JPH08302371A - Synthetic oil and production of (1-methylalkyl) naphthalene compound - Google Patents

Abstract

PURPOSE: To obtain a synthetic oil which has an excellent oxidation resistance and can be suitably used as an industrial oil for many applications. CONSTITUTION: This oil contains a dialkylnaphthalene compd. having one methyl group and one 10-24 C secondary alkyl group bonded to the naphthalene ring or its mixture as the main ingredient provided at least 35mol% of the compd. is one having 1-methylalkyl group as the secondary alkyl group. The oil is obtd. by reacting a naphthalene compd. with a linear α-olefin in the presence of a solid acid catalyst at 80-350 deg.C under the conditions of an LHSV of 3-50h<-1> and an olefin conversion of 50-99%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel synthetic oil, more specifically, one or more dialkylnaphthalene compounds having a specific structure, or one or two dialkylnaphthalene compounds. The present invention relates to a novel synthetic oil containing at least one species as a main component and having excellent oxidation resistance. The present invention also relates to a method for producing a (1-methylalkyl) naphthalene compound, more specifically, an isomer in which a naphthalene ring is bonded to the second position of an alkyl chain useful as a lubricating oil, a heat carrier oil, a plastic raw material, or the like. The present invention relates to a method for producing a (1-methylalkyl) naphthalene compound, which can obtain a product containing a large amount of components and can also be applied as a method for producing the synthetic oil.

[0002]

2. Description of the Related Art Oils are used for various purposes in various industrial fields. For example, oils for automobiles, heat carrier oils, hydraulic oils, compressor oils, metal working oils, grease base oils,
Used as electrical insulating oil, vacuum pump oil, and other industrial lubricating oils. Such industrial oils are required to have various properties or performances according to their uses, for example, oxidation resistance, thermal stability, vapor pressure, flash point, fluidity, toxicity, odor, etc. It is required to simultaneously have various required properties or performances. Among various properties or performances, oxidation resistance is an important performance that greatly affects the life of oil, and improvement of this oxidation resistance is required.

As a base oil for industrial oils, mineral oils and natural fats and oils have been used for a long time, but in recent years, depending on the application, ester type (diester, polyol ester, etc.), ether type, hydrocarbon type (polyether). Various synthetic oils such as α-olefins and alkylbenzenes have also been used. However, mineral oils, natural fats and oils, ester-based synthetic oils, hydrocarbon-based synthetic oils, etc. have limited oxidation resistance, and it is difficult to use them for a long period of time in an atmosphere where oxidation is promoted. Is. There
957, Japanese Patent Publication No. 4-14716, and "Industrial Materials," Vol. 34, No. 6, page 77 (1986), it is composed of a mixture of mono-secondary alkylnaphthalene compounds and has a 1-position substitution product and a 2-position. A synthetic oil having excellent oxidation resistance, in which the selectivity of the substitution position of the alkyl group on the naphthalene ring represented by the molar ratio with the substitution product is 1 or more (1-position substitution product / 2-position substitution product ≧ 1), has been proposed. ing. However, this thing second
Although the mixture of the graded alkylnaphthalene compounds has much better oxidation resistance than conventional mineral oils,
It cannot be said that it still has sufficient oxidation resistance.

On the other hand, of the methods for producing alkylnaphthalenes by alkylation of naphthalenes, the one using the Friedel-Crafts reaction is currently the only industrial and practical method. Alkylation of aromatic compounds by Friedel-Crafts reaction is also very well known and widely practiced. However, when alkylating an aromatic compound by the Friedel-Crafts reaction, carbons at various positions in the alkyl chain are bonded to an aromatic ring, and alkyl groups are substituted at various positions on the aromatic ring. However, it is inevitable that various isomers are simultaneously produced and the composition of the product becomes complicated. The situation is the same when alkylating naphthalene compounds using a long-chain alkyl source, and in such a reaction process rearrangement occurs to carbocation, which is an intermediate derived from a long-chain alkyl source, so that the product obtained is , A mixture of complex composition containing various alkylnaphthalene isomers having different secondary alkyl groups. As described above, in reality, it is difficult to selectively produce a specific alkylnaphthalene isomer.

[0005]

The present invention has been accomplished in view of the above circumstances, and a first object thereof is to provide a synthetic oil having excellent oxidation resistance. A second object of the present invention is to selectively and efficiently and economically produce an isomer having a structure in which the carbon atom at the 2-position carbon of the alkyl chain is bonded to the naphthalene ring when producing a long-chain alkyl-substituted naphthalene compound. Another object of the present invention is to provide a method for producing an alkylnaphthalene compound, which can be used as a method for efficiently producing the above synthetic oil.

