JP2529656C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a hydrogen-containing fluoroalkane compound having a high viscosity index, a low pour point, excellent heat resistance, weather resistance and hydrolysis resistance. The present invention relates to a refrigerating machine oil having excellent compatibility with a refrigerant. [0002] In recent years, the use conditions of lubricating oils have become severer with the rapid development of various industries, and high thermal stability is required along with excellent lubricating oil properties such as viscosity index and pour point. As a result, the performance of conventional mineral oil is not satisfactory. In particular, refrigerating machine oils must have both heat stability and compatibility with refrigerants, but lubricating oils used in a hydrogen-containing fluoroalkane-based refrigerant atmosphere can satisfy both compatibility and heat stability with conventional lubricating oils. Not really. [0003] In view of the above problems, the present invention has excellent lubricating oil properties, heat resistance,
It is an object of the present invention to provide a refrigerating machine oil having excellent weather resistance and hydrolysis resistance, particularly having a compatibility with a hydrogen-containing fluoroalkane-based refrigerant in a wide temperature range. Means for Solving the Problems The present inventors have conducted various studies to achieve the above object, and as a result, have found that a specific ester compound can achieve the above object, and completed the present invention. I came to. That is, the present invention comprises, as a main component, an ester reactant obtained from a hydroxycarboxylic acid polyol ester and a primary and / or secondary aliphatic monocarboxylic acid,
The present invention relates to a refrigerating machine oil used in a hydrogen-containing fluoroalkane-based refrigerant atmosphere. The synthetic lubricating oil according to the present invention can be used as a refrigerating machine oil because it is compatible with a hydrogen-containing fluoroalkane-based refrigerant in a wide temperature range. The hydroxycarboxylic acid polyol ester used in the present invention is a self-condensation of a monoester, a diester, a polyester, a mixture thereof, and a hydroxyalkylaldehyde formed by an esterification reaction of a hydroxycarboxylic acid and a polyvalent hydroxy compound. There is a monoester compound or the like generated by the reaction, but the method for producing the product is not particularly limited. The hydroxycarboxylic acids used in the production of hydroxycarbonic acid polyol esters include glycolic acid, lactic acid, hydroxyisobutyric acid, hydroxypivalic acid, and hydroxyoctanoic acid, and the polyvalent hydroxy compounds are neopentyl. Glycol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythr Litol, dipentaerythritol, tripentaerythritol, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
Polypropylene glycol, 2-ethyl-1,3-hexanediol, glycerin, diglycerin, polyglycerin, 1,2,4-butanthrol, 1,2,2
6-hexanetriol, sorbitol and mannitol, and the like, and hydroxyalkyl aldehydes such as glycolaldehyde, hydroxyisobutyraldehyde, 4-hydroxy-3-methylbutyraldehyde, and hydroxypivalaldehyde Is raised. The primary and / or secondary aliphatic monocarboxylic acids used in the present invention include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, 2-methylvaleric acid, and 3-methylvaleric acid 4, 4-methylvaleric acid,
2-ethylbutyric acid, enanthic 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-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 2-propylpentanoic acid, pelargonic acid, 3, 3,5-trimethylhexanoic acid, 2-methyloctanoic acid,
Examples thereof include 2-ethyloctanoic acid, 2-ethylheptanoic acid, 3-methyloctanoic acid, capric acid, undecanoic acid, and lauric acid, and lower alkyl esters and acid anhydrides thereof can also be used. [0009] The ester reactant obtained in the present invention is produced by a usual 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 and xylene while removing reaction double products such as water out of the system. . After the reaction, post-treatments such as alkali washing, water washing, adsorption and the like can be performed, if necessary. The synthetic lubricating oil of the present invention contains the above-mentioned ester as a main component, but depending on the purpose of use, mineral oil, poly-α-olefin, alkylbenzene, other esters, polyether, perfluoropolyether, phosphorus A synthetic oil such as an acid ester may be blended. If necessary, lubricating oil additives such as antioxidants, extreme pressure agents, oiliness improvers, defoamers, metal deactivators and the like which are usually used can be added. The ester synthetic lubricating oil of the present invention is excellent in lubricating oil properties such as viscosity index and pour point, and is excellent in heat resistance, weather resistance and hydrolysis resistance, and is used under severe conditions. It is excellent as a lubricating oil that has excellent compatibility with hydrogen-containing fluoroalkane-based refrigerants,
Excellent as refrigerating machine oil. Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Example 1 A four-necked flask equipped with a separator equipped with a stirrer, a nitrogen blowing tube, a thermometer, and a cooling tube was charged with 300 g of powdery hydroxypivalaldehyde and dissolved by heating. When the temperature reached ° C, 0.03% of tetrakisacetylacetonatozirconium was added as a catalyst to hydroxypivalaldehyde. Stop heating at the same time as adding catalyst. When the temperature became 148 ° C to 130 ° C, the reaction was stopped by rapid cooling. The obtained product was distilled under reduced pressure at 140 to 153 ° C / 3 to 6 mmHg to obtain 28
