JPH08209162A - Reaction product of ester - Google Patents

Abstract

PURPOSE: To obtain a reaction product of an ester which is excellent not only in oxidation resistance, hydrolysis resistance, etc., but also in compatibility with a hydrogen-containing fluoroalkane refrigerant and is suitable as a synthetic lubricant. CONSTITUTION: This reaction product of an ester is obtd. by using a monoalkylene glycol-hydroxycarboxylic acid ester and an aliph. monocarboxylic acid as the essential components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a synthetic ester lubricating oil having a high viscosity index and a low pour point, which is excellent in heat resistance, weather resistance, and hydrolysis resistance, and particularly a phase with a hydrogen-containing fluoroalkane-based refrigerant. The present invention relates to an ester reaction product suitable for use as a refrigerator oil having excellent solubility.

[0002]

2. Description of the Related Art In recent years, the conditions under which lubricating oils are used have become more severe with the rapid development of various industries, and high thermal stability is required together with excellent lubricating oil properties such as viscosity index and pour point. However, the performance of conventional mineral oil is unsatisfactory. On the other hand, ester synthetic oils have come to be used, but increase in acid value and viscosity change due to oxidation and hydrolysis are likely to occur, and especially as a lubricating oil used at extremely high temperature such as turbo engine oil. Was not completely satisfied. Refrigerating machine oil needs to have thermal stability and compatibility with a refrigerant. Especially, in the case of a lubricating oil used in a hydrogen-containing fluoroalkane-based refrigerant atmosphere, a conventional lubricating oil can satisfy both compatibility and thermal stability. Not really.

[0003]

In view of the above problems, the present invention has excellent lubricating oil characteristics, heat resistance,
It is an object of the present invention to provide an ester reactant suitable for use as a refrigerating machine oil that is compatible with a synthetic lubricating oil having excellent weather resistance and hydrolysis resistance, particularly a hydrogen-containing fluoroalkane-based refrigerant in a wide temperature range.

[0004]

As a result of various studies to achieve the above object, the present inventor has found that a specific ester compound can achieve the above object, and completed the present invention. It was That is, the present invention relates to an ester reaction product obtained from a hydroxycarboxylic acid polyol ester and an aliphatic monocarboxylic acid.

The ester reaction product according to the present invention can be widely used as a main component of automobile engine oils, automobile gear oils, industrial gear oils, lubricating oils for rolling, and the like, and is particularly wide with hydrogen-containing fluoroalkane-based refrigerants. Since it is compatible in the temperature range, it can be used as the main component of refrigerating machine oil.

The hydroxycarboxylic acid polyol ester used in the present invention is a monoester, a diester, a polyester or a mixture thereof produced by an esterification reaction of a hydroxycarboxylic acid and a polyhydroxy compound, a self-condensation of a hydroxyalkyl aldehyde. There are monoester compounds and the like produced by the reaction, but the method for producing the product is not particularly limited.

Hydroxycarboxylic acids used in the production of hydroxycaponic acid polyol ester include glycolic acid, lactic acid, hydroxyisobutyric acid, hydroxypivalic acid and hydroxyoctanoic acid, and polyvalent hydroxy compounds include neopentyl. Glycol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythrium. Lithol, dipentaerythritol,
Tripentaerythritol, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 2-ethyl-1,3-hexanediol
Le, glycerin, diglycerin, polyglycerin, 1,
2,4-butanol, 1,2,6-hexanetriol, sorbitol, mannitol and the like can be mentioned.
As the hydroxyalkyl aldehyde, glyco-
Lualdehyde, hydroxyisobutyraldehyde, 4-
Examples include hydroxy-3-methylbutyraldehyde and hydroxypivalaldehyde.

