Lanthanum-containing compounds, methods of making and using the same

Abstract

The application relates to the grease field and discloses a lanthanum-containing compound, a preparation method and application thereof, and the structure of the compound is R1-A-R2-COO ‑ [LaOH] 2+‑ OOC-R3. The application further discloses a preparation method and application of the compound. The lanthanum-containing compound is used as a thickening agent of the grease, has excellent comprehensive performance, and can be used for bearing lubrication in high-temperature, high-speed, heavy-load operation, oil field drilling and the like.

Description

Technical Field

[0001] This invention relates to the field of lubricating greases, and more specifically to a lanthanum-containing compound, its preparation method, and its applications. Background Technology

[0002] Amide soap-based greases are a class of organic greases whose thickener molecules contain amide and carboxyl groups. Compared with other types of greases, amide greases not only have advantages such as high dropping point, good radiation resistance, and long service life, but also good oxidation stability and mechanical stability. They are mainly used for lubrication of special equipment in specific applications such as aviation, aerospace, and nuclear power plants, or for lubrication in high-temperature environments. Current reports and applications mainly utilize the advantages of sodium terephthalamide grease, such as good high-temperature resistance, long service life, and radiation protection capabilities, but it has disadvantages such as insufficient water resistance, colloidal stability, and extreme pressure anti-wear properties.

[0003] CN109880681A discloses an ultra-high temperature grease using nano-lanthanum borate as a rare earth additive, physically mixed and compounded with nanoparticles such as molybdenum disulfide and tungsten disulfide. CN105505546B discloses a grease modified with nano-cerium oxide and lanthanum oxide, which improves the grease's anti-wear, friction-reducing, extreme pressure, and thermal stability. CN102676285B uses fluorinated oil as the base oil, fluorinated rare earth elements, polytetrafluoroethylene, or perfluoroethylene-propylene copolymer as thickeners, and adds antioxidants and rust inhibitors to prepare a perfluorinated high-temperature grease that can provide long-term lubrication at temperatures above 300°C and can also provide lubrication under high pressure, high vacuum, high load, strong acid and alkali, and strong corrosive conditions. CN111286393B uses polyurea-organic acid lanthanum composite soap as a thickener, and the resulting grease has excellent extreme pressure anti-wear and anti-wear properties.

[0004] However, the overall performance of the lanthanum compounds used in these reports still needs improvement. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a lanthanum-containing compound, its preparation method, and its application.

[0006] To achieve the above objectives, a first aspect of the present invention provides a lanthanum-containing compound, characterized in that the compound has the structure shown in Formula I:

[0007] R1-A-R2-COO - [LaOH] 2+- OOC-R3 type I

[0008] In Formula I, A is an amide bond;

[0009] R1 is H, a C10-C30 hydrocarbon group that is substituted with a halogen or is not substituted;

[0010] R2 is a C6-C40 arylene group that is halogenated or unsubstituted;

[0011] R3 is a C4-C30 hydrocarbon group that is substituted with or unsubstituted with halogen.

[0012] A second aspect of the present invention provides a method for preparing a lanthanum-containing compound, the method comprising: [R1-A-R2-COO] - ] x M1 x+ The amide compound shown, [R3-COO - ] y M2 y+ The carboxylic acid compound, inorganic base, and water-soluble lanthanum salt react to produce a solid product.

[0013] A third aspect of the present invention provides a pre-made soap containing the compound obtained by the method described above.

[0014] A fourth aspect of the present invention provides a method for preparing a lubricating grease, the method comprising: obtaining a solid product according to the method described above; mixing the obtained solid product with a base oil and heating the mixture.

[0015] Using the lanthanum-containing compound of this invention as a thickener for the grease results in excellent overall performance. The resulting grease exhibits good high-temperature resistance, colloidal stability, mechanical stability, and extreme pressure anti-wear properties. This grease can be used for bearing lubrication in high-temperature, high-speed, heavy-load operations, oilfield drilling, and other applications. Attached Figure Description

[0016] Figure 1 The image shows the infrared spectrum of the grease obtained in Example 1. Detailed Implementation

[0017] 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.

[0018] This invention provides a lanthanum-containing compound, characterized in that the compound has the structure shown in Formula I:

[0019] R1-A-R2-COO - [LaOH] 2+- OOC-R3 type I

[0020] In Formula I, A is an amide bond;

[0021] R1 is H, a C10-C30 hydrocarbon group that is substituted with a halogen or is not substituted;

[0022] R2 is a C6-C40 arylene group that is halogenated or unsubstituted;

[0023] R3 is a C4-C30 hydrocarbon group that is substituted with or unsubstituted with halogen.

