JPH06100874A - Refrigerator working fluid composition - Google Patents

Abstract

(57) [Summary] [Composition] A refrigerating machine oil containing a compound represented by the general formula (I) as a base oil, and a composition for a refrigerating machine working fluid containing hydrofluorocarbon. [Effect] The composition for a working fluid for a refrigerator of the present invention is particularly excellent in compatibility because it contains a refrigerating machine oil containing a compound having a plurality of ketone groups in the molecule as a base oil and hydrofluorocarbon. In addition, there is no concern about hydrolyzability, and hygroscopicity is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working fluid composition for refrigerators, and more particularly to a working fluid composition for compression refrigerators for electric refrigerators, air conditioners and the like.

[0002]

2. Description of the Related Art Recently, the problems to be solved by the invention
The use of dichlorodifluoromethane (CFC12), which is used in refrigerators and car coolers to protect the ozone layer, is regulated, and it is about to be prohibited in the future. Therefore, as a substitute for this CFC12, hydrofluorocarbon (HFC) that does not destroy the ozone layer has been developed. However, since hydrofluorocarbon has a higher polarity than CFC12, naphthene-based mineral oil or poly α-, which has been generally used as a refrigerating machine oil, has been used.
When using lubricating oils such as olefins and alkylbenzenes,
The compatibility between these lubricating oils and hydrofluorocarbons is poor, and two-layer separation occurs at low temperatures. When two-layer separation occurs, oil return deteriorates, a thick oil film adheres to the vicinity of the condenser or evaporator as a heat exchanger to hinder heat transfer, and it is important that lubrication failure and foaming at startup occur. Cause defects. Therefore, the conventional refrigerating machine oil cannot be used as the refrigerating machine oil under these new refrigerant atmospheres.

Also, regarding the lubricity, in CFC12, it is partially decomposed to generate hydrogen chloride, and this hydrogen chloride reacts with the friction surface to form a chloride film to improve lubricity. was there. However, since such effects cannot be expected for hydrofluorocarbons that do not contain chlorine atoms, refrigerating machine oils used with hydrofluorocarbons are required to have even better lubricity than conventional ones. Further, the refrigerating machine oil used together with the hydrofluorocarbon must have good thermal stability in the coexistence with the hydrofluorocarbon. In addition, in addition to this, in compression refrigerators of electric refrigerators, there are organic materials used for motors such as insulating materials and enameled wires, so as a working fluid consisting of hydrofluorocarbon and refrigerator oil, these organic materials are used. It is necessary that the material is not adversely affected and that the electrical insulation is good.

Hydrofluorocarbons, eg 1,
1,1,2-Tetrafluoroethane (HFC134a)
As a refrigerating machine oil that can be used together with US Pat. No. 4,755,316, JP-A-1-198694, JP-A-1-256594, and JP-A-1-25.
No. 9093, No. 1-259094, No. 1-259095, No. 2-84491, No. 2-102296, No. 2-129.
No. 294, No. 2-132176, No. 2-132177, No. 2-132178, No. 2-132179, No. 2-173.
195, JP-A-2-180986, JP-A-2-180987, JP-A-2-182780, JP-A-2-242823, and JP-A-2-242.
No. 888, No. 2-258896, No. 2-269195, No. 2-276880, No. 2-27681, and No. 2-272.
097, JP-A-2-281098, JP-A-2-305893, JP-A-3-14894, JP-A-3-28296, and JP-A-3-3319.
No. 2, JP-A-3-33193, etc. disclose polyether compounds.

Since the polyether compound is more polar than the naphthenic mineral oil, the compatibility with HFC134a at low temperature is certainly good. However, US Pat.
As described in Japanese Patent No. 55316, there is a problem that the polyether compound causes two-layer separation when the temperature rises. Further, the polyether compound has some other problems. One is that it has poor electrical insulation. This is a very big problem and cannot be used in refrigerators for electric refrigerators. Another problem is that it is highly hygroscopic. Due to the water content in the polyether compound, the thermal stability in the coexistence of HFC134a is deteriorated, and the PET film or the like which is an organic material is hydrolyzed.

