JPH09110771A - Spirobiindane derivative and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound excellent in compatibility with fluoroalkane-based cooling medium such as 1,1,2-tetrafluoroethane over a wide temperature range, capable of imparting excellent stability and low absorbability to lubricating oils, thus useful for e.g. lubricating oils for the freezing system. SOLUTION: This new compound is expressed by formula I [A is ethylene or isopropylene; R<1> and R<2> are each H, a (substituted) alkyl, (substituted) alkoxyl, halogen or OH; Rf is a 1-25C (partially substituted) fluorocarbon group 0.6-3 in atom number ratio F/C; (l) and (s) are each 1-3; (m) and (n) are each 0-100, (m+n) is not zero], e.g. 6,6'-bis[2-(perfluorobutoxy) ethyloxy]-3,3,3',3'- tetramethyl-1,1'-spirobiindane. The compound of formula I is obtained by reaction of a compound of formula II with a compound of the formula Rf-X (X is Br or I) in the presence of an alkali.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil having excellent compatibility with a fluoroalkane-based refrigerant. More specifically, fluorinated alkanes, which are promising substitutes for chlorine atom-containing refrigerants such as dichlorodifluoromethane (CFC-12) and chlorodifluoromethane (HCFC-22), preferably hydrofluoroalkanes such as hydrofluoroethane, and more preferably Is 1,1,1,2-tetrafluoroethane (HFC-134a)
The present invention relates to a lubricating oil having excellent compatibility with a fluorinated alkane-based refrigerant suitable for a refrigeration system using as a refrigerant.

[0002]

2. Description of the Related Art At present, CFC-12 is mainly used as a refrigerant for refrigerators for car air conditioners and refrigerators, and HCFC-22 is used as a refrigerant for refrigerators for room air conditioners. From the standpoint of the above, it has been desired to develop a refrigerant that can substitute for a chlorine-containing refrigerant such as CFC-12 and HCFC-22. As an alternative refrigerant, lower fluoroalkane is promising, but in particular,
Hydrofluoroalkanes such as hydrofluoroethane are preferred. Among them, HFC-134a is CFC- as a refrigerant.
It has physical properties close to 12, and requires minimal changes in equipment.
It is particularly promising because it can be used as a substitute for CFC-12. In addition, HFC-134a isomers 1, 1, 2,
2-tetrafluoroethane (HFC-134), 1,1-difluoroethane (HFC-152), difluoromethane (HFC-32), which is an alternative candidate for HCFC-22, pentafluoroethane (HFC-125)
It is considered that fluorinated alkanes such as 1,1,1-trifluoroethane (HFC-143a) can be similarly used.

In a refrigeration system using CFC-12, mineral oil is used as a lubricating oil for compressors. CF
C-12 has a high lipophilicity because it contains a chlorine atom and is compatible with mineral oil in a wide temperature range, so that the refrigerant and the lubricating oil are not separated in the refrigeration system in which the refrigerant repeatedly evaporates and condenses. However, various fluorinated alkane-based refrigerants represented by HFC-134a do not have sufficient compatibility with mineral oil because they do not contain chlorine atoms, and when mineral oil is used as lubricating oil, for example, the lubricating oil is replaced by the refrigerant in the compressor. As a result, lubrication becomes insufficient, the heat exchange rate deteriorates, and various serious problems occur. As a lubricating oil for a refrigerator using a fluorinated alkane such as HFC-134a as a refrigerant, at least 0 ° C to 50 ° C, preferably -20
C. to 70.degree. C., particularly preferably -40.degree. C. to 90.degree.
Range, or even wider temperature range, HFC-
Must be compatible with fluorinated alkanes such as 134a. Various polyalkylene glycol-based compounds and polyester-based compounds have been proposed as lubricating oils that are compatible with HFC-134a because they are used together with HFC-134a. For example, polyalkylene glycols having two or more hydroxyl groups, particularly polyoxypropylene glycol, disclosed in U.S. Pat. No. 4,755,316, are said to have a wide temperature range in which they exhibit compatibility. However, the temperature range showing the compatibility is not yet sufficient for a lubricating oil, and it is necessary to improve the compatibility especially in a high temperature range.

