JP5586298B2 - Esters and refrigerator oil - Google Patents

Description

  The present invention relates to esters and refrigeration oils.

  Due to the problem of ozone depletion in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been used as refrigerants in conventional refrigeration equipment, are subject to regulation, and HFC (hydrofluorocarbon) is used as a refrigerant instead. It is being done.

  When CFC or HCFC is used as a refrigerant, mineral oil or hydrocarbon oil such as alkylbenzene has been suitably used as the refrigeration oil. However, when the refrigerant is changed, the refrigeration oil used in the coexistence is compatible with the refrigerant, Refrigerating machine oil needs to be developed for each refrigerant in order to exhibit unpredictable behaviors such as lubricity, melt viscosity with refrigerant, and thermal and chemical stability. Therefore, as a refrigerating machine oil for HFC refrigerant, for example, polyalkylene glycol (see Patent Document 1), ester (see Patent Document 2), carbonate (see Patent Document 3), polyvinyl ether (see Patent Document 4) Etc. are being developed. Among these refrigerating machine oils, esters are widely used for refrigerators and air conditioners.

  Among HFC refrigerants, HFC-134a, R407C, and R410A are standardly used as refrigerants for car air conditioners, refrigerators, and room air conditioners. However, these HFC refrigerants are becoming subject to regulation because of their high global warming potential (GWP) although their ozone depletion potential (ODP) is zero. Therefore, there is an urgent need to develop refrigerants that can replace these HFCs.

  Under such a background, as an alternative to HFC, both ODP and GWP are very small, nonflammable, and the thermodynamic characteristics that are a measure of the refrigerant performance are approximately the same as those of HFC. The use of a fluoropropene refrigerant, which is a kind of saturated fluorinated hydrocarbon refrigerant, has been proposed. Furthermore, the use of a mixed refrigerant of fluoropropene and saturated hydrofluorocarbon, saturated hydrocarbon having 3 to 5 carbon atoms, dimethyl ether, carbon dioxide, bis (trifluoromethyl) sulfide or trifluoroiodomethane is also proposed ( (See Patent Document 5). Among them, difluoromethane refrigerant (HFC-32) is attracting attention as a refrigerant used alone or mixed with fluoropropene because it has a relatively low global warming potential and high refrigeration efficiency among HFC refrigerants.

Japanese Patent Laid-Open No. 02-242888 Japanese Patent Laid-Open No. 03-200895 Japanese Patent Laid-Open No. 03-217495 Japanese Patent Laid-Open No. 06-128578 International Publication WO2006 / 094303 Pamphlet

  An object of the present invention is to provide an ester useful as a base oil for refrigerating machine oil, and a refrigerating machine oil using the ester.

The present invention provides an ester of carboxylic acid and pentaerythritol containing at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid.

The present invention also provides a refrigerating machine oil containing an ester of carboxylic acid and pentaerythritol containing at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid.

  According to the present invention, in a refrigeration system using a difluoromethane refrigerant or a fluoropropene refrigerant, a refrigerating machine oil excellent in low-temperature performance and capable of achieving both refrigerant compatibility and thermal / chemical stability at a high level, and A working fluid composition for a refrigerator is provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The ester according to this embodiment is an ester of a carboxylic acid containing at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid and a polyhydric alcohol (hereinafter referred to as “present”). The ester according to the embodiment ”. Moreover, the refrigerating machine oil which concerns on this embodiment contains the ester which concerns on the said this embodiment.

  The carboxylic acid constituting the ester according to this embodiment may contain either one of 2-ethyl-4-methylpentanoic acid or 2-propyl-4-methylpentanoic acid, or may contain both. . Furthermore, if any one is included, the other carboxylic acid may be included.

  Moreover, as a polyhydric alcohol which comprises the ester concerning this embodiment, the polyhydric alcohol which has 2-6 hydroxyl groups is used preferably.

  Specific examples of the dihydric alcohol (diol) include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, and 2-methyl-1,3- Propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl -1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, , 12-dodecanediol and the like. Specific examples of trihydric or higher alcohols include trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, di- ( Pentaerythritol), tri- (pentaerythritol), glycerin, polyglycerin (glycerin 2-3 trimer), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol Polysaccharides such as xylose, arapinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, and partially etherified products thereof It is. Among these, since it is more excellent in hydrolysis stability, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, di More preferred are esters of hindered alcohols such as-(pentaerythritol), tri- (pentaerythritol), neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane and pentaerythritol, esters of di- (pentaerythritol) Is more preferred, neopentyl glycol, trimethylolpropane, pentaerythritol, di- (pentaerythritol) is more preferred, compatibility with the refrigerant and hydrolysis Since particularly excellent qualitative, pentaerythritol, di - (pentaerythritol) or pentaerythritol and di - mixed esters of (pentaerythritol) is most preferred.

  The ester according to the present embodiment may be a partial ester in which a part of hydroxyl groups of the polyhydric alcohol is not esterified and remains as a hydroxyl group, or a complete ester in which all hydroxyl groups are esterified. Alternatively, it may be a mixture of a partial ester and a complete ester, but is preferably a polyol ester in which two or more of the polyhydric alcohols are esterified, and more preferably a complete ester. The hydroxyl value is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, and most preferably 3 mgKOH / g or less.

  The refrigerating machine oil according to this embodiment may contain one kind of polyol ester having a single structure as the ester according to this embodiment, or two or more kinds of polyol esters having different structures. A mixture of

  In addition, the ester according to this embodiment is an ester of one fatty acid and one polyhydric alcohol, an ester of two or more fatty acids and one polyhydric alcohol, one fatty acid and two or more fatty acids. Either an ester with a polyhydric alcohol, an ester of two or more fatty acids and two or more polyhydric alcohols may be used. Among these, a polyol ester using a mixed fatty acid, particularly a polyol ester constituted by containing two or more fatty acids in the ester molecule is excellent in low temperature characteristics and compatibility with a refrigerant.

