A novel rust preventive and a method for its preparation and use thereof

Abstract

This disclosure relates to a novel rust inhibitor, its preparation method, and its uses. The novel rust inhibitor comprises a cyclic dicarboxylic acid monoester compound having the structure shown in formula (I), wherein n and m are each independently selected from any integer from 0 to 3; y is selected from any integer from 0 to 12; and R1 is selected from substituted or unsubstituted C1-C1 compounds. 40 The alkyl group; the substituent in R1 is selected from C1-C4 straight-chain alkyl groups or branched alkyl groups; R2 is selected from -CH2-, -CH2CH2-, -CH(CH3)CH2- or -CH2CH(CH3)-; R3 is, where A is selected from saturated or unsaturated C4-C6 carbocyclic subunits or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4. Adding the cyclic dicarboxylic acid monoester compound prepared according to this disclosure to base oil can effectively improve the rust-preventive properties of the base oil. Formula (I).

Description

Technical Field

[0001] This disclosure relates to the field of rust inhibitor technology, specifically to a novel rust inhibitor, its preparation method, and its uses. Background Technology

[0002] Using rust-preventive oil to protect metal products is one of the most economical and efficient methods of rust prevention. Rust-preventive oil is a product composed of base oil, rust inhibitor, and other additives. Rust inhibitor, as an additive that enhances the rust-preventive performance, can effectively improve the rust-preventive effect of lubricating oil on metals.

[0003] Saturated hydrocarbon components in mineral oil inhibit the activity of the dicarboxylic acid type rust inhibitor dodecenylsuccinic acid (T746). However, rust inhibitor T746 has drawbacks such as high acid value, lower flash point, increased kinematic viscosity, and disruption of interfacial tension. Dodecenylsuccinic acid half-ester (T747) effectively improves the acid value of oil, with an acid value only half that of dodecenylsuccinic acid, effectively improving the corrosion problem of turbine oil. However, both dodecenylsuccinic acid and dodecenylsuccinic acid half-ester are produced from dodecenylsuccinic anhydride (DDSA), which is produced from blended gasoline (or tetrapropylene), resulting in high energy consumption, numerous byproducts, and complex production processes.

[0004] Therefore, it is urgent to solve the problem of poor rust prevention performance of existing metal rust inhibitors, and at the same time, it is also necessary to solve the problems of high energy consumption, many by-products, and complex production processes of existing technologies. Summary of the Invention

[0005] To address the aforementioned technical problems, the purpose of this disclosure is to further improve the rust-preventive performance of oil-based rust inhibitors.

[0006] To achieve the above objectives, in a first aspect, this disclosure provides a novel rust inhibitor comprising a cyclic dicarboxylic acid monoester compound having a structure as shown in formula (I): Equation (I); Where n and m are each independently selected from any integer between 0 and 3; y is any integer selected from 0 to 12; R1 is selected from substituted or unsubstituted C1-C. 40 The substituents in R1 are selected from C1-C4 straight-chain hydrocarbon groups or branched hydrocarbon groups; R2 is selected from -CH2-, -CH2CH2-, -CH(CH3)CH2-, or -CH2CH(CH3)-; R3 is Wherein, A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4.

[0007] Optionally, n and m are each independently selected from 0 or 1; y is selected from any integer from 0 to 6; R1 is selected from substituted or unsubstituted C1-C. 18 hydrocarbon group; A is selected from saturated or unsaturated C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from C1-C 10 Hydrocarbon group.

[0008] Optionally, y is selected from any integer from 1 to 3; R1 is selected from substituted or unsubstituted C1-C. 10 hydrocarbon group; R2 is selected from -CH2- or -CH2CH2-; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from C1-C5 hydrocarbon groups.

[0009] Optionally, when A is selected from saturated or unsaturated C4-C6 carbocyclic subunits, R3 is... The cyclic dicarboxylic acid monoester compound has the structure shown in formula (Ⅳ): Formula (Ⅳ); In equation (Ⅳ), a is selected from any integer from 2 to 8, n and m are each independently selected from any integer from 0 to 3, x is selected from any integer from 0 to 8, and b1 and b2 are each independently selected from any integer from 0 to 2.

[0010] Optionally, the cyclic dicarboxylic acid monoester compound is selected from one or more of the following: 1,2-cyclopentadicarboxylic acid monoester, 1,2-cyclohexanedicarboxylic acid monoester, tetrahydrophthalic acid monoester, phthalic acid monoester, hexahydrophthalic acid monoester, methylhexahydrophthalic acid monoester, methyltetrahydrophthalic acid monoester, terephthalic acid monoester, 1-methyl-1,2-cyclohexanedicarboxylic acid monoester, 4-methyl-1,2-cyclohexanedicarboxylic acid monoester, 3-methyl-1,2-cyclohexanedicarboxylic acid monoester, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester, and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester.

[0011] Optionally, the cyclic dicarboxylic acid monoester compound is selected from one or more of 1,2-cyclohexanedicarboxylic acid monoester, tetrahydrophthalic acid monoester, phthalic acid monoester, hexahydrophthalic acid monoester, methylhexahydrophthalic acid monoester, and methyltetrahydrophthalic acid monoester.

[0012] Secondly, this disclosure provides a method for preparing a novel rust inhibitor, the method comprising: mixing a dicarboxylic acid or its anhydride with an alcohol, an alcohol ether or a phenol and then reacting the mixture; Wherein, the dicarboxylic acid or its anhydride has the structure shown in formula (II), and the alcohol, alcohol ether or phenol has the structure shown in formula (III); Formula (II); Formula (Ⅲ); Where n and m are each independently selected from any integer between 0 and 3; y is any integer selected from 0 to 12; R1 is selected from substituted or unsubstituted C1-C. 40 The substituents in R1 are selected from C1-C4 straight-chain hydrocarbon groups or branched hydrocarbon groups; R2 is selected from methylene, ethylene, or isopropylene; R3 is Wherein, A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4.