[0006]

Means for Solving the Problems As a result of intensive studies for achieving the first object, the present inventors have found that a synthetic oil containing a mixture of dialkylnaphthalene compounds having a specific structure as a main component is found. The inventors have found that they have much better oxidation resistance than conventional synthetic oils, and have completed the following inventions.

That is, in order to achieve the first object in the present invention, a dialkylnaphthalene having a structure in which one methyl group and one secondary alkyl group having 10 to 24 carbon atoms are substituted on the naphthalene ring. At least one compound is contained, and the ratio of the abundance of the dialkylnaphthalene compound in which the secondary alkyl group is a 1-methylalkyl group to the total abundance of the dialkylnaphthalene compound is 35% or more in a molar ratio. To provide a synthetic oil. The above synthetic oil has excellent oxidation resistance and good physical properties as an industrial oil. On the other hand, if the above conditions are not satisfied, the oxidation resistance or the physical properties of the industrial oil are often insufficient, which is not preferable.

The dialkylnaphthalene compound preferably has a methyl group substituted at the 2-position on the naphthalene ring.

On the other hand, in the process of developing the above synthetic oil, the inventors of the present invention used naphthalenes and long-chain α-olefins as raw materials and used a fixed bed flow type reaction to obtain an extremely high liquid hourly space velocity (hereinafter referred to as “LHSV”). It was found that when a Friedel-Crafts alkylation reaction is carried out under the following conditions, an alkylnaphthalene isomer having a structure in which the 2-position carbon of the alkyl chain is bonded to the naphthalene ring can be obtained at a high concentration, Was completed.

That is, in order to achieve the second object in the present invention, in the method for producing an alkylnaphthalene compound, at least one naphthalene selected from the group consisting of naphthalene, 1-methylnaphthalene and 2-methylnaphthalene. And linear α-olefins in a flow-type catalytic reaction in the presence of a solid acid catalyst at a reaction temperature of 80 to 3
50 ° C., liquid hourly space velocity (LHSV) 3 to 50 h ⁻¹ , linear α
Provided is a method for producing a (1-methylalkyl) naphthalene compound, which comprises reacting at an olefin conversion rate of 50 to 99%. According to this production method, the selectivity of the bond of the naphthalene ring to the second carbon in the alkyl chain is 35%.
It can be at least%.

The solid acid catalyst used in the above production method is preferably activated clay, acid clay, silica-alumina, or zeolite.

In the following, the synthetic oil of the present invention and (1-
The method for producing a methylalkyl) naphthalene compound will be sequentially described in detail. First, the synthetic oil of the present invention will be described. A dialkylnaphthalene compound having a structure in which one methyl group and one secondary alkyl group having 10 to 24 carbon atoms are substituted on the naphthalene ring contained in the synthetic oil of the present invention, that is, methyl- (C _{10 to} C ₂₄ Secondary alkyl)
The chemical structure of naphthalenes is represented by the following formula (Ia) or (Ib)
It is represented by.

[0013]

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[In the formula, R ¹ and R ² each represent an alkyl group, and the total number of carbon atoms of R ¹ and R ² is 9 to 2
It is 3. ]

The compound group represented by the formula (Ia) or the formula (Ib) includes a substitution position of the methyl group and the secondary alkyl group on the naphthalene ring, a carbon atom of the secondary alkyl group bonded to the naphthalene ring. Various compounds or isomers which are distinguished by factors such as position, isomerism of alkyl chain, carbon number of secondary alkyl group, etc. are included, and the synthetic oil of the present invention is included in such a compound group. The dialkylnaphthalene compound may be contained alone or in a mixture containing two or more kinds. However, in the synthetic oil of the present invention, the ratio of the abundance of the dialkylnaphthalene compound in which the secondary alkyl group is a 1-methylalkyl group to the total abundance of the dialkylnaphthalene compound is 35% or more in a molar ratio. It is necessary, and preferably 3
5 to 70%, and particularly preferably 40 to 60%.

That is, the substitution positions on the naphthalene ring are from the 1st position to the 8th position, of which the 1, 4, 5 and 8th positions are α
2, 3, 6, and 7-positions are also called β-positions, but when the secondary alkyl group on the naphthalene ring of the dialkylnaphthalene compound is substituted with a methyl group at the 1-position. Has the 2,3,4,5,6,7 and 8 positions on the naphthalene ring as in the following formula (IIa), while when the substitution position of the methyl group is the 2 position, the following formula (IIb)
There are 1, 3, 4, 5, 6, 7, and 8 positions on the naphthalene ring as in. The synthetic oil of the present invention may contain various isomers based on the difference in the substitution positions of the methyl group and the secondary alkyl group on the naphthalene ring.

