JP2979363B2 - Composition for working fluid of refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for a working fluid of a refrigerator, and more particularly to a composition for a working fluid of a compression refrigerator for an electric refrigerator, an air conditioner, and the like.

[0002]

2. Description of the Related Art Recently,
The use of dichlorodifluoromethane (CFC12), which is used in refrigerators and car coolers to protect the ozone layer, has been regulated, and is banned in the future. Therefore, as an alternative to the CFC 12, a hydrofluorocarbon (HFC) that does not destroy the ozone layer has been developed. However, since hydrofluorocarbons have a higher polarity than CFC12, naphthenic mineral oils and poly-α-hazardous oils which have been generally used as refrigerating machine oils are conventionally used.
With lubricating oils such as olefins and alkylbenzenes,
The compatibility between these lubricating oils and hydrofluorocarbons is poor, causing two-layer separation at low temperatures. If two-layer separation occurs, oil return will deteriorate, and a thick oil film will adhere near the condenser or evaporator as a heat exchanger, hindering heat transfer, and also cause poor lubrication and foaming during startup. It causes defects. Therefore, the conventional refrigerating machine oil cannot be used as a refrigerating machine oil under these new refrigerant atmospheres.

[0003] The lubricating properties of the CFC 12 are also partially decomposed to generate hydrogen chloride, and the hydrogen chloride reacts with the friction surface to form a chloride film and improve lubricity. was there. However, since such effects cannot be expected from hydrofluorocarbons containing no chlorine atom, refrigerating machine oil used with hydrofluorocarbons is required to have better lubricity than conventional oils. Further, the refrigerating machine oil used together with the hydrofluorocarbon needs to have good thermal stability in the presence of the hydrofluorocarbon. In addition, since a compression refrigerator of an electric refrigerator contains an organic material used for a motor such as an insulating material and an enameled wire, a working fluid composed of hydrofluorocarbon and refrigerating machine oil includes these organic fluids. It is necessary that the material has no adverse effect, and that the electrical insulation be good.

Hydrofluorocarbons, such as 1,
1,1,2-tetrafluoroethane (HFC134a)
US Pat. No. 4,755,316, JP-A-1-198694, JP-A-1-256594, and JP-A-1-25
JP-A-9093, JP-A-1-259094, JP-A-1-259095, JP-A-2-84491, JP-A-2-102296, JP-A-2-129
294, JP-A-2-132176, JP-A-2-132177, JP-A-2-132178, JP-A-2-132179, JP-A-2-173
195, JP-A-2-180986, JP-A-2-180987, JP-A-2-182780, JP-A-2-242823, JP-A-2-242
888, JP-A-2-258896, JP-A-2-269195, JP-A-2-276880, JP-A-2-276811, JP-A-2-272
097, JP-A-2-281098, JP-A-2-305893, JP-A-3-14894, JP-A-3-28296, JP-A-3-3319
No. 2, JP-A-3-33193 and the like disclose polyether compounds.

[0005] Since the polyether compound has a higher polarity than the naphthenic mineral oil, its compatibility with HFC134a at low temperatures is certainly good. However, US Pat.
As described in US Pat. No. 55316, polyether compounds have a problem in that, when the temperature rises, two layers separate. The polyether compound also has some other problems. One is that the electrical insulation is poor. This is a very serious problem and cannot be used for refrigerators for electric refrigerators. Another problem is high hygroscopicity. Due to the moisture in the polyether compound, the thermal stability in the coexistence of HFC134a is deteriorated, and the organic material such as a PET film is hydrolyzed.

[0006] Ester-based compounds have been developed in order to solve the problems of the polyether compounds having such electric insulating properties and hygroscopicity. For example, a refrigerating machine oil that can be used with 1,1,1,2-tetrafluoroethane (HFC134a) is disclosed in U.S. Pat. No. 4,851,144.
And Japanese Patent Application Laid-Open No. 2-276894.
No. 158,693 discloses a mixed oil of a polyether oil and an ester oil, and GB 2,216,541 and EP 406,479 disclose an ester oil.

[0007] Ester compounds have excellent compatibility with hydrofluorocarbons and also have excellent thermal stability in the presence of hydrofluorocarbons. Further, as compared with the polyether-based compound, it has extremely excellent electric insulating properties and has considerably low hygroscopicity. However, compared to the conventional working fluid CFC12-mineral oil system, the hydrofluorocarbon-ester oil system has a higher polarity for both chlorofluorocarbon and oil and tends to contain water. Therefore, there is a problem that the ester oil is hydrolyzed to generate a carboxylic acid, and the generated carboxylic acid corrodes the metal and causes abrasion.