[0013] Optionally, the molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether or phenol is 1:(0.1-5), preferably 1:(0.5-3), and more preferably 1:(0.8-1.5).

[0014] Optionally, the reaction conditions include: a reaction temperature of 10-300℃ and a reaction time of 0.1-20h; preferably, a reaction temperature of 20-250℃ and a reaction time of 0.1-15h; more preferably, a reaction temperature of 20-200℃ and a reaction time of 0.1-6h.

[0015] Optionally, a catalyst and / or solvent may also be added to the reaction; The catalyst is selected from one or more of the following: acid catalyst, ionic liquid catalyst, inorganic salt solid-phase catalyst, molecular sieve catalyst, heteropolyacid catalyst, solid superacid catalyst and base catalyst. The solvent is selected from hydrocarbon compounds or mixtures of hydrocarbons.

[0016] Optionally, the dicarboxylic acid or its anhydride has 5-20 carbon atoms, preferably 5-18 carbon atoms, and more preferably 5-15 carbon atoms; optionally, the dicarboxylic acid or its anhydride is selected from 1,2-cyclopentadicarboxylic acid, 1,3-cyclopentadicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanediacetic acid, phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, 1-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, and 1,2-cyclopropanedicarboxylic anhydride. One or more of the following: 1,2-cyclopentadicarboxylic anhydride, 1,3-cyclopentadicarboxylic anhydride, phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, 1,1-cyclohexanediacetic anhydride, tetra-3,4,5,6-tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, 4-methyltetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 1-methyl-1,2-cyclohexanedicarboxylic anhydride, 3-methyl-1,2-cyclohexanedicarboxylic anhydride, 4-methyl-1,2-cyclohexanedicarboxylic anhydride, and methylhexahydrophthalic anhydride.

[0017] Optionally, the alcohol, alcohol ether, or phenol has 1-40 carbon atoms, preferably 1-30 carbon atoms, and more preferably 1-25 carbon atoms; optionally, the alcohol is selected from one or more of monohydric alcohols, fatty alcohols, alicyclic alcohols, and aromatic alcohols.

[0018] Thirdly, this disclosure provides a method for improving the corrosion resistance of metals, the method comprising adding the novel rust inhibitor described in the first aspect to a base oil, or adding the novel rust inhibitor prepared by the method described in the second aspect to a base oil.

[0019] Optionally, the amount of the novel rust inhibitor added is 5-500 μg, preferably 10-200 μg, relative to 1g of the base oil.

[0020] Optionally, the base oil is selected from one or more of gasoline, kerosene, diesel, and lubricating oil.

[0021] Fourthly, this disclosure provides the use of the novel rust inhibitor described in the first aspect, or the novel rust inhibitor prepared by the method described in the second aspect, in the preparation of cetane number improvers, low-temperature flow improvers, anti-wear agents, and corrosion inhibitors.

[0022] By using the above technical solution, adding the cyclic dicarboxylic acid monoester compound prepared in this disclosure to base oil can effectively improve the rust-preventive properties of the base oil. Moreover, only a small amount is needed to achieve a significant improvement in the rust-preventive properties of the base oil. Furthermore, the raw materials for preparing the cyclic dicarboxylic acid monoester compound are readily available, the reaction conditions are mild, and it has advantages such as low energy consumption and a simple preparation method.

[0023] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is the mass spectrum of the novel ring-structured high-efficiency rust inhibitor product prepared in Example 2.

[0025] Figure 2 This is the infrared spectrum of the novel ring-structured high-efficiency rust inhibitor product from Example 2.

[0026] Figure 3 The images show the corrosion test results of metal rods using the rust inhibitor prepared in Example 2 and the rust inhibitor in Comparative Example 1. Detailed Implementation

[0027] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] In a first aspect, this disclosure provides a novel rust inhibitor comprising a cyclic dicarboxylic acid monoester compound having a structure as shown in formula (I): Equation (I); Where n and m are each independently selected from any integer between 0 and 3; y is any integer selected from 0 to 12; R1 is selected from substituted or unsubstituted C1-C. 40The substituents in R1 are selected from C1-C4 straight-chain hydrocarbon groups or branched hydrocarbon groups; R2 is selected from -CH2-, -CH2CH2-, -CH(CH3)CH2-, or -CH2CH(CH3)-; R3 is Wherein, A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4.

[0030] In this disclosure, n and m are each independently selected from any integer from 0 to 3, where n and m may be the same or different; n may be selected from 0, 1, 2 or 3, and m may be selected from 0, 1, 2 or 3. y is selected from any integer from 0 to 12, where y may be selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0031] In this disclosure, the hydrocarbon group can be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, etc.; wherein, the aliphatic hydrocarbon group can be a straight-chain aliphatic hydrocarbon group or a branched aliphatic hydrocarbon group; or, the aliphatic hydrocarbon group can be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group; the unsaturated aliphatic hydrocarbon group can be an aliphatic hydrocarbon group containing at least one carbon-carbon double bond (alkene bond) or at least one carbon-carbon triple bond (alkynyl bond). The alicyclic hydrocarbon group can be a saturated alicyclic hydrocarbon group (cycloalkanes) or an unsaturated alicyclic hydrocarbon group. The aromatic hydrocarbon group can be a monocyclic aromatic hydrocarbon group or a bicyclic or polycyclic aromatic hydrocarbon group. The rings of the alicyclic hydrocarbon group and the aromatic hydrocarbon group can also have various substituents.

[0032] Among them, substituted or unsubstituted C1-C 40 The alkyl group refers to a substituted or unsubstituted alkyl group with a total number of 1 to 40 carbon atoms; for example, the total number of carbon atoms can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 24, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40. The substituent can be selected from C1-C4 straight-chain alkyl groups or branched alkyl groups, which refer to straight-chain alkyl groups or branched alkyl groups with 1 to 4 carbon atoms, for example, the number of carbon atoms can be 1, 2, 3, or 4.