Further, polyoxyalkylene glycol has insufficient lubricity under the conditions of use of lubricating oil and has a large hygroscopicity, so that it freezes water, corrodes metals, and lowers volume resistivity. (Problems with closed-type refrigerators such as refrigerators) easily occur, and it cannot be said that the lubricating oil for refrigeration systems is practically excellent. In addition, JP-A-3-128991
JP-A, JP-A-3-17909 and other polyester compounds disclosed in JP-A-3-179091 are also said to be excellent in compatibility with HFC-134a, but high hygroscopicity because it contains an ester group, also, It is prone to decomposition such as hydrolysis and has a problem in durability.

[0005]

The object of the present invention is to show good compatibility with fluorinated alkanes such as HFC-134a in a wide temperature range from a low temperature region to a high temperature region, and stability, low hygroscopicity, etc. To provide a lubricating oil having excellent properties.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, have found that the compatibility with fluorinated alkanes such as HFC-134a is good, and that the fluorine such as HFC-134a is fluorine-containing. Has found a novel spirobiindane derivative suitable as a lubricating oil for a refrigeration system using a refrigerant containing a halogenated alkane,
The present invention has been completed. That is, the present invention relates to a novel spirobiindane derivative represented by the general formula (I) (Formula 2) and a lubricating oil containing the derivative.

[0007]

Embedded image (In the formula, A represents an ethylene group or an isopropylene group, R represents
¹ , R ² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen atom or a hydroxyl group, and Rf is a carbon atom having 1 to 25 carbon atoms.
And the ratio of the number of fluorine atoms / the number of carbon atoms is 0.6.
Represents a fluorocarbon group or a partial substitution product thereof, wherein l and s each represent an integer of 1 to 3, n and m each represent an integer of 0 to 100, and n + m is not 0)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to HFC- which is a promising refrigerant as a substitute for chlorine atom-containing refrigerants such as CFC-12 and HCFC-22.
A novel spirobiindane derivative showing good compatibility with a fluorinated alkane such as 134a in a wide temperature range from a low temperature region to a high temperature region and having properties suitable as a lubricating oil for a refrigeration system, and its use. is there. The novel spirobiindane derivative represented by the general formula (I) of the present invention is a compound containing a fluorine atom, but since the content of the fluorine atom is low, a fluorine-containing lubricant is
There is an advantage that the manufacturing cost is low. In addition, the spirobiindane derivative has a surprising property that it exhibits a good compatibility with various fluoroalkane-based refrigerants despite its low fluorine atom content. Therefore, the lubricating oil containing the novel spirobiindane derivative represented by the general formula (I) of the present invention is extremely excellent in compatibility with the fluoroalkane-based refrigerant.

Hereinafter, the present invention will be described in more detail. In the spirobiindane derivative represented by the general formula (I) of the present invention, R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen atom or a hydroxyl group. . As the unsubstituted alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-
Butyl group, tert-butyl group, n-pentyl group, n-hexyl group, 2-ethylhexyl group, n-octyl group, n-decyl group,
n-dodecyl group, n-tetradecyl group, n-octadecyl group,
Cyclopentyl group, cyclohexyl group, 4-tert-butylcyclohexyl group, cycloheptyl group, cyclooctyl group, cyclohexylmethyl group, cyclohexylethyl group, tetrahydrofurfuryl group and the like, and the substituted alkyl group, 2-methoxyethyl group , 2-ethoxyethyl group, 2-n-butoxyethyl group, 3-methoxypropyl group,
3-ethoxypropyl group, 3-n-propoxypropyl group,
3-n-butoxypropyl group, 3-n-hexyloxypropyl group, 2-methoxyethoxyethyl group, 2-ethoxyethoxyethyl group, 2-phenoxymethyl group, 2-phenoxyethoxyethyl group, chloromethyl group, 2- Examples thereof include a chloroethyl group, 3-chloropropyl group, 2, 2, 2-trichloroethyl group and the like.

The unsubstituted alkoxy group includes methoxy group, ethoxy group, n-propoxy group, isopropoxy group,
n-butoxy group, isobutoxy group, sec-butoxy group, n-pentyloxy group, n-hexyloxy group, 2-ethylhexyloxy group, n-octyloxy group, n-decyloxy group,
n-dodecyloxy group, n-tetradecyloxy group, n-octadecyloxy group, cyclopentyloxy group, cyclohexyloxy group, 4-tert-butylcyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group, cyclohexylmethoxy group, Examples of the substituted alkoxy group include a cyclohexylethoxy group and the like, and 2-methoxyethoxy group, 2-ethoxyethoxy group, 2-n-butoxyethoxy group, 3-methoxypropoxy group, 3-ethoxypropoxy group, 3-n -Propoxypropoxy group, 3-n-butoxypropoxy group, 3-n-hexyloxypropoxy group, 2-
Methoxyethoxyethoxy group, 2-phenoxymethoxy group, 2-phenoxyethoxyethoxy group, chloromethoxy group, 2-chloroethoxy group, 3-chloropropoxy group, 2,
2,2-trichloroethoxy group and the like can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

