CN111378516A - Organic friction modifier with different isomeric alkyl end chains and preparation method thereof - Google Patents

Abstract

The invention discloses an organic friction modifier with different isomeric alkyl end chains and a preparation method thereof. Use p-hydroxybenzoic acid and hydroquinone to carry out esterification reaction to obtain intermediate product A, and intermediate product A is respectively subjected to esterification reaction with different Guerbet acids to obtain the compound of formula (I). This series of phenyl terephthalate compounds with different isomeric alkyl end chains are synthesized from three benzene rings connected by ester groups and long-chain Guerbet acid. The synergistic effect of the oil solubility of the alkyl group and the rigidity of the benzene ring of the compound itself makes this series of compounds suitable for lubricating oil ester additives.

Description

Organic friction modifier with different isomeric alkyl end chains and preparation method thereof

technical field

The invention belongs to the technical field of lubricants, and in particular relates to an organic friction modifier with different isomeric alkyl end chains and a preparation method thereof.

Background technique

Lubricating grease is widely used in various fields of industry, and improving the performance of lubricating grease is of great significance for saving energy, raw materials and prolonging the service life of machinery. Lubricating grease is generally composed of base oil and additives, and additives are divided into several types, such as detergents, dispersants, antioxidants, anti-corrosion agents, extreme pressure anti-wear agents, friction modifiers, etc. Among them, friction modifiers have been applied and upgraded for many years, from initially limited to industrial applications such as gear oil, automatic transmission fluid, and rail oil, and gradually developed to civil fields such as vehicle oil, marine oil, and aviation oil. The friction modifier can help the grease to form a firm oil film between the surfaces of the friction pair, avoid direct contact between the surfaces of the friction pair, reduce the friction coefficient in the mixed lubrication and boundary lubrication state, and meet the working conditions of the static to dynamic transition. , protect the mechanical equipment from friction damage, and can reduce noise, reduce friction heat and reduce starting torque, so it is more and more widely valued by lubrication professionals. Common friction modifiers include various carboxylic acids and their derivatives, amides, imides, amines and their derivatives, phosphorus and phosphoric acid derivatives, organic polymers and organometallic compounds, which are found in internal combustion engine oils. A class of products that are widely used in the industry, such compounds include molybdenum dialkyldithiocarbamate (MoDTC), molybdenum dialkyldithiophosphoramidate, organic molybdenum mixture, etc. With the improvement of environmental protection requirements, friction modifiers containing sulfur and phosphorus are gradually restricted, and environmentally friendly organic friction modifiers that do not contain metals, sulfur and phosphorus are more and more favored by users.

Currently commonly used organic friction modifiers include long-chain fatty amines, glycerol monooleate, butyl oleate, trimellitate and other organic products containing amine ester groups. The main function is to pass the polar groups contained in them. An oil film is adsorbed on the surface of the friction pair to provide lubrication. Studies have shown that friction modifiers mainly work in boundary lubrication and mixed lubrication conditions, while further research shows that organic friction modifiers work best in mixed lubrication conditions. The patent JP2011046938A applied by Chevron Japan Company provides a bis-type alkenyl substituted succinimide and its derivatives as friction modifiers for automatic transmission oil, and the new friction modifier can effectively improve the friction performance of automatic transmission devices. The patent US2014121142A1 applied by Chevron Oronite USA provides a friction modifier synthesized by using alkylated aromatic ether alcohol, boric acid and polyol, which can obtain more excellent anti-wear performance when used as a passenger car engine oil. Patent US2016068780A1 filed by Dow Company provides a lubricant composition in which an oil-soluble polyoxybutylene polymer can act as a highly active friction modifier. The patent US2016264907A1 applied by Croda Corporation of the United States provides a lubricant composition comprising a hydroxycarboxylic acid derivative friction modifier, which can improve the anti-wear and friction-reducing ability of engine oil, hydraulic oil, gear oil and metal working fluid. For organic friction modifiers, due to their good friction improvement properties and biodegradability, it will become a key direction for future lubricating grease research and development.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an organic friction modifier with different isomeric alkyl end chains and a preparation method thereof. This series of compounds have good anti-friction and anti-wear properties when used as lubricating grease additives.

