Method for creating chemical calculation model molecule

Abstract

To provide a chemical calculation model molecule and the like that enable calculation of chemical reaction energy of a molecule having a prescribed complex fused ring, in short time while maintaining high accuracy, by using a non-empirical molecular orbital method.SOLUTION: Provided is a method for creating a chemical calculation model molecule of a molecule having a complex fused ring constituted by fusing a six-membered ring, and a ring structure containing one or more hetero atoms and one or more double bonds in a cyclic skeleton. The method for creating a chemical calculation model molecule includes: a step of creating a complex monocyclic unit that is a unit in which the six-membered ring has been removed from the complex fused ring and in which a constituent atom of the cyclic skeleton is held in the ring structure; and a step of creating the chemical calculation model molecule that includes the complex monocyclic unit and is constituted by the number of atoms less than the total number of atoms constituting the molecule.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for creating a chemical calculation model molecule, a method for calculating the chemical reaction energy of a molecule using the chemical calculation model molecule created by the method, and a method for selecting a vulcanization accelerator for a diene rubber component. [Background technology]

[0002] Many rubber products are manufactured through a vulcanization reaction in which sulfur is added to rubber components, such as diene rubber components containing double bonds, to form crosslinks. Because the vulcanization reaction with sulfur alone is very slow and the crosslink density is low, sulfur is often used in combination with vulcanization accelerators or zinc oxide. A typical example of a vulcanization accelerator is a molecule containing a heterocyclic fused ring (e.g., a benzothiazole ring) formed by fusing a six-membered ring (e.g., a benzene ring) with a ring structure (e.g., a five-membered ring) containing one or more heteroatoms and one or more double bonds in the ring structure.

[0003] For example, Patent Document 1 discloses N-ethyl-Nt-butyl-1,3-benzothiazole-2-sulfenamide, a vulcanization accelerator that has low bioaccumulation, does not generate carcinogenic nitrosamines, and has performance equivalent to that of DCBS, which is designated as a Type 1 monitored chemical substance under the Chemical Substances Control Law. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-275230 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, when attempting to select a new vulcanization accelerator from a group of molecules with heterocyclic fused rings (including newly designed molecules) as described above, obtaining or synthesizing each one and then experimentally verifying them one by one requires an extremely time-consuming and labor-intensive method. Therefore, a method is conceivable in which the reactivity (chemical reaction energy) is calculated using ab initio molecular orbital methods, which do not use experimental values, and the results are used to select a new vulcanization accelerator. However, the detailed reaction mechanism of the vulcanization reaction of rubber components using ab initio molecular orbital methods has not yet been elucidated. Furthermore, when calculating the chemical reaction energy of a molecule using quantum chemical calculations using ab initio molecular orbital methods, the calculation time is typically three to five times the total number of atoms in the molecule, so even this method is likely to require a significant amount of time. On the other hand, when performing the above calculations by simplifying the molecule, although it is usually possible to shorten the calculation time, the accuracy (consistency with the data of the original molecule, accuracy) is often significantly reduced.

[0006] Therefore, an object of the present invention is to provide a chemical calculation model molecule or the like that can calculate the chemical reaction energy of a molecule having a predetermined hetero-fused ring by the ab initio molecular orbital method in a short time while maintaining high accuracy. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have conducted extensive research and have found that a method for creating a chemical calculation model molecule of a molecule having a heterofused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, the method comprising the steps of: creating a heteromonocyclic unit in which the six-membered ring is removed from the heterofused ring and the cyclic structure retains the constituent atoms of the ring skeleton; and creating the chemical calculation model molecule including the heteromonocyclic unit and consisting of fewer atoms than the total number of atoms constituting the molecule, can provide a chemical calculation model molecule that enables calculation of the chemical reaction energy of the molecule having the heterofused ring by ab initio molecular orbital method while maintaining high accuracy in a short time. Further research led to the completion of the present invention.

