阅读说明：本技术 一种苯甲酸-磷酸酯润滑基础油及其制备方法与应用 (Benzoic acid-phosphate lubricating base oil and preparation method and application thereof ) 是由 张高奇 张梦丽 蔡启航 王通 王羽生 孙洁 于 2021-08-25 设计创作，主要内容包括：本发明涉及一种苯甲酸-磷酸酯润滑基础油及其制备方法与应用,所述制备方法具体为：取三羟甲基氧化磷、脂肪酸和苯甲酸,混合均匀后预热,之后加入催化剂形成反应体系,在真空条件下再继续升温至150-220℃反应5-10h,得到粗酯产品,再经后处理得到所述苯甲酸-磷酸酯润滑基础油。与现有技术相比,本发明制得的苯甲酸-磷酸酯润滑基础油具有优异的润滑性和耐高温性,同时也具有极压抗磨性。(The invention relates to benzoic acid-phosphate ester lubricating base oil and a preparation method and application thereof, wherein the preparation method specifically comprises the following steps: uniformly mixing trihydroxymethyl phosphorus oxide, fatty acid and benzoic acid, preheating, adding a catalyst to form a reaction system, continuously heating to 150-220 ℃ under a vacuum condition, reacting for 5-10h to obtain a crude ester product, and performing post-treatment to obtain the benzoic acid-phosphate ester lubricating base oil. Compared with the prior art, the benzoic acid-phosphate lubricating base oil prepared by the invention has excellent lubricity and high temperature resistance, and also has extreme pressure abrasion resistance.)

1. A preparation method of benzoic acid-phosphate ester lubricating base oil is characterized by comprising the following steps: uniformly mixing trihydroxymethyl phosphorus oxide, fatty acid and benzoic acid, preheating, adding a catalyst to form a reaction system, continuously heating to 150-220 ℃ under a vacuum condition, reacting for 5-10h to obtain a crude ester product, and performing post-treatment to obtain the benzoic acid-phosphate ester lubricating base oil.

2. The method of claim 1, wherein the fatty acid is selected from one or more of linoleic acid, alpha-linolenic acid, oleic acid, caprylic acid, capric acid, lauric acid, isostearic acid, arachidonic acid, isostearic acid, palmitic acid, eicosapentaenoic acid, or docosahexaenoic acid.

3. The method of claim 1, wherein the molar ratio of phosphorous oxytrimethylate, fatty acid and benzoic acid is 1 (1-2.5) to (1-2.5).

4. The method of claim 1, wherein the catalyst is an acidic catalyst.

5. The method of claim 4, wherein the catalyst is selected from one or more of concentrated sulfuric acid, phosphoric acid, p-toluenesulfonic acid, ZnO, and phthalate esters.

6. The method of claim 1, wherein the catalyst is present in an amount of 0.5 to 3 wt% based on the total amount of tris-hydroxymethyl phosphonium oxide, fatty acid and benzoic acid.

7. The method of claim 1, wherein the reaction system is preheated to 50-70 ℃ while adding the catalyst.

8. The method of claim 1, wherein the crude ester product is worked up by molecular distillation.

9. A benzoic acid-phosphoric ester lubricating base oil prepared by the method according to any one of claims 1 to 8, wherein the structures of the main products in the benzoic acid-phosphoric ester lubricating base oil are respectively shown in formulas (I), (II) and (III):

wherein R is a hydrocarbyl group.

10. Use of the benzoic acid-phosphate lubricating base oil of claim 9 in the field of lubrication.

Technical Field

The invention relates to the field of lubrication, and particularly relates to benzoic acid-phosphate lubricating base oil and a preparation method and application thereof.

Background

The lubricating oil is widely applied to automobiles and mechanical equipment, mainly plays roles of lubrication, cooling, rust prevention, cleaning, sealing, buffering and the like so as to reduce friction and protect machinery and workpieces, and is generally liquid or semisolid. The lubricating oil consists of two parts, namely base oil and an additive, wherein the base oil is the main component of the lubricating oil, the basic property of the lubricating oil is determined, the additive can make up and improve the deficiency of the performance of the base oil, and the additive endows certain new performance and is an important component of the lubricating oil.