[0024] In Formula I, the halogen mentioned can be F, Cl, Br or I, preferably F.

[0025] In Formula I, A is -NH-CO-, preferably R1-A-R2-COO in Formula I. - R1-NH-CO-R2-COO - Or R1-CO-NH-R2-COO - .

[0026] In Formula I, R1 can have 12-20 carbon atoms. Preferably, R1 is an alkyl group of 12-20 (such as C12, C13, C14, C15, C16, C17, C18, C19 or C20), especially a straight-chain alkyl group.

[0027] In Formula I, R2 can have 6-15 carbon atoms. Preferably, R2 is an arylene group of C6-15 (such as C6, C7, C8, C9, C10, C11, C12, C13, C14 or C15), more preferably a phenylene group or a phenylene group substituted with an alkyl group of C1-C6 (preferably a straight-chain alkyl group of C1-C4) (wherein, the substitution position can be at least one, preferably 1, 2, 3 or 4).

[0028] In Formula I, R3 can have 6-12 carbon atoms. Preferably, R3 is an aryl group of C6-12 (such as C7, C8, C9, C10, C11 or C12), more preferably a phenyl group or a phenyl group substituted with an alkyl group of C1-C6 (preferably a straight-chain alkyl group of C1-C4) (wherein, the substitution position can be at least one, preferably 1, 2, 3, 4 or 5).

[0029] According to a particularly preferred embodiment of the present invention, R1-A-R2-COO in Formula I - R1-NH-CO-R2-COO - R1 is a C16-C20 straight-chain alkyl group, R2 is a p-phenylene or methyl-substituted phenylene, and R3 is a phenyl or methyl-substituted phenylene.

[0030] The present invention also provides a method for preparing a lanthanum-containing compound (or a method for preparing a thickener (for lubricating grease)), characterized in that the method comprises: [R1-A-R2-COO] - ] x M1 x+ The amide compound shown, [R3-COO - ] y M2 y+ The carboxylic acid compound, inorganic base, and water-soluble lanthanum salt are reacted to yield a solid product. A, R1, R2, and R3 are defined as previously stated. M1 and M2 are each independently a Group IA or Group IIA metal, preferably H, Na, or K. x and y represent valence states and are equal to 1 or 2.

[0031] In this invention, the amide compound is preferably a sodium salt of N-octadecyl terephthalic acid monoamide (which can be prepared by referring to the method in US2820012A), and its structure is shown below:

[0032]

[0033] In this invention, the carboxylic acid compound is preferably a water-soluble compound, that is, a carboxylic acid compound with a solubility in water of 0.01g or more (preferably 1g or 10g or more) at the contact temperature of this invention, preferably at least one of sodium benzoate, sodium 4-methylbenzoate and benzoic acid.

[0034] In this invention, the inorganic base may be selected from hydroxides of alkali metals and / or hydroxides of alkaline earth metals, preferably sodium hydroxide and / or potassium hydroxide.

[0035] In this invention, the water-soluble lanthanum salt is a lanthanum salt whose solubility in water at the contact temperature of this invention is greater than or equal to 0.01g (preferably greater than or equal to 1g or 10g). The water-soluble lanthanum salt is preferably at least one of LaCl3 (usually containing water of crystallization), lanthanum acetate, lanthanum nitrate, lanthanum sulfate, lanthanum citrate, and their hydrates, and more preferably at least one of LaCl3, La(NO3)3, and their hydrates.

[0036] In this invention, the molar ratio of the amide compound to the carboxylic acid compound can be 0.2-5:1 (e.g., 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, 1, 1.05, 1.1, 1.2, 2, 3, 4, 5 or any value between the above), preferably 0.5-1:1. More preferably, the amount of inorganic base used results in a pH of 7-12 for the contact system.

[0037] In this invention, the number of moles of anions provided by the amide compound, carboxylic acid compound, and inorganic base is theoretically equal to three times the number of moles of cations provided by the water-soluble lanthanum salt. However, preferably, the amounts of the amide compound, carboxylic acid compound, and water-soluble lanthanum salt are such that the ratio between the total number of moles of anions provided by the amide compound and carboxylic acid compound and the number of moles of cations provided by the water-soluble lanthanum salt is 200:100-110. In other words, the number of moles of water-soluble lanthanum salt is 1-5 moles in excess.