A represents an ethylene group or an isopropylene group, l and s represent integers of 1 to 3, n and m represent 0 to 1
Represents an integer of 00. However, n + m is not 0. Rf represents an unsubstituted or partially substituted fluorocarbon group having 1 to 25 carbon atoms and having a ratio of the number of fluorine atoms in Rf / the number of carbon atoms of 0.6 to 3. The fluorocarbon residue means a substituent having a structure in which a part or all of hydrogen atoms of various hydrocarbon groups are substituted with fluorine atoms, and examples thereof include a fluoroalkyl group, a fluoroalkenyl group, or an aromatic group. Examples thereof include a fluoroaryl group having a nucleus, and particularly a fluoroalkyl group and a fluoroalkenyl group are easy to synthesize and useful.

Further, as Rf, a part of the fluorine atom or hydrogen atom of the fluorocarbon group is a halogen atom such as chlorine atom, bromine atom, iodine atom, amino group, nitrile group, amide group or acyl group. It may be a partially substituted fluorocarbon residue further substituted with various substituents that are stable under the conditions of use of the refrigerating machine oil, such as a carbonyl-containing group such as a carboxyl group. The number of substituents other than fluorine atoms in the partially substituted fluorocarbon residue is 150% or less, preferably 100% or less, of the total number of fluorine atoms or fluorine atoms and hydrogen atoms in the substituted fluorocarbon residue.
Among the above partially substituted fluorocarbon residues, a fluorochloroalkyl group is preferable because it is easy to synthesize and shows good lubricity.

Rf may have a perfluoropolyether structure. The ratio of the number of fluorine atoms / the number of carbon atoms in Rf is usually 0.6 to 3, preferably 1.0 to
Three are used. If the ratio of the number of fluorine atoms / the number of carbon atoms in Rf is too low, the compatibility with the fluoroalkane becomes low, which is not preferable. The number of carbon atoms in Rf is
It is usually in the range of 1 to 25, preferably in the range of 1 to 10, and more preferably in the range of 1 to 6. To exemplify Rf _{group, -CF 3, -C 2 F 5} , -C 3 F 7, -C 6 F 13, -C
₇ F ₁₅ ,-(CF ₂ ) ₆ H,-(CF ₂ ) ₁₀ H,-(CF ₂ ) ₃ C ₆ H ₅ , -C (CF ₃ )
₂ C ₆ H ₅ , -CH ₂ F, -CHF ₂ , -CF ₂ CH ₃ , -CH ₂ CHF ₂ , -CH ₂ CF
₃ , -CF ₂ CH ₂ F, -CHFCF ₃ , -CF ₂ CHF ₂ , -CHFCF ₃ , -CF = CF
₂ , -CH ₂ CH ₂ CF ₃ , -CClF ₂ , -CCl ₂ F, -CHF ₂ , -CHClF,
_{-CCl 2 CClF 2, -CClFCClF 2,} -CF 2 CCl 2 F, -CClFCCl 2 F, -C
ClFCClF _2, -CF ₂ CClF _2, and the like.

Next, in the present invention, a method for synthesizing the spirobiindane derivative represented by the general formula (I) will be exemplified, but the method is not limited to these methods. The novel spirobiindane derivative represented by the general formula (I) has the general formula (II)
It can be obtained by reacting the dihydroxy compound represented by (Chemical Formula 3) with a halogen compound, an alcohol, or a tosylate as shown in reaction formulas (1) to (3) (Chemical Formula 4).

