RU2191191C1 - (mu-stearic acid)jexastearatolanthanum(iii) trihydrate as antiwear additive for lubricating oils - Google Patents

Abstract

FIELD: oil additives. SUBSTANCE: invention provides novel compound: (mu-stearic acid)jexastearatolanthanum(III) trihydrate with general formula (μ wherein μ is (R)₃La←_O=C(R¹)-(H)O_→La(R)₃•3H₂O, and C₁₈H₃₅O₂ id R¹. This compound can be used as oil-soluble additive for different friction assemblies in transport equipment. EFFECT: improved antiwear and antifriction efficiency. 7 dwg

Description

где R - С₁₈Н₃₅O₂, R¹ - С₁₇Н₃₅,
и может быть использовано в качестве маслорастворимой присадки в различных узлах трения для транспортной техники, в частности, для автотракторной техники, мелиоративно-строительных машин, для улучшения противоизносных и антифрикционных свойств масел.The invention relates to the field of coordination compounds containing an element of group III of the Periodic system D.I. Mendeleev, namely, to new chemical compounds of rare-earth elements - (μ-stearic acid) hexastearatolantane (III) trihydrate (lanthanum stearate trihydrate) of the general formula

where R is C ₁₈ H ₃₅ O ₂ , R ¹ is C ₁₇ H ₃₅ ,
and can be used as an oil-soluble additive in various friction units for transport equipment, in particular, for automotive tractors, reclamation-building machines, to improve antiwear and antifriction properties of oils.

 Known additive for lubricating oils, including 14 wt.% Pyrophoric iron, 43 wt. % oleic acid, the rest is oil (See RF patent 2112782, IPC C 10 M 125/04).

 However, the method of obtaining this additive is quite laborious.

 Known antiwear additive using compounds of rare earth elements (See AS USSR 1373687, IPC C 01 F 17/00, C 10 M 159/18).

 However, it is used to improve the antiwear properties of greases only.

 The objective of the invention is the creation of additives to increase wear resistance, reduce friction losses of base oils, as well as expand the range of oil-soluble additives.

где R - С₁₈Н₃₅O₂, R¹ - С₁₇Н₃₅,
обладающего свойством растворяться в масле. Это свойство, обнаруженное авторами во вновь синтезированном ими веществе, позволяет использовать его в качестве противоизносной присадки.The problem is solved by obtaining a new compound, the structure and property of which are not described in the literature, namely, lanthanum stearate trihydrate of the General formula

where R is C ₁₈ H ₃₅ O ₂ , R ¹ is C ₁₇ H ₃₅ ,
with the ability to dissolve in oil. This property, discovered by the authors in a substance newly synthesized by them, allows its use as an antiwear additive.

An analysis of the data on the use of coordination compounds suggests that their antiwear effect is due to their participation in tribochemical reactions, i.e. they can react with friction surface metals according to the scheme
M + M ¹ A -> MA + M ¹ ,
where M is the metal of the surface layer;
M ¹ - metal complexing agent;
A is an organic ligand.

 The newly formed coordination compound MA ultimately provides a reduction in wear of the main material of the part.

The invention is illustrated by drawings, where
In FIG. Figure 1 shows the graphs of changes in the friction moment during the wear test for AU oil (curve 1) and for AU oil with an additive of lanthanum stearate trihydrate (curve 2).

 Figure 2 shows a graph of the change in the friction moment during the wear test for oil "P" (curve 1) and for oil "P" with an additive of lanthanum stearate trihydrate (curve 2).

 In FIG. Figures 3 and 4 show the wear diagrams of the samples when tested with AU oil (1), with AU oil with an additive of lanthanum stearate trihydrate (2), with P oil (3), with P oil with an additive of lanthanum stearate trihydrate (4); figure 3 - for the roller, figure 4. - for the block.

 In FIG. Figure 5 shows a graph of temperature changes during the wear test for AU oil (curve 1) and for AU oil with an additive (curve 2).

 Figure 6 shows the change in the friction moment during the setting test for oil "AU" (curve 1) and for oil "AU" with an additive (curve 2).

 7 is a diagram of the wear of parts of an axial piston pump for the distributor (1) and for the block (2).

The proposed substance is prepared as follows. 7.52 g (0.29 M) of 7-aqueous lanthanum trichloride are dissolved in 70 ml of distilled water. 17.24 g (1.2 M) of stearic acid are dissolved in 50 ml of ethyl alcohol by heating in a water bath (80 ^{° C.} ). 3.4 g (2.0 M) of potassium hydroxide are dissolved in 30 ml of ethyl alcohol. All solutions are filtered. When draining solutions, a white precipitate immediately precipitates. The resulting salts are filtered on a Bruchner funnel and washed with a water-alcohol solution (1: 1) until a negative reaction to a chlorine ion, and dried in air to constant weight. The yield of the target product is 75%.

Found,%: La - 12.03; C 65.31; H - 10.96
Calculated,%: La - 12.01; C 65.34; H - 10.89
La ₂ (C ₁₈ H ₃₅ O ₂ ) ₆ • C ₁₈ H ₃₆ • O ₂ • 3H ₂ O
The resulting substance is a white crystalline substance. Its crystalline hydrate is stable up to 60 ^o C. Dehydration occurs in the temperature range 60 ^o C-130 ^o C.