[0033] In this disclosure, Represents a connecting bond. A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Selected from C1-C4 alkyl groups. Saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits refer to those with 4-6 carbon atoms in the ring, i.e., 4-6 carbon atoms forming the ring. For example, the number of carbon atoms forming the ring can be 4, 5, or 6. Carbocyclic subunits indicate that all atoms in the ring are carbon atoms, while heterocyclic subunits indicate that the atoms in the ring include both carbon atoms and heteroatoms. The heteroatoms can be one or more of, for example, N, O, and S.

[0034] Among them, C1-C 25 The hydrocarbon group refers to a hydrocarbon group with 1 to 25 carbon atoms; for example, the number of carbon atoms can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25.

[0035] Among them, C1-C4 alkyl refers to alkyl with 1 to 4 carbon atoms, for example, the number of carbon atoms can be 1, 2, 3 or 4; C1-C4 alkyl can be methyl, ethyl, n-propyl or isopropyl.

[0036] In a preferred embodiment of this disclosure, n and m are each independently selected from 0 or 1; y is selected from any integer from 0 to 6; R1 is selected from substituted or unsubstituted C1-C 18 The hydrocarbon group; A is selected from saturated or unsaturated C6 carbocyclic subunits or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from C1-C 10 The hydrocarbon group. In the above embodiments, R2 is selected from -CH2-, -CH2CH2-, -CH(CH3)CH2- or -CH2CH(CH3)-.

[0037] In another preferred embodiment of this disclosure, y is selected from any integer from 1 to 3; R1 is selected from substituted or unsubstituted C1-C. 10 The hydrocarbon group; R2 is selected from -CH2- or -CH2CH2-; R 31 Whether R exists or not, when R 31 When it exists, R 31 Hydrocarbon groups selected from C1-C5. In the above embodiments, n and m are each independently selected from 0 or 1.

[0038] Specifically, when A is selected from saturated or unsaturated C4-C6 carbocyclic subunits, R3 can be... At this point, the cyclic dicarboxylic acid monoester compound described in this disclosure is as shown in structural formula (Ⅳ): Formula (Ⅳ); In equation (Ⅳ), a is selected from any integer from 2 to 8, n and m are each independently selected from any integer from 0 to 3, x is selected from any integer from 0 to 8, and b1 and b2 are each independently selected from any integer from 0 to 2.

[0039] Preferably, in formula (Ⅳ), a is selected from any integer from 2 to 6, n and m are each independently selected from 0 or 1, x is selected from any integer from 0 to 6, and b1 and b2 are each independently selected from any integer from 0 to 2.

[0040] More preferably, in formula (Ⅳ), a is selected from 4 or 5, n and m are each independently 0, x is selected from any integer from 0 to 6, and b1 and b2 are each independently selected from 0 or 1.

[0041] Specifically, when a is 4, x is 0, b1 and b2 are 1, and m and n are 0, the structural formula (Ⅳ) is 1,2-cyclohexanedicarboxylic acid monoester.

[0042] When a is 4, x is 2, b1 and b2 are 1, and m and n are 0, the structural formula (Ⅳ) is 4-cyclohexene-1,2-dicarboxylic acid monoester (tetrahydrophthalic acid monoester).

[0043] When a is 4, x is 4, b1 and b2 are 0, and m and n are 0, the structural formula (Ⅳ) is a phthalic acid monoester.

[0044] When a is 4, x is 6, b1 and b2 are 1, and m and n are 0, structure (Ⅳ) is a monoterephthalic acid ester.

[0045] When a is 5, x is 0, b1 and b2 are 1, and m and n are 0, the structural formula (Ⅳ) is 3-methyl-1,2-cyclohexanedicarboxylic acid monoester (3-methylhexahydrophthalic acid monoester), 4-methyl-1,2-cyclohexanedicarboxylic acid monoester (4-methylhexahydrophthalic acid monoester), methylhexahydrophthalic acid monoester, etc.

[0046] When a is 5, x is 2, b1 and b2 are 1, and m and n are 0, the structural formula (Ⅳ) is methyltetrahydrophthalic acid monoester, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester, etc.

[0047] In one specific embodiment of this disclosure, the cyclic dicarboxylic acid monoester compound is selected from one or more of the following: 1,2-cyclopentadicarboxylic acid monoester, 1,2-cyclohexanedicarboxylic acid monoester, tetrahydrophthalic acid monoester, phthalic acid monoester, hexahydrophthalic acid monoester, methylhexahydrophthalic acid monoester, methyltetrahydrophthalic acid monoester, terephthalic acid monoester, 1-methyl-1,2-cyclohexanedicarboxylic acid monoester, 4-methyl-1,2-cyclohexanedicarboxylic acid monoester, 3-methyl-1,2-cyclohexanedicarboxylic acid monoester, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester, and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester.

[0048] Preferably, the cyclic dicarboxylic acid monoester compound is selected from one or more of 1,2-cyclohexanedicarboxylic acid monoester, tetrahydrophthalic acid monoester, phthalic acid monoester, hexahydrophthalic acid monoester, methylhexahydrophthalic acid monoester, and methyltetrahydrophthalic acid monoester.

[0049] In the above embodiments, "monoester" can be any one or more of methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, tert-butyl ester, pentyl ester, isoamyl ester, n-hexyl ester, n-heptyl ester, n-octyl ester, isoononyl ester, isoundecanyl ester, isotridecyl ester, ethylene glycol monomethyl ether ester, ethylene glycol monobutyl ether ester, ethylene glycol monotert-butyl ether ester, diethylene glycol monomethyl ether ester, diethylene glycol monobutyl ether ester, propylene glycol monomethyl ether ester, propylene glycol monobutyl ether ester, and dipropylene glycol monomethyl ether ester.

