Process for the preparation of imidazoline derivatives and use thereof

Abstract

The application discloses a preparation method of imidazoline derivatives, mainly using organic amine compounds and fatty acids as raw materials to prepare imidazoline derivative intermediates, using hydrocarbon substituent aromatic sulfonic acid and phosphorus oxychloride as raw materials to prepare aryl sulfonic acid chloride, further reacting the imidazoline derivative intermediates and the aryl sulfonic acid chloride, removing by-products through vacuum distillation to obtain the imidazoline derivatives; and the application also discloses application of the imidazoline derivatives as rust-proof agents in industrial oil products. The imidazoline derivatives obtained through the preparation method have good oil solubility, no acid value, excellent rust-proof performance, and can be widely applied to gear oil, turbine oil, ash-free hydraulic oil, rust-proof oil and other industrial oil products as rust-proof agents.

Description

Preparation methods and applications of imidazoline derivatives Technical Field

[0001] This invention belongs to the field of lubricating oil additive technology, specifically relating to a method for preparing an imidazoline derivative, and also relating to the application of the imidazoline derivative. Background Technology

[0002] Imidazoline derivatives are widely used due to their excellent rust-preventive properties and low toxicity. However, heterocyclic rust inhibitors such as imidazolines have poor solubility in base oils. Therefore, imidazoline derivatives used as rust inhibitors in lubricating oils are often prepared using long-chain fatty acids to increase their oil solubility. However, as the saturated hydrocarbon content in the base oil increases, the solubility decreases. Therefore, the solubility of imidazoline derivatives deteriorates in Group II and Group III base oils, resulting in a decrease in the rust-preventive performance of the oil.

[0003] Chinese patent "A Gemini Imidazoline Corrosion Inhibitor and Its Preparation Method" (Publication No.: CN111574453A, Application Date: 20190219, Publication Date: 20200825) discloses a bicyclic imidazoline rust inhibitor prepared from triethylenetetramine and long-chain fatty acids. Although this rust inhibitor has excellent rust-preventing performance, its solubility in Group II and Group III base oils is poor due to the lack of oil-soluble modification. Chinese patent "A Preparation Method of a High-Efficiency Imidazoline Rust Inhibitor and Its Combined Application" (Publication No.: CN11) Patent application 3698350A (application date: 20210701, publication date: 20211126) discloses a method for modifying imidazoline with dodecenyl succinic anhydride to enhance its oil solubility. However, while solving the oil solubility problem of imidazoline derivatives, this method introduces a structure with an acid value. Since organic carboxylic acids compete with extreme pressure anti-wear agents and other additives for adsorption during application, and also negatively impact the demulsification and antioxidant properties of oils, the introduction of an acid value undoubtedly limits its application as a rust inhibitor. Therefore, providing an imidazoline derivative with good oil solubility and no acid value, enabling its widespread application as a rust inhibitor in industrial oils, is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing imidazoline derivatives. The imidazoline derivatives prepared by this method have good oil solubility, no acid value, and excellent rust-preventive properties.

[0005] Another object of the present invention is to provide the application of the above-mentioned imidazoline derivatives as rust inhibitors in industrial oils.

[0006] The technical solution adopted in this invention is a method for preparing imidazoline derivatives, specifically including the following steps:

[0007] Step 1: Add organic amine compounds to the reactor, turn on the stirrer and heat to 140℃~160℃, add fatty acids dropwise and react for 1h~3h, continue to heat to 200℃~240℃ and react for 4h~8h, and the imidazoline derivative intermediate is obtained when the reaction is completed.

[0008] Step 2: Add hydrocarbon-substituted aromatic sulfonic acid and phosphorus oxychloride to the reactor, heat to 170℃~190℃ to react and generate aromatic sulfonyl chloride, then cool to 120℃~140℃ and add solvent and imidazoline derivative intermediate obtained in step 1 to the reactor to react for 2h~5h. After the reaction is completed, remove solvent and by-products by vacuum distillation to obtain imidazoline derivative.

[0009] Another technical solution adopted in this invention is the application of imidazoline derivatives as rust inhibitors in industrial oils.

[0010] The invention is further characterized in that,

[0011] In step 1, the molar ratio of fatty acids to organic amine compounds is 0.8 to 1.05:1.

[0012] The organic amine compound is one of diethylenetriamine, triethylenetetraamine, and tetraethylenepentamine, and the fatty acid is oleic acid.

[0013] The structure of the imidazoline derivative intermediate in step 1 is shown in formula (1):

[0014]

[0015] In the formula, R1 is Where n is 0 to 2; R2 is an aliphatic hydrocarbon group of C11 to C17.