The extreme pressure antiwear performance is an important performance index of base oil in lubricating oil, and the phosphorus-containing compound has outstanding extreme pressure antiwear performance, wherein phosphate ester is the earliest extreme pressure antiwear agent. The phosphate ester has good extreme pressure antiwear performance and mainly comprises the following two factors: on one hand, phosphate reacts with metal (especially Fe) on the metal surface to generate metal phosphide (when the metal is Fe, the metal phosphide is iron phosphide and ferrous phosphate), and the inorganic salts generate plastic flow under the action of frictional heat and pressure to deform and fall into uneven low points on the metal surface, so that the contact area of the metal and the phosphate is increased, the pressure point is reduced, the boundary lubrication of the metal surface is provided, and the metal surface has better extreme pressure abrasion resistance. On the other hand, in the metal processing process, taking Fe as a metal example, phosphide firstly generates an adsorption effect on the iron surface to generate an organic ferric phosphate film, then a C-O bond is broken under the action of extreme pressure and frictional heat, the organic ferric phosphate film can be further reacted and decomposed to generate an inorganic ferric phosphate protective film, so that the metal and the metal are not in direct contact, and the metal surface is protected.

Chinese patent CN 112662448A uses trihydroxymethyl phosphorus oxide and long chain fatty acid to carry out esterification reaction, and obtains trihydroxymethyl phosphorus oxide oleate lubricating base oil after post-treatment, the lubricating base oil also has excellent extreme pressure abrasion resistance, the diameter of four-ball grinding spot is 0.33mm, but has a further improved space. The benzoic acid-phosphate lubricating base oil product greatly improves the wear resistance of phosphate, and the diameter of four-ball grinding spots can be reduced to 0.24 mm.

Disclosure of Invention

It is a first object of the present invention to provide a process for preparing a benzoic acid-phosphoric acid ester lubricating base oil.

The purpose of the invention is realized by the following technical scheme:

a preparation method of benzoic acid-phosphate ester lubricating base oil comprises the following steps: uniformly mixing trihydroxymethyl phosphorus oxide (THPO), fatty acid and benzoic acid, preheating, adding a catalyst to form a reaction system, continuously heating to 150-220 ℃ under a vacuum condition, reacting for 5-10h to obtain a crude ester product, and performing aftertreatment to obtain the benzoic acid-phosphate ester lubricating base oil.

The fatty acid is selected from one or more of linoleic acid, alpha-linolenic acid, oleic acid, caprylic acid, capric acid, lauric acid, isostearic acid, arachidonic acid, isostearic acid, palmitic acid, eicosapentaenoic acid or docosahexaenoic acid.

The molar ratio of the phosphorus oxide, the fatty acid and the benzoic acid is 1 (1-2.5) to 1-2.5. If too little benzoic acid is present, the resulting lubricating base oil product, as defined by the ratio of functional groups, has a reduced structural rigidity, thereby reducing the antiwear properties of the product. Too much benzoic acid leads to a solid state of the lubricating base oil product.

Preferably, the molar ratio of the phosphorous oxytrimethylate, the fatty acid and the benzoic acid is 1 (1-2) to (1-2.1).

The catalyst is an acidic catalyst.

The catalyst is selected from one or more of concentrated sulfuric acid, phosphoric acid, p-toluenesulfonic acid, ZnO or phthalate ester. Phosphoric acid and p-toluenesulfonic acid are commonly used.

The dosage of the catalyst is 0.5-3 wt% of the total dosage of the trihydroxymethyl phosphorus oxide, the fatty acid and the benzoic acid.

Preferably, the catalyst is used in an amount of 0.8 to 1.5 wt% based on the total amount of the phosphorous trimethylol oxide, the fatty acid and the benzoic acid.

Further preferably, the catalyst is used in an amount of 1 wt% based on the total amount of the phosphorous trimethylol oxide, the fatty acid and the benzoic acid.

