Synthetic method of lubricating oil detergent

Abstract

The invention discloses a synthetic method of a lubricating oil detergent. The synthesis method is characterized by comprising the following steps: mixing sulfurized alkylphenate with a solvent to form a uniform mixture; a peroxide is added to the uniform mixture, and the addition amount of the peroxide is 0.005-0.20 parts by mass relative to 1 part by mass of the sulfurized alkylphenate; reacting for 3-8 hours at the temperature of 50-200 DEG C; and after the reaction is finished, filtering and distilling to remove the solvent to obtain the sulfurized alkylphenol salt with reduced content of free alkylphenol. The lubricating oil detergent obtained by the synthetic method of the lubricating oil detergent is low in free alkylphenol content, and the product performance is improved.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil additives, specifically to a method for synthesizing a lubricating oil detergent, and more specifically, to a method for preparing a sulfurized alkylphenol salt with reduced free alkylphenol content. Background Technology

[0002] Lubricating oil detergents are an important component of lubricating oil additives. Their main function is to neutralize acidic substances produced by combustion, prevent the formation of sludge and deposits, and keep the engine interior clean.

[0003] Alkylphenol salts are commonly used lubricating oil detergents, possessing excellent high-temperature detergency and antioxidant properties. In particular, calcium alkylphenol sulfide is a comprehensive and widely used lubricating oil metal detergent with good detergency, acid neutralization ability, and antioxidant properties. It is one of the main additives in mid-to-high-end internal combustion engine oils, marine oils, and other oil products, and is difficult for other detergents to replace.

[0004] On the other hand, alkylphenol calcium sulfide products are produced by neutralizing, sulfiding, carbonating, and refining alkylphenols with sulfur, calcium oxide, and other raw materials. A certain amount of alkylphenol residue (3%–10%) is generally present in the product. It should be noted that the endocrine toxicity, reproductive toxicity, and immunotoxicity of alkylphenols limit the application of alkylphenol calcium sulfide products, making the development of detergents with low free alkylphenol content an inevitable trend.

[0005] In view of the above situation, researchers in this field have done a lot of work on improving the process of alkylphenol calcium sulfide products.

[0006] In Patent Document 1, a calcium alkylphenol sulfide product with low free alkylphenol content was prepared by first subjecting dodecylphenol to a phenolic condensation reaction and then to a sulfidation reaction. The free alkylphenol content was reduced from 6.5-8.1% to 1.7-4.4%. However, the process steps were complicated and the free alkylphenol content was still relatively high.

[0007] Patent document 2 describes the preparation of a sulfurized alkylphenol salt detergent with low alkylphenol content by reacting alkylphenol salts with aldehydes, amines, etc. under alkaline conditions. This detergent can reduce free alkylphenols to 1.3%, but the process is complicated and there are still free alkylphenol residues.

[0008] Patent document 3 describes a process where a sulfurized alkylphenol metal salt is mixed with an intermediate (obtained by reacting anhydride and / or carboxylic acid with an amine compound) and then condensed with an aldehyde to obtain a sulfurized alkylphenol metal salt product with low free alkylphenol content, which can reduce free alkylphenol to 0.26%. However, the process is complex and a small amount of free alkylphenol remains.

[0009] Therefore, there is an urgent need to develop a simple and effective method that can significantly reduce the free alkylphenol content in sulfurized alkylphenol salt detergents while maintaining or improving product performance to meet increasingly stringent environmental protection requirements and application needs.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: US8198225

[0013] Patent Document 2: CN106147937A

[0014] Patent Document 3: CN105037226 A Summary of the Invention

[0015] To address the technical problem of high free alkylphenol content in calcium alkylphenolate products and achieve the technical effect of reducing free alkylphenol content while improving product performance, this invention provides a method for synthesizing a lubricating oil detergent.