[0008] That is, the present invention provides the following: <1> ~ <11> This includes embodiments of the present invention. <1> A method for creating a chemical calculation model molecule of a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, comprising: a step of preparing a heteromonocyclic unit, which is a unit in which the six-membered ring is removed from the heterofused ring contained in the molecule and the constituent atoms of the ring skeleton of the cyclic structure are maintained; and creating the chemical calculation model molecule that includes the heteromonocyclic unit and is composed of fewer atoms than the total number of atoms that constitute the molecule. How to create chemical computational model molecules. <2> the step of preparing the heteromonocyclic unit is a step of preparing the heteromonocyclic unit having 50 to 70% of the total number of atoms constituting the heterofused ring, The step of creating the chemical calculation model molecule is a step of creating the chemical calculation model molecule composed of 50 to 70% of the total number of atoms constituting the molecule. <1> A method for creating a chemical calculation model molecule according to the above. <3> The heteromonocyclic unit is a unit in which the six-membered ring is removed from the heterofused ring, and the ring structure retains all of the constituent atoms and chemical bonds of the ring skeleton. <1> or <2> A method for creating a chemical calculation model molecule according to the above. <4> the step of creating the chemical calculation model molecule is a step of creating a structure added to the heteromonocyclic unit of the chemical calculation model molecule so that the structure is composed of fewer atoms than the total number of atoms constituting the structure added to the heterofused ring of the molecule; <1> ~ <3> 10. A method for creating a chemical computational model molecule according to any one of the above. <5> the heteroatom is a sulfur atom and / or a nitrogen atom; <1> ~ <4> 10. A method for creating a chemical computational model molecule according to any one of the above. <6> the cyclic structure and the heteromonocyclic unit constituting the heterofused ring of the molecule are five-membered rings containing one or more heteroatoms and one or more double bonds in the ring skeleton; <1> ~ <5> 10. A method for creating a chemical computational model molecule according to any one of the above. <7> the six-membered ring constituting the heterofused ring of the molecule is a benzene ring; <1> ~ <6> 10. A method for creating a chemical computational model molecule according to any one of the above. <8> the hetero-fused ring of the molecule is a benzothiazole ring; <1> ~ <7> 10. A method for creating a chemical computational model molecule according to any one of the above. <9> A method for calculating chemical reaction energy of one or more sites in a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, comprising: <1> ~ <8> Calculating the chemical reaction energy by a non-empirical molecular orbital method using a chemical calculation model molecule created by the method for creating a chemical calculation model molecule according to any one of the above. How to calculate the chemical reaction energy of a molecule. <10> A program that causes a computer to execute a chemical reaction energy calculation for a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, the program comprising: The computer, <1> ~ <8> A creation process of creating a chemical calculation model molecule of the molecule by the chemical calculation model molecule creation method described in any one of the above. a calculation process for calculating chemical reaction energy of one or more sites in the molecule by ab initio molecular orbital method using the chemical calculation model molecule; A program for calculating molecular chemical reaction energy. <11> A method for selecting a vulcanization accelerator for a diene rubber component from a group of molecules having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, comprising: <1> ~ <8> Calculating chemical reaction energy of one or more sites in the molecule by ab initio molecular orbital method using chemical calculation model molecules of the plurality of molecules included in the group, which are created by the method for creating a chemical calculation model molecule according to any one of the above items; and comparing the calculated chemical reaction energies to select a vulcanization accelerator for the diene rubber component from the plurality of molecules. Method for selecting vulcanization accelerators for diene rubber components. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a chemical calculation model molecule or the like that can calculate the chemical reaction energy of a molecule having a predetermined hetero-fused ring by the ab initio molecular orbital method in a shorter time while maintaining high accuracy. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are schematic diagrams showing examples of steps of an embodiment of a method for creating a chemical calculation model molecule according to the present invention (Example Process A) and an embodiment of a method for selecting a vulcanization accelerator for a diene rubber component according to the present invention (Example Process B). [Figure 2] 1A and 1B are diagrams showing specific examples of hetero-fused rings possessed by a molecule that is the basis of a chemical calculation model molecule created by an embodiment of a method for creating a chemical calculation model molecule according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will now be described. The present invention is a method for creating a chemical calculation model molecule of a molecule having a heterofused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, the method comprising the steps of: creating a heteromonocyclic unit, which is a unit in which the six-membered ring is removed from the heterofused ring and the cyclic structure retains the constituent atoms of the ring skeleton; and creating the chemical calculation model molecule which includes the heteromonocyclic unit and is formed with a number of atoms that is fewer than the total number of atoms that constitute the molecule. The present invention also includes a method for calculating the chemical reaction energy of a molecule, which includes a step of calculating the chemical reaction energy of one or more sites by ab initio molecular orbital method using a chemical calculation model molecule created by the above-mentioned method for creating a chemical calculation model molecule; a molecular chemical reaction energy calculation execution program that causes a computer to execute arithmetic processing including creating the chemical calculation model molecule and calculating the chemical reaction energy of the one or more sites; and a method for selecting a vulcanization accelerator for a diene rubber component, which includes a step of calculating the chemical reaction energy of one or more sites in the molecule by ab initio molecular orbital method using chemical calculation model molecules of a plurality of molecules included in the group of molecules created by the above-mentioned method for creating a chemical calculation model molecule; and a step of comparing the calculated chemical reaction energies to select a vulcanization accelerator for a diene rubber component from the plurality of molecules. Hereinafter, these will also be referred to as "a method for creating a chemical calculation model molecule according to the present invention," "a method for calculating the chemical reaction energy of a molecule according to the present invention," "a program for executing calculations of the chemical reaction energy of a molecule according to the present invention," and "a method for selecting a vulcanization accelerator for a diene rubber component according to the present invention."

[0012] In the present invention, unless otherwise specified, a numerical range expressed using "to" means a numerical range in which the numerical value before "to" is the lower limit and the numerical value after "to" is the upper limit.