[0016] In step 2, the molar ratio of the imidazoline derivative intermediate to the hydrocarbon-substituted aromatic sulfonic acid is 1:1.

[0017] Hydrocarbon-substituted aromatic sulfonic acids are one of hydrocarbon-substituted benzene sulfonic acids and hydrocarbon-substituted naphthalene sulfonic acids.

[0018] The hydrocarbon-substituted benzenesulfonic acid is one of the long-chain alkylbenzenesulfonic acids with alkyl carbon chains of C12, C18, C20, C22, C24 or C20-24, and the hydrocarbon-substituted naphthalenesulfonic acid is dinonylnaphthalenesulfonic acid.

[0019] The general structural formula of imidazoline derivatives is one of formula (2) or formula (3):

[0020]

[0021] In the formula, R1 is Where n is 0 to 2; R2 is an aliphatic hydrocarbon group of C11 to C17; and R3 is a long-chain alkyl group of C12, C18, C20, C22, C24, or C20-24.

[0022] The solvent in step 2 is xylene.

[0023] The beneficial effects of this invention are that the preparation method of the imidazoline derivative of this invention can improve oil solubility without introducing organic acid functional groups, thereby making the prepared imidazoline derivative have good oil solubility and no acid value, and have excellent rust prevention properties. In addition, the imidazoline derivative also has extreme pressure anti-wear properties, and can be widely used as a rust inhibitor in industrial oils such as gear oil, turbine oil, and ashless hydraulic oil. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments.

[0025] The method for preparing the imidazoline derivative of the present invention specifically includes the following steps:

[0026] Step 1: Add the organic amine compound to the reactor, turn on the stirrer and heat to 140℃~160℃, add fatty acids dropwise and react for 1h~3h, continue to heat to 200℃~240℃ and react for 4h~8h. After the reaction is complete, the imidazoline derivative intermediate is obtained, and its structure is shown in formula (1):

[0027]

[0028] In the formula, R1 is Where n is 0 to 2; R2 is an aliphatic hydrocarbon group of C11 to C17.

[0029] The molar ratio of fatty acids to organic amines is 0.8–1.05:1, the organic amines are one of diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, and the fatty acid is oleic acid.

[0030] Step 2: Add hydrocarbon-substituted aromatic sulfonic acid and phosphorus oxychloride to the reactor, heat to 170℃~190℃ to react and generate aromatic sulfonyl chloride, then cool to 120℃~140℃ and add xylene solvent and the imidazoline derivative intermediate obtained in step 1 to the reactor to react for 2h~5h. After the reaction is completed, remove the solvent and by-products by vacuum distillation to obtain the imidazoline derivative.

[0031] The molar ratio of the imidazoline derivative intermediate to the hydrocarbon-substituted aromatic sulfonic acid is 1:1.

[0032] The hydrocarbon-substituted aromatic sulfonic acid is one of hydrocarbon-substituted benzene sulfonic acid or hydrocarbon-substituted naphthalene sulfonic acid, wherein the hydrocarbon-substituted benzene sulfonic acid is one of long-chain alkylbenzene sulfonic acids with alkyl carbon chains of C12, C18, C20, C22, C24 or C20-24, and the hydrocarbon-substituted naphthalene sulfonic acid is dinonylnaphthalene sulfonic acid.

[0033] There are two types of imidazoline derivatives prepared by the above method, and their structures are shown in formula (2) and formula (3), respectively:

[0034]

[0035] In the formula, R1 is Where n is 0 to 2; R2 is an aliphatic hydrocarbon group of C11 to C17; and R3 is a long-chain alkyl group of C12, C18, C20, C22, C24, or C20-24.

[0036] In the above preparation process, an organic sulfonic acid is introduced to improve the oil solubility of the imidazoline derivative and reacts with the imidazoline derivative intermediate, so that the generated imidazoline derivative has no acid value and is widely used as a rust inhibitor in industrial oils such as gear oil, turbine oil, ashless hydraulic oil, and rust-preventive oil.

[0037] Example 1

[0038] The preparation method of the imidazoline derivative in this embodiment specifically includes the following steps:

[0039] Step 1: Add 146g of triethylenetetramine to a four-necked jacketed reaction flask equipped with a mechanical stirrer and a thermometer. Turn on the mechanical stirrer, heat to 160℃, and add 225g of oleic acid dropwise for 1 hour. Continue to heat to 240℃ and react for 4 hours. Once the reaction is complete, the imidazoline derivative intermediate is obtained. The molar ratio of oleic acid to triethylenetetramine is 0.8:1.