[0050] Secondly, this disclosure provides a method for preparing a novel rust inhibitor, the method comprising: mixing a dicarboxylic acid or its anhydride with an alcohol, an alcohol ether or a phenol and then reacting the mixture; Wherein, the dicarboxylic acid or its anhydride has the structure shown in formula (II), and the alcohol, alcohol ether or phenol has the structure shown in formula (III); Formula (II); Formula (Ⅲ); Where n and m are each independently selected from any integer between 0 and 3; y is any integer selected from 0 to 12; R1 is selected from substituted or unsubstituted C1-C. 40 The substituents in R1 are selected from C1-C4 straight-chain hydrocarbon groups or branched hydrocarbon groups; R2 is selected from methylene, ethylene, or isopropylene; R3 is Wherein, A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4.

[0051] In this disclosure, the raw materials for preparing cyclic dicarboxylic acid monoester compounds are readily available, the reaction conditions are mild, and it has the advantages of low energy consumption and simple preparation method.

[0052] In this disclosure, nitrogen gas can be introduced before the reaction to remove moisture and protect the reactants from oxidation.

[0053] In one embodiment of this disclosure, the molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether or phenol is 1:(0.1-5), preferably 1:(0.5-3), and more preferably 1:(0.8-1.5).

[0054] In one embodiment of this disclosure, the reaction conditions include: a reaction temperature of 10-300°C and a reaction time of 0.1-20 h; preferably, a reaction temperature of 20-250°C and a reaction time of 0.1-15 h; more preferably, a reaction temperature of 20-200°C and a reaction time of 0.1-6 h.

[0055] In one embodiment of this disclosure, a catalyst and / or solvent are also added to the reaction; The catalyst is selected from one or more of the following: acid catalyst, ionic liquid catalyst, inorganic salt solid-phase catalyst, molecular sieve catalyst, heteropolyacid catalyst, solid superacid catalyst and base catalyst. The solvent is selected from hydrocarbon compounds or mixtures of hydrocarbons.

[0056] In the above embodiments, the acid catalyst can be selected from one or more of sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, phosphoric acid, boric acid, and acidic ion exchange resins. Ionic liquid catalysts can include, for example, 1-butylpyridine / AlCl4 ionic liquid; inorganic salt solid-phase catalysts can include, for example, FeCl3 and / or AlCl3; molecular sieve catalysts can be selected from one or more of ZSM-5, HZSM-5, and Al-MCM-41; heteropolyacid catalysts can include, for example, PW12 / MCM-41 and / or SiW12 / MCM-41; and solid superacid catalysts can include, for example, SO4. 2- / ZrO2-TiO2, etc.; alkaline catalysts may include, for example, NaOH, KOH, sodium methoxide, solid superbase, NaH, etc. A solvent may or may not be added during the reaction; solvents may include, for example, alkanes, aromatics, petroleum ethers, gasoline, toluene, xylene, etc.

[0057] In one embodiment of this disclosure, the dicarboxylic acid or its anhydride has 5-20 carbon atoms, preferably 5-18, and more preferably 5-15; the alcohol, alcohol ether, or phenol has 1-40 carbon atoms, preferably 1-30, and more preferably 1-25. Even more preferably, the alcohol, alcohol ether, or phenol has 4-18 carbon atoms.

[0058] Wherein, the dicarboxylic acid or its anhydride is selected from C5-C 18 The cyclic dicarboxylic acid or its anhydride, alcohol, alcohol ether or phenol is selected from C1-C1. 30 When the dicarboxylic acid or its anhydride is an alcohol, alcohol ether, or phenol, the molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether, or phenol is 1:(0.5-3), and the reaction conditions include: a reaction temperature of 20-250℃ and a reaction time of 0.1-15 h. Preferably, the dicarboxylic acid or its anhydride is selected from C5-C6. 15 The cyclic dicarboxylic acid or its anhydride, alcohol, alcohol ether or phenol is selected from C1-C1. 25 When reacting with alcohols, alcohol ethers, or phenols, the molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether, or phenol is 1:(0.5-2), and the reaction conditions include: a reaction temperature of 20-200℃ and a reaction time of 0.1-6h.

[0059] In a preferred embodiment of this disclosure, in the absence of a catalyst and solvent, the number of carbon atoms in the dicarboxylic acid or its anhydride is preferably 5-12, and the number of carbon atoms in the alcohol, alcohol ether, or phenol is preferably 1-18; wherein, the dicarboxylic acid or its anhydride is preferably a cyclic anhydride, and the alcohol, alcohol ether, or phenol is preferably an alcohol or phenol; the molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether, or phenol is 1:(0.8-1.3), and the reaction conditions include: a reaction temperature of 20-180℃ and a reaction time of 0.5-10h.

[0060] In another preferred embodiment of this disclosure, with or without a catalyst and with or without a solvent, the dicarboxylic acid or its anhydride preferably has 5-12 carbon atoms, and the alcohol, alcohol ether, or phenol preferably has 1-18 carbon atoms; wherein, the dicarboxylic acid or its anhydride is preferably a cyclic dicarboxylic acid, and the alcohol, alcohol ether, or phenol is preferably an alcohol or phenol; the molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether, or phenol is 1:(0.8-1.3), and the reaction conditions include: a reaction temperature of 50-250°C and a reaction time of 1-6 h. Further, the reaction also includes reacting a cyclic dicarboxylic acid with 5-12 carbon atoms with sufficient or excess alcohol or phenol with 1-18 carbon atoms, specifically, the molar ratio of the cyclic dicarboxylic acid to the alcohol or phenol is 1:(0.8-1.3), and the reaction conditions include: a reaction temperature of 80-200°C and a reaction time of 3-15 h.