[0017]

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When the secondary alkyl group is bonded to the naphthalene ring, the secondary alkyl group may be bonded to the naphthalene ring by any carbon atom in the alkyl chain unless it is a terminal carbon atom. it can. For example, second
When the primary alkyl group is a tetradecyl group represented by the following formula (III), the 2 to 7-position (8 to 13
Carbon at each position) can be bonded to the naphthalene ring. The synthetic oil of the present invention may contain various isomers based on the difference in the position of the carbon in the secondary alkyl group bonded to the naphthalene ring.

[0019]

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However, in the synthetic oil of the present invention, the methyl- (1-methylalkyl) naphthalene compound represented by the following formula (IVa) or the following formula (IVb) is used with respect to the total content of the dialkylnaphthalene compound. However, it is necessary that the molar ratio occupy 35% or more.
It is preferably 70%, particularly preferably 40 to 60%.

[0021]

[Chemical 4]

[In the formula, R ³ represents an alkyl group having 8 to 22 carbon atoms. ]

Here, if the proportion of the methyl- (1-methylalkyl) naphthalene compound of formula (IVa) or formula (IVb) is less than 35% by mole, sufficient oxidation resistance may not be secured. is there. Further, the upper limit of this molar ratio is not particularly limited, for example, the molar ratio becomes infinite and the dialkylnaphthalene compound may be occupied only by the compound of the formula (IVa) or the formula (IVb), but the synthesis of the present invention is not limited. Considering the production by the Friedel-Crafts reaction, which is one of the most important practical production methods of oil, it is preferable that the molar ratio is 70% or less from the viewpoint of the economical efficiency of the reaction.

The molar ratio of the amount of the dialkylnaphthalene compound whose secondary alkyl group is a 1-methylalkyl group to the total amount of the dialkylnaphthalene compound contained in the synthetic oil of the present invention is The second position of the carbon in the alkyl chain bonded to the naphthalene ring in the dialkylnaphthalene compound group contained in
It can also be defined as the rank selection rate.

The dialkylnaphthalene compound must have one methyl group and one secondary alkyl group on the naphthalene ring. When two or more methyl groups are bonded to the naphthalene ring, it is not preferable in terms of oxidation stability. Further, when considering the production of the synthetic oil of the present invention by the Friedel-Crafts reaction, the methyl group is preferably bonded to the 2-position of the naphthalene ring from the viewpoint of easy availability of raw materials.

In formula (Ia) or formula (Ib),-(R ¹
-) CH (secondary alkyl group represented by -R ^2), it is necessary that the lower limit of the carbon number 10 or more, preferably 12 or more. On the other hand, the upper limit of the carbon number needs to be 24 or less, and preferably 20 or less. When the carbon number is less than 10, the viscosity index and the flash point are lowered, while when the carbon number is more than 24, the pour point is raised, and therefore, in any case, it is preferable as an industrial oil. Absent. When the carbon number is 10 or more or 20 or less, it is easy to set physical properties such as viscosity, viscosity index, pour point, flash point and the like in preferable ranges.

The secondary alkyl group may be a linear secondary alkyl group such as a 1-methyl-tridecyl group or a 1-methyl-pentadecyl group, or a 1,3-dimethyl-tridecyl group. Alternatively, it may be a branched secondary alkyl group such as a 1,3-dimethyl-pentadecyl group. However, a linear secondary alkyl group is preferable from the viewpoint of improving the oxidation stability or setting various physical properties as described above within a preferable range. Specific preferred secondary alkyl groups include 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 Group, 1
-Hexylheptyl group, 1-methyltridecyl 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,
Examples thereof include a 1-propylpentadecyl group, a 1-butyltetradecyl group, a 1-pentyltridecyl group, a 1-hexyldecyl group, a 1-heptylundecyl group and a 1-octyldecyl group.

The synthetic oil of the present invention can be produced by various methods. For example, the methyl- (1-methylalkyl) naphthalene represented by the formula (IVa) or the formula (IVb) alone or in a mixture thereof is the synthetic oil of the present invention. Further, the synthetic oil of the present invention has the formula (IVa) or the formula (IV
methyl b) - it can also be produced by mixing the (C ₁₀ -C ₂₄ secondary alkyl) naphthalene in a predetermined ratio - (1-methyl alkyl) naphthalene and other methyl.

The synthetic oil of the present invention can also be produced in one step by reacting a naphthalene nucleus source with an alkyl source by the Friedel-Crafts reaction. In the case of the Friedel-Crafts reaction, methylnaphthalene is used as a naphthalene nucleus source, and an alkyl halide having 10 to 24 carbon atoms, an alcohol, a monoolefin or the like is used as an alkyl source, and a Lewis acid (aluminum chloride, zinc chloride) is used. ,
The reaction is carried out at a reaction time of 0 to 300 ° C. under an acidic catalyst such as iron chloride), solid acid (activated clay, acid clay, silica-alumina, zeolite, etc.) or sulfuric acid, phosphoric acid, fluoroboric acid and the like. As methylnaphthalene, 1-methylnaphthalene, 2-methylnaphthalene or a mixture thereof can be used, but 2-methylnaphthalene which is easily available is preferably used. Suitable alkyl sources include linear α-olefins from the viewpoint of product properties and properties, and availability.