Ester compounds have been developed in order to improve the problems of the polyether compounds such as the electric insulating property and the hygroscopic property. For example, as a refrigerating machine oil that can be used with 1,1,1,2-tetrafluoroethane (HFC134a), U.S. Pat. No. 4,851,144.
Specification (JP-A-2-276894) and JP-A-2
No. 158693 discloses a mixed oil of a polyether oil and an ester oil, and British Patent No. 2,216,541 and European Patent No. 406,479 disclose an ester oil.

The ester compound is excellent in compatibility with hydrofluorocarbon and also excellent in thermal stability in the presence of hydrofluorocarbon. In addition, it has extremely excellent electrical insulation properties and considerably low hygroscopicity as compared with polyether compounds. However, compared with CFC12-mineral oil system, which is a conventional working fluid, in the hydrofluorocarbon-ester oil system, both CFC and oil have higher polarities and water is likely to be contained. Therefore, there is a problem that the ester oil is hydrolyzed to generate a carboxylic acid, and the generated carboxylic acid corrodes a metal to cause wear.

As described above, the hydrofluorocarbon-polyether oil system which has been developed so far has a problem of hygroscopicity and electric insulation, and the hydrofluorocarbon-ester oil system has a problem of hydrolysis resistance, and the conventional CFC12-mineral. Compared with an oil system, it is likely to contain water, which causes deterioration of thermal stability, deterioration of organic materials, corrosion and wear of metals, etc., and is not satisfactory as a working fluid for a refrigerator. Therefore, an object of the present invention is to provide a composition for a working fluid of a refrigerator, which is free from the above-mentioned problems and is particularly excellent in compatibility.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a compound represented by the following general formula (I) has a compound having a plurality of ketone groups in the molecule. It was found that the above object can be achieved by using a refrigerating machine oil as an oil, and the present invention has been completed. That is, the gist of the present invention relates to a refrigerating machine oil containing a compound represented by the general formula (I) as a base oil, and a composition for a refrigerating machine working fluid containing hydrofluorocarbon.

[0010]

[Chemical 2]

(In the formula, R ¹ and R ² are the same or different and each is a hydrogen atom, or a linear or branched alkyl group, alkenyl group or arylalkyl group having 1 to 36 carbon atoms, or 1 to 15 carbon atoms. A phenyl group which may be substituted with a linear or branched alkyl group or an alkenyl group is shown, wherein R ³ and R ⁴ are the same or different and are a linear or branched alkyl group or alkenyl group having 1 to 36 carbon atoms. Or a phenyl group which may be substituted with an arylalkyl group, or a linear or branched alkyl group or alkenyl group having 1 to 15 carbon atoms, n represents a number of 1 to 19, and m represents 1 to 5 Indicates the number of.)

In the general formula (I), R ¹ , R ² ,
Substituted by a linear or branched alkyl group having 1 to 36 carbon atoms, an alkenyl group, or an arylalkyl group represented by R ³ or R ⁴ , or a linear or branched alkyl group or alkenyl group having 1 to 15 carbon atoms. The phenyl group which may be, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group,
Linear alkyl groups such as nonyl group, decyl group, undecyl group, lauryl group, myristyl group, palmityl group and stearyl group; isopropyl group, isobutyl group, isoamyl group,
Branched-chain alkyl groups such as 2-ethylhexyl group, isostearyl group, 2-heptylundecyl group; alkenyl groups such as vinyl group, propenyl group, isobutenyl group; arylalkyl groups such as benzyl group; phenyl group, methylphenyl group, Examples thereof include a dimethylphenyl group, an isopropenylphenyl group, an isopropylphenyl group and a vinylphenyl group.

In the present invention, it is preferable that the sum of carbon numbers of R ¹ and R ² is 24 or less because of compatibility with hydrofluorocarbon, and R ³ and R ⁴ each have 25 or less carbon atoms. It is preferable to be present because of the compatibility of the hydrofluorocarbon.

In the general formula (I), n represents a number of 1 to 19, preferably n is a number of 1 to 4. When n exceeds 19, the compatibility with hydrofluorocarbon becomes insufficient. m shows the number of 1-5. When m exceeds 5, the compatibility with hydrofluorocarbon becomes insufficient.