5 g of neopentyl glycol monohydroxypivalate monoester were obtained. Of these, 204 g (1 mol), 116 g (1 mol) of caproic acid and 158 g of pelargonic acid
(1 mol) and 0.9 g of dibutyltin oxide as a catalyst were charged into a four-necked flask equipped with a separator equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser tube, and heated to 220 ° C. Was removed until the theoretical amount of water was produced. After completion of the reaction, the product was washed with 5% aqueous sodium hydroxide solution and water and dehydrated, and then subjected to clay treatment to obtain a reaction product A. Example 2 A four-necked flask equipped with a separator equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser tube was charged with 134 g (1 mol) of trimethylolpropane and 118 g (1 mol) of hydroxypivalic acid. Mol) and 0.9 g of tetrabutoxytitanium as a catalyst, heated to 180 ° C., and subjected to an esterification reaction while removing the produced water from the system until a theoretical amount of water was produced. Trimethylolpropane monoester hydroxypivalate I got 260 g (2 mol) of enanthic acid and 2,2-dimethylbutanoic acid 13
0 g (1 mol) was added, the mixture was heated to 220 ° C., and the esterification reaction was carried out while removing the generated water from the system until a theoretical amount of water was generated. After completion of the reaction, the same purification as in Example 1 was performed to obtain a reaction product B. Example 3 A reactor similar to that of 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. The mixture was heated and an esterification reaction was carried out until the theoretical amount of water was produced while removing the produced water out of the system to obtain neopentyl glycol hydroxypivalate. 260 g (2 mol) of enanthic acid was added thereto, and the mixture was heated to 220 ° C., and an esterification reaction was performed until a theoretical amount of water was generated while removing generated water outside the system. After completion of the reaction, the same purification as in Example 1 was performed to obtain a reaction product C. Example 4 A reaction apparatus similar to that of Example 2 was charged with g (1 mol) of hydroxyisobutyric acid, 136 g (1 mol) of pentaerythritol and 1.0 g of dibutyltin oxide as a catalyst, and heated to 180 ° C. Then, an esterification reaction was carried out until a theoretical amount of water was produced while removing generated water from the system to obtain pentaerythritol monoester hydroxyisobutyrate. 288 g (2 mol) of 2-ethylhexanoic acid and 232 g of caproic acid
(2 mol), and the mixture was heated at 220 ° C., and an esterification reaction was carried out until a theoretical amount of water was produced while removing produced water from the system. After completion of the reaction, the same purification as in Example 1 was performed to obtain a reaction product D. Comparative Example 1 The same reactor as in Example 2 was charged with 152 g (2 mol) of propylene glycol, 146 g (1 mol) of adipic acid, and 400 g (2 mol) of lauric acid, and reacted in the same manner as in Example 2. An ester reactant (E) was obtained. Comparative Example 2 A reaction was carried out in the same manner as in Comparative Example 1 using 136 g (1 mol) of pentaerythritol and 520 g (4 mol) of enanthic acid to obtain pentaerythritol tetraenanthate (F). Comparative Example 3 Dioctyl adipate (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. Table 1 shows the physical property values of the respective compounds of the above Examples and Comparative Examples, and Table 2 shows the evaluation results of thermal stability, hydrolyzability, compatibility and the like. In addition, those evaluation methods were implemented by the following methods. Thermal stability: An acid value increase and a kinematic viscosity ratio (40 ° C.) after heating 60 g of sample oil in a 100 ml sample bottle at 140 ° C. for 168 hours were measured. Hydrolysis resistance: In a 250 ml sample bottle, 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 are sealed, and the acid value after heating at 140 ° C. for 168 hours is sealed. The increase and the kinematic viscosity ratio (40 ° C.) were measured. Compatibility with Freon: Freon HFC134a and sample oil were collected and sealed in a Pyrex glass tube with an inner diameter of 7 mm and a length of 240 mm so that the oil ratio was 10%, and the two-phase separation temperature at -70 ° C to 80 ° C was measured. did. [Table 1] [Table 2]

Claims (1)

Claims 1. A refrigerating machine oil used in a hydrogen-containing fluoroalkane-based refrigerant atmosphere, wherein the ester is obtained from a hydroxycarboxylic acid polyol ester and a primary and / or secondary aliphatic monocarboxylic acid. A synthetic lubricating oil comprising a reactant as a main component. 2. The synthetic lubricating oil according to claim 1, wherein said hydroxycarboxylic acid polyol ester is a hydroxycarboxylic acid alkylene glycol ester. 3. The synthetic lubricating oil according to claim 2, wherein the hydroxycarboxylic acid alkylene glycol ester is represented by the following general formula (1). Embedded image (In the formula, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group, which may be the same or different.)