[0016] The technical solution adopted by this invention to solve its technical problem is as follows: a method for synthesizing a lubricating oil detergent, wherein the lubricating oil detergent is a sulfurized alkylphenol salt with reduced free alkylphenol content, comprising the following steps: mixing the sulfurized alkylphenol salt with a solvent to form a homogeneous mixture; adding a peroxide to the homogeneous mixture, wherein the amount of the peroxide added is 0.005 to 0.20 parts by mass relative to 1 part by mass of the sulfurized alkylphenol salt; reacting at 50 to 200°C for 3 to 8 hours; after the reaction is completed, filtering and distilling to remove the solvent, thereby obtaining the sulfurized alkylphenol salt with reduced free alkylphenol content.

[0017] Furthermore, the present invention relates to a lubricating oil detergent obtained by the above-mentioned method for synthesizing lubricating oil detergent.

[0018] The beneficial effects of this invention are as follows: 1. The method for synthesizing the lubricating oil detergent provided by the present invention can significantly reduce the free alkylphenol content in the product by adding an appropriate amount of peroxide to the sulfurized alkylphenol salt and reacting it at a certain temperature.

[0019] 2. While reducing the content of free alkylphenols, the product performance (antioxidant properties, detergency properties, etc.) of the lubricating oil detergent prepared by the synthesis method of the lubricating oil detergent provided by the present invention is improved.

[0020] 3. The synthesis method of the present invention is simple and easy to operate. It only requires adding peroxide to the commercially available alkylphenol calcium sulfide product to carry out the reaction. There are no complicated process steps, and it is easy to realize industrial production. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. However, it should be noted that the following specific embodiments are only for explaining this invention and do not constitute any limitation on the scope of protection of this invention.

[0022] This invention provides a method for synthesizing a lubricating oil detergent, comprising the following steps: mixing a sulfurized alkylphenol salt with a solvent to form a homogeneous mixture; adding a peroxide to the homogeneous mixture, wherein the amount of the peroxide added is 0.005 to 0.20 parts by mass relative to 1 part by mass of the sulfurized alkylphenol salt; reacting at 50 to 200°C for 3 to 8 hours; after the reaction is completed, filtering and distilling to remove the solvent, thereby obtaining the sulfurized alkylphenol salt with reduced free alkylphenol content.

[0023] The peroxide is preferably one or more of peroxide esters, dialkyl peroxides, or diacyl peroxides. More preferably, the peroxide ester is tert-butyl peroxide-2-ethylhexanoate, or the dialkyl peroxide is di-tert-butyl peroxide, or the diacyl peroxide is benzoyl peroxide.

[0024] The amount of peroxide added is 0.005 to 0.20 parts by mass, preferably 0.03 to 0.20 parts by mass, and more preferably 0.04 to 0.06 parts by mass, relative to 1 part by mass of the sulfide alkylphenol salt. If the amount of peroxide added is less than the lower limit of the above range, the content of free alkylphenol cannot be sufficiently reduced. Furthermore, if the amount of peroxide added exceeds the upper limit of the above range, the content of free alkylphenol will not be reduced accordingly, the reduction effect has a limit, and this is disadvantageous from a cost perspective.

[0025] In the synthesis method of the present invention, the temperature is raised to 50–200°C, preferably 80–200°C, more preferably 80–180°C, for the reaction, and the reaction time is 3–8 hours, preferably 4–6 hours. If the reaction temperature or reaction time is outside the above range, the content of free alkylphenols cannot be sufficiently reduced. In particular, if the reaction temperature is too low (e.g., below 50°C), no reaction will occur, or even if a reaction occurs, the resulting product has a high degree of polymerization and a long chain, resulting in a relatively high viscosity. On the other hand, if the reaction temperature is too high, side reactions may occur.

[0026] It should be noted that in this invention, by adding peroxide, the product reacts with free alkylphenols, thereby reducing the free alkylphenol content while improving product performance. The specific reaction formula is as follows.

[0027]

[0028] The reaction mechanism will be explained in more detail below.