The technical scheme that the present invention adopts for realizing the above-mentioned purpose is as follows:

An organic friction modifier with different isomeric alkyl end chains, the structure of which is shown in formula (I),

Among them, n=2～10, m=2～10.

As a preferred embodiment, n=3-6, m=3-6.

As a preferred embodiment, the structure of the organic friction modifier is shown in compounds B1-B5,

The present invention also provides the preparation method of the described organic friction modifier with different isomeric alkyl end chains, comprising the following steps:

Step 1, using p-hydroxybenzoic acid and hydroquinone to carry out esterification reaction to obtain the intermediate product A shown in formula (II);

In step 2, the intermediate product A is esterified with different Guerbet acids to obtain the compound of formula (I).

As a preferred embodiment, the catalyst used in the step (1) is one or more of sulfuric acid, p-toluenesulfonic acid, cation exchange resin, solid super acid, and molecular sieve.

As a preferred embodiment, the solvent in the step (1) is selected from toluene, xylene, chloroform, carbon tetrachloride or methyltetrahydrofuran, and the reaction temperature is raised from room temperature to reflux, and the reaction is performed for 6-24 hours.

As a preferred embodiment, the catalyst used in the step (2) is 4-dimethylaminopyridine, and the condensing agent used is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride Or dicyclohexylcarbodiimide; the solvent is one or more of dichloromethane, dimethylformamide or dioxane, the reaction temperature is 0-40° C., and the reaction time is 24-48 hours.

As a preferred embodiment, the step (2) can also be directly condensed by refluxing toluene or xylene, and the catalyst used is one or more of sulfuric acid, p-toluenesulfonic acid, cation exchange resin, solid superacid, and molecular sieves , the reaction temperature is from room temperature to reflux, and the reaction is carried out for 6 to 48 hours.

The preparation method of organic friction modifiers (B1-B5) with different isomeric alkyl end chains specifically comprises the following steps:

(1) 2 parts of p-hydroxybenzoic acid and 1 part of hydroquinone are mixed in solvent toluene, and under the action of a catalyst, a rigid core intermediate A having three benzene ring structures and containing active phenolic hydroxyl groups is prepared. Wherein the catalyst is sulfuric acid, p-toluenesulfonic acid, cation exchange resin, solid super acid, molecular sieve, etc., stirring at high speed, the reaction temperature is from room temperature to reflux, and the reaction is completed in 6 to 24 hours. After removing the solvent, the obtained product is purified by recrystallization from methanol or ethanol, and a high-quality intermediate A can be obtained.

(2) Mixing 1 part of the rigid core intermediate A obtained with 2 parts of different Guerbet acids (G1-G5) in dichloromethane, and esterification occurs under the action of a condensing agent and a catalyst to obtain a series of The preparation route of the phenyl terephthalate friction modifiers (B1-B5) with different isomeric alkyl end chains is shown in formula (III). The used condensing agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, the catalyst is 4-dimethylaminopyridine, the reaction temperature is 0～40℃, and the reaction time is 24～48 hours; the obtained products (B1-B5) are purified by recrystallization with methanol or ethanol at 50-70°C.

The present invention also provides the application of the organic friction modifier with different isomeric alkyl end chains as the friction modifier of lubricating grease.

The present invention also provides the application of the organic friction modifier with different isomeric alkyl end chains as lubricants.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. The phenyl terephthalate compounds with different isomeric alkyl end chains designed by the present invention have the following characteristics from the molecular structure, so that they can be effectively used in lubricants: (1) have a large number of polar groups Make it easy to adsorb on the metal surface. (2) It has two long isomerized alkyl side chains, which can provide good oil solubility. (3) A rigid core unit with three benzene rings, which is easy to form an oil film layer in the lubricating oil, promotes surface contact lubrication, and provides a certain bearing capacity.

2. From the microscopic observation, the molecules of this group of compounds exhibit a certain lamellar structure, and the combination of rigid benzene rings in the core makes it easier to fit various friction surfaces, including damaged surfaces, which is helpful for the formation of films on the surfaces of friction pairs. ability.

3. In terms of physical properties, this group of compounds has a long isomerized branched chain structure, and has strong low temperature dissolving ability; its boiling point and decomposition temperature are high, and it can be used at a higher temperature.

4. From the perspective of additive components, the compound contains no sulfur and phosphorus, no metal components, four ester-based structures are easy to biodegrade, and it has a certain high-temperature decomposition ability, so it is an environmentally friendly additive.