As fatty acids other than 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid used in the present invention, specifically,
Acetic acid, propionic acid, butanoic acid, 2-methylpropionic acid, pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, 2,2-dimethylpropanoic acid, hexanoic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2-ethylbutanoic acid, 2,2-dimethylbutanoic acid, 2,3-dimethylbutanoic acid, heptanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5- Methylhexanoic acid, 2,2-dimethylpentanoic acid, 2,3-dimethylpentanoic acid, 2,4-dimethylpentanoic acid, 3,3-dimethylpentanoic acid, 3,4-dimethylpentanoic acid, 4,4-dimethylpentane Acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 1,1,2-trimethylbutanoic acid, 1,2,2-trimethylbutanoic acid, 1-methylbutanoic acid, 1-ethyl-2-methylbutanoic acid, octanoic acid, 2-ethylhexanoic acid, 3-ethylhexanoic acid, 3,5-dimethylhexanoic acid, 2,4-dimethylhexanoic acid, 3,4- Dimethylhexanoic acid, 4,5-dimethylhexanoic acid, 2,2-dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 5-methylheptanoic acid, 6-methylheptanoic acid, 2-propylpentanoic acid, 3,5,5-trimethylpentanoic acid, nonanoic acid, 2,2-dimethylheptanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 3-methyloctanoic acid, 2-ethyl-2 , 3,3-trimethylbutyric acid, 2,2,4,4-tetramethylpentanoic acid, 2,2,3,3-tetramethylpentanoic acid, 2,2,3,4-tetra Chirupentan acid, fatty acid 2 to 9 carbon atoms such as 2,2-diisopropyl propionic acid;
Examples include decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, oleic acid and other fatty acids having 10 to 20 carbon atoms.

  In this embodiment, when combining other fatty acids with at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid, the other fatty acids have 5 carbon atoms. It is preferable to use ˜7 fatty acids and / or branched fatty acids having 8 to 9 carbon atoms. When at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid is used in combination with a fatty acid having 5 to 7 carbon atoms and / or a branched fatty acid having 8 to 9 carbon atoms Fatty acids other than at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid and fatty acids having 5 to 7 carbon atoms and / or branched fatty acids having 8 to 9 carbon atoms; Compared with the case of using in combination, the compatibility with the refrigerant tends to be further improved. Also, a combination of at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid and a fatty acid having 5 to 7 carbon atoms and / or a branched fatty acid having 8 to 9 carbon atoms. When used, the proportion of the branched fatty acid having 8 to 9 carbon atoms in the fatty acid constituting the polyhydric alcohol fatty acid ester needs to be 80 mol% or less, preferably 75 mol% or less, preferably 70 mol%. The following is more preferable. When the proportion of the branched fatty acid having 8 to 9 carbon atoms exceeds 80 mol%, the compatibility with the refrigerant becomes insufficient.

  Moreover, in addition to C5-C7 fatty acid and / or C8-C9 branched fatty acid, when using fatty acids other than these fatty acids, C5-C7 in the fatty acid which comprises polyhydric alcohol fatty acid ester The ratio of the fatty acid and / or the branched fatty acid having 8 to 9 carbon atoms is preferably 60 mol% or more, more preferably 70 mol% or more, and further preferably 80 mol% or more. When the proportion of the fatty acid having 5 to 7 carbon atoms and / or the branched fatty acid having 8 to 9 carbon atoms is within the above range, both the stability in the presence of the refrigerant and the compatibility with the refrigerant are higher. It tends to be compatible.

  In this embodiment, the polyhydric alcohol fatty acid ester is a mixture of two or more esters having different molecular structures, and it is not always necessary to satisfy the above conditions for each molecule. The said fatty acid should just satisfy | fill the said conditions as the whole fatty acid which comprises alcohol fatty acid ester.

As a preferable example of the acid component constituting the ester according to this embodiment,
2-ethyl-4-methylpentanoic acid;
2-propyl-4-methylpentanoic acid;
2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid;
One or two selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid, pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, 2,2-dimethylpropanoic acid, Hexanoic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2-ethylbutanoic acid, 2,2-dimethylbutanoic acid, 2,3-dimethylbutanoic acid, heptanoic acid, 2-methylhexanoic acid 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, 2,2-dimethylpentanoic acid, 2,3-dimethylpentanoic acid, 2,4-dimethylpentanoic acid, 3,3-dimethylpentanoic acid 3,4-dimethylpentanoic acid, 4,4-dimethylpentanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 1,1,2-trimethylbutane The combination of acid, 1,2,2-trimethyl butanoic acid, 1-ethyl -1-methylbutanoic acid and one or more fatty acids selected from 1-ethyl-2-methylbutanoic acid, and;
One or two selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid, 2-ethylhexanoic acid, 3-ethylhexanoic acid, 3,5-dimethylhexanoic acid, 2 , 4-dimethylhexanoic acid, 3,4-dimethylhexanoic acid, 4,5-dimethylhexanoic acid, 2,2-dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 5 -Methylheptanoic acid, 6-methylheptanoic acid, 2-propylpentanoic acid, 2,2-dimethylheptanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 3-methyloctanoic acid, 2-ethyl-2,3 , 3-Trimethylbutyric acid, 2,2,4,4-tetramethylpentanoic acid, 2,2,3,3-tetramethylpentanoic acid, 2,2,3,4-tetramethylpentane Combinations of and one or more branched fatty acid selected from 2,2-diisopropyl propionic acid, and;
Etc.

  Although the manufacturing method of the ester which concerns on this embodiment is arbitrary, after synthesize | combining carboxylic acid first, ester can be manufactured by esterification reaction with a polyhydric alcohol.

  Although the synthesis method of carboxylic acid is arbitrary, it can manufacture by aldol condensation, for example. More specifically, as an example of the synthesis of 2-ethyl-4-methylpentanoic acid, n-butyraldehyde and isobutyraldehyde are reacted at 40 to 100 ° C. in the presence of an alkali catalyst to give 2-ethyl-4-methylpentene. Then, hydrogenation reaction is carried out for 1 to 5 hours at a hydrogen pressure of 2 to 10 MPa and a reaction temperature of 60 to 150 ° C. in the presence of a catalyst such as palladium on activated carbon to obtain 2-ethyl-4-methylpentanal. After synthesis, the target product can be obtained by air oxidation or the like. Moreover, as a synthesis example of 2-propyl-4-methylpentanoic acid, it can synthesize | combine by the same method except changing n-butyraldehyde of raw material aldehyde into valeraldehyde.

  Although the synthesis method of ester is also arbitrary, for example, the target ester is obtained by making alcohol and carboxylic acid react at 200-300 degreeC under nitrogen stream, and reacting for 10 to 40 hours, spin-dry | dehydrating.

