JP2623112B2 - Heat transfer oil - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel heat carrier oil, and more particularly to a naphthoic ester having a specific structure, or comprising the naphthoic ester as a main component, The present invention relates to a novel heat carrier oil having particularly excellent oxidation stability.

[Related Art and Problems to be Solved by the Invention] There has been a remarkable progress in the technology in the chemical industry in recent years. In the heating method, instead of the direct heating method, the indirect heating method using oil or the like as a heat medium is used for fiber and papermaking. It is widely used in all industrial fields, such as food, architecture, and chemistry.

As the heat medium of this indirect heating method, heat medium oil is most commonly used, and this heat medium oil usually has (1) excellent heat stability, (2) low vapor pressure and flash point. (3) good low-temperature fluidity; (4) no toxicity and odor; (5) good heating efficiency. Currently, highly refined mineral oil containing antioxidants is required. First, phenyl ether, alkyl naphthalene, and the like are widely used as heat carrier oils.

However, the oxidation stability of these conventionally known heat transfer oils has not been satisfactory.

An object of the present invention is to provide a novel heat transfer oil that is particularly excellent in oxidative stability and can be used stably for a long period of time in order to solve such problems.

The present inventor has conducted studies to develop a heat transfer oil that can achieve the above object, and as a result, a heat transfer oil composed of a naphthoate ester having a specific structure or containing the naphthoate ester as a main component, The inventors have found that the oxidation stability is much higher than that of known heat transfer oils, and have completed the present invention.

[Means for Solving the Problems] That is, the present invention provides a compound represented by the general formula Wherein X is an alkyl group having 1 to 20 carbon atoms or a general formula Wherein R represents an alkylene group having 2 to 20 carbon atoms.] A heat medium oil comprising a naphthoic acid ester represented by the following formula or containing the naphthoic acid ester as a main component: To provide.

 Hereinafter, the contents of the present invention will be described in more detail.

The heat carrier oil of the present invention has a general formula Wherein R ₁ is an alkyl group having 1 to 20, preferably 4 to 18 carbon atoms, and R ₂ is an alkylene group having 2 to 20, preferably 2 to 12 carbon atoms. It is characterized by being composed of an ester or containing the naphthoic acid ester as a main component.

The alkyl naphthoate according to the present invention has a general formula The α-form represented by Although a β-form represented by the following formula can be used, it is preferable to use an α-form from the viewpoints of oxidation stability and availability of raw materials.

The alkylene dinaphthoate of the present invention has a general formula The α, α-form represented by The α, β-form represented by The β, β-form represented by the following formula can also be used, but the α, α-form is preferably used from the viewpoints of oxidation stability, availability of raw materials, and the like.

Further, in the naphthoic acid ester according to the present invention, the alkyl group represented by R ₁ has 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms.
It is necessary that the alkylene group represented by R ₂ has 2 to 20, preferably 2 to 12 carbon atoms. It is not preferable to use a naphthoic acid ester that does not satisfy the above-mentioned numerical values because the oxidation stability and the physical properties as a heat transfer oil are inferior to the naphthoic acid ester used in the present invention.

The alkyl group represented by R ₁ and the alkylene group represented by R ₂ may be linear or branched.