While adding the catalyst, the reaction system was preheated to 50-70 ℃. Benzoic acid is a solid at room temperature, and reactants can be uniformly mixed by preheating, and then a catalyst is added.

The vacuum degree is 0.09 MPa.

The crude ester product is post-treated by molecular distillation, the purpose of the treatment is deacidification, the unreacted acid is discharged out of the system, and the catalyst is discharged at the same time. Molecular distillation is a high separation technique, and light and heavy components are very easy to separate. Preferably, the reaction system is heated to 150 ℃ and 180 ℃ for reaction for 7-8 h.

The second object of the present invention is to provide a benzoic acid-phosphoric ester lubricating base oil obtained by the above preparation method, wherein the structures of main products in the benzoic acid-phosphoric ester lubricating base oil are respectively shown in formulas (I), (II) and (III):

wherein R is a hydrocarbyl group. The prepared benzoic acid-phosphate ester lubricating base oil has excellent lubricating property and high temperature resistance, and also has extreme pressure abrasion resistance. The main occurrence of these three structures of compounds in lubricating base oil products is due to: 1. the invention controls the reaction which can generate other structures as less as possible according to the molar ratio; 2. due to the existence of steric hindrance, the compounds with the structural formula of two adjacent benzene rings can be said to be very few; 3. as a result, if all three substituents are benzoic acid, the product is in a solid state, and the product obtained is a liquid with better fluidity; 4. the infrared spectrum has a benzene ring peak, which indicates that the substituent on the obtained product has a benzene ring structure, so that three substituents cannot be fatty acid. For the above reasons, the probability of generation of compounds other than these three structures is very small and negligible.

Preferably, R is a saturated alkyl group or an unsaturated alkenyl group.

The third purpose of the invention is to provide the application of the benzoic acid-phosphate ester lubricating base oil in the field of lubrication, wherein the benzoic acid-phosphate ester lubricating base oil is directly used as the base oil of lubricating oil.

Trimethylol phosphorus oxide (THPO) is a novel environment-friendly organic phosphorus flame retardant, has the advantages of excellent flame resistance and lubricating property, good thermal stability, hydrolysis resistance, biodegradability, no toxicity and the like, and is applied to the fields of flame retardants, lubricating oil, medical intermediates and the like. On the basis of the research result of trimethylolpropane oleate lubricating oil, phosphorus Trimethyloloxide (THPO) containing P polyalcohol is adopted as a raw material, and fatty acid and benzoic acid (before the invention, no report about improvement of the anti-wear performance of lubricating base oil based on a rigid structure of a benzene ring is provided, and the benzoic acid is the simplest acid with a benzene ring structure, so that whether the acid mixed with the benzoic acid has excellent anti-wear performance cannot be determined) are directly subjected to esterification reaction in a vacuum distillation mode, and the benzoic acid is used for replacing part of the fatty acid to react to generate the lubricating base oil with the rigid structure. The base oil of the phosphate ester contains adsorption centers of a plurality of polar groups such as C ═ O, P ═ O and the like, the special molecular structure enables the base oil to effectively protect the surface of a friction pair at different temperature ranges, and the base oil can be adsorbed on the surface of the friction pair to generate a friction physical and chemical action and form a hard chemical reaction film, thereby effectively protecting the friction pair and reducing the abrasion, and the base oil has good high temperature resistance, good lubricating property, biodegradability and flame resistance.

Compared with the prior art, the invention has the following characteristics:

1. the invention provides a preparation method of benzoic acid-phosphate lubricating base oil, which can improve the extreme pressure wear resistance of the lubricating base oil to a greater extent after rigid molecules are introduced.

2. The invention adopts the polyol containing P as the reaction raw material, provides a new synthetic route for the development of the phosphate base oil, and has certain theoretical value and practical significance.