[0061] In this disclosure, under conditions containing a catalyst and / or solvent, the catalyst and / or solvent are removed after the reaction, and the resulting product can be used as a rust inhibitor. The product can also be separated and purified according to the rust inhibitor product standard requirements, for example, by removing the solvent and unreacted raw materials. Solvents and unreacted raw materials that meet the standard requirements do not affect the performance of the rust inhibitor of this invention. The removal of the catalyst, solvent, or unreacted raw materials can be carried out using methods conventional in the art, such as vacuum distillation.

[0062] In one embodiment of this disclosure, the dicarboxylic acid or its anhydride may be selected from 1,2-cyclopentadicarboxylic acid, 1,3-cyclopentadicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, 1-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, 1,2-cyclopropanedicarboxylic anhydride, 1,2-cyclopentadicarboxylic anhydride, 1,3-cyclopentadicarboxylic anhydride, phthalic anhydride, hexahydrophthalic anhydride (1,2-cyclohexanedicarboxylic anhydride, CAS... 85-42-7), methyl hexahydrophthalic anhydride, 1,1-cyclohexanediacetic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, 4-methyltetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 1-methyl-1,2-cyclohexanedicarboxylic anhydride, 3-methyl-1,2-cyclohexanedicarboxylic anhydride, 4-methyl-1,2-cyclohexanedicarboxylic anhydride, and methyl hexahydrophthalic anhydride, one or more of these.

[0063] Preferably, the dicarboxylic acid or its anhydride may be selected from one or more of 1,2-cyclohexanedicarboxylic acid, phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, 1-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, hexahydrophthalic anhydride (1,2-cyclohexanedicarboxylic anhydride, CAS 85-42-7), tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, 1-methyl-1,2-cyclohexanedicarboxylic anhydride, 3-methyl-1,2-cyclohexanedicarboxylic anhydride, and 4-methyl-1,2-cyclohexanedicarboxylic anhydride.

[0064] In one embodiment of this disclosure, the alcohol is selected from one or more of monohydric alcohols, fatty alcohols, alicyclic alcohols, and aromatic alcohols.

[0065] In a preferred embodiment of this disclosure, when the alcohol is an aliphatic alcohol, it can have 1-30 carbon atoms, preferably 1-18; when the alcohol is an alicyclic alcohol, it can have 3-30 carbon atoms, preferably 4-18; when the alcohol is an aromatic alcohol, it can have 7-30 carbon atoms, preferably 8-18. When an alcohol ether is selected, it can have 3-30 carbon atoms, preferably 4-18. When a phenol is selected, it can have 6-30 carbon atoms, preferably 7-18.

[0066] In this disclosure, the monohydric alcohol can be selected from primary, secondary, or tertiary alcohols. The fatty alcohol can be a saturated fatty alcohol, an unsaturated enol; it can also be a normal fatty alcohol or an isomeric fatty alcohol. The alicyclic alcohol can be a saturated alicyclic alcohol or an unsaturated alicyclic alcohol; wherein the unsaturated alicyclic alcohol may have a carbon-carbon double bond. The hydroxyl group of the alcohol can be attached to a ring or to a cyclic aliphatic chain.

[0067] Preferably, the saturated fatty alcohol can be selected from n-butanol, sec-butanol, n-pentanol, various isomeric pentanol, n-hexanol, various isomeric hexanol, n-heptanol, various isomeric heptanol, n-octanol, various isomeric octanol, n-nonanol, various isomeric nonanol, n-decanol, various isomeric decanol, various isomeric undecanol, lauryl alcohol, n-tridecanol, various isomeric tridecanol, n-tetradecanool, n-hexadecanool, n-octadecanol, etc.

[0068] Preferably, the unsaturated fatty alcohol can be selected from 2-buten-1-ol, 3-buten-1-ol, isopentenol, 3-hexen-1-ol, 1-hepten-3-ol, methylheptenol, 2-octen-1-ol, 3-nonen-1-ol, 2-decen-1-ol, 7-dodecen-1-ol, 1,5-hexadienol, 2,4-nonadien-1-ol, 2,4-decadien-1-ol, 9,11-dodecadienol, oleyl alcohol, etc.

[0069] Preferably, the alicyclic alcohol can be selected from cyclobutanol, cyclopentanol, cyclohexanol, 3-cyclopenten-1-ol, 2-cyclohexenol, 3-cyclohexen-1-methanol, etc.

[0070] Preferably, the aromatic alcohol can be selected from benzyl alcohol, phenylethanol, phenylpropanol, phenylbutanol, 8-phenyl-1-octanol, 1-phenyl-1-propanol, 1-phenyl-1-butanol, 1-phenyl-1-octanol, etc.

[0071] Preferably, the alcohol ether can be selected from ethylene glycol monomethyl ether (2-methoxyethanol), ethylene glycol monobutyl ether (2-butoxyethanol), ethylene glycol monotert-butyl ether, diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol), diethylene glycol monobutyl ether, propylene glycol monomethyl ether (1-methoxy-2-propanol), propylene glycol monobutyl ether, dipropylene glycol monomethyl ether (methoxydipropylene glycol), etc., and especially preferred are ethylene glycol monomethyl ether (2-methoxyethanol), ethylene glycol monobutyl ether (2-butoxyethanol), diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol), propylene glycol monomethyl ether (1-methoxy-2-propanol), and dipropylene glycol monomethyl ether (methoxydipropylene glycol).

[0072] Preferably, the phenol can be selected from propionic acid, butylphenol, pentylphenol, heptaphenol, octylphenol, nonylphenol, decylphenol, dodecylphenol, etc., and especially preferred are p-nonylphenol and p-dodecylphenol.

