Lubricating oil base oils and polyether compounds

Abstract

Provided are: a lubricant base oil having a low viscosity, a high boiling point, and a high flash point; and a polyether compound to be included in the lubricant base oil.　This lubricant base oil includes a polyether represented by formula (1). In formula (1), for example, R1 and R2 each represent an alkyl having 1-12 carbon atoms or an aralkyl having 7-12 carbon atoms, X1 and X2 each represent hydrogen, an alkyl having 1-10 carbon atoms, or an aralkyl having 7-10 carbon atoms, and R3, R4, R5, and R6 each represent hydrogen, an alkyl having 1-10 carbon atoms, or an aralkyl having 7-12 carbon atoms.

Description

Technical Field

[0001] The present invention relates to polyethers for lubricating base oils.

Background Art

[0002] Lubricating oils used in power machinery such as internal combustion engines of automobiles, electric motors of electric vehicles, etc., speed reducers that reduce the power from the power engine, sliding parts of rotary bearings such as turbines, and compressors used in refrigerators and heat pumps, etc., require compounds with lower viscosities for energy-saving purposes. Generally, as a general property of the chemical substances used in lubricating oils, the lower the molecular weight, the lower the viscosity. On the other hand, low molecular weight compounds generally have low boiling points, and accordingly, the flash point also tends to be low. It is obvious that the decrease in the flash point becomes a problem in ensuring the safety of the environment where the lubricating oil is used, and the decrease in the boiling point causes problems such as evaporation and dissipation of the base oil in an open environment.

[0003] Here, as a method for solving the problem of flammability, it is conceivable to impart flame retardancy to the lubricating oil. For example, it is known to contain 10% or more of water in the lubricating oil composition. However, it is obvious that lubricating oils containing water are not suitable for such use environments because water easily evaporates in environments exposed to high temperatures such as internal combustion engines. Also, "a gear oil composition containing a base oil and an extreme pressure agent, wherein, as the base oil, a condensed phosphoric acid ester represented by the following general formula (1) is contained in an amount of 20% by mass or more based on the total amount of the base oil, and as the extreme pressure agent, an extreme pressure agent containing sulfur is contained in an amount of 0.2 to 10% by mass based on the total amount of the gear composition, and the kinematic viscosity of the gear oil composition at 40 °C is 50 to 1000 mm 2A gear oil composition characterized by having / s." (Patent Document 1), "A lubricant composition characterized by containing tricalcium phosphate as a flame retardant and fire-resistant agent." (Patent Document 2), "A base oil and one or more foaming substances selected from dodecafluoroheptanol, hexadecafluorononanol, and tetrafluoro-1,2-diiodoethane as foaming substances that generate inert gas during foaming, wherein when the calorific value of the foaming substance is Q0 (cal / g), the heat generation onset temperature is T0 (°C), and the content of the foaming substance is W (weight %), the formula (VI) log(Q0 × W × 10 -2 Methods for imparting flame retardancy to a lubricating oil composition by adding additives have been disclosed, such as "a method using a flame retardant fluid that satisfies the relationship < 0.6679 × log(T0-25) + 1.132···(VI), and is in liquid or semi-solid form, and is used for applications selected from lubricating oils, hydraulic oils, cutting oils, processing oils, cleaning oils, heat treatment oils, electrical insulating oils, and greases" (Patent Document 3). However, the addition of additives affects the physical properties of the lubricating oil base oil and, in many cases, deteriorates the performance of the base oil, which is low viscosity. Lubricating oils are usually composed of only a single compound; rather, a lubricating oil composition is made by adding additives such as a lubricating oil base oil, antioxidants, dispersants, anti-wear agents, viscosity index improvers, extreme pressure additives, flame retardants, and defoamers. However, if the performance of the lubricating oil base oil is low, a large amount of additives must be added to improve it, which leads to the problem that the performance of the base oil is impaired.

[0004] Furthermore, even when addressing low-viscosity lubricants through composition, low-viscosity base oils often exhibited low boiling and flash points. While it is known that adding halogens to the base oil can increase the flash point, this method results in halogen-containing waste from used lubricants, leading to costly disposal. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-032280 [Patent Document 2] Japanese Patent Publication No. 2009-286951 [Patent Document 3] Japanese Patent Application Publication No. 08-325587 [Patent Document 4] Japanese Patent Publication No. 2021-70785 [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to solve the above-mentioned conventional technical problems and to provide a lubricating oil base oil with low viscosity, high boiling point, and high flash point, and a polyether compound to be contained in this lubricating oil base oil. [Means for solving the problem]

[0007] As a result of diligent research, the inventors of the present invention discovered that a polyether represented by formula (1) can be used as a base oil for lubricating oils with low viscosity, high flash point, and high boiling point, and thus completed the present invention. TIFF0007910570000001.tif3475 In formula (1), R1 and R2 are independently a C1-C12 alkyl or a C7-C12 aralkyl, in which at least one hydrogen may be replaced by a halogen or a C1-C5 alkoxy, and at least one methylene may be replaced by vinylene, oxygen, or sulfur; X1 and X2 are independently a hydrogen, a C1-C10 alkyl or a C7-C10 aralkyl, in which at least one methylene may be replaced by oxygen; and R3, R4, R5, and R6 are independently a hydrogen, a C1-C10 alkyl or a C7-C10 aralkyl. [Effects of the Invention]

[0008] By using the polyether for lubricating oil base oil according to the present invention as a lubricating oil base oil or cooling medium in internal combustion engines, electric motors, speed reducers, bearings, and compressors in refrigerators, it is possible to provide low-viscosity lubricating oils and cooling media with high cooling efficiency, thereby achieving energy savings. [Modes for carrying out the invention]

[0009] The present invention includes the following items, among others. [1] A lubricating oil base oil containing a polyether represented by formula (1). TIFF0007910570000002.tif3475 In formula (1), R1 and R2 are independently a C1-C12 alkyl or a C7-C12 aralkyl, in which at least one hydrogen may be replaced by a halogen or a C1-C5 alkoxy, and at least one methylene may be replaced by vinylene, oxygen, or sulfur; X1 and X2 are independently a hydrogen, a C1-C10 alkyl or a C7-C12 aralkyl, in which at least one methylene may be replaced by oxygen; and R3, R4, R5, and R6 are independently a hydrogen, a C1-C10 alkyl or a C7-C10 aralkyl.

