A method for evaluating the hydrolysis resistance of phosphate ester fire-resistant oil

Abstract

The invention belongs to the field of theoretical calculation of material chemical reactions, and particularly relates to a method for evaluating the hydrolysis resistance of phosphate fire-resistant oils. The method specifically comprises the following steps: optimizing the molecular structures of triaryl phosphate molecules and products after hydrolysis thereof to obtain equilibrium structures, and performing self-consistent calculations based on the equilibrium structures to obtain the Gibbs energy of the triaryl phosphate molecules; performing electrostatic potential energy analysis on the equilibrium structures to obtain electrostatic potential energy surfaces, and predicting electrophilic attack sites and nucleophilic attack sites based on the electrostatic potential energy surfaces; constructing reaction attack structure pairs according to the electrophilic attack sites and nucleophilic attack sites, calculating hydrolysis reaction barriers based on the reaction attack structure pairs, and evaluating the hydrolysis resistance of the triaryl phosphate molecules according to the hydrolysis reaction barriers. The method can predict the thermodynamic properties and hydrolysis resistance of triaryl phosphate molecular structures with different structures, and realize the performance screening of a plurality of different phosphoric acid molecular structures.

Description

Technical Field

[0001] The invention belongs to the field of theoretical calculation of material chemical reactions, and particularly relates to a method for evaluating the hydrolysis resistance of phosphate fire-resistant oil. Background Art

[0002] Phosphate is a general term for many small molecule phosphorus-containing esters, such as alkanes, hydrocarbons, and aromatic phosphates. Triaryl phosphates are aromatic molecules containing three phosphate ester bonds. Fire-resistant oils with triaryl phosphates as the main component can also be used in the hydraulic control system of steam turbines used in power plants. Through the self-feedback method of the sensor, the oil pressure is adjusted to control the stable output of the power generation of the steam turbine. In this scenario, triaryl phosphates are required to have the ability to resist high temperature, oxidation, and hydrolysis.

[0003] The ability of phosphates to react with water molecules to generate diaryl phosphates and phenolic compounds is a key indicator for characterizing the hydrolysis resistance of phosphates. For example, Hui Gao et al. proposed that the hydrolysis catalytic mechanism of 2-hydroxypropyl-4-nitrophenyl phosphate is that the nucleophilic 2-hydroxypropyl group first undergoes a deprotonation reaction at equilibrium, and then the nucleophilic molecule attacks the central phosphorus atom. However, water molecules also have electrophilic and nucleophilic properties, and the details of the hydrolysis reaction (the direction of water molecule attack, reaction path, etc.) are not yet clear. Therefore, although there have been relevant studies on phosphate bond compounds, the method for rapid characterization of the hydrolysis resistance of triphosphate aromatic ester compounds is still imperfect.

[0004] Calculating the thermodynamic properties of materials with the help of theoretical means can help predict molecular stability and thus better explain the reaction mechanism. The conventional method for calculating thermodynamic properties includes the following steps: first, the energy and structure of the material are calculated based on density functional theory; second, under the premise of structural convergence, the contribution of vibration is considered based on quasi-harmonic approximation (QHA), and the reaction microscopic 3D structure of phosphate + water molecules is constructed to calculate thermodynamic properties such as transition potential barriers. However, the current method requires manual determination of the reaction steps of phosphates and construction of reaction structures, especially the nucleophilic and electrophilic attack directions, and cannot achieve automated modeling and screening.

[0005] Therefore, there is an urgent need for a comprehensive evaluation method for the hydrolysis resistance of triphosphates to determine the overall hydrolysis reaction process of triaryl phosphates and to meet the needs of rapid screening of high-performance phosphates. Summary of the invention

[0006] The object of the present invention is to provide a method for evaluating the hydrolysis resistance of phosphate fire-resistant oils, which can predict the thermodynamic properties and hydrolysis resistance of triaryl phosphate molecular structures with different structures, and realize the performance screening of multiple different phosphoric acid molecular structures.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for evaluating the hydrolysis resistance of a phosphate fire-resistant oil, which specifically comprises the following steps:

[0009] S1. Optimizing the molecular structure of the triaryl phosphate molecule and its hydrolysis product to obtain an equilibrium structure, and performing self-consistent calculation based on the equilibrium structure to obtain the Gibbs energy of the triaryl phosphate molecule;

[0010] S2. Perform electrostatic potential energy analysis on the equilibrium structure to obtain the electrostatic potential energy surface, and predict the electrophilic attack site and nucleophilic attack site based on the electrostatic potential energy surface;

[0011] S3. Construct a reaction attack structure pair according to the electrophilic attack site and the nucleophilic attack site, calculate the hydrolysis reaction barrier based on the reaction attack structure pair, and evaluate the hydrolysis resistance of the triaryl phosphate molecule according to the hydrolysis reaction barrier.