Although the use of the ester which concerns on this embodiment is not specifically limited, It is mainly used as a base oil of lubricating oil. Specifically, for example, engine oil such as gasoline engine oil and diesel engine oil; gear oil such as automobile gear oil (automatic transmission oil, manual transmission oil, differential oil) and industrial gear oil; refrigerator oil Turbine oil; hydraulic oil; air compressor oil; cutting oil, grinding oil, plastic working oil (rolling oil, press oil, forging oil, drawing oil, drawing oil, punching oil, etc.), heat treatment oil, electric discharge machining oil, etc. metalworking oil; machine oil; slideways oil; bearing oil; rust oil; thermal oil; electrically insulating oil; and grease base oil and the like.

  The ester according to this embodiment is particularly preferable when used as a base oil for refrigerator oil. When the ester according to the present embodiment is used as a base oil for refrigerating machine oil, only the ester according to the present embodiment may be used alone (that is, the content of the ester according to the present embodiment is 100% by mass). In addition, a base oil other than the ester according to the present embodiment may be used in combination to such an extent that the excellent performance is not impaired.

  Examples of base oils other than esters according to this embodiment include mineral oils, hydrocarbon-based oils such as olefin polymer alkyldiphenylalkanes, alkylnaphthalenes, and alkylbenzenes, and esters other than esters according to this embodiment (monoesters and constituent fatty acids). 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid-free polyol ester, alkyl aromatic ester, alicyclic carboxylic acid ester, etc.), polyglycol, polyvinyl ether, ketone, polyphenyl ether In addition, synthetic oils containing oxygen such as silicone, polysiloxane, perfluoroether may be used in combination.

  As the synthetic oil containing oxygen, among the above, esters other than the ester according to the present embodiment, polyglycol, and polyvinyl ether are preferably used. Among them, particularly preferred are esters other than the esters according to this embodiment. Examples of esters other than the ester according to this embodiment include esters of polyhydric alcohols and fatty acids such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, and dipentaerythritol, and particularly preferable ones are: An ester of neopentyl glycol and a fatty acid and an ester of dipentaerythritol and a fatty acid.

  The neopentyl glycol ester is preferably a fatty acid ester having 5 to 9 carbon atoms. Specific examples of such neopentyl glycol esters include neopentyl glycol di 3,5,5-trimethyl hexanate, neopentyl glycol di 2-ethyl hexanate, neopentyl glycol di 2-methyl hexanate, Neopentyl glycol di-2-ethylpentanoate, neopentyl glycol and 2-methylhexanoic acid 2-ethylpentanoic acid ester, neopentyl glycol and 3-methylhexanoic acid 5-methylhexanoic acid ester, neopentyl glycol Esters of 2-methylhexanoic acid, 2-ethylhexanoic acid, neopentyl glycol and 3,5-dimethylhexanoic acid, 4,5-dimethylhexanoic acid, 3,4-dimethylhexanoic acid, neopentyl glycol dipentanate , Neo Emissions chill glycol di-2-ethyl pig sulfonate, neopentyl glycol di-2-methyl-pentanate, neopentyl glycol di-2-methyl-pig sulfonate, neopentyl glycol di methyl-pig sulfonates, and the like.

As dipentaerythritol esters, dipentaerythritol and esters of fatty acids having 5 to 7 carbon atoms, dipentaerythritol and esters of fatty acids having 5 to 7 carbon atoms and fatty acids having 8 to 9 carbon atoms are preferable. Specific examples of such dipentaerythritol esters include esters of dipentaerythritol and the following fatty acids.
2-methylbutanoic acid; 3-methylbutanoic acid; hexanoic acid; 2-methylpentanoic acid; 2-ethylbutanoic acid; 2-ethylpentanoic acid; 2-methylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutane 2 types selected from the group consisting of acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid and hexane 3 types selected from the group consisting of acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2 -From methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid Selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid 5 types selected: 6 selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid Species: Seven types selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid; Acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid and 2-ethylbutane And 2-ethylpentanoic acid and 2-methylhexanoic acid; pentanoic acid and 3,5,5-trimethylhexanoic acid; 2-methylbutanoic acid and 3,5,5-trimethylhexanoic acid; 3-methylbutanoic acid and 3,5,5 5-trimethylhexanoic acid; hexanoic acid and 3,5,5-trimethylhexanoic acid; 2-methylpentanoic acid and 3,5,5-trimethylhexanoic acid; 2-ethylbutanoic acid and 3,5,5-trimethylhexanoic acid; 2-ethylpentanoic acid and 3,5,5-trimethylhexanoic acid; 2-methylhexanoic acid and 3,5,5-trimethylhexanoic acid; pentanoic acid and 2-ethylhexanoic acid; 2-methylbutanoic acid and 2-ethylhexane Acid; 3-methylbutanoic acid and 2-ethylhexanoic acid; hexanoic acid and 2-ethylhexanoic acid; 2-methylpentanoic acid and 2-ethylhexanoic acid; 2 -Ethylbutanoic acid and 2-ethylhexanoic acid; 2-ethylpentanoic acid and 2-ethylhexanoic acid; 2-methylhexanoic acid and 2-ethylhexanoic acid; pentanoic acid, 2-ethylhexanoic acid and 3,5,5-trimethyl Hexanoic acid; 2-methylbutanoic acid, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; 3-methylbutanoic acid, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; hexanoic acid and 2- Ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; 2-methylpentanoic acid and 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; 2-ethylbutanoic acid and 2-ethylhexanoic acid and 3,5 , 5-trimethylhexanoic acid; 2-ethylpentanoic acid, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; 2-methylhexane And 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2 types selected from the group consisting of 2-methylhexanoic acid and 3,5,5-trimethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid And 2-ethylhexanoic acid selected from the group consisting of 2-ethylpentanoic acid and 2-methylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2 2-ethyl and 2-ethyl selected from the group consisting of ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid Xanthic acid and 3,5,5-trimethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexane 3 types selected from the group consisting of acids and 3,5,5-trimethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethyl 3 types selected from the group consisting of pentanoic acid and 2-methylhexanoic acid and 2-ethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 3 types selected from the group consisting of 2-ethylpentanoic acid and 2-methylhexanoic acid, 2-ethylhexanoic acid and 3, 5,5-trimethylhexanoic acid; from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid 4 types selected and 3,5,5-trimethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2- 4 types selected from the group consisting of methylhexanoic acid and 2-ethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid And 4 selected from the group consisting of 2-methylhexanoic acid, 2-ethylhexanoic acid and 3,5,5-trimethyl 5-Hexane selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid; 3,5,5-trimethylhexanoic acid; consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid 5 types selected from the group and 2-ethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexane 5 types selected from the group consisting of acids, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid 6 and 3,5 selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid , 5-trimethylhexanoic acid; selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid 6 types and 2-ethylhexanoic acid; consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid 6 types selected from the group, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; pentanoic acid, 2 7 types selected from the group consisting of -methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid and 3,5,5-trimethyl Hexanoic acid; seven kinds selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid; 2-ethylhexanoic acid; selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid and 2-methylhexanoic acid 7 types, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid; pentanoic acid and 2-methylbutane And 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid, 2-methylhexanoic acid, 3,5,5-trimethylhexanoic acid; pentanoic acid and 2-methylbutanoic acid 3-methylbutanoic acid, hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid; pentanoic acid, 2-methylbutanoic acid, and 3-methylbutanoic acid Hexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, 2-ethylpentanoic acid, 2-methylhexanoic acid, 3,5,5-trimethylhexanoic acid and 2-ethylhexanoic acid.