[0010] [2] The lubricating oil base oil described in item [1], wherein the flash point of the polyether represented by formula (1) is 100°C or higher.

[0011] [3] A lubricating oil base oil according to item [1] or [2], wherein the boiling point at atmospheric pressure of the polyether represented by formula (1) is 250°C or higher.

[0012] [4] A lubricating oil base oil according to any one of items [1] to [3], wherein the total number of carbon atoms of the polyether represented by formula (1) is 40 or less.

[0013] [5] A lubricating oil base oil according to any one of items [1] to [4], containing 50% by mass or more of a polyether represented by formula (1).

[0014] [6] Further, the lubricating base oil according to any one of items [1] to [5] containing a hydrocarbon.

[0015] [7] The lubricating base oil according to item [6], wherein the hydrocarbon is a poly-α-olefin.

[0016] [8] The lubricating base oil according to item [6] or [7], wherein the hydrocarbon is a hydrocarbon refrigerant.

[0017] [9] A lubricating oil composition containing the lubricating base oil according to any one of items [1] to [8] and an additive.

[0018]

[10] The lubricating base oil according to any one of items [1] to [8] for a drive system.

[0019]

[11] The lubricating base oil according to any one of items [1] to [8] for an internal combustion engine.

[0020]

[12] The lubricating base oil according to any one of items [1] to [8] for a refrigerator.

[0021]

[13] The lubricating base oil according to any one of items [1] to [8] as a cooling medium.

[0022]

[14] The compound represented by formula (2). TIFF0007910570000003.tif3475 In formula (2), R1 and R2 are independently alkyl having 1 to 12 carbon atoms or aralkyl having 7 to 12 carbon atoms, X1 and X2 are independently hydrogen, alkyl having 1 to 10 carbon atoms in which at least one methylene may be replaced by oxygen, or aralkyl having 7 to 10 carbon atoms in which at least one methylene may be replaced by oxygen, and when one of X1 and X2 is hydrogen, the other is alkyl having 1 to 10 carbon atoms or aralkyl having 7 to 10 carbon atoms, and R3, R4, R5, and R6 are independently hydrogen, alkyl having 1 to 10 carbon atoms, or aralkyl having 7 to 10 carbon atoms.

[0023]

[15] The compound described in item

[14] , wherein in formula (2), R1 and R2 are independently C5 to C12 alkyl or C7 to C12 aralkyl, R3 is a C3 to C5 branched alkyl, R4, R5, and R6 are hydrogen, and X1 and X2 are methyl.

[0024]

[16] The compound according to item

[14] , wherein in formula (2), R1 and R2 are independently 2-methylpropyl, 2-ethylbutyl, or 2-ethylhexyl, R3, R4, R5, and R6 are hydrogen, and X1 and X2 are independently 2-methylpropyloxymethyl, 2-ethylbutyloxymethyl, or 2-ethylhexyl.

[0025]

[17] The compound according to item

[14] , wherein in formula (2), R1 and R2 are independently 2-methylpropyl or 2-ethylbutyl, R3, R4, R5, and R6 are hydrogen, and X1 and X2 are methyl.

[0026] In formula (1), R1 and R2 are independently alkyl groups having 1 to 12 carbon atoms or aralkyl groups having 7 to 12 carbon atoms. Examples of alkyl groups having 1 to 12 carbon atoms include those with straight or branched chains. Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0027] Specific examples of branched alkyl groups include isopropyl, 1-methylpropyl, 2-methylpropyl, t-butyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, 2-ethylpropyl, 1,1-diethylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,3,3-trimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 3,3-dimethylbutyl 1-Propylbutyl, 1-Methylpentyl, 2-Methylpentyl, 3-Methylpentyl, 4-Methylpentyl, 4,4-Dimethylpentyl, 1-Ethylpentyl, 2-Ethylpentyl, 3-Ethylpentyl, 4-Ethylpentyl, 1-Propylpentyl, 2-Propylpentyl, 1-Butylpentyl, 1-Methylhexyl, 2-Methylhexyl, 3-Methylhexyl, 4-Methylhexyl, 5-Methylhexyl, 5,5-Dimethylhexyl, 1-Ethylhexyl, 2-Ethylhexyl, 3-Ethylhexyl 4-ethylhexyl, 1-propylhexyl, 2-propylhexyl, 3-propylhexyl, 1-butylhexyl, 2-butylhexyl, 1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl, 5-methylheptyl, 6-methylheptyl, 6,6-dimethylheptyl, 1-ethylheptyl, 2-ethylheptyl, 3-ethylheptyl, 4-ethylheptyl, 5-ethylheptyl, 1-propylheptyl, 2-propylheptyl, 3-propylheptyl, 1-methyloctyl Examples include 2-methyloctyl, 3-methyloctyl, 4-methyloctyl, 5-methyloctyl, 6-methyloctyl, 7-methyloctyl, 7,7-dimethyloctyl, 1-ethyloctyl, 2-ethyloctyl, 3-ethyloctyl, 4-ethyloctyl, 5-ethyloctyl, 6-ethyloctyl, 1-methylnonyl, 2-methylnonyl, 3-methylnonyl, 4-methylnonyl, 5-methylnonyl, 6-methylnonyl, 7-methylnonyl, 8-methylnonyl, and 3,5,5-trimethylhexyl.

[0028] In formula (1), for the aralkyl group having 7 to 10 carbon atoms, R1 or R2, at least one hydrogen atom may be replaced by a halogen or an alkoxy group having 1 to 5 carbon atoms, and at least one methylene atom may be replaced by vinylene, oxygen, or sulfur. Here, this substitution may result in a total carbon number greater than 10. Examples of aralkyls include benzyl, phenethyl, 2-phenylpropyl, cumyl, hydrocinnamyl, benshydryl, methylbenzyl, and t-butylbenzyl.

[0029] X1 and X2 are independently hydrogen, a C1-C10 alkyl group in which at least one methylene group may be replaced by oxygen, or a C7-C10 aralkyl group in which at least one methylene group may be replaced by oxygen, and when one of X1 and X2 is hydrogen, the other is a C1-C10 alkyl group or a C7-C10 aralkyl group.