[0013] Preferred embodiments of the method for creating a chemical computational model molecule according to the present invention will be described below. Note that the preferred embodiments listed below are merely examples, and the present invention is not limited to the configurations of the following embodiments.

[0014] First, an embodiment of a method for creating a chemical calculation model molecule according to the present invention will be described. The method for creating a chemical calculation model molecule according to this embodiment includes the steps of: creating a heteromonocyclic unit, which is a unit in which a molecule having a heterofused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, removes the six-membered ring from the heterofused ring and retains the constituent atoms of the ring skeleton; and creating a chemical calculation model molecule containing this heteromonocyclic unit and consisting of fewer atoms than the total number of atoms constituting the molecule (e.g., S13 in Examples A and B of FIG. 1). Each of these steps will be described in detail below.

[0015] [Step of Producing Heteromonocyclic Unit] The step of creating a heteromonocyclic unit in the method for creating a chemical computation model molecule according to this embodiment is a step of creating a predetermined heteromonocyclic unit, which will be the main component of the chemical computation model molecule, from a heterofused ring possessed by a base molecule.

[0016] The molecule from which a chemical calculation model molecule is created by the method for creating a chemical calculation model molecule according to this embodiment is a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton. In other words, the hetero-fused ring of this molecule is formed by fusing two predetermined cyclic structures. Here, the phrase "formed by "fusion" of the two cyclic structures described above" means that the chemical bond forming the ring skeleton of the six-membered ring and the chemical bond forming the ring skeleton of another cyclic structure have one or more common chemical bonds (one or more common chemical bonds forming each ring skeleton, two or more adjacent ring skeleton-constituting atoms form both the ring skeleton of the six-membered ring and the ring skeleton of the cyclic structure). In particular, a hetero-fused ring having one common chemical bond is more preferred.

[0017] The six-membered ring constituting this heterofused ring is not limited as long as it is an organic six-membered ring having six constituent atoms in the ring skeleton (a six-membered ring containing one or more carbon atoms as constituent atoms in the ring skeleton), but since the effects of the present invention are more easily exhibited, this six-membered ring preferably contains one or more, more preferably two or more, double bonds, and more preferably two or more, more preferably three or more, or even four or more carbon atoms, and is even more preferably a benzene ring.

[0018] The other cyclic structure constituting this heterofused ring is not limited as long as it is an organic cyclic structure (a cyclic structure containing one or more carbon atoms in the cyclic structure) containing one or more heteroatoms and one or more double bonds in the cyclic structure. However, since the effects of the present invention are more easily achieved, this cyclic structure is more preferably a five-membered ring (a cyclic structure containing five constituent atoms in the cyclic structure) containing one or more heteroatoms and one or more double bonds in the cyclic structure. The heteroatom is also not limited and may be a nitrogen atom, sulfur atom, oxygen atom, phosphorus atom, etc., but since the effects of the present invention are also more easily achieved, this heteroatom is more preferably a sulfur atom and / or a nitrogen atom, and even more preferably a five-membered ring containing sulfur atoms and / or nitrogen atoms as heteroatoms and one or more double bonds. The double bond contained in the cyclic structure may also be contained in the cyclic structure of the six-membered ring (shared with the cyclic structure of the six-membered ring). On the other hand, it is preferable that the heteroatom contained in the cyclic structure is not contained in the cyclic structure of the six-membered ring (is not a constituent atom of the six-membered ring).

[0019] Specific examples of this heterofused ring include any of the structures shown in Figure 2. Among these, it is particularly preferable that this heterofused ring is a benzothiazole ring having a structure represented by the following formula (1) (the structure on the right side of the bottom row in Figure 2), as this makes it easier to achieve the effects of the present invention. It is also preferable that this heterofused ring is a benzimidazole ring (the structure in the center of the top row of Figure 2 (the third from both the left and right)). Note that this benzothiazole ring and benzimidazole ring also include those that have been modified into stable structures by substituents on the side chains, etc.

[0020] [ka]

[0021] Furthermore, the structure of the original molecule other than the hetero-fused ring (the structure added to the hetero-fused ring) is not particularly limited, but since the effects of the present invention are easily exhibited, it is more preferable that the structure contains a substituent on the carbon atom adjacent to the heteroatom (adjacent to the heteroatom) contained in the cyclic structure of the hetero-fused ring, and it is even more preferable that all the attachment sites other than this position are hydrogen atoms. The above-mentioned substituent is also not particularly limited, but it is more preferable that it is a substituent (particularly an organic substituent) containing a sulfur atom and / or a nitrogen atom. For example, when the hetero-fused ring of the original molecule is the benzothiazole ring of the above formula (1), it is more preferable that the molecule has a substituent (particularly an organic substituent) containing a sulfur atom and / or a nitrogen atom added to the carbon atom adjacent to both the nitrogen atom and the sulfur atom (the carbon atom sandwiched between these heteroatoms, the carbon atom adjacent to both of these heteroatoms), and it is even more preferable that all the addition sites other than these positions have a structure in which hydrogen atoms are added. Similarly, when the hetero-fused ring of the original molecule is the above-mentioned benzimidazole ring, it is more preferable that the molecule has a substituent (particularly an organic substituent) containing a sulfur atom and / or a nitrogen atom added to the carbon atom adjacent to both of the two nitrogen atoms, and it is even more preferable that all the addition sites other than these positions have a structure in which hydrogen atoms are added.