  When blending other oxygen-containing synthetic oil with the refrigerating machine oil according to the present embodiment, the blending amount of the other oxygen-containing synthetic oil is not particularly limited as long as the excellent lubricity and compatibility as the refrigerating machine oil are not impaired. However, when an ester other than the ester according to the present embodiment is blended, it is necessary that it is 90% by mass or less, preferably 85% by mass or less, and 80% by mass or less, based on the total amount of refrigerating machine oil. More preferably, it is 70% by mass or less, even more preferably 60% by mass or less, and most preferably 50% by mass or less; oxygen-containing synthetic oil other than ester Is required to be 50% by mass or less based on the total amount of the refrigerating machine oil, preferably 40% by mass or less, and more preferably 30% by mass or less. If the blending amount of an ester other than pentaerythritol fatty acid ester or other oxygen-containing synthetic oil exceeds the upper limit, the effect of the present invention may be impaired.

  The ester other than the ester according to this embodiment may be a partial ester in which a part of the hydroxyl groups of the polyhydric alcohol is not esterified and remains as a hydroxyl group, or a complete ester having all the hydroxyl groups esterified. An ester or a mixture of a partial ester and a complete ester may be used, but the hydroxyl value is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, and most preferably 3 mgKOH / g or less. preferable.

  When the refrigerating machine oil according to the present embodiment contains an ester other than the ester according to the present embodiment, the ester other than the ester according to the present embodiment may be composed of one kind of ester having a single structure. Also, it may be a mixture of two or more esters having different structures.

  Further, esters other than the esters according to the present embodiment are esters of one fatty acid and one polyhydric alcohol, esters of two or more fatty acids and one polyhydric alcohol, one fatty acid and two. Any of ester with 2 or more types of polyhydric alcohol, ester of 2 or more types of fatty acid, and 2 or more types of polyhydric alcohol may be sufficient. Among these, a polyol ester using a mixed fatty acid, particularly a polyol ester constituted by containing two or more fatty acids in the ester molecule is excellent in low temperature characteristics and compatibility with a refrigerant.

  In the refrigerating machine oil according to the present embodiment, the ester content according to the present embodiment is not particularly limited, but is excellent in various performances such as low-temperature performance, lubricity, refrigerant compatibility, thermal / chemical stability, and electrical insulation. In terms of total amount of refrigerating machine oil, it is preferable to contain 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and more preferably 90% by mass or more. Most preferred.

  Moreover, the refrigerating machine oil which concerns on this embodiment can also be used in the form which mix | blended various additives as needed.

  In order to further improve the wear resistance and load resistance of the refrigerating machine oil according to this embodiment, phosphoric acid ester, acidic phosphoric acid ester, thiophosphoric acid ester, amine salt of acidic phosphoric acid ester, chlorinated phosphoric acid ester and At least one phosphorus compound selected from the group consisting of phosphate esters can be blended. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols and polyether type alcohols or derivatives thereof.

  Specifically, for example, as phosphate ester, tryptyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate, tridodecyl phosphate, tritridecyl phosphate Decyl phosphate, tritetradecyl phosphate, tripentadecyl phosphate, trihexadecyl phosphate, triheptadecyl phosphate, trioctadecyl phosphate, trioleyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, And xylenyl diphenyl phosphate.

  Examples of acidic phosphate esters include monobutyl acyl phosphate, monopentyl acid phosphate, monohexyl acid phosphate, monoheptyl acid phosphate, monooctyl acid phosphate, monononyl acid phosphate, monodecyl acid phosphate, monoundecyl acid phosphate, monododecyl Acid phosphate, monotridecyl acid phosphate, monotetradecyl acid phosphate, monopentadecyl acid phosphate, monohexadecyl acid phosphate, monoheptadecyl acid phosphate, monooctadecyl acid phosphate, monooleyl acid phosphate, dibutyl acid phosphate, dipentyl acid , Dihexyl reed Dophosphate, diheptyl acid phosphate, dioctyl acid phosphate, dinonyl acid phosphate, didecyl acid phosphate, diundecyl acid phosphate, didodecyl acid phosphate, ditridecyl acid phosphate, ditetradecyl acid phosphate, dipentadecyl acid, dipentadecyl acid Examples include hexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, dioleyl acid phosphate, and the like.

  Examples of thiophosphates include tryptyl phosphorothioate, tripentyl phosphorothionate, trihexyl phosphorothioate, triheptyl phosphorothionate, trioctyl phosphorothionate, trinonyl phosphorothionate, tridecyl Phosphorothioate, triundecyl phosphorothionate, tridodecyl phosphorothionate, tritridecyl phosphorothionate, tritetradecyl phosphorothionate, tripentadecyl phosphorothionate, trihexadecyl phosphorothionate , Triheptadecyl phosphorothioate, trioctadecyl phosphorothionate, trioleyl phosphorothionate, triphenyl phosphorothionate, tricresyl phosphorothionate, trixyl Cycloalkenyl phosphorothionate, cresyldiphenyl phosphorothionate, like carboxymethyl Les sulfonyl diphenyl phosphorothionate.