[0030] Examples of alkyl groups with 1 to 10 carbon atoms are as follows: Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0031] Specific examples of branched alkyl groups include isopropyl, 1-methylpropyl, 2-methylpropyl, t-butyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, 2-ethylpropyl, 1,1-diethylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,3,3-trimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 3,3-dimethylbutyl 1-Propylbutyl, 1-Methylpentyl, 2-Methylpentyl, 3-Methylpentyl, 4-Methylpentyl, 4,4-Dimethylpentyl, 1-Ethylpentyl, 2-Ethylpentyl, 3-Ethylpentyl, 4-Ethylpentyl, 1-Propylpentyl, 2-Propylpentyl, 1-Butylpentyl, 1-Methylhexyl, 2-Methylhexyl, 3-Methylhexyl, 4-Methylhexyl, 5-Methylhexyl, 5,5-Dimethylhexyl, 1-Ethylhexyl, 2-Ethylhexyl, 3-Ethylhexyl 4-ethylhexyl, 1-propylhexyl, 2-propylhexyl, 3-propylhexyl, 1-butylhexyl, 2-butylhexyl, 1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl, 5-methylheptyl, 6-methylheptyl, 6,6-dimethylheptyl, 1-ethylheptyl, 2-ethylheptyl, 3-ethylheptyl, 4-ethylheptyl, 5-ethylheptyl, 1-propylheptyl, 2-propylheptyl, 3-propylheptyl, 1-methyloctyl Examples include 2-methyloctyl, 3-methyloctyl, 4-methyloctyl, 5-methyloctyl, 6-methyloctyl, 7-methyloctyl, 7,7-dimethyloctyl, 1-ethyloctyl, 2-ethyloctyl, 3-ethyloctyl, 4-ethyloctyl, 5-ethyloctyl, 6-ethyloctyl, 1-methylnonyl, 2-methylnonyl, 3-methylnonyl, 4-methylnonyl, 5-methylnonyl, 6-methylnonyl, 7-methylnonyl, 8-methylnonyl, and 3,5,5-trimethylhexyl.

[0032] Examples of alkyl groups in which at least one methylene group is replaced by oxygen include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonanooxy, decanooxy, methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl, methoxyhexyl, methoxyheptyl, methoxyoctyl, methoxynonyl, methoxydecyl, ethoxymethyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, propoxymethyl, butoxymethyl, pentyloxymethyl, hexyloxymethyl, heptyloxymethyl, octyloxymethyl, nonyloxymethyl, 2-propoxymethyl Examples include 2-butenyloxy, 2-pentenyloxy, 2-hexenyloxymethyl, 2-propenyloxymethyl, 2-butenyloxymethyl, 2-pentenyloxymethyl, 2-hexenyloxymethyl, 2-methylpropyloxymethyl, 2-methylpropyloxyethyl, 2-methylpropyloxypropyl, 2-methylpropyloxybutyl, 2-methylpropyloxypentyl, 2-methylpropyloxyhexyl, 2-ethylbutyloxymethyl, 2-ethylbutyloxyethyl, 2-ethylbutyloxypropyl, 2-ethylbutyloxybutyl, 2-ethylhexyloxymethyl, 2-ethylhexyloxyethyl, etc.

[0033] R3, R4, R5, and R6 are independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms. Examples of alkyl groups with 1 to 10 carbon atoms are as follows: Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0034] Specific examples of branched alkyl groups include isopropyl, 1-methylpropyl, 2-methylpropyl, t-butyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, 2-ethylpropyl, 1,1-diethylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,3,3-trimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 3,3-dimethylbutyl 1-Propylbutyl, 1-Methylpentyl, 2-Methylpentyl, 3-Methylpentyl, 4-Methylpentyl, 4,4-Dimethylpentyl, 1-Ethylpentyl, 2-Ethylpentyl, 3-Ethylpentyl, 4-Ethylpentyl, 1-Propylpentyl, 2-Propylpentyl, 1-Butylpentyl, 1-Methylhexyl, 2-Methylhexyl, 3-Methylhexyl, 4-Methylhexyl, 5-Methylhexyl, 5,5-Dimethylhexyl, 1-Ethylhexyl, 2-Ethylhexyl, 3-Ethylhexyl 4-ethylhexyl, 1-propylhexyl, 2-propylhexyl, 3-propylhexyl, 1-butylhexyl, 2-butylhexyl, 1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl, 5-methylheptyl, 6-methylheptyl, 6,6-dimethylheptyl, 1-ethylheptyl, 2-ethylheptyl, 3-ethylheptyl, 4-ethylheptyl, 5-ethylheptyl, 1-propylheptyl, 2-propylheptyl, 3-propylheptyl, 1-methyloctyl Examples include 2-methyloctyl, 3-methyloctyl, 4-methyloctyl, 5-methyloctyl, 6-methyloctyl, 7-methyloctyl, 7,7-dimethyloctyl, 1-ethyloctyl, 2-ethyloctyl, 3-ethyloctyl, 4-ethyloctyl, 5-ethyloctyl, 6-ethyloctyl, 1-methylnonyl, 2-methylnonyl, 3-methylnonyl, 4-methylnonyl, 5-methylnonyl, 6-methylnonyl, 7-methylnonyl, 8-methylnonyl, and 3,5,5-trimethylhexyl.

[0035] Examples of alkyl groups in which at least one methylene group is replaced by oxygen include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonanooxy, decanooxy, methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl, methoxyhexyl, methoxyheptyl, methoxyoctyl, methoxynonyl, methoxydecyl, ethoxymethyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, propoxymethyl, butoxymethyl, pentoxymethyl, 2-propenyloxy, 2-butenyloxy, 2-pentenyloxy, hexyloxymethyl, heptyloxymethyl, octyloxymethyl, These include nonyloxymethyl, 2-propenyloxy, 2-butenyloxy, 2-pentenyloxy, 2-hexenyloxymethyl, 2-propenyloxymethyl, 2-butenyloxymethyl, 2-pentenyloxymethyl, 2-hexenyloxymethyl, 2-methylpropyloxymethyl, 2-methylpropyloxyethyl, 2-methylpropyloxypropyl, 2-methylpropyloxybutyl, 2-methylpropyloxypentyl, 2-methylpropyloxyhexyl, 2-ethylbutyloxymethyl, 2-ethylbutyloxyethyl, 2-ethylbutyloxypropyl, 2-ethylbutyloxybutyl, 2-ethylhexyloxymethyl, 2-ethylhexyloxyethyl, etc.