[0038] In this invention, there are no particular requirements for the contact conditions, but preferably, the contact conditions include: a temperature of 6-85°C (e.g., 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 85°C or any value between these values). Preferably, the contact conditions also include: a time of 0.2-8 hours. To promote the metathesis reaction, the contact is carried out in a high-shear mixing emulsifier, or it can be carried out under ultrasonic conditions. The rotation speed of the high-shear mixing emulsifier can be controlled at 1000-12000 r / min. More preferably, the contact method is as follows: (1) mixing the amide compound, the water-soluble lanthanum salt, and the solvent, and stirring for 0.2-4 h (e.g., 0.4, 0.5, 0.6, 0.8, 1, 1.5, 2, 2.2, 2.5, 2.8, 3, 3.5 h or any value between the above values); (2) mixing the product of step (1) with the carboxylic acid compound, and stirring for 0.2-4 h (e.g., 0.4, 0.5, 0.6, 1, 1.5, 1.8, 2, 2.2, 3, 3.5 h or any value between the above values); (3) adjusting the pH of the product of step (2) to 7-12 using an inorganic base. To make the reaction more complete, the amide compound, the carboxylic acid compound, and the water-soluble lanthanum salt are all used in the form of a solution (or dispersion), and the solvent can be common solvents such as water or alcohol.

[0039] In this invention, the precipitate (solid product) obtained after the reaction can be used directly as a thickener for lubricating grease, or the precipitate can be washed and dried before being used as a thickener for lubricating grease.

[0040] The present invention also provides a pre-made soap containing the compound obtained by the method described above (or a thickener obtained by the method described above).

[0041] In addition, the present invention provides a grease comprising: a base oil, a thickener, and optional additives, characterized in that the thickener is a compound or pre-made soap as described above.

[0042] In this invention, based on the total weight of the grease, the content of thickener in the grease is 5-50% by weight, preferably 6-25% by weight.

[0043] In this invention, based on the total weight of the grease, the content of base oil in the grease can be 50-95% by weight, preferably 75-94% by weight. The kinematic viscosity of the base oil at 100°C is 2-150 mmHg. 2 / s, preferably 5-100mm 2 / s, preferably 8-50mm 2 / s. The test method for "kinematic viscosity" is GB / T 30515-2014. The base oil can be at least one of mineral oil, ester oil, synthetic hydrocarbons (such as polyalphaolefin synthetic oils), or vegetable oil.

[0044] In this invention, the lubricating grease may or may not contain additives. The additives may be at least one of antioxidants, anti-wear agents, rust inhibitors, extreme pressure agents, etc., or other common additives. Based on the total weight of the lubricating grease, the content of the additives may be 0.2-15% by weight.

[0045] The grease of the present invention can be prepared in a conventional manner. Preferably, the method includes: obtaining a solid product as described above; mixing the obtained solid product with a base oil and heating it. More specifically, the preparation method of the grease of the present invention may include: mixing the solid product and the base oil and heating them, and then mixing them with optional additives. Specifically, it may include: first mixing the base oil and the solid product at room temperature, heating to 90-120°C, holding for 5-30 minutes, continuing to heat to 160-210°C, stopping heating and cooling, and introducing optional additives at 80-120°C, grinding and homogenizing to obtain the grease.

[0046] The present invention will be described in detail below through examples. The drying temperature is 120°C and the time is 60 minutes.

[0047] Example 1

[0048] (1) At room temperature, 4.37 g of sodium benzoate was dissolved in 50 g of water, and lanthanum chloride hydrate LaCl3·7H2O was dissolved in 50 g of water. The sodium salt of N-octadecyl terephthalic acid monoamide was mixed with 200 g of water and sheared for 0.5 h using a high-shear mixing emulsifier to ensure thorough dispersion. Shearing continued while the above lanthanum chloride solution was slowly added. After the addition was complete, shearing was maintained at 8000 r / min for 0.5 h. Shearing continued while the above sodium benzoate solution was slowly added. After the addition was complete, shearing was maintained at 8000 r / min for 2 h. The pH was adjusted to 7.5 with NaOH, and a white precipitate was obtained by filtration. The precipitate was washed with a large amount of water and dried to obtain the composite amide lanthanum-based thickener. The molar ratio of sodium benzoate, LaCl3·7H2O and sodium salt of N-octadecyl terephthalic acid monoamide was 1:1:1.