  Examples of the amine salt of an acidic phosphate ester include an amine salt of an acidic phosphate ester and an amine having a primary or tertiary alkyl group having 1 to 24 carbon atoms, preferably 5 to 18 carbon atoms.

  Examples of the amine constituting the acid phosphate ester salt include linear or branched methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, Dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, oleylamine, tetracosylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, Diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine, ditetradecylamine, dipenta Silamine, dihexadecylamine, diheptadecylamine, dioctadecylamine, dioleylamine, ditetracosylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine , Trinonylamine, tridecylamine, triundecylamine, tridodecylamine, tritridecylamine, tritetradecylamine, tripentadecylamine, trihexadecylamine, triheptadecylamine, trioctadecylamine, trioleylamine tritetra And salts with amines such as cosylamine. The amine may be a single compound or a mixture of two or more compounds.

  Examples of the chlorinated phosphate ester include tris-dichloropropyl phosphate, tris-chloroethyl phosphate, tris-chlorophenyl phosphate, polyoxyalkylene bis [di (chloroalkyl)] phosphate, and the like. As phosphites, dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, didodecyl phosphite, dioleyl Phosphite, diphenyl phosphite, dicresyl phosphite, triptyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl Examples thereof include phosphite, tridodecyl phosphite, trioleyl phosphite, triphenyl phosphite, and tricresyl phosphite. Mixtures of these can also be used.

  When the refrigerating machine oil according to the present embodiment contains the phosphorus compound, the content of the phosphorus compound is not particularly limited. It is more preferable that it is 02-3.0 mass%. In addition, the said phosphorus compound may be used individually by 1 type, and may use 2 or more types together.

  Moreover, in order to further improve the thermal / chemical stability of the refrigerating machine oil according to this embodiment, a terpene compound can be added. The “terpene compound” in the present invention means a compound obtained by polymerizing isoprene and a derivative thereof, and a dimer to octamer of isoprene is preferably used. Specific examples of the terpene compound include graniol, nerol, linalool, citral (including granial), citronellol, menthol, limonene, terpineol, carpon, yonon, tuyon, camphor, borneol and other monoterpenes, farnesene, Farnesol, nerolidol, juvenile hormone, humulene, cariophyllene, elemen, casinol, casquitene, tutin and other sesquiterpenes, granyl graniol, phytol, abietic acid, pimaragen, daphnetoxin, taxol, abietic acid, pimaric acid and other diterpenes, Sesterterpenes such as nilfarnesene, triterpenes such as squalene, limonin, cameliagenin, hopane and lanosterol, and tetraterpenes such as carotenoids And the like.

  Among these terpene compounds, monoterpenes, sesquiterpenes and diterpenes are preferable, sesquiterpenes are more preferable, α-farnesene (3,7,11-trimethyldodeca-1,3,6,10-tetraene) and / or β-farnesene. (7,11-dimethyl-3-methylidene deca-1,6,10-triene) is particularly preferred. In this invention, a terpene compound may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the terpene compound in the refrigerating machine oil according to this embodiment is not particularly limited, but is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0, based on the total amount of the refrigerating machine oil. 0.05 to 3% by mass. When the content of the terpene compound is less than 0.001% by mass, the effect of improving the thermal and chemical stability tends to be insufficient, and when it exceeds 10% by mass, the lubricity tends to be insufficient. is there.

  In addition, the refrigerating machine oil according to the present embodiment has a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an allyl oxirane compound, an alkyl, in order to further improve its thermal and chemical stability. It can contain at least one epoxy compound selected from oxirane compounds, alicyclic epoxy compounds, epoxidized fatty acid monoesters, and epoxidized vegetable oils.

  Specific examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. As used herein, the alkylphenyl glycidyl ether includes those having 1 to 3 alkyl groups having 1 to 13 carbon atoms, and those having one alkyl group having 4 to 10 carbon atoms, such as n-butylphenyl glycidyl. Ether, i-butylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, decyl Phenyl glycidyl ether etc. can be illustrated as a preferable thing.

  As the alkyl glycidyl ether type epoxy compound, specifically, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 2-ethylhexyl glycidyl ether, neopentyl glycol diglycidyl ether, Examples include trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, polyalkylene glycol diglycidyl ether, and the like.

  Specific examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, alkenyl glycidyl ester and the like, and preferable ones include glycidyl-2,2-dimethyloctanoate, glycidyl benzoate, glycidyl. Examples include acrylate and glycidyl methacrylate.

  Specific examples of the allyloxirane compound include 1,2-epoxystyrene and alkyl-1,2-epoxystyrene.

  Specific examples of the alkyloxirane compound include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2- Epoxy nonane, 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1,2- Examples include epoxyhexadecane, 1,2-epoxyheptadecane, 1,2-epoxyoctadecane, 1,2-epoxynonadecane, 1,2-epoxyicosane and the like.

  Specific examples of the alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3, 4-epoxycyclohexylmethyl) adipate, exo 2,3-epoxynorpolnan, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] hept-3 -Yl) -spiro (1,3-dioxane-5,3 ′-[7] oxabicyclo [4.1.0] heptane, 4- (1′-methylepoxyethyl) -1,2-epoxy-2- Examples thereof include methylcyclohexane and 4-epoxyethyl-1,2-epoxycyclohexane.

  Specific examples of the epoxidized fatty acid monoester include esters of an epoxidized fatty acid having 12 to 20 carbon atoms with an alcohol or phenol having 1 to 8 carbon atoms or an alkylphenol. In particular, ptyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and ptylphenyl esters of epoxy stearic acid are preferably used.

  Specific examples of the epoxidized vegetable oil include epoxy compounds of vegetable oils such as soybean oil, linseed oil and cottonseed oil.

  Among these epoxy compounds, phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, alicyclic epoxy compounds and epoxidized fatty acid monoesters are preferred. Of these, phenyl glycidyl ether type epoxy compounds and glycidyl ester type epoxy compounds are more preferred, and phenyl glycidyl ether, butylphenyl glycidyl ether, alkyl glycidyl esters or mixtures thereof are particularly preferred.