[0036] For aralkyl groups having 7 to 10 carbon atoms, at least one hydrogen atom may be replaced by a halogen or an alkoxy group having 1 to 5 carbon atoms, and at least one methylene atom may be replaced by vinylene, oxygen, or sulfur. Here, this replacement may result in a total carbon number greater than 10. Examples of aralkyls include benzyl, phenethyl, 2-phenylpropyl, cumyl, hydrocinnamyl, benshydryl, methylbenzyl, and t-butylbenzyl.

[0037] The polyethers used in the lubricating oil base oil of the present invention include 1,2,3-trisbutoxypropane, 1,2,3-tris(2-methylpropyloxy)propane, 1,2,3-trispentoxypropane, 1,2,3-trishexytoxypropane, 1,2,3-trisheptoxypropane, 1,2,3-trisoctoxypropane, 1,2,3-tris(2-ethylhexyloxy)propane, 2,2-bis(butoxymethyl)-1,3-bis(butoxy)propane, and 2,2-bis(2-methylpropyloxymethyl)-1,3-bis(2-methyl Propyloxy)propane, 2,2-bis(pentoxymethyl)-1,3-bis(pentoxy)propane, 2,2-bis(hexythoxymethyl)-1,3-bis(hexythoxy)propane, 2,2-bis(heptoxymethyl)-1,3-bis(heptoxy)propane, 2,2-bis(octoxymethyl)-1,3-bis(octoxy)propane, 2,2-bis(2-ethylhexyloxymethyl)-1,3-bis(2-ethylhexyloxy)propane, 2,2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane, 2,2,4- Rimethyl-1,3-bis(butoxy)pentane, 2,2,4-trimethyl-1,3-bis(2-methylpropyloxy)pentane, 2,2,4-trimethyl-1,3-bis(pentoxy)pentane, 2,2,4-trimethyl-1,3-bis(hexythoxy)pentane, 2,2,4-trimethyl-1,3-bis(heptoxy)pentane, 2,2,4-trimethyl-1,3-bis(octoxy)pentane, 2,2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane, 2,2-dimethyl-1,3-bis(butoxy)propane, 2,2-di Examples include methyl-1,3-bis(2-methylpropyloxy)propane, 2,2-dimethyl-1,3-bis(pentoxy)propane, 2,2-dimethyl-1,3-bis(hexythoxy)propane, 2,2-dimethyl-1,3-bis(heptoxy)propane, 2,2-dimethyl-1,3-bis(octoxy)propane, 2,2-dimethyl-1,3-bis(2-ethylhexyloxy)propane, etc., and 1,2,3-tris-[(2-ethylhexyl)oxy]propane, 2,2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane, 2,2-Bis(2-ethylhexyloxymethyl)-1,3-bis(2-ethylhexyloxy)propane, 2, and 2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane are preferred, and 1,2,3-tris(2-ethylhexyloxy)propane is particularly preferred.

[0038] The following are preferred examples of compound (1) of the present invention.

[0039] TIFF0007910570000004.tif245165

[0040] TIFF0007910570000005.tif226150

[0041] TIFF0007910570000006.tif237154

[0042] TIFF0007910570000007.tif235154

[0043] TIFF0007910570000008.tif109142

[0044] TIFF0007910570000009.tif159170

[0045] TIFF0007910570000010.tif109142

[0046] TIFF0007910570000011.tif141157

[0047] TIFF0007910570000012.tif231148

[0048] TIFF0007910570000013.tif233155

[0049] TIFF0007910570000014.tif208143

[0050] TIFF0007910570000015.tif114138

[0051] TIFF0007910570000016.tif114149

[0052] TIFF0007910570000017.tif245170

[0053] TIFF0007910570000018.tif226135

[0054] TIFF0007910570000019.tif239146

[0055] TIFF0007910570000020.tif235150

[0056] TIFF0007910570000021.tif109142

[0057] TIFF0007910570000022.tif145144

[0058] TIFF0007910570000023.tif248169

[0059] TIFF0007910570000024.tif239158

[0060] TIFF0007910570000025.tif203144

[0061] TIFF0007910570000026.tif242170

[0062] TIFF0007910570000027.tif78139

[0063] TIFF0007910570000028.tif239168

[0064] TIFF0007910570000029.tif208144

[0065] TIFF0007910570000030.tif242170

[0066] TIFF0007910570000031.tif78136

[0067] Next, the method for producing compound (1) will be described. The synthesis method for compound (1) will be described. Compounds (Pr-1) and (Pr-2) can be synthesized by appropriately combining methods of organic synthesis. Methods for introducing the required terminal groups, rings, and bonding groups into the starting materials are described in textbooks such as "Organic Syntheses" (John Wiley & Sons, Inc.), "Organic Reactions" (John Wiley & Sons, Inc.), "Comprehensive Organic Synthesis" (Pergamon Press), and "New Experimental Chemistry Course" (Maruzen).

[0068] Compound (1) can be produced by the aforementioned organic chemical methods or by a dehydration reaction using an acid catalyst between commercially available compounds (Pr-1) and (Pr-2). TIFF0007910570000032.tif33166 Furthermore, compound (1) is synthesized by combining compound (Pr-3), which is a halide that can be produced from Pr-2 by halogenation with hydrobromic acid, methanesulfonic anhydride (Ms2O), and mesylate (OMs) and tosylate (OTs) derived from p-toluenesulfonyl chloride (TsCl), with compound (Pr-1) in the presence of a base such as potassium carbonate.

[0069] TIFF0007910570000033.tif33166

[0070] R 1 and R 2 Compound (1) with asymmetric properties can be produced by carrying out the above manufacturing conditions in multiple steps. TIFF0007910570000034.tif66153

[0071] TIFF0007910570000035.tif71155

[0072] The moisture content in the polyether used as the base oil for the lubricating oil is preferably in the range of 0 to 98% by weight.

[0073] The lubricating oil base oil content may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of refrigeration oil.

[0074] Examples of lubricating oil additives include acid scavengers, antioxidants, extreme pressure agents, oiliness agents, defoamers, metal deactivators, anti-wear agents, viscosity index improvers, pour point depressants, and detergent dispersants. The content of these additives may be 10% by mass or less or 5% by mass or less based on the total amount of lubricating oil.

[0075] α-olefin polymers are polymers that have structural units derived from α-olefins. α-olefin polymers may be used alone or in combination of two or more types.