To sum up, this series of phenyl terephthalate compounds with different isomeric alkyl end chains are synthesized from three benzene rings connected by ester groups and long-chain Guerbet acid, and the polar ester groups contained are synthesized. The synergistic effect of various aspects makes this series of compounds suitable for lubricating oil ester additives.

Description of drawings

Figure 1 is a schematic diagram of the melting points of the compounds B1-B5 of the series of formula (I) in the present invention.

Figure 2 is the infrared spectrum of the compounds B1-B5 of the formula (I) series of the present invention.

Figure 3 is a hydrogen nuclear magnetic spectrum of the compound B2 of the formula (I) series of the present invention.

Figures 4a-4b are the topography diagrams of wear scars obtained after the friction test of the UMT-tribolab universal friction tester in the present invention. Among them, Fig. 4a is the wear scar morphology of the second-class base oil 150n alone; Fig. 4b is the wear-spot morphology of the second-class base oil 150n with 1% compound B1 added.

Figure 5 is a scatter diagram of friction coefficients obtained by using UMT-tribolab universal friction tester to conduct friction experiments after dissolving the compounds B1-B5 of the series of molecular formula (I) in the second-class base oil for 150n at 75°C.

FIG. 6 is a schematic diagram of the wear scar depth measured by the second-class base oil 150n at different temperature points in the present invention and after adding 1% of the compounds B1-B5 of the formula (I) series to it respectively.

Detailed ways

The technical solutions of the present invention will be described in detail below with reference to the embodiments. The materials, reagents, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

The preparation of embodiment 1 compound B1

69g of p-hydroxybenzoic acid and 27.51g of hydroquinone were put into a 1000mL three-necked bottle, and 1g of catalyst p-toluenesulfonic acid and 450mL of solvent toluene were poured into the bottle. Install an oil-water separator above the three-necked bottle. The temperature was raised to 70°C, kept at a constant temperature for 30 minutes, then gradually heated to reflux, and reacted for 30h. After the reaction, the crude product was obtained by filtration. It was recrystallized with absolute ethanol to obtain the intermediate product Compound A, the yield was 85%, and the measured melting point was 340°C.

4 g of Guerbet acid G1 and 3.5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were placed in 100 mL of dichloromethane and magnetically stirred until completely dissolved. Subsequently, 2 g of triethylamine was dropped into the flask, 20 mL of dichloromethane was added, and the mixture was cooled to -20°C in an ice-salt bath. 2 g of the intermediate product A and 0.05 g of 4-dimethylaminopyridine were dissolved in 30 mL of dichloromethane, slowly added dropwise to the reaction system, the reaction was carried out for 24 hours, and then the reaction was raised to room temperature for 10 hours. After the reaction was completed, 3 mL of deionized water was added to the flask to quench the reaction. The reaction solution was extracted and washed with 1M hydrochloric acid solution, saturated sodium bicarbonate solution and saturated sodium chloride solution, respectively, and the organic layer was collected by rotary evaporation to remove the solvent to obtain the crude product. High-purity product B1 can be obtained by column chromatography with a yield of 62%. The reaction formula is shown in (IV).

The preparation of embodiment 2 compound B2

6 g of Guerbet acid G1 and 7.8 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were placed in 200 mL of dichloromethane and magnetically stirred until completely dissolved. Then, 5 g of triethylamine was dropped into the flask, 30 mL of dichloromethane was added, and the solution was cooled to -20°C in an ice-salt bath. 3.5 g of intermediate product A and 0.1 g of 4-dimethylaminopyridine were dissolved in 50 mL of dichloromethane, slowly added dropwise to the reaction system, the reaction was carried out for 24 hours, and then the reaction was raised to room temperature for 15 hours. After the reaction was completed, 3 mL of deionized water was added to the flask to quench the reaction. The reaction solution was extracted and washed with 1M hydrochloric acid solution, saturated sodium bicarbonate solution and saturated sodium chloride solution, respectively, and the organic layer was collected by rotary evaporation to remove the solvent to obtain the crude product. High-purity product B2 can be obtained by column chromatography with a yield of 70%. The reaction formula is shown in (V).

Organic friction modifiers B3-B5 were prepared using the same method as above.