[0040] Step 2: Add 326g of dodecylbenzenesulfonic acid and 76.5g of phosphorus oxychloride to a four-necked jacketed reaction flask equipped with a mechanical stirrer and thermometer. Heat to 170℃ to generate arylsulfonyl chloride. Then cool to 140℃ and add 300g of xylene solvent and the imidazoline derivative intermediate obtained in Step 1 to the reaction flask. React for 5h. After the reaction is completed, remove the solvent and byproducts by vacuum distillation to obtain the imidazoline derivative, the structure of which is shown in formula (4):

[0041]

[0042] Example 2

[0043] The preparation method of the imidazoline derivative in this embodiment specifically includes the following steps:

[0044] Step 1: Add 103g of diethylenetriamine to a four-necked jacketed reaction flask equipped with a mechanical stirrer and a thermometer. Turn on the mechanical stirrer, heat to 150°C, and add 282g of oleic acid dropwise for 2 hours. Continue to heat to 220°C and react for 8 hours. Once the reaction is complete, the imidazoline derivative intermediate is obtained. The molar ratio of oleic acid to diethylenetriamine is 1:1.

[0045] Step 2: Add 410g of octadecylbenzenesulfonic acid and 76.5g of phosphorus oxychloride to a four-necked jacketed reaction flask equipped with a mechanical stirrer and thermometer. Heat to 180℃ to generate arylsulfonyl chloride. Then cool to 120℃ and add 380g of xylene solvent and the imidazoline derivative intermediate obtained in Step 1 to the reaction flask. React for 2 hours. After the reaction is completed, remove the solvent and byproducts by vacuum distillation to obtain the imidazoline derivative, the structure of which is shown in formula (5):

[0046]

[0047] Example 3

[0048] The preparation method of the imidazoline derivative in this embodiment specifically includes the following steps:

[0049] Step 1: Add 189g of tetraethylenepentamine to a four-necked jacketed reaction flask equipped with a mechanical stirrer and a thermometer. Turn on the mechanical stirrer, heat to 140℃, and add 296g of oleic acid dropwise for 3 hours. Continue to heat to 230℃ and react for 6 hours. Once the reaction is complete, the imidazoline derivative intermediate is obtained. The molar ratio of oleic acid to tetraethylenepentamine is 1.05:1.

[0050] Step 2: Add 460g of dinonylnaphthalenesulfonic acid and 76.5g of phosphorus oxychloride to a four-necked jacketed reaction flask equipped with a mechanical stirrer and thermometer. Heat to 190℃ to generate arylsulfonyl chloride. Then cool to 130℃ and add 420g of xylene solvent and the imidazoline derivative intermediate obtained in Step 1 to the reaction flask. React for 4h. After the reaction is completed, remove the solvent and byproducts by vacuum distillation to obtain the imidazoline derivative, the structure of which is shown in formula (6):

[0051]

[0052] Comparative Example 1

[0053] An imidazoline-type rust inhibitor was synthesized using the method disclosed in Chinese Patent "A Preparation Method and Combined Application of a High-Efficiency Imidazoline-Type Rust Inhibitor" (Publication No.: CN113698350A, Application Date: 20210701, Publication Date: 20211126), and compared with the imidazoline derivative of the present invention.

[0054] Comparative Example 2

[0055] A bicyclic imidazoline type rust inhibitor was synthesized using the method disclosed in Chinese Patent "A Gemini Imidazoline Corrosion Inhibitor and Its Preparation Method" (Publication No.: CN111574453A, Application Date: 20190219, Publication Date: 20200825), and its oil solubility was compared with that of the imidazoline derivative of the present invention.

[0056] Performance testing:

[0057] To further verify the oil solubility and rust-preventive properties of the imidazoline derivatives of this invention, the present invention uses existing technology, namely the methods of Comparative Examples 1 and 2, to synthesize imidazoline-type rust inhibitors, and compares their performance with that of the imidazoline derivative rust inhibitors prepared in Examples 1 and 3, as detailed below:

[0058] (1) The rust inhibitors prepared in Comparative Examples 1-2 and Examples 1-3 were added at 1% (mass fraction) to Group I base oil HVI150, Group II base oil HVIP8, Group III base oil VHVI10, and synthetic ester base oil Kunlun KE3028, and their solubility was investigated. The results are shown in Table 1. The table shows that the rust inhibitors prepared in Comparative Examples 1 and Examples 1-3 exhibited good oil solubility in all types of base oils. The rust inhibitor prepared in Comparative Example 2 showed good solubility in Group I base oils, but poor solubility in hydrogenated base oils and synthetic ester base oils.