  When the refrigerating machine oil according to the present embodiment contains the epoxy compound, the content of the epoxy compound is not particularly limited, but is preferably 0.1 to 5.0% by mass based on the total amount of the refrigerating machine oil. It is more preferable that it is 2-2.0 mass%. In addition, the said epoxy compound may be used individually by 1 type, and may use 2 or more types together.

  In addition, the refrigerating machine oil according to the present embodiment can contain a conventionally known refrigerating machine oil additive as necessary in order to further enhance the performance. Examples of such additives include phenolic antioxidants such as di-tert-butyl-p-cresol and bisphenol A, phenyl-α-naphthylamine, N, N-di (2-naphthyl) -p-phenylenediamine, and the like. Amine-based antioxidants, anti-wear agents such as zinc dithiophosphate, extreme pressure agents such as chlorinated paraffin and sulfur compounds, oil-based agents such as fatty acids, antifoaming agents such as silicones, metal inertness such as benzotriazole Agents, viscosity index improvers, pour point depressants, detergent dispersants and the like. These additives may be used individually by 1 type, and may be used in combination of 2 or more type. The content of these additives is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of refrigerating machine oil.

Further, the volume resistivity of the refrigerating machine oil according to the present embodiment is not particularly limited, but is preferably 1.0 × 10 ¹² Ω · cm or more, more preferably 1.0 × 10 ¹³ Ω · cm or more, most preferably 1. 0.0 × 10 ¹⁴ Ω · cm or more. In particular, when it is used for a hermetic refrigerator, high electrical insulation tends to be required. In the present invention, the volume resistivity means a value at 25 ° C. measured in accordance with JIS C2101 “Electrical Insulating Oil Test Method”.

  In addition, the water content of the refrigerating machine oil according to the present embodiment is not particularly limited, but is preferably 200 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm or less based on the total quantity of refrigerating machine oil. In particular, when it is used for a hermetic type refrigerator, the moisture content is required to be small from the viewpoint of the influence on the thermal / chemical stability and electrical insulation of the refrigerator oil.

  Further, the acid value of the refrigerating machine oil according to the present embodiment is not particularly limited, but is contained in the refrigerating machine oil for fluoropropene refrigerant according to the present embodiment in order to prevent corrosion to the metal used in the refrigerating machine or piping. In order to prevent degradation of the ester oil, it is preferably 0.1 mgKOH / g or less, more preferably 0.05 mgKOH / g or less. In addition, in this invention, an acid value means the acid value measured based on JISK2501 "Petroleum product and lubricating oil one-neutralization number test method".

  Further, the ash content of the refrigerating machine oil according to the present embodiment is not particularly limited, but is preferably 100 ppm or less in order to increase the thermal and chemical stability of the fluoropropene refrigerant refrigerating machine oil according to the present embodiment and suppress the generation of sludge and the like. More preferably, it can be 50 ppm or less. In the present invention, the ash means the value of ash measured in accordance with JIS K2272 “Testing method for ash and sulfated ash of crude oil and petroleum products”.

  The refrigerating machine oil according to the present invention can be suitably used with various refrigerants, and is particularly excellent in compatibility and stability. Specifically, as the refrigerator in which the refrigerator oil according to the present embodiment is used, a room air conditioner, a packaged air conditioner, a refrigerator, an automotive air conditioner, a dehumidifier, a freezer, a freezer / refrigerated warehouse, a vending machine, a showcase, a chemical Although cooling apparatuses, such as a plant, are mentioned, Above all, it is particularly preferably used in a refrigerator having a hermetic compressor. Further, the refrigerating machine oil for difluoromethane refrigerant of the present invention can be used in any type of compressor such as a reciprocating type, a rotary type, a centrifugal type and the like.

  That is, the working fluid composition for a refrigerator according to the present embodiment contains the ester or the refrigerator oil according to the present embodiment and a refrigerant. Here, the blending ratio of the ester or the refrigerating machine oil and the difluoromethane refrigerant according to the present embodiment is not particularly limited, but the blending quantity of the refrigerating machine oil is usually 1 to 1000 parts by weight with respect to 100 parts by weight of the difluoromethane. The amount is preferably 2 to 800 parts by weight.

  The working fluid composition for a refrigerator according to this embodiment includes an HFC refrigerant, an unsaturated fluorinated hydrocarbon (HFO) refrigerant, a trifluoroiodomethane refrigerant, a fluorinated ether refrigerant such as perfluoroethers, dimethyl ether, and the like. Non-fluorine-containing ether refrigerants, natural refrigerants such as ammonia, carbon dioxide and hydrocarbons may be contained.

  Examples of the HFC refrigerant include hydrofluorocarbons having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms. Specifically, for example, difluoromethane (HFC-32), trifluoromethane (HFC-23), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1, 1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1 1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3 , 3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa), and 1,1 1,3,3-pentafluorobutane (HFC-365mfc), or a mixture of two or more thereof. These refrigerants are appropriately selected depending on the application and required performance. For example, HFC-32 alone; HFC-23 alone; HFC-134a alone; HFC-125 alone; HFC-134a / HFC-32 = 60 to 80 mass % / 40-20 mass% mixture; HFC-32 / HFC-125 = 40-70 mass% / 60-30 mass% mixture; HFC-125 / HFC-143a = 40-60 mass% / 60-40 mass % Mixture; HFC-134a / HFC-32 / HFC-125 = 60 wt% / 30 wt% / 10 wt% mixture; HFC-134a / HFC-32 / HFC-125 = 40-70 wt% / 15- 35 mass% / 5 to 40 mass% mixture; HFC-125 / HFC-134a / HFC-143a = 35-55 mass% / 1-15 mass% / 40-60 mass Such as a mixture of preferred examples include. More specifically, a mixture of HFC-134a / HFC-32 = 70/30 mass%; a mixture of HFC-32 / HFC-125 = 60/40 mass%; HFC-32 / HFC-125 = 50/50 mass % Mixture (R410A); HFC-32 / HFC-125 = 45/55 wt% mixture (R410B); HFC-125 / HFC-143a = 50/50 wt% mixture (R507C); HFC-32 / HFC -125 / HFC-134a = 30/10/60 wt% mixture; HFC-32 / HFC-125 / HFC-134a = 23/25/52 wt% mixture (R407C); HFC-32 / HFC-125 / HFC-134a = 25/15/60 mass% mixture (R407E); HFC-125 / HFC-134a / HFC-143a = Mixtures of 4/4/52 wt% (R404A), and the like.