Example 3 Structural identification of organic friction modifiers B1-B5

The prepared compounds B1-B5 were characterized by Fourier transform infrared spectroscopy, and the results were completely consistent with the chemical structures of the target compounds. The infrared spectral data were as follows:

B1: FT-IR(ATR) v _max /cm ^-1 : 2962–2871 (–CH ₃ ,–CH ₂ –), 1760-1735 (C=O), 1609, 1504 (Ar–), 1300-1060 ( CO).

B2: FT-IR(ATR) v _max /cm ^-1 : 2965–2876 (–CH ₃ ,–CH ₂ –), 1761-1731 (C=O), 1611, 1503 (Ar–), 1305-1061 ( CO).

B3: FT-IR(ATR) v _max /cm ^-1 : 2970–2880 (–CH ₃ ,–CH ₂ –), 1761-1732 (C=O), 1603, 1501 (Ar–), 1302-1064 ( CO).

B4: FT-IR(ATR) v _max /cm ^-1 : 2962–2873 (–CH ₃ ,–CH ₂ –), 1765-1734 (C=O), 1601, 1505 (Ar–), 1301-1065 ( CO).

B5: FT-IR(ATR) v _max /cm ^-1 : 2970–2882(–CH ₃ ,–CH ₂ –), 1763-1730(C=O), 1606, 1503(Ar–), 1304-1067( CO).

The prepared compounds B1-B5 were characterized by ¹ H-NMR, and the results were completely consistent with the structure of the target compound. The 1 H-NMR data were as follows:

B1: ¹ H-NMR (500MHz, Chloroform-d) δ 8.24(d, J=8.8Hz, 4H), 7.28(s, 4H), 7.24(s, 4H), 2.63(s, 2H), 1.97– 0.75(m,36H).

B2: ¹ H-NMR (500 MHz, Chloroform-d) δ 8.24 (d, J=8.8 Hz, 4H), 7.28 (s, 4H), 7.23 (d, J=8.8 Hz, 4H), 2.61 (s, 2H), 1.86–0.83 (m, 43H).

B3: ¹ H-NMR (500 MHz, Chloroform-d) δ 8.24 (d, J=8.8 Hz, 4H), 7.28 (s, 4H), 7.23 (d, J=8.8 Hz, 4H), 2.63 (s, 2H), 2.09–0.45 (m, 53H).

B4: ¹ H-NMR (500 MHz, Chloroform-d) δ 8.24 (d, J=8.7 Hz, 4H), 7.28 (s, 4H), 7.23 (d, J=8.7 Hz, 4H), 2.61 (s, 2H), 2.12–0.70 (m, 63H).

B5: ¹ H-NMR (500 MHz, Chloroform-d) δ 8.24 (d, J=2.0 Hz, 4H), 7.28 (s, 4H), 7.24-7.20 (m, 4H), 2.62 (d, J=8.9 Hz, 2H), 1.86–0.80 (m, 73H).

The prepared compounds B1-B5 were characterized by FT-IR and 1H-NMR, and they all conformed to the structural characteristics of the target product, which proved that the synthesized compounds B1-B5 of the series of formula (I) were consistent with the target molecular structure. Referring to Figures 1 to 3, Figure 1 is a schematic diagram of the melting points of the compounds B1-B5 of the series of formula (I) in the present invention. Figure 2 is the infrared spectrum of the compounds B1-B5 of the formula (I) series of the present invention. Fig. 3 is the hydrogen NMR spectrum of the compound B2 of the series of formula (I) in the present invention; the hydrogen NMR spectra of other compounds are similar, only the number of alkyl H between 0.5 and 2.0 ppm is different.

Embodiment 4 Lubrication performance detection of organic friction modifiers B1-B5

Referring to Figures 4a-4b, it is the topography of the wear scar obtained after the friction test of the UMT-tribolab universal friction tester in the present invention. Among them, Fig. 4a is the wear scar morphology of the second-class base oil 150n alone; Fig. 4b is the wear-spot morphology of the second-class base oil 150n with 1% compound B1 added. 4a and 4b, it can be clearly observed that the wear spot in Fig. 4b is smaller and the morphology is smoother than that in Fig. 4a. The experimental results show that even adding a small amount of this kind of additives can still play the role of reducing friction and anti-wear.