[0022] In the process of preparing this heteromonocyclic unit, the six-membered ring is removed from the above-described heterofused ring of the original molecule, and another cyclic structure (a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton) is prepared, which is a monocyclic unit having a monocyclic structure in which the constituent atoms of the ring skeleton are maintained. Here, the phrase "the constituent atoms of the ring skeleton are maintained" of the cyclic structure means that the type, number, and arrangement of the constituent atoms of the ring skeleton are unchanged (maintained) from the above-described cyclic structure of the heterofused ring of the original molecule. For example, if the heterocyclic fused ring of the original molecule is the benzothiazole ring of the above formula (1), the six-membered benzene ring is removed and the constituent atoms (and chemical bonds) of the five-membered ring skeleton are maintained, to create a heteromonocyclic unit having a structure represented by the following formula (2). Note that the double bond of this five-membered ring may be changed to a single bond, but it is more preferable to maintain the chemical bond as well, as described below.

[0023] [ka]

[0024] Here, the step of preparing this heteromonocyclic unit is a step of preparing the ring skeleton of the heteromonocyclic unit from the ring skeleton of the heterofused ring possessed by the original molecule, and atoms and molecules (such as their side chains and substituents) other than the atoms constituting the ring skeleton of the cyclic structure constituting the heterofused ring do not need to be taken into consideration in this step. In other words, in the step of preparing this heteromonocyclic unit, attention is paid to the atoms (their number, type, arrangement, etc.) constituting the ring skeleton of the cyclic structure constituting the heterofused ring possessed by the original molecule and their chemical bonds, but hydrogen atoms and substituents attached thereto are not taken into consideration, and hydrogen atoms and substituents to be attached to the heteromonocyclic unit to be prepared are not taken into consideration in this step.

[0025] In order to more easily exert the effects of the present invention, it is preferable that in the step of preparing this heteromonocyclic unit, the six-membered ring is removed from the heterofused ring of the original molecule, and the cyclic structure is a heteromonocyclic unit in which the constituent atoms and chemical bonds of the ring skeleton are all maintained. Here, the phrase "the chemical bonds of the ring skeleton are maintained" of the cyclic structure means that the type (single bond, double bond, etc.) and arrangement of the chemical bonds of the ring skeleton are not changed (maintained) from the cyclic structure of the heterofused ring of the original molecule. For example, when the cyclic structure constituting the heterofused ring of the original molecule is a five-membered ring containing one or more heteroatoms and one or more double bonds in the ring skeleton as described above (for example, the above formula (1)), it is preferable that this heteromonocyclic unit is also a five-membered ring containing one or more heteroatoms and one or more double bonds at the same positions in the ring skeleton (for example, the above formula (2)).

[0026] Using the heteromonocyclic unit produced by the above-described process for producing a heteromonocyclic unit, a chemical calculation model molecule having this as its main constituent part is produced by the following process for producing a chemical calculation model molecule.

[0027] [Process for creating chemical calculation model molecules] The step of creating a chemical calculation model molecule in the method for creating a chemical calculation model molecule according to this embodiment is a step of using the heteromonocyclic unit created in the step of creating the heteromonocyclic unit described above to create a chemical calculation model molecule that includes this heteromonocyclic unit and is composed of a number of atoms that is smaller than the total number of atoms that constitute the original molecule (the total number of atoms including hydrogen atoms and atoms that constitute substituents). That is, the chemical calculation model molecule is created so that it contains the heteromonocyclic unit created in the step of creating the heteromonocyclic unit as it is, and the total number of atoms in the entire chemical calculation model molecule is less than the total number of atoms constituting the original molecule, thereby making it possible to create a chemical calculation model molecule in which the heteromonocyclic unit is the main constituent part.

[0028] For example, when a heteromonocyclic unit having the structure represented by the formula (2) is prepared from a molecule having a benzothiazole ring having the structure represented by the formula (1) as a heterofused ring, a hydrogen atom or a substituent attached to the original five-membered ring can be added to this heteromonocyclic unit at the same position to create a chemical calculation model molecule. However, as long as the total number of atoms is less than the total number of atoms constituting the original molecule, a substituent not attached to the original five-membered ring may be added. Furthermore, when the base molecule has a structure in which a hydrogen atom is added to the heterocyclic fused ring (a structure without a substituent), the process of creating the heteromonocyclic unit and the process of creating this chemical calculation model molecule may be performed simultaneously. For example, when the base molecule is benzothiazole (CAS No. 95-16-9), the six-membered benzene ring is removed and hydrogen atoms are added to both carbon atoms (adjacent carbon atoms) at the part where the benzene ring and the five-membered ring were fused (the process of creating the heteromonocyclic unit and the process of creating the chemical calculation model molecule are performed simultaneously), thereby creating a chemical calculation model molecule with the same structure as thiazole (CAS No. 288-47-1). Furthermore, the same process may be performed even when the base molecule has one or more substituents.