[0015]

Embedded image [In the formula, R ¹ , R ² , A, 1, m, n and s have the same meanings as in the case of the formula (I)]

[0016]

Embedded image

In the reaction formulas (1) and (3), examples of the alkali include hydroxides such as sodium hydroxide and potassium hydroxide, carbonates such as sodium carbonate, potassium carbonate and calcium carbonate, sodium hydrogen carbonate, Examples thereof include hydrogen carbonates such as potassium hydrogen carbonate, and oxides such as zinc oxide, magnesium oxide, and aluminum oxide. In the reaction formula (2), examples of the acid include mineral acids such as sulfuric acid and hydrochloric acid, methanesulfonic acid, Organic acids such as trifluoromethanesulfonic acid, p-toluenesulfonic acid, dimethylsulfate and diethylsulfate can be mentioned. Moreover, reaction formula (1)-
A solvent may be used in the reaction of (3). Examples of the solvent include hydrocarbons such as octane, decane and dodecane, halogenated hydrocarbons such as 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochlorobenzene and dichlorobenzene, sulfolane, N, N- Dimethyl sulfoxide, sulfur-containing solvent such as dimethyl sulfone, N-methylpyrrolidone, N, N-dimethylformamide, N, N-containing solvent such as dimethylimidazolidinone, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, Examples include ethers such as ethylene glycol dipropyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether.

The spirobiindane derivative represented by the general formula (I) can be used alone or as a mixture of two or more thereof as a lubricating oil for a refrigeration system using a refrigerant containing a fluorinated alkane. Further, the spirobiindane derivative represented by the general formula (I) can be used by mixing with other lubricating oil. Other lubricating oils that can be mixed and used are usually selected from those exhibiting a certain degree of solubility in fluorinated alkane-based refrigerants, for example, perfluoropolyether oils, or carboxyl groups, carboxylate groups, amide groups, ketones. Carbonyl-containing group such as group or ester group, hydroxyl group, amino group,
Perfluoroether oil, chlorofluorocarbon oil, fluorinated silicone oil containing polar substituents such as imide group, ether group, benzimidazole group, phosphite group, phosphinic acid, nitrile group, phosphotriazine group or triazine group Etc. From these, an appropriate type is selected in consideration of the compatibility with the spirobiindane derivative represented by the general formula (I), the viscosity of the resulting lubricating oil composition, the lubricating characteristics, and the like. When the spirobiindane derivative represented by the general formula (I) is used as a mixture with other lubricating oil, the amount of the spirobiindane derivative depends on the compatibility of the resulting lubricating oil composition with the refrigerant, the viscosity of the composition, and the like. However, it is usually at least 0.
The range is 1% by weight or more, preferably 25% by weight or more, and more preferably 50% by weight or more.

When the spirobiindane derivative represented by the general formula (I) of the present invention is used alone as a lubricating oil for a refrigerator using a refrigerant containing a fluorinated alkane, the spirobiindane derivative at 40 ° C. The kinematic viscosity is usually in the range of 2 to 500 centistokes (cst), preferably in the range of 3 to 300 cst, more preferably in the range of 5 to 170 cst, particularly preferably 10
Those in the range of ~ 150cst are used. The kinematic viscosity at 100 ° C. is usually 0.5 to 100 cst, preferably 1 to
50 cst, particularly preferably in the range of 2 to 30 cst is used. If the viscosity is too low, the rotating torque of the compressor part becomes high, which is not preferable. The general formula (I)
When using a mixture of several kinds of spirobiindane derivative represented by, or when used by mixing with other lubricating oil, the viscosity of the spirobiindane derivative is not particularly limited,
The viscosity of the mixed system may be in the same range as in the above case where the spirobiindane derivative is used alone. Further, even when the spirobiindane derivative is a solid, the viscosity of the refrigerant composition comprising the fluoroalkane-based refrigerant and the substance is about the same as a refrigerant composition using a lubricating oil containing a spirobiindane derivative having a kinematic viscosity in the above range. If so, it can be used.

In the present invention, the weight ratio of total amount of refrigerant / total amount of lubricating oil in the refrigeration system is usually 99/1 to 1 /
The range is 99, preferably 95/5 to 10/90, particularly preferably 90/10 to 20/80. The spirobiindane derivative represented by the general formula (I) exhibits good compatibility with a fluoroalkane-based refrigerant such as HFC-134a in a wide temperature range. That is, the spirobiindane derivative represented by the general formula (I) can be compatible with fluorinated alkanes such as HFC-134a even at -78 ° C or lower. Further, with the spirobiindane derivative represented by the general formula (I), it is possible to easily obtain a spirobiindane derivative having a compatibility with a fluorinated alkane-based refrigerant such as HFC-134a having an upper limit temperature of 90 ° C. or higher. Further, the spirobiindane derivative represented by the general formula (I) similarly exhibits good compatibility with various fluorinated alkane-based refrigerants and mixed solvents with chlorine-containing fluorinated alkane-based refrigerants.