[0076] Among the additives mentioned above, refrigerant oil preferably contains extreme pressure agents from the viewpoint of providing even better wear resistance. Suitable extreme pressure agents include phosphorus-based extreme pressure agents. Examples of phosphorus-based extreme pressure agents include phosphate esters, acidic phosphate esters, amine salts of acidic phosphate esters, chlorinated phosphate esters, phosphite esters, and phosphothionates. The phosphate ester is preferably triphenyl phosphate (TPP) or tricresyl phosphate (TCP). The content of the phosphorus-based extreme pressure agent may be, for example, 0.2% by mass or more on a basis of the total amount of refrigerant oil, preferably 0.5 to 5% by mass, more preferably 1 to 4% by mass, and particularly preferably 1.5 to 3% by mass.

[0077] The refrigerant oil according to this embodiment typically exists in a refrigeration unit as a working fluid composition mixed with the refrigerant. That is, the working fluid composition for the refrigeration unit according to this embodiment contains the above-mentioned refrigerant oil and refrigerant. The content of the refrigerant oil in the working fluid composition for the refrigeration unit may be 1 to 500 parts by mass, or 2 to 400 parts by mass, per 100 parts by mass of refrigerant.

[0078] Examples of refrigerants include hydrocarbon refrigerants, saturated fluorinated hydrocarbon refrigerants, unsaturated fluorinated hydrocarbon refrigerants, fluorinated ether-based refrigerants such as perfluoroethers, bis(trifluoromethyl) sulfide refrigerants, trifluorinated iodide methane refrigerants, and naturally occurring refrigerants such as ammonia and carbon dioxide.

[0079] The hydrocarbon refrigerant is preferably a hydrocarbon having 1 to 5 carbon atoms, more preferably a hydrocarbon having 2 to 4 carbon atoms. Specific examples of hydrocarbons include methane, ethylene, ethane, propylene, propane (R290), cyclopropane, n-butane, isobutane (R600a), cyclobutane, methylcyclopropane, 2-methylbutane, n-pentane, or mixtures of two or more of these. Among these, the hydrocarbon refrigerant is preferably a gaseous hydrocarbon refrigerant at 25°C and 1 atm, and more preferably propane, n-butane, isobutane, 2-methylbutane, or mixtures thereof.

[0080] Saturated fluorinated hydrocarbon refrigerants are preferably saturated fluorinated hydrocarbons having 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms. Specific examples of saturated fluorinated hydrocarbon refrigerants include difluoromethane (R32), trifluoromethane (R23), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), 1,1-difluoroethane (R152a), fluoroethane (R161), 1, Examples include 1,1,2,3,3,3-heptafluoropropane (R227ea), 1,1,1,2,3,3-hexafluoropropane (R236ea), 1,1,1,3,3,3-hexafluoropropane (R236fa), 1,1,1,3,3-pentafluoropropane (R245fa), and 1,1,1,3,3-pentafluorobutane (R365mfc), or mixtures of two or more of these.

[0081] Saturated fluorinated hydrocarbon refrigerants are selected from the above options as appropriate, depending on the application and required performance. Saturated fluorinated hydrocarbon refrigerants include, for example, R32 alone; R23 alone; R134a alone; R125 alone; mixtures of R134a / R32 = 60-80 mass% / 40-20 mass%; mixtures of R32 / R125 = 40-70 mass% / 60-30 mass%; mixtures of R125 / R143a = 40-60 mass% / 60-40 mass%; mixtures of R134a / R32 / R125 = 60 mass% / 30 mass% / 10 mass%; mixtures of R134a / R32 / R125 = 40-70 mass% / 15-35 mass% / 5-40 mass%; and mixtures of R125 / R134a / R143a = 35-55 mass% / 1-15 mass% / 40-60 mass%. Saturated fluorinated hydrocarbon refrigerants are more specifically: mixtures of R134a / R32 = 70 / 30 mass%; mixtures of R32 / R125 = 60 / 40 mass%; mixtures of R32 / R125 = 50 / 50 mass% (R410A); mixtures of R32 / R125 = 45 / 55 mass% (R410B); and mixtures of R125 / R143a = 50 / 50 mass% (R507C). This could be a mixture of R32 / R125 / R134a = 30 / 10 / 60 mass%; a mixture of R32 / R125 / R134a = 23 / 25 / 52 mass% (R407C); a mixture of R32 / R125 / R134a = 25 / 15 / 60 mass% (R407E); a mixture of R125 / R134a / R143a = 44 / 4 / 52 mass% (R404A), etc.

[0082] The unsaturated fluorinated hydrocarbon (HFO) refrigerant is preferably an unsaturated fluorinated hydrocarbon having 2 to 3 carbon atoms, more preferably a fluoropropene, and even more preferably a fluoropropene having 3 to 5 fluorine atoms. The unsaturated fluorinated hydrocarbon refrigerant is preferably one or more of the following: 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). From the viewpoint of refrigerant properties, the unsaturated fluorinated hydrocarbon refrigerant is preferably one or more selected from HFO-1225ye, HFO-1234ze, and HFO-1234yf. The unsaturated fluorinated hydrocarbon refrigerant may be fluoroethylene, preferably 1,1,2,3-trifluoroethylene.

[0083] The refrigerant oil and working fluid composition for refrigeration according to this embodiment are suitably used in air conditioners, refrigerators, open or sealed car air conditioners, dehumidifiers, water heaters, freezers, cold storage warehouses, vending machines, display cases, chemical plants, etc., which have reciprocating or rotary sealed compressors, as well as refrigeration systems with centrifugal compressors. The refrigerant oil and working fluid composition for refrigeration according to this embodiment can be used together with the above-mentioned refrigerants, but are particularly suitably used together with hydrocarbon refrigerants in terms of low-temperature characteristics and compatibility when mixed with refrigerants. Among the additives mentioned above, refrigerant oil preferably contains extreme pressure agents from the viewpoint of providing even better wear resistance. Suitable extreme pressure agents include phosphorus-based extreme pressure agents. Examples of phosphorus-based extreme pressure agents include phosphate esters, acidic phosphate esters, amine salts of acidic phosphate esters, chlorinated phosphate esters, phosphite esters, and phosphothionates. The phosphate ester is preferably triphenyl phosphate (TPP) or tricresyl phosphate (TCP). The content of the phosphorus-based extreme pressure agent may be, for example, 0.2% by mass or more based on the total amount of refrigerant oil, preferably 0.5 to 5% by mass, more preferably 1 to 4% by mass, and particularly preferably 1.5 to 3% by mass. Using a lubricating oil base oil with an aniline point of 70°C or higher tends to improve the effectiveness of the extreme pressure agent.