Preferred examples of the alkyl group represented by R ₁ of the naphthoic acid ester in the present invention include, for example,
Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,
Hexadecyl group, heptadecyl group, octadecyl group, 1
-Methylpropyl group, 1-methylbutyl group, 1-ethylpropyl group, 1-methylpentyl group, 1-ethylbutyl group, 1-methylhexyl group, 1-ethylpentyl group, 1
-Propylbutyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group, 1-butylpentyl group, 1-methylnonyl group , 1
-Ethyloctyl group, 1-propylheptyl group, 1-butylhexyl group, 1-methyldecyl group, 1-ethylnonyl group, 1-propyloctyl group, 1-butylheptyl group, 1-pentylhexyl group, 1-methylundecyl Group, 1-ethyldecyl group, 1-propylnonyl group, 1-
Butyloctyl group, 1-pentylheptyl group, 1-methyldodecyl group, 1-ethylundecyl group, 1-propyldecyl group, 1-butylnonyl group, 1-pentyloctyl group, 1-hexylheptyl group, 1-methyltri Decyl group, 1-ethyldodecyl group, 1-propylundecyl group, 1-butyldecyl group, 1-pentylnonyl group, 1-
Hexyloctyl group, 1-methyltetradecyl group, 1-
Ethyltridecyl group, 1-propyldodecyl group, 1-butylundecyl group, 1-pentyldecyl group, 1-hexylnonyl group, 1-heptyloctyl group, 1-methylpentadecyl group, 1-ethyltetradecyl group, 1-propyltridecyl group, 1-butyldodecyl group, 1-pentylundecyl group, 1-hexyldecyl group, 1-heptylnonyl group, 1-methylhexadecyl group, 1-ethylpentadecyl group, 1-propyltetradecyl Group, 1-butyltridecyl group, 1-pentyldodecyl group, 1-hexylundecyl group, 1-heptyldecyl group, 1-octylnonyl group, 1-methylheptadecyl group, 1-ethylhexadecyl group, 1-propyl Pentadecyl group, 1-butyltetradecyl group, 1-pentyltridecyl group, 1-hexyldodecyl group, Chiruundeshiru group, 1-octyl-decyl group, tert- butyl group, tert- amyl group, 1,1-dimethylbutyl group, 1-ethyl-1-methylpropyl group, 1,
1-dimethylpentyl group, 1-ethyl-1-methylbutyl group, 1,1-diethylpropyl group, 1,1-dimethylhexyl group, 1-ethyl-1-methylpentyl group, 1,1-diethylbutyl group, 1 , 1-dimethylheptyl group, 1-ethyl-1-methylhexyl group, 1,1-diethylpentyl group,
1,1-dimethyloctyl group, 1-ethyl-1-methylheptyl group, 1,1-diethylhexyl group, 1,1-dimethylnonyl group, 1-ethyl-1-methyloctyl group, 1,1-diethylheptyl Group, 1,1-dimethyldecyl group, 1-ethyl-1-methylnonyl group, 1,1-diethyloctyl group,
1,1-dimethylundecyl group, 1-ethyl-1-methyldecyl group, 1,1-diethylnonyl group, 1,1-dimethyldodecyl group, 1-ethyl-1-methylundecyl group, 1,1-
Diethyldecyl group, 1,1-dimethyltridecyl group, 1-
Ethyl-1-methyldodecyl group, 1,1-diethylundecyl group, 1,1-dimethyltetradecyl group, 1-ethyl-
1-methyltridecyl group, 1,1-diethyldodecyl group,
1,1-dimethylpentadecyl group, 1-ethyl-1-methyltetradecyl group, 1,1-diethyltridecyl group, 1,1-
Dimethylhexadecyl group, 1-ethyl-1-methylpentadecyl group, 1,1-diethyltetradecyl group, 2-ethylhexyl group, 2-hexyldecyl group, 2- (1,3,3-
Trimethylbutyl) -5,7,7-trimethyloctyl group.

Preferred examples of the alkylene group represented by R ₂ of the naphthoic acid ester in the present invention include, for example, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group. Octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, methylethylene group, 1-methyltrimethylene group, ethylethylene group, 1-methyltetramethylene group, 1-ethyltrimethylene group, 1 -Methylpentamethylene group, 1-ethyltetramethylene group, 1-methylhexamethylene group, 1-
Ethylpentamethylene group, 1-methylheptamethylene group, 1-ethylhexamethylene group, 1-methyloctamethylene group, 1-ethylheptamethylene group, 1-methylnonamethylene group, 1-ethyloctamethylene group, 1-methyl Decamethylene group, 1-ethylnonamethylene group, 1-methylundecamethylene group, 1-ethyldecamethylene group,
1,1-dimethylethylene group, 1,1-dimethyltrimethylene group, 1,1-dimethyltetramethylene group, 1,1-dimethylpentamethylene group, 1,1-dimethylhexamethylene group, 1,1
-Dimethylheptamethylene group, 1,1-dimethyloctamethylene group, 1,1-dimethylnonamethylene group and the like.

If the structure of the naphthoic acid ester according to the present invention is within the above range, the heat carrier oil of the present invention may be a specific compound or a mixture of two or more.

The naphthoic acid ester in the present invention can be usually obtained by an esterification reaction between naphthoic acid and an alcohol. That is, a monohydric alcohol having 1 to 20 carbon atoms,
It can be obtained by using a dihydric alcohol having 2 to 20 carbon atoms and reacting with naphthoic acid at a reaction temperature of 100 to 180 ° C in the presence of an acid catalyst such as sulfuric acid.