[0049] (2) Add 94.6g of 500N oil (kinematic viscosity 11mm at 100℃) 2 15.4 g of the newly prepared composite amide lanthanum-based thickener was added to an atmospheric pressure grease pot, stirred, heated to 105°C and held at that temperature for 10 min, then heated to 210°C and the heating was stopped. The mixture was stirred and cooled, and then ground at room temperature to obtain the composite amide lanthanum-based grease. Grease composition: base oil 86 wt%, thickener 14 wt%. The physicochemical properties of the obtained grease are detailed in Table 1 below, and the infrared spectroscopy test results are shown in [Table 1]. Figure 1 .

[0050] Example 2

[0051] (1) At room temperature, 2.18 g of sodium benzoate was dissolved in 20 g of water, and anhydrous lanthanum chloride hydrate LaCl3 was dissolved in 20 g of water. The sodium salt of N-octadecyl terephthalic acid monoamide was mixed with 200 g of water and sonicated for 0.5 h to disperse it fully. The mixture was then taken out, stirred, and heated to 80 °C. The above lanthanum chloride solution was slowly added while stirring rapidly. After the addition was complete, the temperature was maintained at 80 °C for 2 h, followed by sonication for 0.5 h. The above sodium benzoate solution was slowly added while stirring rapidly. The temperature was maintained at 80 °C for 2 h, followed by sonication for 0.5 h. NaOH solution was added dropwise to adjust the pH to ≈ 9, and the mixture was sonicated for 0.5 h. A white precipitate was obtained by filtration. The precipitate was washed with a large amount of water and dried to obtain the composite amide lanthanum-based thickener. The molar ratio of sodium benzoate, LaCl3, and sodium salt of N-octadecyl terephthalic acid monoamide was 1:1:1.

[0052] (2) 35.2 g of diisooctyl sebacate (DOS, kinematic viscosity at 100℃ is 3.1 mm) 2 4.8 g of the newly prepared composite amide lanthanum-based thickener was added to an atmospheric pressure grease pot, stirred, heated to 105°C and held at that temperature for 10 min, then heated to 210°C and the heating was stopped. The mixture was stirred and cooled, and then ground at room temperature to obtain the composite amide lanthanum-based grease. Grease composition: base oil 88% by weight, thickener 12% by weight. The physicochemical properties of the obtained grease are detailed in Table 1 below.

[0053] Example 3

[0054] The grease was prepared according to the method in Example 1, except that sodium 4-methylbenzoate was used instead of sodium benzoate, while maintaining the same molar ratio of the three components. The base oil used was polyalphaolefin (PAO10, kinematic viscosity of 10 mmHg at 100°C). 2 / s). Grease composition: base oil 91% by weight, thickener 9% by weight. The properties of the resulting grease are detailed in Table 1 below.

[0055] Comparative Example 1

[0056] 91g of 500N oil (kinematic viscosity 11mm at 100℃) 2 9g of sodium salt of N-octadecyl terephthalic acid monoamide was added to an atmospheric pressure grease tank, stirred, heated to 105℃ and held at that temperature for 10 min, then heated to 210℃ and the heating was stopped. The mixture was stirred and cooled, and then ground at room temperature to obtain sodium amide-based grease. Grease composition: base oil 91% by weight, thickener 9% by weight. The physicochemical properties of the obtained grease are detailed in Table 1 below.

[0057] Comparative Example 2

[0058] The grease was prepared according to the method in Example 1, except that sodium salt of N-octadecyl terephthalic acid monoamide was used instead of sodium benzoate. A lanthanum diamide thickener was first prepared, and then the grease was prepared using this thickener. The composition of the grease was: base oil 86 wt%, thickener 14 wt%. The physicochemical properties of the obtained grease are detailed in Table 1 below.

[0059] Comparative Example 3

[0060] The grease was prepared according to the method in Example 1, except that the sodium salt of N-octadecyl terephthalic acid monoamide was replaced with sodium benzoate, while keeping other proportions unchanged, to obtain the lanthanum salt of benzoic acid. The prepared grease was fluid and did not form grease.

[0061] Comparative Example 4

[0062] (1) The lanthanum diamide thickener prepared according to Comparative Example 2 and the lanthanum salt of benzoic acid prepared according to Comparative Example 3 were mixed in a molar ratio of 1:1 to obtain a mixed thickener.

[0063] (2) The grease was prepared according to the method of Example 1, except that the thickener was replaced with the mixed thickener obtained in step (1). The physicochemical properties of the grease are detailed in Table 1 below.