As described above, the hydrofluorocarbon-polyether oil system developed so far has a problem of hygroscopicity and electric insulation, the hydrofluorocarbon-ester oil system has a problem of hydrolysis resistance, and the conventional CFC12-mineral oil has a problem. It contains water more easily than oil-based ones, and 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. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a composition for a working fluid of a refrigerator which does not have the above-mentioned problems and which is particularly excellent in compatibility.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, based on the compound having a plurality of ketone groups in the molecule represented by the following general formula (I): It has been 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]

Embedded image

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

In the general formula (I), R ¹ , R ² ,
R ^3, linear or branched alkyl group having a carbon number of 1 to 36 represented by R ^4, alkenyl or substituted arylalkyl group or a linear or branched alkyl or alkenyl group having 1 to 15 carbon atoms, Examples of 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, stearyl group; isopropyl group, isobutyl group, isoamyl group,
A branched-chain alkyl group such as a 2-ethylhexyl group, an isostearyl group or a 2-heptylundecyl group; an alkenyl group such as a vinyl group, a propenyl group or an isobutenyl group; an arylalkyl group such as a benzyl group; a phenyl group, a methylphenyl group; Examples include a dimethylphenyl group, an isopropenylphenyl group, an isopropylphenyl group, and a vinylphenyl group.

In the present invention, the sum of the carbon numbers of R ¹ and R ² is preferably 24 or less for compatibility with the hydrofluorocarbon, and the carbon numbers of R ³ and R ⁴ are each 25 or less. This is preferred because of the compatibility of the hydrofluorocarbon.

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

The compound represented by the general formula (I) includes various compounds, and is 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-tridecandione, 2,4-pentadecandione, 8-methyl-2,4-nonanedione, 7-ethyl-
2,4-undecandione, 7-hexyl-2,4-pentadecandione, 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-tetradecandione, 2,5-hexadecandione, 10-methyl- 2,5-undecandione, 8-ethyl-2,5
-Dodecandione, 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-heptanetrione and the like.

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

These compounds having a plurality of ketone groups in the molecule have 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 the hydrofluorocarbon deteriorates. The viscosity at 40 ° C. is 1 to 10,000 cst.
Is more preferable, 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 a low temperature with the hydrofluorocarbon is low, and 0 ° C. or lower, more preferably −10 ° C. or lower. The compound having a plurality of ketone groups in the molecule used in the present invention may be a mineral oil, a poly-α-olefin, an alkylbenzene, an ester, a polyether, a perfluoropolyether, or phosphorus as long as the compatibility with the hydrofluorocarbon is not impaired. Synthetic oils such as acid esters may be mixed.

Further, the refrigerating machine oil used in the present invention, which is based on a compound having a plurality of ketone groups in a molecule, has an epoxy group for trapping water or acid in the composition, if necessary. To add additives such as compounds, orthoesters, and acetal, and to improve lubricity, triaryl phosphate and / or triaryl phosphite, trialkyl phosphate and / or trialkyl phosphite, alkyl and / or Zinc aryldithiophosphate and molybdenum dithiophosphate,
Abrasion inhibitors such as molybdenum dithiocarbamate, tartrate 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, An aromatic amine compound may be added.

Examples of the compound having an epoxy group used herein 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 addition amount is based on 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 5.0 parts by weight.
2.0 parts by weight.

The orthoester or acetal used in the present invention has 3 to 75 carbon atoms, and is added in an amount of 0.01 to 100 parts by weight based on 100 parts by weight of the base oil. The anti-wear 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 based on 100 parts by weight of the base oil. The compound having two adjacent hydroxyl groups used in the present invention has 6 to 75 carbon atoms, and the amount of addition is 0.01 to 100 parts by weight based on 100 parts by weight of the base oil. The phenolic compound or aromatic amine compound used in the present invention has radical trapping ability and has 6 to 100 carbon atoms. The addition amount is 0.05 to 2.0 parts by weight based on 100 parts by weight of the base oil.

In the composition for a working fluid of a refrigerator according to the present invention, a refrigerating machine oil comprising a hydrofluorocarbon and a compound having a plurality of ketone groups in a molecule used in the present invention as a base oil or an additive is added to the base oil. 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).

The hydrofluorocarbon used in the present invention includes 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.
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. The evaluation of the performance of the composition for a working fluid in a refrigerator in Examples and Comparative Examples was performed by the following test methods.

The viscosities at 40 ° C. and 100 ° C. of oils 1 to 5 used in the product of the present invention and oil 6 used in the comparative product shown in Table 1 were measured by JI.
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 which are compositions with C32) and Comparative product 1
Were prepared and their compatibility was examined. That is, 1,
The two-layer separation temperature at a low temperature at each oil concentration of 10, 20, 30 vol% with respect to 1,1,2-tetrafluoroethane or difluoromethane was measured.