[0029] 1. The peroxide bonds in peroxides break under light or heat conditions, generating free radicals.

[0030]

[0031] (R2 and R3 can be different groups or the same group;)

[0032] 2. The generated free radical abstracts H from the benzene ring of the free alkylphenol to obtain a free alkylphenol free radical.

[0033]

[0034] 3. A free alkylphenol radical takes a hydrogen atom from another free alkylphenol, and the free alkylphenol forms a chain.

[0035]

[0036] 4. The generated free radicals combine, terminating the chain.

[0037]

[0038] Thus, free alkylphenols ultimately become free alkylphenol detergent soaps with a chain length of two or more, thereby enhancing the product's cleaning power while reducing the content of free alkylphenols.

[0039] The free alkylphenol content in the lubricating oil detergent obtained by the above-described synthesis method of the present invention is 0.12% by mass or less, preferably 0.11% by mass or less, and more preferably no free phenol content is detected.

[0040] Example

[0041] The invention described below will be further described in more detail based on the embodiments.

[0042] Comparative Example 1

[0043] Commercially available alkylphenol calcium B-1 was used.

[0044] Example 1

[0045] Take 200g of commercially available alkylphenol calcium 1, add 100g of 200# solvent oil, mix evenly, then pass in low-flow-rate nitrogen as a protective gas, add 11.0g of tert-butyl peroxide-2-ethylhexanoate, heat to 80℃ and maintain for 1 hour, then slowly heat to 180℃ for 3 hours. After the reaction is completed, purify to obtain alkylphenol calcium 1 with low free alkylphenol.

[0046] Example 2

[0047] Take 200g of commercially available alkylphenol calcium 1, add 100g of 200# solvent oil, mix evenly, then pass in low-flow-rate nitrogen as a protective gas, add 11.0g of tert-butyl peroxide-2-ethylhexanoate, heat to 80℃ and maintain for 7 hours, and after the reaction is completed, purify to obtain alkylphenol calcium 1-2 with low free alkylphenol.

[0048] Comparative Example 2

[0049] Take 200g of commercially available alkylphenol calcium 1, add 100g of 200# solvent oil, mix well, and then pass in low-flow-rate nitrogen as a protective gas. Add 0.9g of tert-butyl peroxide-2-ethylhexanoate, heat to 80℃ and maintain for 1 hour, then slowly heat to 180℃ for 3 hours. After the reaction is completed, purify to obtain alkylphenol calcium 1 B-2 with low free alkylphenol.

[0050] Example 3

[0051] Take 200g of commercially available alkylphenol calcium 1, add 100g of 200# solvent oil, mix evenly, then introduce nitrogen gas at a low flow rate as a protective gas, add 7.5g of di-tert-butyl peroxide, heat to 80℃ and maintain for 1 hour, then slowly heat to 180℃ for 3 hours. After the reaction is completed, purify to obtain alkylphenol calcium 1 A-3 with low free alkylphenol.

[0052] Example 4

[0053] Take 200g of commercially available alkylphenol calcium 1, add 100g of 200# solvent oil, mix evenly, then pass in nitrogen gas at a low flow rate as a protective gas, add 12.4g of benzoyl peroxide, heat to 80℃ and maintain for 1 hour, then slowly heat to 180℃ for 3 hours. After the reaction is completed, purify to obtain alkylphenol calcium 1-4 with low free alkylphenol.

[0054] Example 5

[0055] Take 200g of commercially available alkylphenol calcium 1, add 100g of 200# solvent oil, mix evenly, then pass in nitrogen gas at a low flow rate as a protective gas, add 19.4g of benzoyl peroxide, heat to 80℃ and maintain for 1 hour, then slowly heat to 180℃ for 3 hours. After the reaction is completed, purify to obtain alkylphenol calcium 1A-5 with low free alkylphenol.

[0056] The following tests were conducted on the products obtained from the above embodiments and comparative examples.