[0012] Preferably, the hydrolysis product includes diarylphosphoric acid and phenolic compounds.

[0013] Preferably, the specific method for optimizing the molecular structure of the triaryl phosphate molecule and its hydrolysis product is: using Gaussian software for molecular modeling and first-principles calculations, using RB3LYP functional as calculation parameter, using 6-31G as basis set, adding D3 to correct van der Waals forces, and performing structural optimization.

[0014] Preferably, S1 also includes calculating the frequency of the equilibrium structure, determining the stability of the molecular structure, and eliminating unstable molecular structures.

[0015] Preferably, the specific method for performing electrostatic potential energy analysis on the equilibrium structure is: using Multiwfn software to calculate the electrostatic potential energy surface of the equilibrium structure; wherein the equilibrium structure surface is defined by an isosurface with electron density = 0.001 au.

[0016] Preferably, the specific method for predicting the electrophilic attack site and the nucleophilic attack site is: according to the electrostatic potential analysis, the maximum site and the minimum site of the electrostatic potential energy surface are calculated, and after considering the molecular symmetry, the equivalent sites therein are deleted, and the independent sites are obtained and sorted to obtain the electrophilic attack site and the nucleophilic attack site.

[0017] Preferably, the specific method for constructing the reaction attack structure pair is: the water molecule attack site is one or more of the electrophilic attack site and the nucleophilic attack site, all water molecule attack sites are numbered and correspond to the products after hydrolysis, and a composite structure of the water molecule structure and the triaryl phosphate is constructed.

[0018] Preferably, the specific method for calculating the hydrolysis reaction barrier is: using transition state calculation and TS method search, then performing 200 steps of IRC calculation, calculating the transition state path, taking the highest energy point of the transition state path as the transition state Gibbs energy, and using the transition state energy to subtract the total energy of the reactants before the reaction to obtain the hydrolysis reaction barrier.

[0019] Preferably, the formula for using the transition state energy minus the total energy of the reactants before the reaction is: ;in, is the energy difference between the energy before the reaction and the transition state energy, is the transition state Gibbs energy, is the sum of the Gibbs energy of the triaryl phosphate molecule and the energy of the water molecule.

[0020] Preferably, the specific method for evaluating the hydrolysis resistance of the triaryl phosphate molecule is: the higher the hydrolysis reaction barrier, the stronger the hydrolysis resistance.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention optimizes the structure of the molecules involved in the hydrolysis reaction process of the phosphate ester and performs self-consistent calculations to obtain the thermodynamic properties of different molecules after considering the contribution of vibration energy. The potential reaction direction of nucleophilic and electrophilic is quickly screened and determined by electrostatic potential, and the size of the reaction Gibbs free energy difference of each reaction is compared, and then the reaction energy barrier and product energy are calculated to characterize the anti-hydrolysis performance of the molecule. The method of the present invention can be used to evaluate the stability of phosphate molecules, establish a method for evaluating the anti-hydrolysis of phosphate molecules based on modeling calculation, provide favorable theoretical support for the evaluation of the stability performance of fire-resistant oils, and provide guidance for the adjustment of fire-resistant oil formulas.

[0023] Furthermore, the present invention adopts first-principles calculation to obtain the stable structure and electrostatic potential energy surface of phosphate ester molecules, automatically builds and calculates the hydrolysis reaction energy barrier and other thermodynamic properties, obtains the chemical reaction barrier of the molecule through first-principles simulation, and can calculate the thermodynamic properties of phosphate esters. The purpose of predicting the different structural properties of materials is achieved. The present invention overcomes the problem of artificially building chemical reaction transition state structures, overcomes the problem of low calculation efficiency, and broadens the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic flow chart of a method for evaluating the hydrolysis resistance of a phosphate fire-resistant oil according to the present invention;

[0026] Figure 2 This is the optimization process of the phosphate reactants and products in the embodiments of the present invention;

[0027] Figure 3 Analysis of the electrostatic potential attack direction of tri(p-tert-butylphenyl) phosphate;

