaction site is less than 5, and the special atom forms a hydrogen bond or a conjugate with the benzene ring, the proportion of the reaction temperature T and the reaction pressure P is 26-30%, the proportion of the reactant molecular weight M is 18-22%, and the proportion of the distance D between the special atom and the reaction site is 22-26%.

3. The method for predicting the heat risk of substituted chlorination reaction according to claim 2, characterized in that, When the scene is that the reactant has no special atom or the number of carbon atoms between the special atom and the reaction site is greater than 5, the proportion of the reaction temperature T and the reaction pressure P is 35%, and the proportion of the reactant molecular weight M is 30%; when the scene is that the reactant has a special atom and the number of carbon atoms between the special atom and the reaction site is less than 5, and the special atom forms a hydrogen bond or a conjugate with the benzene ring, the proportion of the reaction temperature T and the reaction pressure P is 28%, the proportion of the reactant molecular weight M is 20%, and the proportion of the distance D between the special atom and the reaction site is 24%.

4. The method of claim 3, wherein the reaction heat risk of the substitution chlorination is estimated by the following equation: ###0001### wherein R is a substituent of the compound of formula (I). When the scene is that the reactant has no special atom, the calculation formula of the thermal risk value R is R=T×35%+P×35%×100+ (1+1 / M) ×30%×10.

5. The method for predicting the heat risk of substituted chlorination reaction according to claim 3, characterized in that, When the scene is that the reactant has a special atom and the number of carbon atoms between the special atom and the reaction site is less than 5, the calculation formula of the thermal risk value R is R=T×28%+P×28%×100+ (1+1 / M) ×20%×10+ (1+1 / D) ×24%×100.

6. The method of claim 3, wherein the reaction heat risk of the substitution chlorination is estimated by the following equation: ###0001### wherein R is a substituent of the compound of formula (I). When the scene is that the reactant has a special atom and the number of carbon atoms between the special atom and the reaction site is greater than 5, the calculation formula of the thermal risk value R is R=T×35%+P×35%×100+ (1+1 / M) ×30%×10.

7. The method of claim 3, wherein the reaction heat risk of the substitution chlorination is estimated by the following equation: ###00002### wherein R is a substituent of the compound of formula (I). When the special atom and benzene ring form hydrogen bond or conjugation, the formula of the thermal risk value R is: R=T*28%+P*28%*100+(1+1 / M)*20%*10+(1+1 / D)*24%*200.

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