[0064] Table 1 Physicochemical Properties of Lubricating Greases

[0065]

[0066]

[0067] The above results show that the composite lanthanum-based grease prepared according to this invention has superior thickening ability, extreme pressure anti-wear performance, colloidal stability, and water resistance. Compared with Comparative Example 1, the grease P prepared according to this invention... D When the value is close to that of the grease prepared according to the method of the present invention, the P value is... B The grease exhibits a higher dropping point, a smaller taper diameter (D), and better colloidal stability compared to Comparative Examples 2 and 4. It also demonstrates superior overall performance.

[0068] From the infrared spectrum of the lubricating grease of the present invention (e.g. Figure 1 As can be seen, the composite lanthanum amide thickener prepared by this invention contains carbonyl and amide bonds. Based on the preparation process, it can be understood that the composite lanthanum amide thickener mainly contains the compound shown in Formula I.

[0069] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A lanthanum-containing compound, characterized in that, The structure of the compound is shown in Formula I: R1-A-R2-COO - [LaOH] 2+- OOC-R3 Formula I In Formula I, A is an amide bond; R1 is a C12-C20 straight-chain alkyl group; R2 is a phenylene or a phenylene substituted with a C1-C6 alkyl group; R3 is a phenyl or a phenyl substituted with a C1-C6 alkyl group.

2. The compound according to claim 1, wherein, In formula I, R1-A-R2-COO - R1-NH-CO-R2-COO - Or R1-CO-NH-R2-COO - .

3. The compound according to claim 1 or 2, wherein, In formula I, R1-A-R2-COO - R1-NH-CO-R2-COO - R1 is a C16-C20 straight-chain alkyl group, R2 is a p-phenylene or methyl-substituted phenylene, and R3 is a phenyl or methyl-substituted phenylene.

4. A method for preparing the lanthanum-containing compound of claim 1, characterized in that, The method includes: [R1-A-R2-COO] - ] x M1 x+ The amide compound shown, [R3-COO - ] y M2 y+ The carboxylic acid compound shown reacts with an inorganic base and a water-soluble lanthanum salt to give a solid product, wherein A is an amide bond; R1 is a C12-C20 straight-chain alkyl group; R2 is a phenylene or a phenylene substituted with a C1-C6 alkyl group; R3 is a phenyl or a phenyl substituted with a C1-C6 alkyl group; M1 and M2 are each independently H, a Group IA metal, or a Group IIA metal; x and y represent valence states and are equal to 1 or 2.

5. The method according to claim 4, wherein, R1-A-R2-COO in amide compounds - R1-NH-CO-R2-COO - Or R1-CO-NH-R2-COO - ; And / or, M1 and M2 are each independently H, Na, or K; And / or, the inorganic base is selected from alkali metal hydroxides and / or alkaline earth metal hydroxides.

6. The method according to claim 4 or 5, wherein, R1-A-R2-COO in amide compounds - R1-NH-CO-R2-COO - R1 is a C16-C20 straight-chain alkyl group, R2 is a p-phenylene or methyl-substituted phenylene, R3 is a phenyl or methyl-substituted phenylene, and the water-soluble lanthanum salt is at least one of LaCl3, La(NO3)3 and their hydrates.

7. The method according to claim 4 or 5, wherein, The molar ratio of the amide compound to the carboxylic acid compound is 0.2-5:1; And / or, the amount of the inorganic base used makes the pH of the contact system 7-12; And / or, the amounts of the amide compound, carboxylic acid compound, and water-soluble lanthanum salt are such that the ratio of the total number of moles of anions provided by the amide compound and carboxylic acid compound to the number of moles of cations provided by the water-soluble lanthanum salt is 200:100-110.

8. The method according to claim 4 or 5, wherein, The molar ratio of the amide compound to the carboxylic acid compound is 0.5-1:

1.

9. The method according to claim 4 or 5, wherein, The contact conditions include a temperature of 6-85℃ and a time of 0.2-8h.

10. The method according to claim 4 or 5, wherein, The contact method is as follows: (1) Mix the amide compound, water-soluble lanthanum salt and solvent, and stir for 0.2-4 h; (2) Mix the product of step (1) with a carboxylic acid compound and stir for 0.2-4 hours; (3) Adjust the pH of the product from step (2) to 7-12 using an inorganic base.

11. A thickener containing the compound obtained by the method of any one of claims 4-10, wherein, The thickener is a solid product obtained after the reaction.

12. A method for preparing lubricating grease, characterized in that, The method includes: obtaining a solid product according to any one of claims 4-10; mixing the obtained solid product with a base oil and heating it to a higher temperature.

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