  As the unsaturated fluorinated hydrocarbon refrigerant, those having 2 to 5 carbon atoms are preferably used, and among them, a refrigerant having 3 carbon atoms (fluoropropene refrigerant) is preferably used. As the fluoropropene refrigerant, fluoropropene having 3 to 5 fluorine atoms is preferable. 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3,3,3-tetrafluoropropene (HFO) -1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye), and 3,3,3-trifluoropropene (HFO) -1243zf) is preferably one or a mixture of two or more. From the viewpoint of the physical properties of the refrigerant, one or more selected from HFO-1225ye, HFO-1234ze, and HFO-1234yf are preferable.

  The hydrocarbon refrigerant is preferably a hydrocarbon having 3 to 5 carbon atoms, specifically, for example, methane, ethylene, ethane, propylene, propane, cyclopropane, normal butane, isobutane, cyclobutane, methylcyclopropane, 2-methylbutane. , Normal pentane, or a mixture of two or more thereof. Among these, gas at 25 ° C. and 1 atm is preferably used, and propane, normal butane, isobutane, 2-methylbutane or a mixture thereof is preferable.

  Specific examples of the fluorinated ether refrigerant include HFE-134p, HFE-245mc, HFE-236mf, HFE-236me, HFE-338mcf, HFE-365mcf, HFE-245mf, HFE-347mmy, HFE-347mcc, HFE-125, HFE-143m, HFE-134m, HFE-227me, etc. are mentioned, These refrigerant | coolants are suitably selected according to a use or required performance.

  The blending ratio of the refrigerating machine oil and the refrigerant in the working fluid composition for a refrigerator according to the present embodiment, and the blending ratio of the refrigerating machine oil and the refrigerant in the working fluid composition for a refrigerator according to the present embodiment are not particularly limited, The refrigerating machine oil is preferably 1 to 500 parts by mass, more preferably 2 to 400 parts by mass with respect to 100 parts by mass of the refrigerant.

  The working fluid composition for a refrigerator according to the present embodiment is preferably used for an air conditioner, a refrigerator, or an open or sealed car air conditioner having a reciprocating or rotating hermetic compressor. Further, the refrigerating machine oil and the working fluid composition for the refrigerating machine according to the present embodiment are preferably used for a dehumidifier, a water heater, a freezer, a freezer / refrigerated warehouse, a vending machine, a showcase, a cooling device for a chemical plant, and the like. Furthermore, the refrigerating machine oil and the working fluid composition for a refrigerating machine according to the present embodiment are preferably used for those having a centrifugal compressor.

  Typical configurations of the refrigerant circulation cycle included in the refrigerator to which the working fluid composition for a refrigerator according to the present embodiment is applied include a compressor, a condenser, an expansion mechanism and an evaporator, and a dryer as necessary. Are provided.

  The compressor includes a motor composed of a rotor and a stator in a sealed container for storing refrigerating machine oil, a rotating shaft fitted to the rotor, and a compression connected to the motor via the rotating shaft. A high-pressure container type compressor in which high-pressure refrigerant gas discharged from the compressor unit stays in a sealed container, a motor composed of a rotor and a stator in a sealed container storing refrigerating machine oil, The rotary shaft fitted to the rotor and the compressor unit connected to the motor via the rotary shaft are housed, and the high-pressure refrigerant gas discharged from the compressor unit is outside the sealed container. Examples include a low-pressure container type compressor that is directly discharged.

  As an insulating film which is an electric insulation system material of a motor part, a crystalline plastic film having a glass transition point of 50 ° C. or more, specifically, for example, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ether ketone, polyethylene naphthalate, Polyamideimide, at least one insulating film selected from the group of polyimides, or a composite film in which a resin layer having a high glass transition temperature is coated on a film having a low glass transition temperature is less likely to cause deterioration of tensile strength characteristics and electrical insulation characteristics. Are preferably used. Moreover, as a magnet wire used for the motor part, an enamel coating having a glass transition temperature of 120 ° C. or higher, for example, a single layer such as polyester, polyesterimide, polyamide and polyamideimide, or a layer having a low glass transition temperature as a lower layer, Those having an enamel coating in which a high layer is composite-coated on the upper layer are preferably used. Examples of the composite enameled wire include polyester imide as a lower layer and polyamide imide as an upper layer (AI / EI), polyester as a lower layer and polyamide imide as an upper layer (AI / PE), and the like. .

  As the desiccant to be filled in the dryer, silicic acid and alkali metal aluminate composite salt having a pore diameter of 3.3 angstroms or less and a carbon dioxide absorption capacity at 25 ° C. carbon dioxide partial pressure of 250 mmHg is 1.0% or less. The synthetic zeolite is preferably used. Specifically, trade names XH-9, XH-10, XH-11, XH-600 manufactured by Union Showa Co., Ltd., and the like can be given.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Example 1]
<Synthesis of 2-ethyl-4-methylpentanoic acid>
First, in order to synthesize 2-ethyl-4-methyl-2-pentenal, 100 ml (80 g, 1.11 mol) of n-butyraldehyde and 100 ml (79 g, 1.1 mol) of isobutyraldehyde were added to a stirrer and a condenser tube. Into a 500 ml four-necked flask, 200 ml of 2.5 mol% aqueous sodium hydroxide solution was added dropwise over 15 minutes while stirring at 80 ° C. Three hours after the start of dropping, the mixture was cooled to room temperature, the aqueous layer was separated, and the organic layer was washed with water three times. After confirming that the washing water was not alkaline, distillation was performed to obtain 50 g (0.40 mol) of 2-ethyl-4-methylpentenal.
Next, 50 g (0.4 mol) of 2-ethyl-4-methylpentenal was placed in an autoclave having an internal volume of 150 ml, 0.5 g of 5% by weight palladium-supported activated carbon was added as a catalyst, hydrogen pressure 5 MPa, reaction temperature 100 The hydrogenation reaction was carried out at 2 ° C. for 2 hours. 50 g of crude 2-ethyl-4-methylpentanal obtained by filtering the catalyst was put into a three-necked flask equipped with a cooling pipe and a gas introduction pipe, and air was blown at a flow rate of 80 ml / min at 40 ° C. The oxidation reaction was performed for 20 hours. Purification by distillation gave 40 g (0.28 mol) of 2-ethyl-4-methylpentanoic acid.
<Synthesis of ester>
2 g of pentaerythritol and 10.7 g of 2-ethyl-4-methylpentanoic acid were placed in a 100 ml three-necked flask equipped with a Dean-Stark oil / water separator and heated at 250 ° C. in a nitrogen atmosphere. When generation of water vapor became intense and bumping by water occurred, nitrogen was passed at 12.5 ml / min, and the reaction was carried out for 24 hours while dehydrating. Unreacted carboxylic acid was removed under reduced pressure under a nitrogen stream to obtain 9.3 g of tetraester of pentaerythritol and 2-ethyl-4-methylpentanoic acid.