[0028] Figure 4 The hydrolysis process and energy change of phosphate ester in the embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0030] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0031] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0033] like Figure 1 As shown, the present invention provides a method for evaluating the hydrolysis resistance of phosphate fire-resistant oil, which specifically comprises the following steps:

[0034] S1. Optimizing the molecular structure of the triaryl phosphate molecule and its hydrolysis product to obtain an equilibrium structure, and performing self-consistent calculation based on the equilibrium structure to obtain the Gibbs energy of the triaryl phosphate molecule;

[0035] S2. Perform electrostatic potential energy analysis on the equilibrium structure to obtain the electrostatic potential energy surface, and predict the electrophilic attack site and nucleophilic attack site based on the electrostatic potential energy surface;

[0036] S3. Construct a reaction attack structure pair according to the electrophilic attack site and the nucleophilic attack site, calculate the hydrolysis reaction barrier based on the reaction attack structure pair, and evaluate the hydrolysis resistance of the triaryl phosphate molecule according to the hydrolysis reaction barrier.

[0037] The present invention optimizes the molecular structure of triaryl phosphate molecules and their hydrolysis products to obtain a more stable and practical molecular configuration, thereby ensuring the accuracy of subsequent calculations. The Gibbs energy of triaryl phosphate molecules is obtained by self-consistent calculation, and its thermodynamic properties can be obtained, and basic data can be provided for subsequent calculations. Electrostatic potential energy analysis can intuitively display the charge distribution inside the molecule. Through the electrostatic potential energy surface, the electrophilic attack site and the nucleophilic attack site can be accurately predicted, and the attack direction of the water molecule can be obtained. The attack direction of the water molecule is one or more of all electrophilic attack sites and nucleophilic attack sites (there may be more than a dozen). By building a reaction attack structure pair, the real process of the hydrolysis reaction can be simulated, including the configuration change of the reactant, the formation of the transition state, and the generation of the product. Calculating the hydrolysis reaction barrier can quantitatively evaluate the hydrolysis resistance of the triaryl phosphate molecule. The higher the reaction barrier, the greater the difference in Gibbs free energy, indicating that the molecule is more difficult to undergo a hydrolysis reaction, that is, the stronger the anti-hydrolysis performance.

[0038] The product after the hydrolysis includes diaryl phosphoric acid and phenolic compounds. The same triaryl phosphate may have a variety of hydrolysis products, including diaryl phosphoric acid and phenolic compounds, traversing all possible combinations of single branched hydrolysis, and storing candidate products in the form of diaryl phosphoric acid+phenolic pairs. The list of candidate products can also be used as a reference for experimental verification. In actual experiments, corresponding detection and analysis methods can be designed and implemented based on these candidate products to verify whether the products and paths of the hydrolysis reaction meet expectations.

[0039] The specific method for optimizing the molecular structure of triaryl phosphate molecules and their hydrolysis products is: using Gaussian software for molecular modeling and first-principles calculations, using RB3LYP functional as calculation parameters, using 6-31G as basis set, and adding D3 to correct van der Waals forces (gd3bj) for structural optimization. Gaussian software is capable of high-precision molecular modeling and first-principles calculations. RB3LYP functional is a widely used hybrid density functional method that combines the high accuracy and speed advantages of B3LYP, while correcting the shortcomings of B3LYP in some cases. The 6-31G basis set is a basis set that balances computational efficiency and accuracy and is suitable for the calculation of most organic molecules. Secondly, in intermolecular interactions, van der Waals forces are an important non-covalent interaction, and adding D3 to correct van der Waals forces can more accurately describe intermolecular interactions.

[0040] S1 also includes frequency calculation of equilibrium structure, judging the stability of molecular structure and eliminating unstable molecular structure. By calculating the molecular vibration frequency, it is possible to identify whether there is imaginary frequency (i.e. negative frequency). The existence of imaginary frequency indicates that the molecular structure may not be a true equilibrium structure, but is in a transition state or unstable state, thereby verifying whether the obtained equilibrium structure is stable.

[0041] The specific method for performing electrostatic potential energy analysis on the equilibrium structure is: using quantum chemical wave function analysis program (Multifunctional wavefunction analyzer, Multiwfn) software to calculate the electrostatic potential energy surface of the equilibrium structure; wherein the equilibrium structure surface is defined by an isosurface with electron density = 0.001 au. The present invention uses Multiwfn software to perform electrostatic potential energy analysis and defines the equilibrium structure surface with an isosurface with electron density = 0.001 au, which can accurately describe the electrostatic characteristics of the molecular surface, deeply understand the intermolecular interaction, improve the prediction accuracy, promote research efficiency, and enhance the repeatability of the research.