Examples of the compound represented by the general formula (I) include various compounds, and are not particularly limited. Specifically, for example, 3-octyl-2,4-
Pentanedione, 3-decyl-2,4-pentanedione, 3-isoamyl-2,4-pentanedione, 3-
(2-ethylhexyl) -2,4-pentanedione, 3
-(2-hexyldecyl) -2,4-pentanedione,
2,4-tridecanedione, 2,4-pentadecanedione, 8-methyl-2,4-nonanedione, 7-ethyl-
2,4-undecanedione, 7-hexyl-2,4-pentadecanedione, 3-octyl-2,5-hexanedione, 3-decyl-2,5-hexanedione, 3-isoamyl-2,5-hexanedione , 3- (2-ethylhexyl) -2,5-hexanedione, 3- (2-hexyldecyl) -2,5-hexanedione, 2,5-tetradecanedione, 2,5-hexadecanedione, 10-methyl- 2,5-undecandione, 8-ethyl-2,5
-Dodecanedione, 8-hexyl-2,5-hexadecandione, 3- (2-methylpropenyl) -2,4-pentanedione, 3-benzyl-2,4-pentanedione, 3-phenyl-2,4- Pentanedione, 3,5-
Dioctyl-2,4,6-heptantrione and the like can be mentioned.

As a method for obtaining these compounds, a known method can be used. For example, polyketones such as acetylacetone (2,4-pentanedione) are radical-added to an olefin by using an organic peroxide as an initiator. Or polyketones such as Na, NaH, M
After treating with a metal compound such as eONa or EtONa, a method of reacting with an alkyl halide can be used.

The compound having a plurality of ketone groups in the molecule has a viscosity at 100 ° C. of 0.5 to 100 cs.
t is preferable, and more preferably 0.5 to 30 cst. If the viscosity at 100 ° C. exceeds 100 cst, the compatibility between this compound and hydrofluorocarbon becomes poor. The viscosity at 40 ° C is 1 to 10,000 cst.
Is preferred, and more preferably 1 to 1,000 cst. Further, among those having a viscosity at 100 ° C. of 0.5 to 100 cst, it is desirable that the two-layer separation temperature at low temperature with hydrofluorocarbon is low, and the temperature is 0 ° C. or less, more preferably −10 ° C. or less. The compound having a plurality of ketone groups in the molecule used in the present invention is a mineral oil, poly α-olefin, alkylbenzene, ester, polyether, perfluoropolyether, phosphorus, as long as the compatibility with hydrofluorocarbon is not impaired. You may mix synthetic oils, such as acid ester.

Further, the refrigerating machine oil having a compound having a plurality of ketone groups in the molecule as a base oil used in the present invention has an epoxy group for trapping water or acid in the composition, if necessary. Addition of additives such as compounds, orthoesters and acetals, and triaryl phosphate and / or triaryl phosphite, trialkyl phosphate and / or trialkyl phosphite, alkyl and / or in order to improve lubricity Zinc aryldithiophosphate or molybdenum dithiophosphate,
Anti-wear agents such as molybdenum dithiocarbamate, tartaric acid esters, glyceryl ethers, glyceryl esters, and other compounds having two hydroxyl groups at adjacent positions, and phenolic compounds having radical trapping ability to improve thermal stability, Aromatic amine compounds may be added.

Examples of the compound having an epoxy group used here include a glycidyl ether compound and an alicyclic epoxy compound, and a compound having an epoxycyclohexyl group or an epoxycyclopentyl group is particularly preferable. The epoxy compound used in the present invention has 5 to 60 carbon atoms, preferably 5 to 40 carbon atoms. The amount added is 100 parts by weight of the base oil used in the present invention,
0.05 to 5.0 parts by weight, preferably 0.05 to
2.0 parts by weight.