[Example 2]
<Synthesis of 2-propyl-4-methylpentanoic acid>
2-propyl-4-methylpentanoic acid was synthesized in the same manner as in Example 1 except that valeraldehyde was used in place of n-butyraldehyde. As a result, 39 g (0.25 mol) of 2-propyl-4-methylpentanoic acid was obtained.
<Synthesis of ester>
Tetraester of pentaerythritol and 2-propyl-4-methylpentanoic acid in the same manner as in Example 1 except that 2-propyl-4-methylpentanoic acid was used instead of 2-ethyl-4-methylpentanoic acid. Got.

[Example 3]
Instead of 2-ethyl-4-methylpentanoic acid, a carboxylic acid mixture of 2-ethyl-4-methylpentanoic acid and 3,5,5-trimethylhexanoic acid (50% by mole of 2-ethyl-4-methylpentanoic acid) , 3,5,5-trimethylhexanoic acid 50 mol%) was used in the same manner as in Example 1 to obtain a tetraester of pentaerythritol and the above carboxylic acid mixture.

[Example 4]
Instead of 2-ethyl-4-methylpentanoic acid, a carboxylic acid mixture of 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid (50% by mole of 2-ethyl-4-methylpentanoic acid) The tetraester of pentaerythritol and the above carboxylic acid mixture was obtained in the same manner as in Example 1 except that 2-propyl-4-methylpentanoic acid (50 mol%) was used.

[Example 5]
Instead of 2-ethyl-4-methylpentanoic acid, a carboxylic acid mixture of 2-ethyl-4-methylpentanoic acid and 2-ethylhexanoic acid (50% by mole of 2-ethyl-4-methylpentanoic acid, 2-ethyl A tetraester of pentaerythritol and the above carboxylic acid mixture was obtained in the same manner as in Example 1 except that 50 mol% of hexanoic acid was used.

[Example 6]
Instead of 2-ethyl-4-methylpentanoic acid, a carboxylic acid mixture of 2-ethylhexanoic acid and 2-propyl-4-methylpentanoic acid (2-ethylhexanoic acid 50 mol%, 2-propyl-4-methyl A tetraester of pentaerythritol and the above carboxylic acid mixture was obtained in the same manner as in Example 1 except that 50 mol% of pentanoic acid was used.

[Comparative Example 1]
A tetraester of pentaerythritol and 2-ethylhexanoic acid was obtained in the same manner as in Example 1 except that 2-ethylhexanoic acid was used instead of 2-ethyl-4-methylpentanoic acid.

[Comparative Example 2]
Instead of 2-ethyl-4-methylpentanoic acid, a carboxylic acid mixture of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid (2-ethylhexanoic acid 50 mol%, 3,5,5-trimethyl) A tetraester of pentaerythritol and the above carboxylic acid mixture was obtained in the same manner as in Example 1 except that 50 mol% of hexanoic acid was used.

[Comparative Example 3]
In the same manner as in Example 1 except that 3,5,5-trimethylhexanoic acid was used in place of 2-ethyl-4-methylpentanoic acid, a tetraethyl pentaerythritol and 3,5,5-trimethylhexanoic acid was used. An ester was obtained.

The molecular structure of 2-propyl-4-methylpentanoic acid obtained in Example 1, 2-ethyl-4-methylpentanoic acid obtained in Example 2, and each ester obtained in Examples 1-6 is They were identified by performing ¹ H-NMR analysis under the following measurement conditions. The results of ¹ H-NMR analysis are shown in Table 1. In addition, Tables 2 and 3 show kinematic viscosities and viscosity indices at 40 ° C. and 100 ° C. of the esters of Examples 1 to 6, respectively.
Measurement condition:
Device name: VARIAN INOVA 600 MHZ NMR
Solvent: CDCl ₃
Temperature: room temperature

Formulas (1) to (8) in Table 1 are as follows.

  Next, the evaluation test as the refrigerating machine oil shown below was performed for the esters of Examples 1 to 6 and Comparative Examples 1 to 3.

<Compatibility test with refrigerant>
In accordance with JIS-K-2211 “Refrigerating machine oil” “Compatibility testing method with refrigerant”, the mixture of refrigerant 16 g and refrigerant oil 4 g shown in the table is gradually cooled from 30 ° C. to −40 ° C. The temperature at which phase separation or cloudiness occurred was measured. The obtained results are shown in Tables 2 and 3. In Tables 2 and 3, “HFO-1234yf + R32” means a mixed refrigerant (HFO-1234yf / R32 = 50/50 mass%) of HFO-1234yf and R32. In Tables 2 and 3, “<−40” indicates that phase separation and cloudiness were not observed in the measurement temperature range of this test. In Table 3, “separation” means that phase separation or cloudiness has already occurred at 30 ° C.

<Stability test>
In a 200 ml autoclave, 30 g of refrigerating machine oil whose water content was adjusted to 1000 ppm, 30 g of HFO-1234yf and 90 ml of air were sealed, and the acid value of the refrigerating machine oil after heating at 175 ° C. for 336 hours was measured. The obtained results are shown in Tables 2 and 3.

Claims (3)

An ester of a carboxylic acid containing at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid and pentaerythritol . A base oil comprising an ester of a carboxylic acid containing at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid and pentaerythritol. A refrigerating machine oil containing an ester of carboxylic acid and pentaerythritol containing at least one selected from 2-ethyl-4-methylpentanoic acid and 2-propyl-4-methylpentanoic acid.