3. The preparation method of the one-step synthesis provided by the invention is simple and easy to control.

Drawings

FIG. 1 is an infrared spectrum of a benzoic acid-phosphate lubricating base oil;

FIG. 2 is a thermal stability analysis plot of a benzoic acid-phosphate lubricating base oil;

FIG. 3 is a plot of the appearance of a plaque formed by four-ball performance testing of one lower ball in example 5 lubricated with benzoic acid-phosphate lubricating base oil.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

Example 1

The preparation method comprises the following steps: putting 14.16g (0.101mol) of trihydroxymethyl phosphorus oxide (THPO), 56.43g (0.200mol) of Oleic Acid (OA) and 13.26g (0.109mol) of Benzoic Acid (BA) into a four-neck flask, uniformly mixing, heating to 60 ℃, adding 0.832g of p-toluenesulfonic acid, keeping the vacuum degree at 0.09MPa, heating to 180 ℃ under stirring, continuing to react for 8 hours, and obtaining crude ester after the reaction is finished; after molecular distillation (the set temperature is 230 ℃, in the separation process, a liquid sample is quickly scraped into a layer of liquid film, after 230 ℃, the liquid film is evaporated and diffused, the average free path of a substance with small molecular weight is large, the diffusion speed is high, the liquid is collected through an internal condenser, and on the contrary, the average free path of the substance with large molecular weight is small, the diffusion speed is low, the substance with small molecular weight does not reach the condenser and is separated from the substance with small molecular weight, so that light and heavy components are separated due to different diffusion speeds), benzoic acid-phosphate ester lubricating base oil (the same below) is obtained, the esterification rate reaches 93.12%, and the product is tested, and the test results are shown in table 1.

The formula of the esterification rate is as follows:

in the formula:

x is the esterification rate%

I is the acid value mgKOH/g of the reaction system; (test according to GB/T264-83, same below)

I₁The initial acid value is mgKOH/g;

the infrared spectrum of the product is shown in figure 1, and 3005cm can be seen^-1The absorption peaks around are-C-H stretching vibration absorption peaks; 2923. 2856cm^-1Absorption peaks at left and right are respectively-CH₃and-CH₂-a stretching vibration absorption peak; 1752cm^-1The absorption peak at (a) is a typical ester carbonyl-C ═ O stretching vibration absorption peak; 1601cm^-1Is shown as a benzene ring absorption peak; 1461cm^-1The absorption peak is the P ═ O stretching vibration absorption peak, and the obtained product can be proved to be matched with the target product.

The thermal stability of the product is shown in fig. 2, wherein TG is thermogravimetric analysis curve and DTG is microtransmeric thermogravimetric analysis curve, it can be seen that the decomposition temperature of benzoic acid-phosphate lubricating base oil is 375 ℃, the complete decomposition temperature is more than 700 ℃, indicating that the product has excellent thermal stability.

Example 2

Putting 14.45g (0.103mol) of phosphorus trimethyloloxide, 35.37g (0.125mol) of oleic acid and 25.23g (0.207mol) of benzoic acid into a four-neck flask, uniformly mixing, heating to 60 ℃, adding 0.766g of phosphoric acid, keeping the vacuum degree at 0.09MPa, heating to 150 ℃ under stirring, continuing to react for 8 hours, and obtaining crude ester after the reaction is finished; the crude ester was deacidified and post-treated to obtain benzoic acid-phosphate ester lubricating base oil with an esterification rate of 80.15%, and the product was tested with the test results shown in table 1.

Example 3

Putting 14.82g (0.106mol) of phosphorus trimethyloloxide, 30.03g (0.107mol) of palmitic acid and 27.45g (0.225mol) of benzoic acid into a four-neck flask, uniformly mixing, heating to 60 ℃, adding 0.689g of p-toluenesulfonic acid, keeping the vacuum degree at 0.09MPa, heating to 160 ℃ under stirring, continuing to react for 7 hours, and obtaining crude ester after the reaction is finished; performing deacidification post-treatment to obtain the benzoic acid-phosphate lubricating base oil, wherein the esterification rate reaches 82.77%, and the product is tested, and the test result is shown in table 1.