[0073] More preferably, the alcohol, alcohol ether, or phenol may be selected from methanol, ethanol, propanol, n-butanol, sec-butanol, isoamyl alcohol, cyclohexanol, 3-cyclohexene-1-methanol, benzyl alcohol, isooctyl alcohol, isononanol, decyl alcohol, isodecanol, lauryl alcohol, oleyl alcohol, ethylene glycol monomethyl ether (2-methoxyethanol), ethylene glycol monobutyl ether (2-butoxyethanol), diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol), propylene glycol monomethyl ether (1-methoxy-2-propanol), dipropylene glycol monomethyl ether (methoxydipropylene glycol), nonylphenol, and various isomeric alcohols obtained by polymerization of ethylene, propylene, or butene, such as isononanol, isoundecanol, and isotridecyl alcohol.

[0074] Thirdly, this disclosure provides a method for improving the corrosion resistance of metals, the method comprising adding the novel rust inhibitor described in the first aspect to a base oil, or adding the novel rust inhibitor prepared by the method described in the second aspect to a base oil to form a composition.

[0075] The inventors of this disclosure have discovered that adding the cyclic dicarboxylic acid monoester compound prepared in this disclosure to base oil can effectively improve the rust prevention performance of the base oil. This is because the protective film formed by the adsorption of polar groups on the metal surface isolates water molecules from direct contact with the metal surface, thereby effectively preventing rust on the metal surface.

[0076] Adding only a small amount to the base oil can significantly improve its rust-preventive properties. In one embodiment of this disclosure, the amount of the novel rust inhibitor added is 5-500 μg, preferably 10-200 μg, relative to 1g of the base oil.

[0077] In one embodiment of this disclosure, the base oil is selected from one or more of gasoline, kerosene, diesel oil, and lubricating oil.

[0078] Fourthly, this disclosure provides the use of the novel rust inhibitor described in the first aspect, or the novel rust inhibitor prepared by the method described in the second aspect, in the preparation of cetane number improvers, low-temperature flow improvers, anti-wear agents, and corrosion inhibitors.

[0079] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereto. Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present disclosure were all purchased commercially.

[0080] Example 1 100g of 1,2-cyclohexanedicarboxylic acid (95% purity, Shanghai Yuanye Biotechnology Co., Ltd.) was placed in a 250mL reactor equipped with an electric stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube. 77g of isoamyl alcohol (99% purity, Shanghai Maclean Biochemical Technology Co., Ltd.) and 0.5g of p-toluenesulfonic acid (99% purity, Shanghai Aladdin Biochemical Technology Co., Ltd.) were added. Nitrogen gas was introduced for 10min, and the mixture was stirred at a constant temperature of 80℃ for 12h. The molar ratio of 1,2-cyclohexanedicarboxylic acid to isoamyl alcohol was 1:1.5. Unreacted reactants were removed by vacuum distillation to obtain a novel cyclic high-efficiency rust inhibitor, cyclohexane-1,2-diacid monoisoamyl ester. Gas chromatography analysis showed that the content of the main product, cyclohexane-1,2-diacid monoisoamyl ester, was 85.3%.

[0081] Example 2 100g of methylhexahydrophthalic anhydride (98% purity, methyl isomer mixture, Shanghai Maclean Biochemical Technology Co., Ltd.) was placed in a 250mL reactor equipped with an electric stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube. 84g of ethylene glycol monobutyl ether (2-butoxyethanol, 99% purity, Shanghai Maclean Biochemical Technology Co., Ltd.) was added. Nitrogen gas was introduced for 10min, and the mixture was stirred at a constant temperature of 120℃ for 6h. The molar ratio of methylhexahydrophthalic anhydride to ethylene glycol monobutyl ether was 1:1.2. Unreacted reactants were removed by vacuum distillation to obtain a novel cyclic high-efficiency rust inhibitor product, methylhexahydrophthalic acid monoethylene glycol monobutyl ether ester. Chromatographic analysis showed that the content of the main product, methylhexahydrophthalic acid monoethylene glycol monobutyl ether ester, was 87.9%.

[0082] The reaction formula for this embodiment is as follows:

[0083] like Figure 1 As shown, Figure 1 This is the mass spectrum of the novel cyclic structure high-efficiency rust inhibitor product prepared in Example 2; where m / z=309.2 is the sodium ion mass spectrometry addition peak of the novel cyclic structure high-efficiency rust inhibitor product prepared in Example 2, which corresponds to the methyl hexahydrophthalic acid monoethylene glycol butyl ether ester product.

[0084] like Figure 2 As shown, Figure 2 This is the infrared spectrum of the novel ring-shaped high-efficiency rust inhibitor product from Example 2; the wavenumber is 3200~2500 cm⁻¹. -1 The peaks are broad and diffuse, and the peak length is 1455 cm⁻¹. -1 The characteristic peak at 1741 cm⁻¹ belongs to the carboxyl stretching vibration peak; -1 The peak at 867 cm⁻¹ belongs to the stretching vibration of the carbonyl oxygen (C=O) of the ester group. -1 and 973cm -1 The peak corresponds to the bending vibration of the ether bond (COC). Since the product molecule contains both ester-ether oxygen bonds and ether bonds, the peak range is 1301–1035 cm⁻¹. -1 The stretching vibration peaks belonging to the ester group ether oxygen bond and ether bond (COC) show divergence and overlap; wavenumber 2925 cm⁻¹ -1 and 2852cm -1 The peaks are attributed to the stretching vibrations of the methylene (-CH2-) and methyl (-CH3) groups in the molecular structure.