The fluorinated alkane type refrigerant in the present invention is
Lower fluorinated alkanes that can be used as a refrigerant (for example, fluorinated alkanes having about 1 to 5 carbon atoms), especially 1 to 4 carbon atoms
It is preferable to contain the hydrofluoroalkane of
For example, CH ₂ CF ₂ [HFC-32], CHF ₃ [HFC-23], CF ₃ CH ₂ F
[HFC-134a], CHF ₂ CHF ₂ [HFC-134], CF ₃ CH ₃ [HFC-143a],
CH ₃ CHF ₂ [HFC-152a], CF ₃ CHF ₂ [HFC-125], CF ₃ CHF ₂ [H
FC-125], CF ₃ CHFCF ₃ [HFC-227ea], CHF ₂ CF ₂ CF ₃ [HFC-2
27ca], CF ₃ CH ₂ CF ₃ , CF ₃ CHFCHF ₂ , CF ₃ CF ₂ CH ₂ F, CHF ₂ CF ₂
CHF ₂ , CF ₃ CH ₂ CHF ₂ , CF ₃ CF ₂ CH ₃ , CHF ₂ CF ₂ CH ₂ F, CF ₃ CF
₂ CF ₂ CH ₃ , CF ₃ CHFCHFCF ₃ , CF ₃ CHFCHFCF ₂ CF _{3 and} other fluorinated methane, fluorinated ethane, various fluorinated alkanes such as fluorinated butane can be exemplified, It is not limited to these.

As the chlorine-containing fluoroalkane-based refrigerant, a lower chlorine-containing fluoroalkane which can be used as a refrigerant (for example, a chlorine-containing fluoroalkane having about 1 to 5 carbon atoms), preferably 1 to 1 carbon atoms. 3 is a chlorine-containing fluorinated alkane of 3. For example, CHClF ₂ [HCFH-22], CCl ₂ F ₂ [CFC-1
2], CClF ₂ CH ₃ [HCFC-142b], CCl ₂ FCH ₃ [HCFC-141b], CC
lF ₂ CHF ₂ [HCFC-124a], CF ₃ CHClF [HCFC-124], CHClFC
ClF ₂ [HCFC-123a], CF ₃ CHCl ₂ [HCFC-123], CHF ₂ CF ₂ CHC
l ₂ [HCFC-235ca], CF ₃ CF ₂ CH ₂ Cl [HCFC-235cd], CClF ₂ CF ₂
Various lower chlorine-containing fluorinated alkanes such as CH ₂ F [HCFC-235cc] can be exemplified, but the present invention is not limited thereto.

Further, the spirobiindane derivative represented by the general formula (I) is added in the presence of a metal such as copper, brass, aluminum or carbon steel, water and a fluorinated alkane such as HFC-134a, or HFC-134a. With fluorinated alkane
When subjected to a stability test (so-called shield tube test) in which a chlorine-containing fluoroalkane such as CFC-12 coexists with a mixed refrigerant, even at 175 ° C, the spirobiindane derivative represented by the general formula (I) and the mixed solvent Is stable and the metal surface remains almost unchanged. Usually, the ester oil is hydrolyzed by coexisting water, and its total acid value increases. Further, when a chlorine-containing fluoroalkane-based refrigerant coexists, this hydrolysis is further accelerated, and absorption attributed to carboxylic acid appears in the IR spectrum of the oil after the test. However, the spirobiindane derivative represented by the general formula (I) of the present invention has a very low hygroscopic property, and like an ester oil having a high hygroscopic property, deterioration of electric properties of oil due to water and a fluorine-containing compound such as HFC-134a. There is no problem such as decomposition of the alkane compound.

As described above, the spirobiindane derivative represented by the general formula (I) of the present invention exhibits good compatibility with a fluoroalkane-based refrigerant or a chlorine-containing fluoroalkane-based refrigerant in a very wide temperature range. . Further, the spirobiindane derivative of the present invention has extremely low hygroscopicity, and there are no problems such as deterioration of electric properties of oil due to water and promotion of decomposition of fluorinated alkane. Furthermore, the spirobiindane derivative of the present invention is stable even in the presence of chlorine-containing fluoroalkane. Therefore, the spirobiindane derivative of the present invention can be substituted for an alternative refrigerant composition of an existing refrigerator. Further, the lubricating properties of the spirobiindane derivative of the present invention were evaluated in the presence or absence of a fluorinated alkane, and in any case, extreme pressure (baking load), wear resistance, and a friction coefficient show extremely good performance. It was confirmed.