[0084] When a lubricating oil base oil containing a polyether represented by formula (1) is used as a cooling medium, it is preferable that the lubricating oil base oil composition is substantially free of water.

[0085] The lubricating oil base oil composition containing the polyether represented by formula (1) has excellent insulating properties and heat resistance, as well as improved heat transfer characteristics. In particular, because it has excellent insulating properties, even if the coolant composition leaks due to an accident, secondary damage such as short circuits can be suppressed. Furthermore, the lubricating oil base oil composition containing polyether of the present invention has excellent heat resistance, so its insulating properties do not easily deteriorate even when heated in a cooling system. In addition, the lubricating oil base oil composition containing polyether of the present invention has excellent heat transfer properties, and therefore has high cooling performance. For this reason, it can be preferably used in electrical equipment and automobiles equipped with driving motors such as hybrid vehicles and electric vehicles.

[0086] One example of a means of cooling electronic equipment is to immerse the electronic equipment at least partially (partially or completely) in a cooling fluid composition. For example, a power card can be placed in physical contact with the cooling medium for cooling. While such a cooling structure has excellent thermal conductivity, the cooling fluid composition requires excellent insulation properties because the electronic equipment and the cooling fluid composition are in direct contact. The polyether-containing lubricating oil base oil composition of the present invention has excellent insulation properties, is non-toxic, and is resistant to corrosion, making it suitable for use in cooling systems with such a cooling structure.

[0087] When a lubricating oil base oil containing a polyether represented by formula (1) is used as a cooling medium, in addition to the components described above, it may also contain optional components such as antioxidants, rust inhibitors, friction reducers, corrosion inhibitors, viscosity index modifiers, pour point depressants, dispersants / surfactants, anti-wear agents, or solid lubricants. The content of the optional components in the lubricating oil base oil is, for example, 0.1 to 20% by mass, preferably 10% by mass or less, preferably 5% by mass or less, and preferably 1% by mass or less. [Examples]

[0088] The effects of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0089] The properties and performance of the lubricating oil composition were measured by the following method. <Method for measuring the properties of lubricating oil compositions> (1) Kinematic viscosity (40℃, 100℃) Measurements were taken at each temperature using a glass capillary viscometer in accordance with JIS K2283 and JIS Z8803. (2) Flash point The measurements in the examples were taken in accordance with JIS K2265-4 (Cleveland open type). (3) Boiling point Here, "boiling point" refers to the standard boiling point (boiling point at 1 atmosphere), and the boiling point was measured in accordance with JIS K2254. (4) Viscosity index The viscosity index was determined according to the method compliant with JIS K2283. (5) Density The density was determined using a method compliant with JIS K2249.

[0090] [Synthesis Example 1] <Synthesis of 1,2,3-Tris-[(2-ethylhexyl)oxy]propane (compound 1-1001)> TIFF0007910570000036.tif44165

[0091] In a four-necked flask equipped with a stirring device, 7.5 g of glycerin (Fujifilm Wako Pure Chemical Industries, special grade, 16.3 mmol) was mixed with 300 ml of N-methylpyrrolidone (Fujifilm Wako Pure Chemical Industries, special grade) to form a homogeneous solution. Then, 19.5 g of sodium hydride (60 wt%) (Fujifilm Wako Pure Chemical Industries, special grade, 488.6 mmol) was added. 70.8 g of 2-ethylhexyl bromide (special grade, 366.5 mmol, manufactured by Fujifilm Wako Pure Chemical Industries) was added to the above solution in small increments. After removing the resulting salt by filtration, 99 GC% of 1,2,3-tris-[(2-ethylhexyl)oxy]propane (compound 1-1001) was obtained by vacuum distillation. The results of the physical property measurements are summarized in Table 1.

[0092] [Example 2] <Synthesis of 2,2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane (compound 1-2001)> TIFF0007910570000037.tif34152

[0093] In a four-necked flask equipped with a stirring device, 25 g of 2,2,4-trimethyl-1,3-pentanediol (170 mmol, special grade, manufactured by Fujifilm Wako Pure Chemical Industries) was mixed with 200 mL of distilled water. Then, 192 g of potassium hydroxide (3.4 mol, special grade, manufactured by Fujifilm Wako Pure Chemical Industries) and 5.5 g of tetrabutylammonium bromide (17.1 mmol, special grade, manufactured by Fujifilm Wako Pure Chemical Industries) were added. 99.0 g (513.0 mmol) of 2-ethylhexyl bromide was added to the above solution in small increments. After removing the resulting salt by filtration, 99 GC% of 2,2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane (compound 1-2001) was obtained by vacuum distillation. The results of the physical property measurements are summarized in Table 1.

[0094] [Example 3] <Synthesis of 2,2-bis(2-ethylhexyloxymethyl)-1,3-bis(2-ethylhexyloxy)propane (compound 1-3001)> TIFF0007910570000038.tif41152 TIFF0007910570000039.tif37167

[0095] [First stage] In a four-necked flask equipped with a stirrer, 200 g (1536 mmol) of 2-ethylhexanol (A-1) and 233 g (3204 mmol) of triethylamine were dissolved in 1600 mL of methylene chloride and cooled to -5°C in a sodium chloride-ice bath. 202 g (1766 mmol) of methanesulfonyl chloride was added dropwise while maintaining the temperature at -5°C, and the mixture was stirred for 1 hour while cooling in an ice bath. Cold 1N hydrochloric acid was added dropwise to the reaction mixture to stop the reaction, and then the organic layer was separated. The aqueous layer was extracted with methylene chloride. The organic layers were combined, washed with 1N hydrochloric acid, washed with saturated sodium bicarbonate aqueous solution and saturated brine, and dried over anhydrous sodium sulfate. After filtering off sodium sulfate, the organic solvent was removed by reduced pressure distillation, and the resulting residue was purified by silica gel column chromatography (eluent: dichloromethane) to obtain 311 g (1495 mmol, yield 97.3%) of 2-ethylhexyl methanesulfonate (compound A-2).