[0029] In order to more easily achieve the effects of the present invention, it is more preferable that the step of preparing the heteromonocyclic unit described above is the embodiment described above and is a step of preparing a heteromonocyclic unit composed of 50 to 70% of the total number of atoms (the number of atoms constituting the ring skeleton of the monocyclic ring) of the heterofused ring of the original molecule (the total number of atoms constituting the ring skeleton of the heterofused ring), and that the step of preparing this chemical calculation model molecule is the embodiment described above and is a step of preparing a chemical calculation model molecule composed of 50 to 70% of the total number of atoms constituting the original molecule.Moreover, it is more preferable that the upper limit of the proportion of the number of atoms in the step of preparing the heteromonocyclic unit is 60% or less, and it is also more preferable that the upper limit of the proportion of the number of atoms in the step of preparing the chemical calculation model molecule is 60% or less.

[0030] Similarly, since the effects of the present invention are more easily achieved, it is more preferable that the process for creating this chemical calculation model molecule is the embodiment described above, and that the structure added to the heteromonocyclic unit of the created chemical calculation model molecule (all hydrogen atoms and substituents added to the heteromonocyclic unit) is created so that the total number of atoms is fewer than the total number of atoms constituting the structure added to the heterofused ring of the original molecule (all hydrogen atoms and substituents added to the heterofused ring). In other words, it is more preferable to create a chemical calculation model molecule by simplifying both the heterofused ring and the structure other than the heterofused ring as a whole while leaving the main structure of the original molecule under predetermined conditions. For example, this can be achieved by replacing some of the substituents added to the cyclic structure of the heterofused ring of the original molecule with hydrogen atoms and adding them to the heteromonocyclic unit.

[0031] By the method for creating a chemical calculation model molecule according to the present embodiment as described above, it is possible to provide a chemical calculation model molecule (a simplified molecule for calculating chemical reaction energy) that can calculate the chemical reaction energy of a molecule having a hetero-fused ring as described above by the ab initio molecular orbital method in a shorter time while maintaining high accuracy. The method for creating a chemical calculation model molecule according to the present embodiment can also be performed using a computer (for example, a computer as described below) in which the above procedures and the like are pre-stored as a program.

[0032] Next, embodiments of a molecular chemical reaction energy calculation method and a molecular chemical reaction energy calculation execution program according to the present invention will be described. The chemical reaction energy calculation method according to this embodiment includes a step (e.g., S21 in step example B of FIG. 1 ) of calculating the chemical reaction energy of one or more sites in a molecule having a hetero-fused ring as described above, using a chemical calculation model molecule created by the method for creating a chemical calculation model molecule according to this embodiment. Furthermore, the molecular chemical reaction energy calculation execution program according to this embodiment is a program that causes a computer to execute a chemical reaction energy calculation for a molecule having a hetero-fused ring as described above, and executes arithmetic processing including: a creation process for creating a chemical calculation model molecule for this molecule using the method for creating a chemical calculation model molecule according to this embodiment; and a calculation process for calculating the chemical reaction energy of one or more sites in the molecule using the ab initio molecular orbital method, using the chemical calculation model molecule created by this creation process. Each of these steps will be described in detail below.

[0033] [Creation process for creating chemical calculation model molecules] The chemical calculation model molecule used in the chemical reaction energy calculation method according to this embodiment, and the chemical calculation model molecule in the molecular chemical reaction energy calculation execution program according to this embodiment, can be created by the chemical calculation model molecule creation method according to the present embodiment described above. The molecular chemical reaction energy calculation execution program according to this embodiment executes this creation as a creation process on a computer. For example, the structural information of a molecule having a predetermined heterofused ring can be described (converted into data) using a linear notation of a compound, regardless of the chemical structure. Using this descriptor (data), the initial structure of the molecule can be input into a computer using known software such as Gaussview (manufactured by Gaussian) or Psi4 (Python). Using this as a base, the computer automatically processes the structure by using software programmed to delete the six-membered ring contained in the heterofused ring of the molecule and the substituents attached to this six-membered ring, leaving the other ring structure and the substituents attached thereto intact, and simultaneously adding hydrogen atoms to the portion where the six-membered ring was deleted. The chemical calculation model molecule obtained by this automatic processing can then be output.