[0059] Table 1. Solubility of Rust Inhibitors

[0060] Base Oil Comparison Example 1 Comparison Example 2 Example 1 Example 2 Example 3 HVI150 Clear Clear Clear Clear Clear Clear HVIP8 Clear Cloudy Clear Clear Clear Clear VHVI10 Clear Cloudy Clear Clear Clear Clear KE3068 Clear Cloudy Clear Clear Clear Clear surface

[0061] (2) The imidazoline derivatives prepared in Comparative Examples 1-2 and Examples 1-3 were added to HVI150 base oil at 0.1% (mass fraction), and their rust-preventive performance was examined by liquid phase corrosion (GB / T 11143 (B method)). The results are shown in Table 2. The table shows that the rust inhibitor prepared in Comparative Example 1 has a higher acid value and poorer rust-preventive performance, while the rust inhibitors prepared in Comparative Example 2 and Examples 1-3 have lower acid values ​​and significantly better rust-preventive performance than the rust inhibitor in Comparative Example 1.

[0062] Table 2. Physicochemical properties and rust-preventive performance of rust inhibitors

[0063] Comparative Example 1 | Comparative Example 2 | Example 1 | Example 2 | Example 3 | Acid Value (mg KOH / g) | 6 | 0.6 | 0.5 | 0.1 | 0.1 | 2 | 0.09 | Liquid Phase Corrosion | Heavy Rust | No Rust | No Rust | No Rust | No Rust surface

[0064] (3) Commercially available corrosion inhibitor T561 is a sulfur-containing additive with certain extreme pressure anti-wear properties. Therefore, T561, the rust inhibitors prepared in Comparative Examples 1-2 and Examples 1-3 were added to HVI500 base oil at 1.0% (mass fraction). Their extreme pressure anti-wear properties were examined using standard methods GB / T3142 and NB / SH / T0189. The results are shown in Table 3. As can be seen from the table, the products prepared in Examples 1-3 have comparable extreme pressure anti-wear properties to the commercially available product T561, and are significantly superior to the products prepared in Comparative Examples 1 and 2.

[0065] Table 3 Extreme Pressure Anti-wear Properties

[0066]

Claims

1. A method for preparing an imidazoline derivative, characterized in that, Specifically, the following steps are included: Step 1: Add organic amine compounds to the reactor, turn on the stirrer and heat to 140℃~160℃, add fatty acids dropwise and react for 1h~3h, continue to heat to 200℃~240℃ and react for 4h~8h, and the reaction is completed to obtain the imidazoline derivative intermediate; Step 2: Add hydrocarbon-substituted aromatic sulfonic acid to the reactor and add phosphorus oxychloride, heat to 170℃~190℃ to react to generate aromatic sulfonyl chloride, then cool to 120℃~140℃ and add the solvent and the imidazoline derivative intermediate obtained in Step 1 to the reactor and react for 2h~5h, and after the reaction is completed, remove the solvent and by-products by vacuum distillation to obtain the imidazoline derivative; The molar ratio of fatty acid to organic amine compounds in Step 1 is 0.8~1.05:1; The organic amine compounds are one of diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, and the fatty acid is oleic acid; The structure of the imidazoline derivative intermediate in Step 1 is shown in formula (1): In the formula, R1 is Where n is 0~2; R2 is a C11~C17 aliphatic hydrocarbon group; the molar ratio of the imidazoline derivative intermediate to the hydrocarbon-substituted aromatic sulfonic acid in step 2 is 1:1; the hydrocarbon-substituted aromatic sulfonic acid is one of hydrocarbon-substituted benzenesulfonic acid and hydrocarbon-substituted naphthalenesulfonic acid; the hydrocarbon-substituted benzenesulfonic acid is one of long-chain alkylbenzenesulfonic acid with alkyl carbon chain C12, C18 or C20-24, and the hydrocarbon-substituted naphthalenesulfonic acid is dinonylnaphthalenesulfonic acid; the general structural formula of the imidazoline derivative is one of formula (2) or formula (3): In the formula, R1 is Where n is 0~2; R2 is a C11~C17 aliphatic hydrocarbon group; R3 is a long-chain alkyl group of C12, C18, C20, C22, C24, or C20-24; and the solvent in step 2 is xylene.

2. The application of an imidazoline derivative prepared as claimed in claim 1 as a rust inhibitor in industrial oils.

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