[0042] The specific method for predicting the electrophilic attack site and the nucleophilic attack site is as follows: according to the electrostatic potential analysis, the maximum site and the minimum site of the electrostatic potential energy surface are calculated, and after considering the molecular symmetry, the equivalent sites therein are deleted, and the independent sites are obtained and sorted to obtain the electrophilic attack site and the nucleophilic attack site.

[0043] The specific method of building the reaction attack structure pair is: the water molecule attack site is one or more of the electrophilic attack site and the nucleophilic attack site, all water molecule attack sites are numbered and correspond to the products after hydrolysis, and a composite structure of the water molecule structure and the triaryl phosphate is built. Among them, the distribution of electrostatic potential on the van der Waals surface of the equilibrium structure is analyzed to predict which chemical reaction is most likely to occur at which site. It is generally believed that the atoms corresponding to the places with extremely small or extremely large electrostatic potential are more likely to undergo electrophilic or nucleophilic reactions; according to the surface electrostatic potential analysis, near the ester bond, the four points with extremely large and extremely small electrostatic potential energy may be the attack direction of water molecules.

[0044] The specific method for calculating the hydrolysis reaction barrier is: using transition state calculation and searching using the TS method, then performing 200 steps of intrinsic reaction coordinate (IRC) calculation, calculating the transition state path, taking the highest energy point of the transition state path as the transition state Gibbs energy, and using the transition state energy to subtract the total energy of the reactants before the reaction to obtain the hydrolysis reaction barrier. Through the TS method, we can obtain the highest energy point in the process of converting reactants to products, that is, the transition state, thereby revealing detailed information on the reaction path. Through IRC calculation, it is possible to proceed along the reaction path, showing the complete process from reactants to transition states and then to products, which helps us understand the structural changes in the reaction process, and can also reveal the reaction kinetics and thermodynamic characteristics.

[0045] The formula for using the transition state energy minus the total energy of the reactants before the reaction is: ;in, is the energy difference between the energy before the reaction and the transition state energy, is the transition state Gibbs energy, is the sum of the Gibbs energy of the triaryl phosphate molecule and the energy of the water molecule.

[0046] The specific method for evaluating the hydrolysis resistance of the triaryl phosphate molecule is: the higher the hydrolysis reaction barrier, the stronger the hydrolysis resistance.

[0047] Among them, the present invention uses the Gaussian program and Multiwfn software commonly used in the industry to calculate thermodynamic properties in combination to obtain the data required in each step of the present invention. Gaussian software is used for molecular modeling and first-principles calculations, the calculation parameters use RB3LYP functional, the basis set uses 6-31G (the energy difference is close to 6-31G* after testing), and D3 is added to correct van der Waals forces (gd3bj) for frequency calculations. All convergence conditions use the default parameters of Gaussian software. All structural energies are electronic energy + zero-point energy correction. The calculation process does not consider the effects of temperature, solvent and acid and base.

[0048] The present invention adopts first-principles calculation to obtain the stable structure and electrostatic potential energy surface of phosphate ester molecules, automatically builds and calculates the hydrolysis reaction energy barrier and other thermodynamic properties, obtains the chemical reaction barrier of the molecule through first-principles simulation, and can calculate the thermodynamic properties of phosphate esters. The purpose of predicting the different structural properties of materials is achieved. The present invention overcomes the problem of artificially building chemical reaction transition state structures, overcomes the problem of low calculation efficiency, and broadens the scope of application.

[0049] Example

[0050] S1. First, the molecular structures of two phosphate molecules, tri(p-tert-butylphenyl) phosphate and triphenyl phosphate, and their respective hydrolysis products, diaromatic phosphate and phenol, were optimized to obtain the equilibrium structure, and self-consistent calculations were performed to obtain the Gibbs free energy of reactants and products. The calculation case results are shown in the figure. Figure 2 As shown in the figure, the self-consistent calculation process of the initial structure requires multiple ion step optimizations before the energy gradually converges and stabilizes. The hydrolysis process is the cleavage of the ester bond to generate the corresponding di-tert-butyl phosphate and p-tert-butyl phenol. Figure 2 In the figure, a is the hydrolysis process of tri(p-tert-butylbenzene) phosphate, in which the ester bond is broken to generate the corresponding di-tert-butyl phosphate and p-tert-butylphenol; b is the hydrolysis process of triphenyl phosphate to generate diphenyl phosphate and phenol.