[0034] [Calculation of chemical reaction energy, etc.] The step of calculating the chemical reaction energy in the chemical reaction energy calculation method according to this embodiment, and the calculation process of calculating the chemical reaction energy in the molecular chemical reaction energy calculation execution program according to this embodiment, are steps or processes that use the chemical calculation model molecule created above to calculate the chemical reaction energy of one or more sites in the original molecule (i.e., one or more sites of this chemical calculation model molecule that are common to the original molecule) using ab initio molecular orbital methods. The sites for which this chemical reaction energy calculation is performed are not particularly limited as long as they can contribute to the chemical reaction, but preferably include sites with lower chemical reaction energy (higher reactivity, more susceptible to reaction) than other sites. Any known software may be used for this chemical reaction energy calculation and calculation process, such as Gaussian (a product of Gaussian Inc.) or GAMESS. Any known calculation method may also be used, such as a DFT calculation using B3LYP (functional) / 6-31+G(d) (basis function). Specifically, the energy of the entire chemical calculation model molecule and the energy of each radical molecule or atom when the molecule is assumed to be cleaved at that site (transition state energy) can be calculated by a computer using the software and the method described above, and the difference between them can be confirmed. The transition state energy may also be calculated as a state in which the molecule coexists with zinc oxide or the like (such as a zinc complex state). While the calculation method is not limited to the above, a variety of calculation methods are used when comparative studies are performed.

[0035] The molecular chemical reaction energy calculation execution program according to this embodiment can be executed by a general-purpose computer. This computer may be, for example, a desktop personal computer (PC), or a portable terminal such as a portable PC, smartphone, or tablet, or even a dedicated computer. There are no particular limitations on the computer provided it has a means for inputting information, including the structure of the original molecule. Examples include a keyboard, mouse, scanner, etc., and a configuration in which a display device and an input device, such as a touch panel, are integrated. Furthermore, the computer may include a storage means such as a memory capable of storing the input information or performing and storing calculations based on the input information. Additionally, the computer may include a central processing unit (CPU) capable of performing predetermined calculations based on the information stored in the storage means, and an output means such as a display capable of outputting the calculation results.

[0036] By using the chemical reaction energy calculation method according to the present embodiment and the molecular chemical reaction energy calculation execution program according to the present embodiment, the chemical reaction energy of a molecule having a hetero-fused ring as described above can be calculated in a short time while maintaining high accuracy by the ab initio molecular orbital method using the chemical calculation model molecule. As an example of using this calculated chemical reaction energy, it can be used to carry out the method for selecting a vulcanization accelerator for a diene rubber component according to the present embodiment. The method for selecting a vulcanization accelerator for a diene rubber component according to the present embodiment includes the following steps: for a group of molecules having a hetero-fused ring as described above (a group including not only known molecules having the hetero-fused ring but also newly designed molecules having the hetero-fused ring), calculate the chemical reaction energy of one or more sites in the plurality of molecules by the ab initio molecular orbital method using chemical calculation model molecules of a plurality of molecules included in this group, which are created by the method for creating a chemical calculation model molecule according to the present embodiment; and compare the calculated chemical reaction energies to select a vulcanization accelerator for the diene rubber component from the plurality of molecules. Each of these steps will be described in detail below.

[0037] [Process for calculating chemical reaction energy] The step of calculating the chemical reaction energy in the method for selecting a vulcanization accelerator for a diene rubber component according to this embodiment may be performed by the above-described method for calculating chemical reaction energy according to this embodiment, etc. The chemical reaction energy to be calculated is not limited, but is more preferably the chemical reaction energy of a site common to these multiple molecules (a site having a common structure composed of the same atoms and the same chemical bonds).

[0038] [Process for selecting vulcanization accelerators for diene rubber components] The step of selecting a vulcanization accelerator for a diene rubber component in the method for selecting a vulcanization accelerator for a diene rubber component according to this embodiment is a step of comparing the calculated chemical reaction energies and selecting a vulcanization accelerator for a diene rubber component from a plurality of molecules (for example, S31 in Step Example B in FIG. 1). Specifically, the chemical reaction energies of the common sites among the plurality of molecules are compared, and the one with the lowest chemical reaction energy (the one with the smallest difference as described above) is selected as the vulcanization accelerator for the diene rubber component. However, from the viewpoint of maintaining the vulcanization reaction of the diene rubber in an appropriate state or from the viewpoint of ease of synthesis or availability, the chemical reaction energies of different sites among the plurality of molecules may be compared, or even when the chemical reaction energies of the common sites among the plurality of molecules are compared, the one with a moderately low chemical reaction energy may be selected as the vulcanization accelerator for the diene rubber component, rather than the one with the lowest chemical reaction energy.

[0039] The diene rubber component is a rubber component having a double bond in the polymer main chain, and specific examples thereof include natural rubber (NR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), styrene-isoprene copolymer rubber, and isoprene-butadiene copolymer rubber.

[0040] The weight average molecular weight of the target diene rubber component is preferably 50,000 to 3,000,000, and more preferably 100,000 to 2,000,000. In the present invention, the "weight average molecular weight" refers to a value measured in terms of standard polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. The GPC measurement is carried out at 40°C using a column (MIXED-B, manufactured by Polymer Laboratories) as a measuring instrument.