The orthoester or acetal used in the present invention has a carbon number of 3 to 75, and its addition amount is 0.01 to 100 parts by weight with respect to 100 parts by weight of the base oil. The antiwear agent used in the present invention has 3 to 70 carbon atoms, and its addition amount is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the base oil. The compound having two hydroxyl groups at adjacent positions used in the present invention has 6 to 75 carbon atoms, and its addition amount is 0.01 to 100 parts by weight with respect to 100 parts by weight of base oil. The phenolic compound or aromatic amine compound used in the present invention has a radical trapping ability and has 6 to 100 carbon atoms. The amount added is 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the base oil.

In the composition for a working fluid for a refrigerator of the present invention, an additive is added to a hydrofluorocarbon and a refrigerator oil having a compound having a plurality of ketone groups in a molecule used in the present invention as a base oil or a base oil thereof. The mixing ratio with the refrigerating machine oil is usually hydrofluorocarbon / oil = 5/1 to 1
/ 10 (weight ratio), preferably 2/1 to 1/5 (weight ratio).

Hydrofluorocarbons used in the present invention include difluoromethane (HFC32), 1,1-
Difluoroethane (HFC152a), 1,1,1-trifluoroethane (HFCl43a), 1,1,1,2
-Tetrafluoroethane (HFCl34a), 1,1,
2,2-tetrafluoroethane (HFCl34), pentafluoroethane (HFCl25) and the like, particularly 1,
1,1,2-Tetrafluoroethane, difluoromethane or mixtures thereof are preferred.

[0023]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Performance evaluation of the compositions for refrigerator working fluids in Examples and Comparative Examples is based on the following test methods.

Viscosity Regarding the oils 1 to 5 used in the products of the present invention and the oil 6 used in the comparative product shown in Table 1, the viscosities at 40 ° C. and 100 ° C.
It was measured according to SK-2283.

The oil 6 is used in oil 1 to 5 and comparative products used in the present invention product shown in compatibility Table 1, respectively 1,1,1,2-tetrafluoroethane (HFC134a) or difluoromethane (HF
Inventive products 1 to 5 and comparative product 1 which are compositions with C32)
Were prepared and their compatibility was investigated. That is, 1,
The low temperature two-layer separation temperature at each oil concentration of 10, 20, 30 vol% for 1,1,2-tetrafluoroethane or difluoromethane was measured.

Example 1 200.2 g (2.0 mol) of acetylacetone was added to a reactor equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropping device, and a fractionator equipped with a cooling tube. The mixture was heated to 120 ° C with stirring. Next, 200.2 g (2.0 mol) of acetylacetone and 1-octene 112.
A mixture of 2 g (1.0 mol) and 48.1 g (0.2 mol) of benzoyl peroxide as a radical initiator was added dropwise over 4 hours, and the mixture was aged for 1 hour to obtain a reaction-terminated product. Next, 10% NaOH aqueous solution was added to the acid value of the reaction-completed product at 1.1
The product was extracted with hexane by doubling to neutralize. Then, vacuum distillation (130-150 ° C / 0.3-0.5To)
rr) gave 266.4 g of the desired product (Oil 1). IR
It was confirmed that the absorption of an alkyl group and a 1,3-dicarbonyl group was confirmed by 1H-NMR, and that the compound obtained from ¹ H-NMR was a 1 mol adduct of acetylacetone and 1-octene (gas chromatographic purity 83.3%). The obtained oil 1 was used to evaluate the viscosity and the compatibility by the methods described above. The results are shown in Table 1.

Example 2 Using a reactor equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropping machine, and a fractionator equipped with a cooling tube, 450.6 g (4.0 mol) of acetonylacetone was added thereto. In addition,
The mixture was heated to 180 ° C with stirring. Next, 112.2 g (1.0 mol) of 1-octene and 29.2 g of di-tert-butyl peroxide (0.
(2 mol) was added dropwise over 5 hours and aged for 1 hour to obtain a reaction-terminated product. Then, vacuum distillation is performed to
Fraction 0-176 ° C / 3-4 Torr to Oil 2 (84.
0 g) was obtained. It was confirmed by IR and ¹ H-NMR that Oil 2 was a 1 mol adduct of acetonylacetone and 1-octene (gas chromatographic purity 90.2%). The oil obtained 2
Was used to evaluate viscosity and compatibility by the method described above.
The results are shown in Table 1.