X-ray diffraction calculated interplanar distances and intensities of reflexes of lanthanum (III) 3-water stearate. The most intense reflexes; d _n , A: 12.678; 9.668; 6,917.

The structure of lanthanum stearate is confirmed by IR spectra. Thus, in the spectrum of lanthanum stearate, absorption bands with maxima of 1550-1520 cm ^-1 and 1400-1390 cm ^{-1 are} assigned to stretching antisymmetric and symmetric vibrations of the dissociated СOO ^- group, which indicates the replacement of hydrogen of the carboxyl group by metal. The fact that the molecule of the undissociated acid is part of the compound is evidenced by the absorption band with a maximum of 2550 cm ^-1 , which is attributed to stretching vibrations of the bound hydroxyl group of OH in the undissociated carboxyl group, and is present both in the IR spectrum of the acid and the IR spectrum of stearate La. As well as the absorption band with a maximum of 1740 cm ^-1 , corresponding to the stretching vibrations of carbonyl CO, which is also present in the IR spectra of acid and lanthanum stearate. It can be assumed that the stearic acid molecule is bound to two molecules of the LaR ₃ salt through two oxygen atoms by donor-acceptor bonds, since oxygen atoms have lone electron pairs and act as a donor, and free metal orbitals as acceptors. Two broad absorption bands with maxima of 3410 cm ^–1 and 3170 cm ^{–1 are} assigned to stretching antisymmetric and symmetric vibrations of the water group, and the absorption band with a maximum of 1650 cm ^–1 is attributed to deformation vibrations of OH water.

The resulting lanthanum stearate has the ability to dissolve in oils. At a temperature of 25 ^o With its solubility in 100 ml of oil is 0.8 g. Thus, the inventive substance can be used as an additive in base oils, in the following ratio, wt.%:
(μ-stearic acid) hexastearatolantane (III) trihydrate - 0.8
base oil - the rest
The effectiveness of the proposed additives was tested in laboratory tests on a friction machine SMC-2. The tests were carried out according to the "roller-block" scheme at a constant frequency of rotation of the roller 300 min ^-1 and a load of 200 N applied to the run-in samples. The test time is 6 hours at a sliding speed of 0.785 m / s. The roller is made of steel 45, and the block of gray cast iron C _h -20. Spindle oil “AU” GOST 1642-75 and oil “P” GOST 38801434-87, used as RZHG (hydraulic fluid), were taken as base oils.

 Tribological technical tests of RGGs were carried out according to the following output characteristics: the magnitude of the moment due to friction, wear in units of mass, temperature in the contact zone, setting load.

 As follows from the drawings, the friction moment of the samples tested on oil "AU", decreased from 3.4 to 2.9 Nm (Figure 1).

 The introduction of lanthanum stearate trihydrate into it allows you to reduce the friction moment during the entire period of work and especially intensively at the beginning of the established mode of operation. The moment at the beginning of the work was 3.3 Nm, and at the end 2.1 Nm, which is 25% less compared to the base oil.

 Figure 2 shows that the friction moment of the samples tested on oil "P" decreased from 4.05 to 3.5 Nm. The introduction of lanthanum stearate trihydrate reduced the friction moment from 4.0 to 2.45 Nm.

 The wear of the samples in oil "AU" for the roller amounted to 0.0024 g (Figure 3) and 1.31 g for the pads (Figure 4). The wear of the samples in oil "P" for the roller amounted to 0.0027 g (figure 3) and 1.45 g for the pads (Figure 4).

The introduction of lanthanum stearate trihydrate allowed to reduce the wear of the roller and the pads, respectively, to 0.0017 g and 1.18 g in oil "AU" and 0.0021 g and 1.33 g, respectively, for oil "P" (Figs. 3, 4). Compared to base oil, wear is reduced by 10%. During testing, the temperature of the oil was recorded. As can be seen from the graph (Figure 5), the additive allowed to reduce the temperature of the samples from 105 to 65 ^o C (oil "AU" - from 110 to 85 ^o C). The graph (Figure 6) shows the changes in the friction moment during the setting test. With the introduction of additives in the "AU" tribological conjugation remains operational up to 1700 N, in oil, up to 1200 N (Fig.6). The setting of samples working on base oil occurred 27 minutes after the start of the test, and working on oil with an additive - after 50.5 minutes. The additive allowed to increase the setting load by 1.65 times and extend the operating time of the tribo-conjugation by 1.8 times. This is very important in actual use, as in case of sudden sharp overloads, the friction pair will remain operational for a sufficiently long period of time.

 Operational tests of additives in "AU" were carried out in a real friction unit - in an axial piston pump for a distributor and a unit. The total duration of the tests was 300 hours (Fig.7). Figure 7 shows that the wear of the parts was 2.76 g and 2.51 g, respectively, for the distributor and 3.16 g and 2.83 g for the block, respectively, on the base lubricant and lubricant with an additive. There is an improvement in antiwear properties by 10% when using the proposed lubricant additives compared with the base lubricant.

Claims (1)

(μ-Stearic acid) hexastearatolantane (III) trihydrate of the general formula

where R is C ₁₈ H ₃₅ O ₂ , R ¹ is C ₁₇ H ₃₅ ,
as an antiwear additive to base oils.

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