The aliphatic monocarboxylic acid used in the present invention includes acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, caproic acid, 2
-Methylvaleric acid, 3-methylvaleric acid, 4-methylvaleric acid, 2,2-dimethylbutyric acid, 2-ethylbutyric acid, tert-butylbutyric acid, enanthic acid, 2,2-dimethylpentanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 2-methylhexanoic acid, 4 -Methylhexanoic acid, 5-methylhexanoic acid, caprylic acid, 2-ethylhexanoic acid, 3,5-dimethylhexanoic acid, 2,2-dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 2-propylpentanoic acid, pelargonic acid , 2,2-dimethylheptanoic acid,
3,3,5-trimethylhexanoic acid, 2-methyloctanoic acid, 2-ethyloctanoic acid, 2-ethylheptanoic acid,
Examples thereof include 3-methyloctanoic acid, capric acid, undecanoic acid, and lauric acid, and lower alkyl esters and acid anhydrides thereof can be used as well.

The ester reaction product obtained in the present invention is produced by a conventional esterification method. For example, the reaction is carried out at a reaction temperature of 100 to 250 ° C. in the presence or absence of a catalyst and, if necessary, in the presence of a solvent such as toluene or xylene, while removing a reaction double product such as water out of the system. . Further, after the reaction, if necessary, post-treatment such as alkali washing, water washing, adsorption and the like can be performed.

The synthetic lubricating oil according to the present invention contains the above ester as a main component, but depending on the purpose of use, mineral oil, poly α-olefins, alkylbenzenes, esters other than the above, polyethers, perfluoropolyethers. Alternatively, a synthetic oil such as phosphate ester may be blended. If necessary, a lubricating oil additive such as an antioxidant, an extreme pressure agent, an oiliness improver, an antifoaming agent, a metal deactivator, etc., which is usually used, can be added.

[0011]

INDUSTRIAL APPLICABILITY The ester reaction product of the present invention is excellent in lubricating oil properties such as viscosity index and pour point, and also excellent in heat resistance, weather resistance and hydrolysis resistance, and is used as a lubricating oil used under severe conditions. It is excellent, has excellent compatibility with a hydrogen-containing fluoroalkane-based refrigerant, and is also excellent as a refrigerating machine oil.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0013]

[Production Example 1] 300 g of powdered hydroxypivalaldehyde was charged into a four-necked flask equipped with a stirrer, a nitrogen blowing tube, a thermometer, and a separator equipped with a cooling tube, and dissolved by heating to reach 90 ° C. At that time, tetrakisacetylacetonatozirconium as a catalyst was added at 0.03% to hydroxypivalaldehyde. Stop heating at the same time as the catalyst is added. When the temperature reached 148 ° C to 130 ° C, the reaction was stopped by quenching. The product obtained is from 140
Vacuum distillation was performed at 153 ° C./3 to 6 mmHg to obtain 285 g of hydroxypivalic acid neopentyl glycol monoester. Of this, 204 g (1 mol) and caproic acid 11
6 g (1 mol), 158 g (1 mol) of pelargonic acid and 0.9 g of dibutyltin oxide as a stirrer,
A four-necked flask equipped with a nitrogen blow-in tube, a thermometer, and a separator equipped with a condenser was charged into a four-necked flask and heated to 220 ° C., and the produced water was removed from the system to esterify until a theoretical amount of water was produced. The reaction was carried out. After completion of the reaction, the product was washed with a 5% aqueous sodium hydroxide solution and washed with water, dehydrated, and treated with clay to obtain a reaction product A.

[0014]

[Production Example 2] In a four-necked flask equipped with a stirrer, a nitrogen blowing tube, a thermometer, and a separator equipped with a cooling tube, 134 g (1 mol) of trimethylolpropane, 118 g (1 mol) of hydroxypivalic acid and 0.9 g of tetrabutoxytitanium was charged as a catalyst, the mixture was heated to 180 ° C., the esterification reaction was carried out until the theoretical amount of water was generated while removing the generated water outside the system, and hydroxypivalic acid trimethylolpropane monoester was obtained. . Enanthate 260
g (2 mol), 2,2-dimethylbutanoic acid 130 g (1
Mol) was added and the mixture was heated to 220 ° C., and the esterification reaction was carried out until the theoretical amount of water was produced while removing the produced water out of the system. After completion of the reaction, the same purification as in Production Example 1 was carried out to obtain a reaction product B.