[0096] [Second stage] In a four-necked flask equipped with a stirrer, 25 g (183.6 mmol) of 2,2-bis(hydroxymethyl)-1,3-propanediol (pentaerythritol) was dissolved in 1000 mL of N,N-dimethylformamide (DMF). 51.4 g of 60% sodium hydride was then added, followed by dropwise addition of 153 g (734.5 mmol) of 2-ethylhexyl methanesulfonate (compound A-2) in 200 mL of DMF. The temperature was then gradually increased to 50°C until the foaming subsided, and then further increased to 60-70°C. The reaction was allowed to proceed at this temperature for 3 hours. The reaction mixture was then poured into ice water at room temperature to stop the reaction. The organic layer was separated, the aqueous layer was extracted with cyclopentyl methyl ether, and the organic layers were combined. The mixture was washed with 1N hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine, and then dried over anhydrous sodium sulfate. After filtration, the solvent was removed by rinsing, and the residue was purified by silica gel column chromatography (eluent: heptane). Following vacuum distillation, 40.0 g (68.4 mmol, yield 37.3%) of 2,2-bis(2-ethylhexyloxymethyl)-1,3-bis(2-ethylhexyloxy)propane (compound 1-3001) was obtained. The results of the physical property measurements are summarized in Table 1.

[0097] [Example 4] <Synthesis of 2,2-dimethyl-1,3-bis(2-ethylhexyloxy)propane (compounds 1-4)> TIFF0007910570000040.tif33136 TIFF0007910570000041.tif31168

[0098] [First stage] In a four-necked flask equipped with a stirrer, 35 g (336 mmol) of 2,2-dimethyl-1,3-propanediol was dissolved in 1000 mL of N,N-dimethylformamide (DMF). 53.8 g (1344 mmol) of 60% sodium hydride was then added, followed by the dropwise addition of 210 g (1008 mmol) of 2-ethylhexyl methanesulfonate (compound A-2) in 300 mL of DMF. The temperature was then gradually increased to 50°C until the foaming subsided, and then further increased to 60-70°C. The reaction was allowed to proceed at this temperature for 3 hours. The reaction mixture was then poured into ice water at room temperature to stop the reaction. The organic layer was separated, the aqueous layer was extracted with cyclopentyl methyl ether, and the organic layers were combined. The mixture was washed with 1N hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine, and then dried over anhydrous sodium sulfate. After filtration and solvent removal, the residue was purified by silica gel column chromatography (eluent: heptane), and 63.0 g (191.7 mmol, yield 57.1%) of 2,2-dimethyl-1,3-bis(2-ethylhexyloxy)propane (compound 1-4) was obtained by vacuum distillation. The results of the physical property measurements are summarized in Table 1.

[0099] [Example 5] <Synthesis of 1,3-bis-[(2-methylpropyl)oxy]propane (compound 1-4003)> TIFF0007910570000042.tif33118 TIFF0007910570000043.tif23168

[0100] [First stage] In a four-necked flask equipped with a stirrer, 70 g (994.4 mmol) of 2-methylpropanol (B-1) and 143.3 g (1417 mmol) of triethylamine were dissolved in 1000 mL of methylene chloride and cooled to -5°C in a sodium chloride-ice bath. 124 g (1086 mmol) of methanesulfonyl chloride was added dropwise while maintaining the temperature at -5°C, and the mixture was stirred for 1 hour while cooling in an ice bath. Cold 1N hydrochloric acid was added dropwise to the reaction mixture to stop the reaction. The organic layer was then separated, and the aqueous layer was extracted with methylene chloride. The organic layers were combined, washed with 1N hydrochloric acid, then washed with saturated sodium bicarbonate aqueous solution and saturated brine, and dried over anhydrous sodium sulfate. After filtering off the sodium sulfate, the organic solvent was removed by reduced pressure distillation, and the resulting residue was purified by silica gel column chromatography (eluent: dichloromethane) to obtain 106 g (698 mmol, yield 70.2%) of 2-methylpropyl methanesulfonate (compound A-2).

[0101] [Second stage] In a four-necked flask equipped with a stirrer, 25 g (240 mmol) of 2,2-dimethyl-1,3-propanediol was dissolved in 700 mL of N,N-dimethylformamide (DMF). Then, 28.8 g (720.1 mmol) of 60% sodium hydride was added, followed by the dropwise addition of 102.3 g (672.1 mmol) of 2-methylpropyl methanesulfonate (compound B-2) in 200 mL of DMF. The temperature was then gradually raised to 50°C until the foaming subsided, and then further raised to 60-70°C. The reaction was allowed to proceed at this temperature for 3 hours. The reaction mixture was then poured into ice water at room temperature to stop the reaction. The organic layer was separated, the aqueous layer was extracted with cyclopentyl methyl ether, and the organic layers were combined. The mixture was washed with 1N hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine, and then dried over anhydrous sodium sulfate. After filtration, the solvent was removed by rinsing, and the residue was purified by silica gel column chromatography (eluent: heptane). Following vacuum distillation, 26.2 g (121.1 mmol, yield 50.5%) of 1,3-bis-[(2-methylpropyl)oxy]propane (compound 1-4003) was obtained. The results of the physical property measurements are summarized in Table 1.

[0102] [Example 6] <Synthesis of 2,2,4-trimethyl-1,3-bis(2-methylpropyloxy)pentane (compound 1-2003)> TIFF0007910570000044.tif38120 TIFF0007910570000045.tif34164

[0103] [First stage] In a four-necked flask equipped with a stirrer, 35 g (239.4 mmol) of 2,2,4-trimethyl-1,3-pentanediol was dissolved in 700 mL of N,N-dimethylformamide (DMF). 34.5 g (861.7 mmol) of 60% sodium hydride was then added, followed by dropwise addition of 131.2 g (861.7 mmol) of 2-methylpropyl methanesulfonate (compound B-2) in 200 mL of DMF. The temperature was then gradually increased to 50°C until the foaming subsided, and then further increased to 60-70°C. The reaction was allowed to proceed at this temperature for 3 hours. The reaction mixture was then poured into ice water at room temperature to stop the reaction. The organic layer was separated, the aqueous layer was extracted with cyclopentyl methyl ether, and the organic layers were combined. The mixture was washed with 1N hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine, and then dried over anhydrous sodium sulfate. After filtration and solvent removal, the residue was purified by silica gel column chromatography (eluent: heptane), and 16.6 g (64.2 mmol, yield 2,2,4-trimethyl-1,3-bis(2-methylpropyloxy)pentane (compound 1-2003) was obtained by vacuum distillation. The results of the physical property measurements are summarized in Table 1.