Example 4

Putting 15.22g (0.108mol) of trihydroxymethyl phosphorus oxide, 59.78g (0.213mol) of linoleic acid and 13.56g (0.111mol) of BA into a four-neck flask, uniformly mixing, heating to 60 ℃, adding 0.887g of p-toluenesulfonic acid, keeping the vacuum degree at 0.09MPa, heating to 160 ℃ under stirring, continuing to react for 8 hours, and obtaining crude ester after the reaction is finished; the crude ester was deacidified and post-treated to obtain benzoic acid-phosphate ester lubricating base oil with an esterification rate of 91.45%, and the product was tested, with the test results shown in table 1.

TABLE 1 test results for benzoic acid-phosphate lubricating base oils prepared in examples 1-4

Item	Appearance state	Acid value (mgKOH/g)	Esterification ratio (%)
				Example 1	Light yellow, clear and transparent	10.1	93.12
Example 2	Deep yellow turbidity	35.2	80.15
				Example 3	Yellow, clear and transparent	20.3	82.77
Example 4	Light yellow, clear and transparent	13.7	91.45

The acid value is an index of lubricating oil products, and the use of the lubricating oil and the damage degree of the lubricating oil to machinery are influenced by the acid value. As can be seen from Table 1, the acid numbers of several lubricating base oils produced by the present invention are within reasonable ranges.

Example 5

Research on extreme pressure antiwear performance of benzoic acid-phosphate ester lubricating base oil:

the wear resistance of the lubricating oil is measured by using a four-ball tester according to NB/SH/T0189-. The specific method comprises the following steps: three steel balls (hereinafter referred to as "lower balls") having a diameter of 12.7mm were taken, clamped in an oil box and immersed in the test oil (i.e., the benzoic acid-phosphoric ester lubricating base oil prepared in example 1), another steel ball (hereinafter referred to as "upper ball") having the same diameter was placed on the top of the three lower balls, subjected to the test force with a predetermined load, in three-point contact with the three lower balls in the oil box, after which the test oil was heated, and when the test oil reached a predetermined test temperature (i.e., 75 ℃), the upper ball was rotated at a predetermined rotational speed for 60min, and then the test was completed. The wear-resisting performance of the lubricating base oil is evaluated by measuring the wear-resisting diameters of three lower balls and taking the average value of the wear-resisting diameters.

The test conditions were:

test load: 15.0kgf rotation speed: 1200rmp

Operating time: 3600s initial temperature: 75 deg.C

FIG. 3 is a morphology chart of a grinding spot formed by a four-ball method performance test of one lower ball under the lubrication of benzoic acid-phosphate lubricating base oil (the scale bar of FIG. 3 is 0.5mm), and it can be seen from FIG. 3 that under the lubrication of the lubricating base oil, the grinding spot width of the lower ball is small, the grinding scar is light, the friction surface is smooth and flat, and no serious furrow appears. The average measured wear scar diameter was 0.238mm and is summarized in Table 2 (i.e., the target product in Table 2).

Comparative example 1

The mineral oils were tested according to NB/SH/T0189-2017, the remaining parameters being the same as in example 5, and the average value of the measured wear-mark diameters was 0.56mm, which is summarized in Table 2.

Comparative example 2

The synthetic hydrocarbons were tested according to NB/SH/T0189-2017, the remaining parameters being the same as in example 5, and the average value of the measured wear-mark diameters was 0.53mm, which is summarized in Table 2.

Comparative example 3

Triphenyl phosphate was tested according to NB/SH/T0189-2017, the remaining parameters being the same as in example 5, and the average value of the measured wear-mark diameters was 0.54mm, which is summarized in Table 2.

TABLE 2 test results of example 5 and comparative examples 1 to 3 using four-ball method for performance test

Sample (I)	Mineral oil	Synthetic hydrocarbons	Tricresyl phosphate	Target product
					Test load/kfg	15.0	15.0	15.0	15.0
Initial temperature/. degree.C	75	75	75	75
					Run time/s	3600	3600	3600	3600
Abrasive grain diameter/mm	0.56	0.53	0.54	0.24

As can be seen from Table 2, compared with other products, the benzoic acid-phosphate ester lubricating base oil prepared by the invention has relatively small diameter of the generated abrasion marks, which shows that the base oil has excellent wear resistance, can effectively reduce the abrasion and achieves the effect of protecting parts.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.