[0015]

Production Example 3 A reactor similar to that of Production Example 2 was charged with 104 g (1 mol) of neopentyl glycol, 236 g (2 mol) of hydroxypivalic acid, and 0.9 g of dibutyltin oxide as a catalyst, and heated to 180 ° C. The produced water was removed from the system, and the esterification reaction was performed until a theoretical amount of water was produced to obtain hydroxypivalic acid neopentyl glycol ester. To this, 260 g (2 mol) of enanthic acid was added, heated to 220 ° C., and the esterification reaction was carried out until the theoretical amount of water was produced while removing the produced water out of the system. After completion of the reaction, the same purification as in Production Example 1 was carried out to obtain a reaction product C.

[0016]

PRODUCTION EXAMPLE 4 Hydroxyisobutyric acid g (1 mol) and pentaerythritol 136 g were placed in the same reactor as in Production Example 2.
(1 mol) and dibutyltin oxide as a catalyst 1.
0 g was charged and the mixture was heated to 180 ° C., and the esterification reaction was performed until the theoretical amount of water was generated while removing the generated water out of the system to obtain hydroxyisobutyric acid pentaerythritol monoester. To this was added 288 g (2 mol) of 2-ethylhexanoic acid and 232 g (2 mol) of caproic acid, and the temperature was 220 ° C.
The esterification reaction was performed until the theoretical amount of water was produced while the produced water was removed from the system. After completion of the reaction, the same purification as in Production Example 1 was carried out to obtain a reaction product D.

[0017]

Comparative Example 1 In the same reactor as in Production Example 152, propylene glycol 152 g (2 mol) and adipic acid 146 g (1
Mol) and 400 g (2 mol) of lauric acid were charged and reacted in the same manner as in Production Example 2 to obtain an ester reaction product (E).

[0018]

Comparative Example 2 Comparative Example 1 using 136 g (1 mol) of pentaerythritol and 520 g (4 mol) of enanthate.
Was reacted in the same manner as in to obtain pentaerythritol tetraenanthate (F).

[0019]

Comparative Example 3 Adipic acid dioctyl ester (G) was obtained by the same reaction as in Comparative Example 1 using 146 g (1 mol) of adipic acid and 260 g (2 mol) of 2-ethylhexanol.

The physical properties of the compounds of the above Production Examples and Comparative Examples are shown in Table 1, and the evaluation results of thermal stability, hydrolyzability and compatibility are shown in Table 2. The evaluation methods were as follows.

Thermal stability: 60 g of sample oil was placed in a 100 ml sample bottle and the increase in acid value and kinematic viscosity ratio (40 ° C.) after heating at 140 ° C. for 168 hours were measured.

Hydrolysis resistance: 60 g of sample oil, 10,000 ppm of water, copper, iron and aluminum having a diameter of 3 mm and a length of 27 mm as a catalyst were put in a 250 ml sample bottle and sealed, and the acid value after heating at 140 ° C. for 168 hours. The increase amount and the kinematic viscosity ratio (40 ° C.) were measured.

Compatibility with Freon: Inner diameter 7 mm, length 24
Freon HFC134a and sample oil were sampled and sealed in a 0 mm Pyrex glass tube so that the oil ratio was 10%.
The two phase separation temperature at 70 ° C-80 ° C was measured.

[0024]

[Table 1]

[0025]

[Table 2]

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Claims (3)

[Claims] 1. An ester reaction product obtained from a hydroxycarboxylic acid polyol ester and an aliphatic monocarboxylic acid. 2. The ester reaction product according to claim 1, wherein the hydroxycarboxylic acid polyol ester is a hydroxycarboxylic acid alkylene glycol ester. 3. The hydroxycarboxylic acid alkylene glycol ester is represented by the general formula 1 The ester reaction product according to claim 2, wherein