[0051] S2. Use Gaussian to perform frequency calculations on the above two phosphate structures to confirm that the molecular vibration frequency is positive, thereby confirming the thermal stability of the molecular structure and eliminating unstable molecular structures (negative molecular vibration frequency). The same phosphate may have multiple hydrolysis products, including diaromatic phosphates and phenolic compounds. Traverse all possible combinations of single branch hydrolysis, store candidate products in the form of diaromatic phosphate + phenol pairs, and finally calculate 3 phosphate + phenol pairs.

[0052] S3. Perform electrostatic potential energy analysis on triaryl phosphate molecules. Use Multiwfn software to calculate the electrostatic potential energy surface for the optimized self-consistent structure, obtain the electrostatic potential energy surface, and automatically estimate the electrophilic and nucleophilic attack sites. The molecular surface is defined by an isosurface with an electron density of 0.001 au (corresponding to the definition of the van der Waals surface by Bader charge).

[0053] S4. Predict which chemical reaction is most likely to occur at which site by analyzing the distribution of electrostatic potential on the van der Waals surface of the molecule. It is generally believed that the atoms corresponding to the places with maximum (minimum) electrostatic potential are more likely to undergo electrophilic (nucleophilic) reactions. According to the surface electrostatic potential analysis, the four points with maximum and minimum electrostatic potential energy near the ester bond may all be the attack direction of water molecules, and the spatial coordinates of the maximum and minimum sites of the electrostatic potential energy surface are obtained.

[0054] S5. Considering the symmetry of the molecule, after deleting the equivalent sites, the independent sites are obtained and sorted as the attack direction of the water molecules. All attack sites are numbered and correspond to phosphoric acid + phenol. Since tert-butyl diphenyl phosphate has 6 attack sites, the other two types of phosphates have 4 attack sites. The four phosphate molecules build a total of 10 (1*6+1*4) non-equivalent water attack three-dimensional molecular structures for subsequent calculations.

[0055] S6. According to the electrophilic attack site and the nucleophilic attack site, a reaction attack structure pair was constructed, and the hydrolysis reaction barrier was calculated based on the reaction attack structure pair. The hydrolysis resistance of the triaryl phosphate molecule was evaluated based on the hydrolysis reaction barrier. The transition state calculation was performed using the TS method, and 200 steps of IRC calculation were performed to display the transition state path. The calculation results are shown in Figure 1. Figure 3 As shown. Figure 3 As shown, the free red and blue balls represent the maximum and minimum positions of the electrostatic potential energy, respectively. We only need to consider the site positions around the phosphate bond, where a is the maximum point diagonally below the oxygen atom of the ester bond; b is the minimum point at the angle between the two branches; c is the minimum point directly below the phosphorus atom; and d is the maximum point directly above the oxygen atom. The scale is ESP (Electrostatic Potentia, electrostatic potential), and the size is a relative value. Calculate the energy difference between the energy before the reaction and the energy of the transition state, that is, the barrier energy, and the calculation formula is: , is the transition state Gibbs energy, is the Gibbs energy of the triaryl phosphate molecule and the energy of the water molecule.

[0056] exist Figure 4 In the figure, a and b are schematic diagrams of the transition state structures of the two molecules, at which the water molecule dissociates, and c and d correspond to the IRC transition state path energy change curves of the two phosphate molecules. In the c and d curves, the ordinate is the total energy (Total Energy), the unit is hartree (1 hartree =27.1 eV), and the abscissa is the number of optimization steps (Optimization Stop Number), the unit is 1. The title is the energy along the IRC path (Total Energy alongIRC). The abscissa is the intrinsic reaction coordinate (Instrinsic reaction corrdinate), the unit is 1.

[0057] The calculated As shown in Table 1:

[0058] Table 1 Transition barrier values ​​of tri(p-tert-butylphenyl) phosphate and triphenyl phosphate

[0059]

[0060] Tri(p-tert-butylphenyl) phosphate and triphenyl phosphate They are 0.658 eV and 0.597 eV respectively. Therefore, tri(p-tert-butylphenyl) phosphate has a higher hydrolysis barrier.