Referring to FIG. 5 , it is a scatter diagram of friction coefficients obtained by using UMT-tribolab universal friction testing machine to conduct friction experiments after dissolving the compounds B1-B5 of the series of molecular formula (I) at 75°C for 150 n of the second-class base oil. It can be seen from Figure 5 that adding 1% of (I) series compounds can significantly improve the friction coefficient and friction running-in period, and compounds B1 to B5 can greatly improve the antifriction performance of the base oil.

Figure 6 is a schematic diagram showing the depth of wear scars measured by the second-class base oil 150n at different temperature points in the present invention and after adding 1% of the compounds B1-B5 of the formula (I) series to it respectively. It can be seen from Figure 6 that at 75-150°C, adding compounds B1-B5 to the second-class base oil 150n can all play a role in reducing friction and anti-wear.

The organic friction modifiers B1~B5 were dissolved in the second-class base oil 150n, and the reciprocating module of the UMT-Tribolab friction and wear testing machine was used to test their anti-friction and anti-wear properties (frequency 2Hz, load 5N, time 600s, temperature 25-150 °C). The measured data results are shown in Tables 1 and 2.

Table 1

Table 2

From the data results in Table 1 and Table 2, it can be seen that the compounds B1-B5 of the formula (I) series have good anti-friction and anti-wear properties, and can be used as lubricating grease friction modifiers, and can also be used alone for lubrication in solid friction.

The above are only some preferred embodiments of the present invention, and the present invention is not limited to the contents of the embodiments. For those skilled in the art, various changes and modifications can be made within the scope of the technical solution of the present invention, and any changes and modifications made are within the protection scope of the present invention.

Claims (10)

1. An organic friction modifier with different isomeric alkyl end chains, the structure of which is shown in formula (I),

Among them, n=2～10, m=2～10. 2 . The organic friction modifier with different isomeric alkyl end chains according to claim 1 , wherein: the n=3～6, m=3～6. 3 . 3. the organic friction modifier with different isomeric alkyl end chains as claimed in claim 1, is characterized in that: the structure of described organic friction modifier is as shown in compound B1-B5,

4. the preparation method of the organic friction modifier with different isomeric alkyl end chains according to claim 1, comprises the steps: Step 1, using p-hydroxybenzoic acid and hydroquinone to carry out esterification reaction to obtain the intermediate product A shown in formula (II);

In step 2, the intermediate product A is esterified with different Guerbet acids to obtain the compound of formula (I). 5. the preparation method of the organic friction modifier with different isomeric alkyl end chains as claimed in claim 4, is characterized in that: the catalyzer used in described step (1) is sulfuric acid, p-toluenesulfonic acid, One or more of cation exchange resin, solid super acid and molecular sieve. 6. the preparation method of the organic friction modifier with different isomeric alkyl end chains as claimed in claim 4, is characterized in that: the solvent of described step (1) is selected from toluene, xylene, chloroform, tetrachloride Carbon or methyltetrahydrofuran, the reaction temperature is raised from room temperature to reflux, and the reaction is carried out for 6-24 hours. 7. the preparation method of the organic friction modifier with different isomeric alkyl end chains as claimed in claim 4, is characterized in that: the catalyzer used in the described step (2) is 4-dimethylaminopyridine, N, N'-carbonyldiimidazole, imidazole; the condensing agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dicyclohexylcarbodiimide, N,N'-di Isopropylcarbodiimide; the solvent is one or more of dichloromethane, dimethylformamide, dioxane, tetrahydrofuran or N-methylpyrrolidone, the reaction temperature is 0～40℃, and the reaction time 24 to 48 hours. 8. the preparation method of the organic friction modifier with different isomeric alkyl end chains as claimed in claim 4, is characterized in that: described step (2) can also adopt toluene or xylene backflow direct condensation, used catalyst is One or more of sulfuric acid, p-toluenesulfonic acid, cation exchange resin, solid super acid and molecular sieve, the reaction temperature is from room temperature to reflux, and the reaction is carried out for 6 to 48 hours. 9. Application of the organic friction modifier with different isomeric alkyl end chains as claimed in any one of claims 1 to 3 as a friction modifier for lubricating grease. 10. The application of the organic friction modifier with different isomeric alkyl end chains as claimed in any one of claims 1 to 3 as a lubricant.

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