Therefore, the spirobiindane derivative or the lubricant composition containing the derivative of the present invention is used in a refrigerator, a freezer, a car air conditioner or the like.
It is useful not only as a lubricating oil for various refrigerators that use a fluoroalkane, which is a promising substitute for a refrigerant such as CFC-22, but also as a general lubricating oil. The lubricating oil for a refrigerator of the present invention is a rust preventive, an antioxidant, a viscosity index improver,
Additives such as a corrosion inhibitor, an oiliness improver, a pour point depressant, and a load-bearing additive may be added in an amount usually used.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Synthesis Example 1 6,6'-dihydroxyethyloxy-3,3,3 ', 3'-tetramethyl-1,1'-spirobiindane 20g, perfluoroiodide 36.7g in a reactor equipped with a stirrer and a thermometer Then, 10.5 g of sodium carbonate and 200 g of tetrahydrofuran were charged, and the mixture was heated and stirred under reflux for 3 hours. Then drain into 2 liters of water,
The precipitated solid was filtered off, washed with water and dried. Yield 41.9
g. The results of elemental analysis and mass spectrometry are shown below. -Mass spectrometry result: m / e 832 (M ⁺ )

Synthesis Example 2 6,6'-dihydroxyisopropyloxy-3,3,3 ', 3'-tetramethyl-1,1'-in a reactor equipped with a stirrer and a thermometer
Spirobiindane 30g, perfluorooctyl iodide 81
g, sodium carbonate 7.9 g and toluene 100 g were charged, and the mixture was heated with stirring under reflux for 4 hours. Then, it was discharged into 2 liters of water, and the precipitated solid was separated by filtration, washed with water and dried. Yield 4
8.1g. The results of elemental analysis and mass spectrometry are shown below. -Mass spectrometry result: m / e 714 (M ^<+> ) Synthesis Examples 3-12 The compound shown in Table 1 (Table 1) was synthesize | combined similarly to the synthesis example 1. The structure was confirmed by elemental analysis and mass spectrometry.

Examples 1 to 12 Compatibility, water absorption and heat resistance of the compounds synthesized in Synthesis Examples 1 to 12 were evaluated according to the following methods. The evaluation results are summarized in Table 2 (Table 2). -Compatibility 0.2g of the compound of the present invention was put into a glass tube, the glass tube was cooled with liquid nitrogen, and then depressurized to HFC-13.
4a About 1.5g was introduced. After sealing the glass tube,
After the temperature was adjusted to equilibrium and the temperature reached equilibrium, the compatibility of oil with HFC-134a was visually determined. Also, 40 ℃
Was measured using an E-type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd.). -Equilibrium water absorption was measured when it was allowed to stand at a constant temperature and humidity of 25 ° C and 70% relative humidity. -A heat-resistant glass tube was filled with 0.6 ml of the purified compound of the present invention, 0.6 ml of the refrigerant HFC-134a, 0.01 ml of water, and a test piece of iron, copper, and aluminum, and the sealed refrigerant composition was sealed at 175 ° C.
After heating for 10 days, the hue change and the surface of the metal piece were visually observed.

Comparative Examples 1 and 2 Evaluations were carried out by the method described in Examples using the ester oils described in Examples of JP-A No. 3-179091 and polypropylene glycol having Mn of 1500. Table-Results
2 is shown.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

EFFECTS OF THE INVENTION The fluorine-containing spirobiindane derivative of the present invention, when used as a lubricating oil for a refrigeration system, has a good phase with a fluoroalkane-based refrigerant represented by HFC-134a in a wide temperature range from a low temperature region to a high temperature region. Shows solubility. Further, the lubricating oil containing the derivative has excellent physical properties such as stability and low absorbency, and can be an excellent lubricating oil for refrigeration systems. Furthermore, since this lubricating oil has very excellent lubricating properties, it is useful not only for refrigerators but also as general lubricating oil.

Claims (2)

[Claims] 1. A spirobiindane derivative represented by the general formula (I) (formula 1). Embedded image (In the formula, A represents an ethylene group or an isopropylene group, R represents
¹ , R ² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen atom or a hydroxyl group, and Rf is a carbon atom having 1 to 25 carbon atoms.
And the ratio of the number of fluorine atoms / the number of carbon atoms is 0.6.
Represents a fluorocarbon group or a partial substitution product thereof, wherein l and s each represent an integer of 1 to 3, n and m each represent an integer of 0 to 100, and n + m is not 0) 2. A lubricating oil containing the spirobiindane derivative according to claim 1.