[0057] <Alkalinity>

[0058] Tests were conducted in accordance with ASTM D2896.

[0059] <Kinetic viscosity>

[0060] Tests were conducted in accordance with GB / T 265.

[0061] <Free alkylphenols>

[0062] The test was performed using HPLC. For details, please refer to "Determination of Free Alkylphenol Content in Calcium Sulfide Alkylphenol by High Performance Liquid Chromatography" (Wan Xinshui et al.), Vol. 48, No. 8, Petroleum Refining and Chemical Engineering.

[0063] <Antioxidant Time>

[0064] The high-pressure differential scanning calorimetry method was used for testing, and the tests were conducted in accordance with ASTM D6186.

[0065] Purity

[0066] The test was conducted in accordance with SH / T 0300.

[0067] The results are shown in Table 1 below.

[0068] [Table 1]

[0069] The test results above show that the alkylphenol calcium sulfurized detergent products manufactured in Examples 1-5 of the present invention, compared with the commercially available alkylphenol calcium sulfurized product of Comparative Example 1, not only have a lower free phenol content (at most only 0.12%), but also exhibit superior detergent and antioxidant properties. In particular, in Examples 1, 2, and 3, the free phenol content was reduced to an undetectable level, achieving effects that cannot be achieved by the prior art.

[0070] Furthermore, a comparison between Example 1 and Example 2 shows that the amount of peroxide added is the same, but the reaction temperature in Example 2 is lower. Therefore, although the content of free alkylphenol can be reduced, the generated chain is longer and the sample viscosity increases.

[0071] Furthermore, a comparison between Example 1 and Comparative Example 2 shows that the reaction temperature, time, and type of peroxide are the same, but the amount of peroxide added in Comparative Example 2 is less and not within the scope of this application. Therefore, it is not possible to reduce the free alkylphenol to a lower level in Comparative Example 2.

[0072] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for synthesizing a lubricating oil detergent, wherein the lubricating oil detergent is a sulfurized alkylphenol salt with reduced free alkylphenol content, the synthesis method being characterized by comprising the following steps: The sulfide alkylphenol salt is mixed with a solvent to form a homogeneous mixture; A peroxide is added to the homogeneous mixture, wherein the amount of the peroxide added is 0.005 to 0.20 parts by mass relative to 1 part by mass of the sulfide alkylphenol salt; React at 50–200°C for 3–8 hours; After the reaction is complete, the solvent is removed by filtration and distillation to obtain the sulfide alkylphenol salt with reduced free alkylphenol content.

2. The method for synthesizing the lubricating oil detergent as described in claim 1, characterized in that, The peroxide is one or more of peroxide esters, dialkyl peroxides, or diacyl peroxides.

3. The method for synthesizing the lubricating oil detergent as described in claim 2, characterized in that, The peroxide ester is tert-butyl peroxide-2-ethylhexanoate.

4. The method for synthesizing the lubricating oil detergent as described in claim 2, characterized in that, The dialkyl peroxide is di-tert-butyl peroxide.

5. The method for synthesizing the lubricating oil detergent as described in claim 2, characterized in that, The diacyl peroxide is benzoyl peroxide.

6. The method for synthesizing the lubricating oil detergent as described in claim 1, characterized in that, The amount of the peroxide added is 0.04 to 0.06 parts by mass relative to 1 part by mass of the sulfide alkylphenol salt.

7. The method for synthesizing the lubricating oil detergent as described in claim 1, characterized in that, The reaction is carried out by raising the temperature to 100–180°C.

8. The method for synthesizing the lubricating oil detergent as described in claim 1, characterized in that, The reaction time is 4 to 6 hours.

9. A lubricating oil detergent obtained by the synthesis method of the lubricating oil detergent according to any one of claims 1 to 8.

10. The lubricating oil detergent as described in claim 9, characterized in that, The free alkylphenol content in the lubricating oil detergent is less than 0.1% by mass.

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