[0041] By the method for selecting a vulcanization accelerator for a diene rubber component according to the present embodiment as described above, it is possible to easily select (search) a molecule suitable as a vulcanization accelerator for a diene rubber component from a plurality of molecular groups having a hetero-fused ring as described above without conducting experiments. Furthermore, by comparing the chemical reaction energies as described above, it is also possible to select a vulcanization accelerator suitable for combination with zinc oxide, which is often used in the vulcanization reaction of a diene rubber component. From another perspective, it can be said that by adding a newly designed molecule to the above group in the above embodiment or by forming a group consisting of the newly designed molecules, a method for designing a molecule having a predetermined hetero-fused ring suitable for a vulcanization accelerator for a diene rubber component can be provided.

[0042] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples, and various modifications are possible within the technical concept of the present invention. [Example]

[0043] Example 1 2-mercaptobenzothiazole (CAS No. 149-30-4) with the structure shown in the following formula (3) was used as a molecule (Comparative Example A) having a hetero-fused ring formed by fusing a six-membered ring with a five-membered ring containing one or more heteroatoms and one or more double bonds in the ring skeleton. The hetero-fused ring of this molecule is a type of benzothiazole ring (stable structure).

[0044] [ka]

[0045] Then, a heteromonocyclic unit was created by removing the six-membered benzene ring from the heterofused ring of this molecule and retaining the constituent atoms and chemical bonds of the five-membered ring skeleton. A sulfur atom was added to this unit via a double bond at the same position as in the above molecule, and hydrogen atoms were added to the other positions, creating a chemical calculation model molecule No. 4 with a structure represented by the following formula (4).

[0046] [ka]

[0047] Furthermore, chemical calculation model molecule No. 5, which has a structure represented by the following formula (5), was created by breaking and deleting part of the five-membered ring in chemical calculation model molecule No. 4 and adding a hydrogen atom at the added position. Chemical calculation model molecule No. 6, which has a structure represented by the following formula (6), was also created by changing the double bond of the five-membered ring in chemical calculation model molecule No. 4 to a single bond and adding a hydrogen atom (changing the chemical bond).

[0048] [ka]

[0049] [ka]

[0050] The protonation energies of the NH bonds (NH protonation energies) in these chemical calculation model molecules were calculated by DFT calculations using Gaussian 16W (a product of Gaussian) and B3LYP (functional) / 6-31+G(d) (basis function). The calculation times and calculated NH protonation energies are shown in the upper part of Table 1 below as relative values ​​(index values) with the calculation time and value of Control Example A set to 100.

[0051] Example 2 N-(tert-butyl)-2-benzothiazolesulfenamide (CAS No. 95-31-8) having the structure represented by the following formula (7) was used as a molecule (Comparative Example B) having a hetero-fused ring formed by fusing a six-membered ring with a five-membered ring containing one or more heteroatoms and one or more double bonds in the ring skeleton.

[0052] [ka]

[0053] Then, a heteromonocyclic unit was created in which the six-membered benzene ring was removed from the heterofused ring of this molecule, and the five-membered ring retained all of the constituent atoms and chemical bonds of the ring skeleton. Two methyl groups at the terminals of the substituents added to the heterofused ring of the molecule were removed and replaced with hydrogen atoms at the same positions as in the molecule above (carbon atoms adjacent to both the nitrogen atom and the sulfur atom), and hydrogen atoms were added to the other positions, creating a chemical calculation model molecule No. 8 with the structure represented by the following formula (8).

[0054] [ka]

[0055] Furthermore, the substituents added to the heterofused ring of the molecule of Comparative Example B were added to the above heteromonocyclic unit as they were, and hydrogen atoms were added to the other attachment positions to create chemical calculation model molecule No. 9 with a structure represented by the following formula (9). In addition, chemical calculation model molecule No. 10 with a structure represented by the following formula (10) was also created by adding to the heterofused ring of the molecule of Comparative Example B a substituent in which all three terminal methyl groups of the substituents added to the heterofused ring of the molecule were replaced with hydrogen atoms.

[0056] [ka]

[0057] [ka]

[0058] The NS bond cleavage energies (NS bond energies) in these chemical calculation model molecules were calculated by DFT calculations using Gaussian 16W (a product of Gaussian) as a program and B3LYP (functional) / 6-31+G(d) (basis function), as in Example 1. The calculation times and calculated NS bond energies are shown in the lower part of Table 1 below as relative values ​​(index values) when the calculation time and value for Control Example B are set to 100.