Example 3 The distillation residue obtained in Example 2 was further distilled under reduced pressure to obtain Oil 3 from a fraction of 176 to 200 ° C./3 to 4 Torr. It was confirmed by IR and ¹ H-NMR that Oil 3 was a 2 mol adduct of acetonylacetone and 1-octene. The obtained oil 3 was used to evaluate the viscosity and the compatibility by the methods described above. The results are shown in Table 1.

Example 4 Using a 500 ml four-necked flask equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropping device, and a reflux condenser, 50.0 g (0.5 mol) of acetylacetone and 100 cc of acetone were used. , And potassium carbonate 69.
0 g (0.5 mol) was added, and the mixture was heated to 60 ° C while stirring. Next, 99.0 g (0.5 mol) of isoamyl iodide was added dropwise over 1 hour, followed by aging for 30 hours under reflux of acetone. Then, vacuum distillation (110 ° C / 20 Tor)
r) gave 38.0 g of the desired product (oil 4). IR, ¹
The compound obtained from 1 H-NMR is 3-isoamyl-
It was confirmed to be 2,4-pentanedione (gas chromatographic purity 76%). The obtained oil 4 was used to evaluate the viscosity and the compatibility by the methods described above. The results are shown in Table 1.

Example 5 A 500 ml four-necked flask equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropping device, and a reflux condenser was used, and 50.0 g (0.5 mol) of acetylacetone and 100 cc of acetone were added thereto. , And potassium carbonate 69.
0 g (0.5 mol) was added, and the mixture was heated to 60 ° C while stirring. Next, 63.3 g (0.5 mol) of benzyl chloride was added dropwise over 1 hour, and the mixture was aged for 30 hours under reflux of acetone. Then, vacuum distillation (143 to 146 ° C / 10To)
rr) gave 42.8 g of the desired product (Oil 5). IR,
^The compound obtained from ¹ H-NMR was 3-benzyl-
It was confirmed to be 2,4-pentanedione (gas chromatographic purity 82%). The obtained oil 5 was used to evaluate the viscosity and the compatibility by the methods described above. The results are shown in Table 1.

Comparative Example 1 Using naphthene oil as the oil 6, the viscosity and the compatibility were evaluated by the above-mentioned methods. The results are shown in Table 1.

[0032]

[Table 1]

As shown in Table 1, the compositions for refrigerator working fluids of Examples 1 to 5 have a low two-layer separation temperature and excellent compatibility at any oil concentration. On the other hand, Comparative Example 1
The refrigerating machine working fluid composition has a high two-phase separation temperature and inferior compatibility at any oil concentration.

[0034]

EFFECTS OF THE INVENTION The composition for a working fluid of a refrigerator of the present invention is particularly excellent in compatibility since it contains a refrigerating machine oil having a compound having a plurality of ketone groups in the molecule as a base oil and hydrofluorocarbon. In addition, there is no concern about hydrolyzability, and hygroscopicity is low.

Claims (2)

[Claims] 1. A composition for a working fluid of a refrigerating machine, comprising a refrigerating machine oil containing a compound represented by the general formula (I) as a base oil, and hydrofluorocarbon. [Chemical 1] (In the formula, R ¹ and R ² are the same or different and each is a hydrogen atom, or a linear or branched alkyl group, alkenyl group or arylalkyl group having 1 to 36 carbon atoms, or 1 carbon atom.
~ 15 represents a phenyl group which may be substituted with a linear or branched alkyl group or alkenyl group. R ³ ,
R ⁴ is the same or different and is substituted with a linear or branched alkyl group having 1 to 36 carbon atoms, an alkenyl group or an arylalkyl group, or a linear or branched alkyl group or alkenyl group having 1 to 15 carbon atoms. Represents a phenyl group which may be present. n represents a number from 1 to 19, and m represents a number from 1 to 5. ) 2. A compound represented by the general formula (I) is R ¹
And the sum of carbon numbers of R ² is 24 or less, and R ³ , R ⁴
The composition for a working fluid of a refrigerator according to claim 1, wherein the carbon number of each is 25 or less.