Consist of a naphthoic acid ester mixture according to the invention,
Alternatively, the heat carrier oil containing this as a main component alone has both the various properties required for a normal heat carrier oil and the excellent property of particularly excellent oxidation stability, but the heat carrier oil of the present invention may be used as needed. Known additives commonly used,
For example, antioxidants, cleaning dispersants, viscosity index improvers, pour point depressants, corrosion inhibitors, metal deactivators, rust inhibitors,
An antifoaming agent, a coloring agent and the like may be added. For details of these various additives, see, for example, “Journal of the Japan Lubricating Oil Society, Vol. 15, No. 6,” or “Edited by Toshio Sakurai,“ Petroleum Product Additives ”(Koshobo)”.
And so on. The total amount of these various additives is 10 wt% or less, preferably
It is at most 5 wt%, particularly preferably at most 3 wt%.

Further, the heat carrier oil of the present invention is a mineral oil or a known synthetic oil, if necessary, as long as the high oxidation stability is not impaired.
For example, synthetic oils such as polybutene, α-olefin oligomer, alkyl benzene, alkyl naphthalene, diester, polyol ester, polyglycol, polyphenyl ether, tricresyl phosphate, silicone oil, perfluoroalkyl ether, etc. %, Preferably 30% by weight or less, particularly preferably 20% by weight or less.

EXAMPLES Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1 A 4-neck flask was charged with 1 mol (172 g) of α-naphthoic acid, 1.5 mol (195 g) of octyl alcohol and 3 ml of concentrated sulfuric acid, heated to 120 ° C under a nitrogen atmosphere, and stirred for 5 hours.
After completion of the reaction, the mixture was cooled, water, sulfuric acid, unreacted naphthoic acid and alcohol were removed with a separating funnel, and the mixture was distilled under reduced pressure to obtain 230 g of the desired octyl-α-naphthoate. The boiling point was 200-202 ° C / 4mmHg.

In order to evaluate the performance of this octyl-α-naphthoate, the following evaluation tests were performed, and the results are shown in Table 1.

[Viscosity] The kinematic viscosities at 40 ° C and 100 ° C were measured according to the kinematic viscosity test method for crude oil and petroleum products specified in JIS K 2283.

[Oxidation test life] A rotating cylinder type oxidation test specified in JIS K 2514-3.3 was performed. The oxidation performance was evaluated by the time until the oxygen pressure decreased by 1.8 kg / cm ² .

Test temperature: 150 ° C. Oxygen pressure: 13 kg / cm ² Catalyst: copper wire 1.60 mmφ Example 2 241 g of dodecyl-α-naphthoate was obtained in the same manner as in Example 1, except that dodecyl alcohol was used instead of octyl alcohol. The boiling point was 240-244 ° C / 5mmHg.

The performance of this dodecyl-α-naphthoate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyloctyl alcohol was used in place of octyl alcohol, and 2- (1,3,3 (Trimethylbutyl) -5,7,7-trimethyloctyl-α-naphthoate was obtained in an amount of 192 g. Boiling point was 246-248 ° C / 4mmHg.

The performance of 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyloctyl-α-naphthoate was evaluated in the same manner as in Example 1, and the results are shown in Table 1. .

Example 4 In the same manner as in Example 1 except that 2-ethylhexyl alcohol was used instead of octyl alcohol, 240 g of 2-ethylhexyl-α-naphthoate was obtained. Boiling point 198-2
It was 00 ° C / 3 mmHg.

The performance of this 2-ethylhexyl-α-naphthoate was evaluated in the same manner as in the examples, and the results are shown in Table 1.

Comparative Examples 1 to 3 Refined naphthene-based mineral oil (Comparative Example 1), diisopropylnaphthalene (Comparative Example 2), and And expressions Was evaluated in the same manner as in Example 1 and the results are shown in Table 1.

As is evident from the results of the oxidation test life in Table 1, the heat transfer medium oil composed of the naphthoic acid ester according to the present invention is:
It shows very high high temperature oxidation stability. On the other hand, it can be seen that conventional heat transfer oils such as refined mineral oil, alkylnaphthalene, and phenyl ether are much inferior in oxidation test life to the heat transfer oil of the present invention.

[Effects of the Invention] As described above, the heat carrier oil comprising a naphthoic acid ester of the present invention has a high oxidation stability that cannot be attained by a conventionally known heat carrier oil.

Claims (1)

(57) [Claims] (1) General formula Wherein X is an alkyl group having 1 to 20 carbon atoms or a general formula Wherein R represents an alkylene group having 2 to 20 carbon atoms.] A heat carrier oil comprising a naphthoic acid ester represented by the following formula or containing the naphthoic acid ester as a main component.