[0059] [Table 1]

[0060] From these results, chemical calculation model molecule No. 4, in which a heteromonocyclic unit was created by removing the six-membered ring from the heterofused ring of control A and retaining all of the constituent atoms and chemical bonds of the five-membered ring, and a chemical calculation model molecule was created that included this heteromonocyclic unit and had 60% of the total number of atoms constituting the molecule of control A; and chemical calculation model molecule No. 8, in which a heteromonocyclic unit was created by removing the six-membered ring from the heterofused ring of control B and retaining all of the constituent atoms and chemical bonds of the five-membered ring, and a chemical calculation model molecule was created that included this heteromonocyclic unit and had 59% of the total number of atoms constituting the molecule of control B, both showed a significant reduction in calculation time for the above energies to less than 20% of the control examples, and the accuracy was maintained at approximately the same level. In addition, in chemical calculation model molecule No. 6, in which the double bond of the five-membered ring in chemical calculation model molecule No. 4 was changed to a single bond, that is, a heteromonocyclic unit was created by removing the six-membered ring from the heterofused ring of control example A and retaining the constituent atoms of the ring skeleton of the five-membered ring, and a chemical calculation model molecule was created that included this and had a fewer number of atoms than the total number of atoms that constitute the molecule of control example A; and in chemical calculation model molecule No. 9, in which the six-membered ring was removed from the heterofused ring of control example B and a heteromonocyclic unit was created by retaining the constituent atoms and chemical bonds of the ring skeleton of the five-membered ring, and a chemical calculation model molecule was created that included this and had a fewer number of atoms than the total number of atoms that constitute the molecule of control example B, the calculation time for the above energy was reduced to about 50 to 70% of that of the control examples, and the accuracy was relatively maintained. On the other hand, at least in the case of chemical calculation model molecule No. 10 in which the six-membered ring of the hetero-fused ring of Comparative Example B was not removed, it was clearly impossible to achieve both the reduction in calculation time for the above energy and the maintenance of accuracy.

Claims

1. A method for creating a chemical calculation model molecule of a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, comprising: a step of preparing a heteromonocyclic unit, which is a unit in which the six-membered ring is removed from the heterofused ring contained in the molecule and the constituent atoms of the ring skeleton of the cyclic structure are maintained; and creating the chemical calculation model molecule that includes the heteromonocyclic unit and is composed of fewer atoms than the total number of atoms that constitute the molecule. How to create chemical computational model molecules.

2. the step of preparing the heteromonocyclic unit is a step of preparing the heteromonocyclic unit having 50 to 70% of the total number of atoms constituting the heterofused ring, the step of creating the chemical calculation model molecule is a step of creating the chemical calculation model molecule composed of 50 to 70% of the total number of atoms constituting the molecule; The method for creating a chemical computational model molecule according to claim 1 .

3. 3. The method for creating a chemical computational model molecule according to claim 1, wherein the heteromonocyclic unit is a unit in which the six-membered ring is removed from the heterofused ring and the ring structure retains all of the constituent atoms and chemical bonds of the ring skeleton.

4. 3. The method for creating a chemical calculation model molecule according to claim 1 or 2, wherein the step of creating the chemical calculation model molecule is a step of creating a structure added to the heteromonocyclic unit of the chemical calculation model molecule so that the structure is composed of fewer atoms than the total number of atoms constituting the structure added to the heterofused ring of the molecule.

5. 3. The method for creating a chemical computational model molecule according to claim 1, wherein the heteroatom is a sulfur atom and / or a nitrogen atom.

6. 3. The method for creating a chemical computational model molecule according to claim 1 or 2, wherein the cyclic structure and the heteromonocyclic unit constituting the heterofused ring of the molecule are five-membered rings containing one or more heteroatoms and one or more double bonds in the ring skeleton.

7. 3. The method for creating a chemical computation model molecule according to claim 1, wherein the six-membered ring constituting the hetero-fused ring of the molecule is a benzene ring.

8. 3. The method for creating a chemical computational model molecule according to claim 1, wherein the hetero-fused ring of the molecule is a benzothiazole ring.

9. A method for calculating chemical reaction energy of one or more sites in a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, comprising:

3. A method for producing a chemical calculation model molecule according to claim 1, further comprising the step of calculating the chemical reaction energy by ab initio molecular orbital method using the chemical calculation model molecule produced by the method for producing a chemical calculation model molecule according to claim 1 or 2. How to calculate the chemical reaction energy of a molecule.

10. A program that causes a computer to execute a chemical reaction energy calculation for a molecule having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, the program comprising: A process of creating a chemical calculation model molecule of the molecule by the method for creating a chemical calculation model molecule according to claim 1 or 2 in the computer; a calculation process for calculating chemical reaction energy of one or more sites in the molecule by ab initio molecular orbital method using the chemical calculation model molecule; A program for calculating molecular chemical reaction energy.

11. A method for selecting a vulcanization accelerator for a diene rubber component from a group of molecules having a hetero-fused ring formed by fusing a six-membered ring with a cyclic structure containing one or more heteroatoms and one or more double bonds in the ring skeleton, comprising: Calculating chemical reaction energy of one or more sites in the molecule by ab initio molecular orbital method using chemical calculation model molecules of the plurality of molecules included in the group, which are created by the method for creating a chemical calculation model molecule according to claim 1 or 2; and comparing the calculated chemical reaction energies to select a vulcanization accelerator for the diene rubber component from the plurality of molecules. Method for selecting vulcanization accelerators for diene rubber components.

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