[0085] Example 3 100g of methylhexahydrophthalic anhydride (98% purity, methyl isomer mixture, Shanghai Maclean Biochemical Technology Co., Ltd.) was placed in a 250mL reactor equipped with an electric stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube. 81g of diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol, 99% purity, Aladdin Biochemical Technology Co., Ltd.) was added. The molar ratio of methylhexahydrophthalic anhydride to diethylene glycol monomethyl ether was approximately 1:1.13. The mixture was stirred at a constant temperature of 85℃ for 6 hours. Unreacted reactants were removed by vacuum distillation to obtain a novel cyclic structure high-efficiency rust inhibitor product, methylhexahydrophthalic acid mono(diethylene glycol monomethyl ether) ester. Gas chromatography analysis showed that the content of the main product, methylhexahydrophthalic acid mono(diethylene glycol monomethyl ether) ester, was 79.4%.

[0086] Example 4 100g of methylhexahydrophthalic anhydride (98% purity, methyl isomer mixture, Shanghai Maclean Biochemical Technology Co., Ltd.) was placed in a 250mL reactor equipped with an electric stirrer, thermometer, water separator, reflux condenser and nitrogen inlet tube. 83.8g of isooctanol (99.5% purity, Shanghai Maclean Biochemical Technology Co., Ltd.) was added. The molar ratio of methylhexahydrophthalic anhydride to isooctanol was approximately 1:1.1. The mixture was stirred at a constant temperature of 95℃ and reacted for 5 hours. Unreacted reactants were removed by vacuum distillation to obtain a novel cyclic structure high-efficiency rust inhibitor product, methylhexahydrophthalic acid monoisooctyl ester. Gas chromatography analysis showed that the content of the main product, methylhexahydrophthalic acid monoisooctyl ester, was 88.6%.

[0087] Example 5 100g of methyltetrahydrophthalic anhydride (98% purity, methyl isomer mixture, Shanghai Maclean Biochemical Technology Co., Ltd.) was placed in a 250mL reactor equipped with an electric stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube. 53.8g of ethylene glycol monomethyl ether (2-methoxyethanol, 99% purity, Shanghai Maclean Biochemical Technology Co., Ltd.) was added. The molar ratio of methyltetrahydrophthalic anhydride to ethylene glycol monomethyl ether was 1:1.2. The mixture was stirred at a constant temperature of 80℃ for 6 hours. Unreacted reactants were removed by vacuum distillation to obtain a novel cyclic structure high-efficiency rust inhibitor. Gas chromatography analysis showed that the main product, methyltetrahydrophthalic acid mono(ethylene glycol monomethyl ether) ester, had a content of 90.9%.

[0088] Comparative Example 1 Industrial rust inhibitor T747 (Jinzhou Xinxing Petroleum Additives Co., Ltd.)

[0089] Test Example 1 This test example illustrates the testing of rust prevention performance.

[0090] The rust inhibitor products of the examples and comparative examples were tested for rust prevention performance. The specific test method was GB / T11143—2008 "Test Method for Rust Prevention Performance of Mineral Oils with Added Inhibitors in the Presence of Water". The specific steps were as follows: 300 mL of sample and 30 mL of synthetic seawater were mixed, and the cylindrical test steel rod was completely immersed in the mixture. The mixture was stirred at 60°C for 24 hours. At the end of the test, the rust marks and the degree of rust on the test steel rod were observed.

[0091] The test results are shown in Table 1 and Figure 3 As shown, Figure 3 In the figures, I represents a rust test metal rod containing diesel fuel with the rust inhibitor from Example 2 (20 μg / g), and II represents a rust test metal rod containing diesel fuel with the rust inhibitor from Comparative Example 1 (20 μg / g). The blank diesel fuel was No. 10 automotive diesel fuel conforming to GB 19147-2016 and purchased from Yanshan Petrochemical Branch of China Petroleum & Chemical Corporation.

[0092] Table 1

[0093] Note: Rust levels: a is no rust, b is light rust, c is medium rust, and d is heavy rust.

[0094] From Table 1 and Figure 3 It can be seen that the rust inhibitor prepared in this disclosure can effectively improve the rust prevention performance of base oil, and only a small amount needs to be added to the base oil to achieve a significant improvement in the rust prevention performance of the base oil.

[0095] Test Example 2 This test case illustrates the liquidity advantages of the embodiments.

[0096] The kinematic viscosity and pour point of the example products and the comparative products were tested. The kinematic viscosity was measured at 100°C according to the GB / T 265 method, and the pour point was measured according to the GB / T 510 method. The results are shown in Table 2. Table 2

[0097] As shown in Table 2, the kinematic viscosity of the rust inhibitors prepared in Examples 1-5 is much lower than that of Comparative Example 1, which is viscous like honey at room temperature. Therefore, the rust inhibitors prepared in Examples 1-5 are more convenient to store, transport, and add to compared with the rust inhibitor prepared in Comparative Example 1. The pour point results show that the pour point of the rust inhibitors prepared in Examples 1-5 is much lower than that of the rust inhibitor prepared in Comparative Example 1. Therefore, the rust inhibitors disclosed herein are more convenient for storage, transportation, and addition at low temperatures in winter, and are also more suitable for oils with low pour points or low freezing points.

[0098] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0099] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0100] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A novel rust inhibitor, characterized in that, The novel rust inhibitor comprises a cyclic dicarboxylic acid monoester compound having a structure as shown in formula (I): Equation (I); Where n and m are each independently selected from any integer between 0 and 3; y is any integer selected from 0 to 12; R1 is selected from substituted or unsubstituted C1-C. 40 The substituents in R1 are selected from C1-C4 straight-chain hydrocarbon groups or branched hydrocarbon groups; R2 is selected from -CH2-, -CH2CH2-, -CH(CH3)CH2-, or -CH2CH(CH3)-; R3 is Wherein, A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4.

2. The novel rust inhibitor according to claim 1, wherein, n and m are each independently selected from 0 or 1; y is selected from any integer from 0 to 6; R1 is selected from substituted or unsubstituted C1-C. 18 hydrocarbon group; A is selected from saturated or unsaturated C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from C1-C 10 Hydrocarbon group.