Example 1 Using a reactor equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropper, and a fractionator equipped with a cooling tube, 200.2 g (2.0 mol) of acetylacetone was added thereto. 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 completed product. Next, a 10% aqueous solution of NaOH was added to the reaction product at an acid value of 1.1%.
The mixture was neutralized twice, and the product was extracted with hexane. Then, vacuum distillation (130-150 ° C / 0.3-0.5To)
rr) to obtain 266.4 g of the desired product (oil 1). IR
And the absorption of an alkyl group and a 1,3-dicarbonyl group was confirmed from 1H-NMR. The obtained compound was also confirmed by ¹ H-NMR to be a 1-mol adduct of acetylacetone and 1-octene (gas chromatography purity). 83.3%). Using the obtained oil 1, the viscosity and the compatibility were evaluated by the methods described above. Table 1 shows the results.

Example 2 Using a reactor equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropper, 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 (0.2 mol) of ditert-butyl peroxide as a radical initiator were used.
2 mol) was added dropwise over 5 hours, and the mixture was aged for 1 hour to obtain a reaction completed product. Thereafter, vacuum distillation was carried out, and 17
Oil 2 (84.degree. C.) from a fraction of 0 to 176 DEG C./3 to 4 Torr.
0 g). By IR and ¹ H-NMR, it was confirmed that Oil 2 was a 1 mol adduct of acetonylacetone and 1-octene (gas chromatography purity: 90.2%). Oil 2 obtained
And the viscosity and compatibility were evaluated by the above-mentioned methods.
Table 1 shows the results.

Example 3 The distillation residue obtained in Example 2 was further subjected to distillation under reduced pressure to obtain Oil 3 from a fraction at 176 to 200 ° C./3 to 4 Torr. IR and ¹ H-NMR confirmed that Oil 3 was a 2-mol adduct of acetonylacetone and 1-octene. Using the obtained oil 3, the viscosity and the compatibility were evaluated by the methods described above. Table 1 shows the results.

Example 4 Using a 500 ml four-necked flask equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropper, and a reflux condenser, 50.0 g (0.5 mol) of acetylacetone and 100 cc of acetone were added. And potassium carbonate
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, and aging was performed for 30 hours under acetone reflux. Then, vacuum distillation (110 ° C./20 Torr)
By r), 38.0 g of the target product (oil 4) was obtained. IR, ¹
The compound obtained from H-NMR was 3-isoamyl-
It was confirmed to be 2,4-pentanedione (gas chromatography purity: 76%). Using the obtained oil 4, the viscosity and the compatibility were evaluated by the methods described above. Table 1 shows the results.

Example 5 Using a 500 ml four-necked flask equipped with a stirrer, a nitrogen gas blowing tube, a thermometer, a dropper, and a reflux condenser, 50.0 g (0.5 mol) of acetylacetone and 100 cc of acetone were added. And potassium carbonate
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 aging was performed under reflux of acetone for 30 hours. Thereafter, distillation under reduced pressure (143 to 146 ° C./10 To
rr) to obtain 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 chromatography purity: 82%). Using the obtained oil 5, the viscosity and compatibility were evaluated by the methods described above. Table 1 shows the results.

Comparative Example 1 Using naphthenic oil as oil 6, the viscosity and compatibility were evaluated by the above-mentioned methods. Table 1 shows the results.

[0032]

[Table 1]

As shown in Table 1, the compositions for working fluids of refrigerators 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 composition for a working fluid of a refrigerator has a high two-layer separation temperature and inferior compatibility at any oil concentration.

[0034]

The composition for a working fluid of a refrigerator according to the present invention is particularly excellent in compatibility because it contains a refrigerator oil having a compound having a plurality of ketone groups in a molecule as a base oil and hydrofluorocarbon. In addition, there is no concern about hydrolytic properties, and it has low hygroscopicity.

Continuation of the front page (72) Inventor Yukita Yokota 208-10 Tottori, Hannan-shi, Osaka (56) References JP-A-53-83148 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10M 105/20 C09K 5/04 C10N 40:30 CA (STN)

Claims (2)

(57) [Claims] 1. A refrigerating machine fluid containing a compound represented by the general formula (I) as a base oil, and a composition for a refrigerating machine working fluid containing a hydrofluorocarbon. Embedded image (Wherein R ¹ and R ² are the same or different and are each 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.
And 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 by a linear or branched alkyl, alkenyl or arylalkyl group having 1 to 36 carbon atoms, or a linear or branched alkyl or alkenyl group having 1 to 15 carbon atoms. Represents a phenyl group which may be substituted. n represents a number from 1 to 4 , 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 the carbon number of R ² is 24 or less, and R ³ and R ⁴
The composition for a refrigerator working fluid according to claim 1, wherein each of the carbon atoms has a carbon number of 25 or less.