[0061] The present invention performs structural optimization and self-consistent calculation on the molecules involved in the hydrolysis reaction process of phosphate to obtain the stable energy of each molecule. Subsequently, Gaussian software is used to perform molecular modeling and first principle calculations to calculate the thermodynamic properties of different molecules after considering the contribution of vibrational energy, such as Gibbs free energy, etc. The potential reaction direction of nucleophilic and electrophilic is judged by rapid screening through electrostatic potential, the size of the reaction Gibbs free energy difference of each reaction is compared, and then the reaction energy barrier and product energy are calculated to characterize the anti-hydrolysis performance of the molecule. This method can be used to evaluate the stability of phosphate molecules, establish a method for evaluating the anti-hydrolysis of phosphate molecules based on modeling calculation, provide favorable theoretical support for the evaluation of stability performance of fire-resistant oils, etc., and provide guidance for the adjustment of fire-resistant oil formulations.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for evaluating the hydrolysis resistance of phosphate fire-resistant oils, characterized in that: The specific steps include: S1. Optimizing the molecular structure of the triaryl phosphate molecule and its hydrolysis product to obtain an equilibrium structure, and performing self-consistent calculation based on the equilibrium structure to obtain the Gibbs energy of the triaryl phosphate molecule; S2. Perform electrostatic potential energy analysis on the equilibrium structure to obtain the electrostatic potential energy surface, and predict the electrophilic attack site and nucleophilic attack site based on the electrostatic potential energy surface; S3, constructing a reaction attack structure pair according to the electrophilic attack site and the nucleophilic attack site, calculating a hydrolysis reaction barrier based on the reaction attack structure pair, and evaluating the hydrolysis resistance of the triaryl phosphate molecule according to the hydrolysis reaction barrier; The specific method for optimizing the molecular structure of the triaryl phosphate molecule and its hydrolyzed product is: using Gaussian software for molecular modeling and first-principles calculation, using RB3LYP functional as calculation parameter, using 6-31G as basis set, adding D3 to correct van der Waals force, and performing structural optimization; The specific method for predicting the electrophilic attack site and the nucleophilic attack site is as follows: according to the electrostatic potential analysis, the maximum site and the minimum site of the electrostatic potential energy surface are calculated, and after the equivalent sites are deleted considering the molecular symmetry, the independent sites are obtained and sorted to obtain the electrophilic attack site and the nucleophilic attack site; The specific method of constructing the reaction attack structure pair is as follows: the water molecule attack site is one or more of the electrophilic attack site and the nucleophilic attack site, all water molecule attack sites are numbered and correspond to the products after hydrolysis, and a composite structure of the water molecule structure and the triaryl phosphate is constructed; The specific method for calculating the hydrolysis reaction barrier is: using transition state calculation and TS method search, then performing 200 steps of IRC calculation, calculating the transition state path, taking the highest energy point of the transition state path as the transition state Gibbs energy, and using the transition state energy to subtract the total energy of the reactants before the reaction to obtain the hydrolysis reaction barrier.

2. The method for evaluating the hydrolysis resistance of phosphate fire-resistant oil according to claim 1, characterized in that: The hydrolyzed products include diarylphosphoric acid and phenolic compounds.

3. The method for evaluating the hydrolysis resistance of phosphate ester fire-resistant oil according to claim 1, characterized in that: S1 also includes frequency calculation of equilibrium structures, judging the stability of molecular structures, and eliminating unstable molecular structures.

4. The method for evaluating the hydrolysis resistance of phosphate fire-resistant oil according to claim 1, characterized in that: The specific method for performing electrostatic potential energy analysis on the equilibrium structure is: using Multiwfn software to calculate the electrostatic potential energy surface of the equilibrium structure; wherein the equilibrium structure surface is defined by an isosurface with an electron density of 0.001 au.

5. The method for evaluating the hydrolysis resistance of phosphate fire-resistant oil according to claim 1, characterized in that: The formula for using the transition state energy minus the total energy of the reactants before the reaction is: ;in, is the energy difference between the energy before the reaction and the transition state energy, is the transition state Gibbs energy, is the sum of the Gibbs energy of the triaryl phosphate molecule and the energy of the water molecule.

6. The method for evaluating the hydrolysis resistance of phosphate fire-resistant oil according to claim 1, characterized in that: The specific method for evaluating the hydrolysis resistance of the triaryl phosphate molecule is: the higher the hydrolysis reaction barrier, the stronger the hydrolysis resistance.

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