3. The novel rust inhibitor according to claim 2, wherein, y is any integer from 1 to 3; R1 is selected from substituted or unsubstituted C1-C. 10 hydrocarbon group; R2 is selected from -CH2- or -CH2CH2-; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from C1-C5 hydrocarbon groups.

4. The novel rust inhibitor according to claim 3, wherein, When A is selected from a saturated or unsaturated C4-C6 carbocyclic subunit, R3 is... The cyclic dicarboxylic acid monoester compound has the structure shown in formula (Ⅳ): Formula (Ⅳ); Where a is any integer from 2 to 8, n and m are each independently selected from any integer from 0 to 3, x is any integer from 0 to 8, and b1 and b2 are each independently selected from any integer from 0 to 2.

5. The novel rust inhibitor according to claim 4, wherein, The cyclic dicarboxylic acid monoester compound is selected from one or more of the following: 1,2-cyclopentadicarboxylic acid monoester, 1,2-cyclohexanedicarboxylic acid monoester, tetrahydrophthalic acid monoester, phthalic acid monoester, hexahydrophthalic acid monoester, methylhexahydrophthalic acid monoester, methyltetrahydrophthalic acid monoester, terephthalic acid monoester, 1-methyl-1,2-cyclohexanedicarboxylic acid monoester, 4-methyl-1,2-cyclohexanedicarboxylic acid monoester, 3-methyl-1,2-cyclohexanedicarboxylic acid monoester, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester, and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid monoester.

6. The novel rust inhibitor according to claim 5, wherein, The cyclic dicarboxylic acid monoester compound is selected from one or more of 1,2-cyclohexanedicarboxylic acid monoester, tetrahydrophthalic acid monoester, phthalic acid monoester, hexahydrophthalic acid monoester, methylhexahydrophthalic acid monoester, and methyltetrahydrophthalic acid monoester.

7. A method for preparing a novel rust inhibitor, characterized in that, The method includes: reacting a dicarboxylic acid or its anhydride with an alcohol, alcohol ether or phenol; Wherein, the dicarboxylic acid or its anhydride has the structure shown in formula (II), and the alcohol, alcohol ether or phenol has the structure shown in formula (III); Formula (II); Formula (Ⅲ); Where n and m are each independently selected from any integer between 0 and 3; y is any integer selected from 0 to 12; R1 is selected from substituted or unsubstituted C1-C. 40 The substituents in R1 are selected from C1-C4 straight-chain hydrocarbon groups or branched hydrocarbon groups; R2 is selected from methylene, ethylene, or isopropylene; R3 is Wherein, A is selected from saturated or unsaturated C4-C6 carbocyclic or heterocyclic subunits; R 31 Whether R exists or not, when R 31 When it exists, R 31 Selected from H, C1-C 25 hydrocarbon group or -COOR 311 R 311 Alkyl groups selected from C1-C4.

8. The method according to claim 7, wherein, The molar ratio of the dicarboxylic acid or its anhydride to the alcohol, alcohol ether or phenol is 1:(0.1-5), preferably 1:(0.5-3), and more preferably 1:(0.8-1.5).

9. The method according to claim 7, wherein, The reaction conditions include: a reaction temperature of 10-300℃ and a reaction time of 0.1-20h; preferably, a reaction temperature of 20-250℃ and a reaction time of 0.1-15h; more preferably, a reaction temperature of 20-200℃ and a reaction time of 0.1-6h.

10. The method according to claim 7, wherein, The reaction also includes the addition of a catalyst and / or solvent; The catalyst is selected from one or more of the following: acid catalysts, ionic liquid catalysts, inorganic salt solid-phase catalysts, molecular sieve catalysts, heteropolyacid catalysts, solid superacid catalysts, and base catalysts. The solvent is selected from hydrocarbon compounds or mixtures of hydrocarbons.

11. The method according to claim 8, wherein, The dicarboxylic acid or its anhydride has 5-20 carbon atoms, preferably 5-18 carbon atoms, and more preferably 5-15 carbon atoms; Optionally, the dicarboxylic acid or its anhydride is selected from 1,2-cyclopentadicarboxylic acid, 1,3-cyclopentadicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanediacetic acid, phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, 1-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, 1,2-cyclopropanedicarboxylic anhydride, 1,2-cyclopentadicarboxylic anhydride, 1,3-cyclopentadicarboxylic anhydride, phthalic acid, etc. One or more of the following: dicarboxylic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, 1,1-cyclohexanediacetic anhydride, tetra-3,4,5,6-tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, 4-methyltetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 1-methyl-1,2-cyclohexanediacetic anhydride, 3-methyl-1,2-cyclohexanediacetic anhydride, 4-methyl-1,2-cyclohexanediacetic anhydride, and methylhexahydrophthalic anhydride.

12. The method according to claim 8, wherein, The alcohol, alcohol ether, or phenol has 1-40 carbon atoms, preferably 1-30 carbon atoms, and more preferably 1-25 carbon atoms; Optionally, the alcohol is selected from one or more of monohydric alcohols, fatty alcohols, alicyclic alcohols, and aromatic alcohols.

13. A method for improving metal corrosion resistance, characterized in that, The method includes adding the novel rust inhibitor of any one of claims 1-6 to the base oil, or adding the novel rust inhibitor prepared by the method of any one of claims 7-12 to the base oil.

14. The method according to claim 13, wherein, The amount of the novel rust inhibitor added is 5-500 μg, preferably 10-200 μg, relative to 1g of the base oil.

15. The method according to claim 13, wherein, The base oil is selected from one or more of gasoline, kerosene, diesel, and lubricating oil.

16. Use of the novel rust inhibitor according to any one of claims 1-6, or the novel rust inhibitor prepared by the method according to any one of claims 7-12, in the preparation of cetane number improvers, low-temperature flow improvers, anti-wear agents, and corrosion inhibitors.

Images