[0104] Table 1. Properties of compounds in examples and comparative examples TIFF0007910570000046.tif135144

[0105] [Comparative Example 1] Table 1 shows 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (Ex-1), an existing polyvalent ester, as a high flash point substance, as Comparative Example 1. 2,2,4-trimethyl-1,3-pentanediol diisobutyrate has a flash point exceeding 100°C, but its kinematic viscosity is high, making it unsuitable as a base oil for low-viscosity lubricants. TIFF0007910570000047.tif4461

[0106] [Comparative Example 2] As a low-viscosity substance, 1,2,3-trimethoxyethoxypropane (triethylene: Ex-2), an existing polyether with a small number of carbon atoms, is shown in Table 1 as Comparative Example 2. Although 1,2,3-trimethoxyethoxypropane has low viscosity, its low boiling point makes it unsuitable as a base oil for low-viscosity lubricants. TIFF0007910570000048.tif3047

[0107] [Comparative Example 3] As a low-viscosity substance, bis(2-ethylhexyl) ether, an existing polyether with a small number of carbon atoms, is shown in Table 1 as Comparative Example 3. (2-ethylhexyl) ether (Ex-3) has low viscosity but a low flash point and a low boiling point, making it unsuitable as a base oil for low-viscosity lubricants. TIFF0007910570000049.tif2869

[0108] [Comparative Examples 4-6] The kinematic viscosity of polyalphaolefins (PAOs), commonly used as low-viscosity lubricant base oils, was measured and compared. The kinematic viscosity of commercially available PAO-based synthetic base oils (manufactured by INEOS, UK), DS164 (Comparative Example 4), DS166 (Comparative Example 5), and DS168 (Comparative Example 6), was measured and is shown in Table 1 as Comparative Examples 4-6. The kinematic viscosity of the compounds in Examples 1 to 3, which are the present invention, was lower than that of any of the commercially available lubricating oil base oils in Comparative Examples 4 to 6. This confirmed that the compounds in Examples 1 to 3, which are the present invention, are superior as low-viscosity lubricating oil base oils.

[0109] [Examples 7-9: Viscosity Index] The kinematic viscosities of Compound 1-1001, Compound 1-2001, and Compound 1-3001 were measured, and the viscosity index was calculated therefrom and shown in Table 2. As described above, the viscosity index was determined by a method compliant with JIS K2283. The respective calculation methods are as follows. Method A is the calculation method when the viscosity index is less than 100, and Method B is the calculation method when the viscosity index is 100 or more.

[0110] <Method A> TIFF0007910570000050.tif2651 Vl: Viscosity index, U: Measured value of kinematic viscosity (40 °C), H, L: Quoted from the values described in JIS K2283:2000.

[0111] <Method B> TIFF0007910570000051.tif1976 N = (logH - logU) / logY Y: Measured value of kinematic viscosity (100 °C), H, L: Quoted from the values described in JIS K2283:2000.

[0112] Table 2. Viscosity Index of Compounds in Examples TIFF0007910570000052.tif52143

[0113] [Examples 10 - 15, Comparative Examples 8 - 9: Density] The densities of Compound 1-1001, Compound 1-2001, Compound 1-3001, Compound 1-4001, Compound 1-4003, Compound 1-2003, water, and heptane were measured, and the specific gravity was calculated therefrom. As described above, the viscosity index was calculated by a vibration method density test using a vibrating densitometer (densitometer: MDA4500 <manufactured by Anton Paar>, measurement temperature: 15 °C) in accordance with the method compliant with JIS K2249. They are shown in Table 3 as Comparative Examples 10 - 15, Comparative Examples 8 - 9.

[0114] Table 3. Densities (Specific Gravity) of Compounds in Examples and Comparative Examples TIFF0007910570000053.tif88142

[0115] [Examples of lubricating oil base oil composition containing compound (1): Composition Examples 1-23] The present invention will be further described in detail by compositional examples containing compound (1). Since the compositional examples are typical examples, the present invention is not limited by the compositional examples. For example, the present invention includes, in addition to the compositions of the compositional examples, a mixture of the composition of compositional example 1 and the composition of compositional example 2. The present invention also includes a mixture prepared by mixing at least two of the compositions of the compositional examples. DS164, DS166, and DS168 used in the composition examples are commercially available PAO-based synthetic base oils (manufactured by INEOS Ltd., UK). The proportion (percentage) of each component is the weight percentage (wt%) based on the weight of each component excluding additives. The composition table summarizes the kinematic viscosity (measured at 40°C and 100°C) along with the weight of each component. Physical properties were measured according to the method described above, and the measured values ​​are listed in Table 4 (without extrapolation).

[0116] Table 4. Composition and kinematic viscosity of the composition examples. TIFF0007910570000054.tif253170 [Industrial applicability]

[0117] The compounds of the present invention have low viscosity, a high flash point, and excellent viscosity-temperature characteristics and low-temperature fluidity, making them useful for applications such as internal combustion engines, drive systems, and refrigerants such as refrigeration oils.

Claims

1. A lubricating oil base oil containing at least one polyether selected from (a) to (d) below. (a) 1,2,3-Tris[(2-ethylhexyl)oxy]propane (b) 2,2,4-trimethyl-1,3-bis(2-ethylhexyloxy)pentane (c) 2,2-bis(2-ethylhexyloxymethyl)-1,3-bis(2-ethylhexyloxy)propane (d) 2,2-dimethyl-1,3-bis(2-ethylhexyloxy)propane

2. The lubricating oil base oil according to claim 1, wherein the polyether has a flash point of 100°C or higher.

3. The lubricating oil base oil according to claim 1, wherein the boiling point of the polyether at atmospheric pressure is 250°C or higher.

4. The lubricating oil base oil according to claim 1, wherein the total content of polyether selected from (a) to (d) is 50% by mass or more.

5. Furthermore, the lubricating oil base oil according to any one of claims 1 to 4, further containing hydrocarbons.

6. The lubricating oil base oil according to claim 5, wherein the hydrocarbon is a poly-α-olefin.

7. A lubricating oil composition containing the lubricating oil base oil and additives according to any one of claims 1 to 4.

8. A lubricating oil base oil according to any one of claims 1 to 4, for use in a drive system.

9. A lubricating oil base oil according to any one of claims 1 to 4, for use in an internal combustion engine.

10. A lubricating oil base oil according to any one of claims 1 to 4, for use in a refrigerator.

11. A lubricating oil base oil according to any one of claims 1 to 4, which is a cooling medium.

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