When the naphthalene nucleus source and the alkyl source are reacted by the Friedel-Crafts reaction, usually the substitution position of the methyl group and the secondary alkyl group on the naphthalene ring and the carbon of the secondary alkyl group bonded to the naphthalene ring. Position of,
Alternatively, a mixture of various isomers having different types of secondary alkyl groups is produced. The isomer composition of this product is the kind and composition of reaction raw materials such as naphthalene nucleus source and alkyl source,
Since it varies depending on the reaction conditions such as the type of catalyst, reaction temperature, reaction time, etc., it is necessary to adjust the reaction conditions so that the above molar ratio in the product is 35% or more.

The synthetic oil of the present invention has the formula (Ia) or the formula (I)
Although the main component is the dialkylnaphthalene compound represented by b), it may be composed only of the dialkylnaphthalene compound or may contain other additives or base oil.

The dialkylnaphthalene compound represented by the formula (Ia) or the formula (Ib) or a mixture thereof has the formula (IVa)
Alternatively, as long as the methyl- (1-methylalkyl) naphthalene represented by the formula (IVb) is contained in the above-mentioned certain ratio, it has extremely excellent oxidation resistance and various performances usually required for industrial oils. It also has
It is preferably used as various industrial oils, but if necessary, known additives commonly used, for example, antioxidants, detergent dispersants, viscosity index improvers, pour point depressants, oiliness agents, An antiwear agent, an extreme pressure agent, a corrosion inhibitor, a metal deactivator, a rust inhibitor, an antifoaming agent, an emulsifier, an antiemulsifier, a bactericide, a colorant and the like can be added and used.

If necessary, the dialkylnaphthalene compound or the mixture thereof may contain mineral oil or a known synthetic oil in an amount of 75% by weight or less, as long as it does not substantially impair its excellent oxidation resistance. Can be used in a mixture of 50% by weight or less, particularly preferably 25% by weight or less.

The synthetic oil of the present invention is used as various industrial oils such as electric insulating oil, gasoline engine oil, diesel engine oil, turbine oil, gear oil, hydraulic oil,
Compressor oil, vacuum pump oil, metalworking oil, sliding guide surface oil,
It can be used as a bearing oil, a heat carrier oil, a grease base oil, and other industrial lubricating oils.

Next, a method for producing the alkylnaphthalene compound of the present invention will be described. The production method of the present invention includes the following main reaction, and the target (1-methylalkyl) naphthalene compound can be obtained by the main reaction.

[0036]

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[In the formula, R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents a primary linear alkyl group. ]

In the production method of the present invention, naphthalene and linear α-olefin are used as reaction raw materials. Examples of the naphthalene represented by the formula (V) include naphthalene,
1-methylnaphthalene, 2-methylnaphthalene or a mixture thereof is used.

The straight chain α-olefin represented by the formula (VI) is a preferable alkyl source because it is easily available and improves the bond selectivity of the naphthalene ring to the 2nd carbon of the alkyl chain. Linear α-olefins are two or more types of linear α
It may be a mixture of olefins. In the method of the present invention, the carbon number of the linear α-olefin is not particularly limited. That is, it is also possible to use a long-chain one as the linear α-olefin, and for example, the product is a lubricating oil,
When used as a medium oil or a raw material for plastics, it is suitable to use a long-chain linear α-olefin having 10 to 24 carbon atoms. According to the method of the present invention, when substituting a long-chain alkyl group on a naphthalene ring, the second carbon atom of the alkyl chain and the naphthalene ring are selectively bonded without involving rearrangement reaction of the long-chain alkyl chain. be able to.

As the reaction method, it is necessary to adopt a flow reaction method, and it is preferable to adopt a fixed bed flow reaction method from the viewpoint of efficiency and economy.

The catalyst used in the method of the present invention is selected from among the solid acids. Many solid acid catalysts used in the Friedel-Crafts reaction are known, and specific examples thereof include silica-alumina, silica gel, alumina, zeolite, activated clay, and acid clay. Among them, activated clay, acid clay, silica-alumina and zeolite are preferable.

In the method of the present invention, the liquid hourly space velocity (L
It is necessary to set the lower limit of (HSV) to 3h ^-1 or more, and 5h
^-1 or more is preferable, while the upper limit is 50h
^-1 or less, preferably 25 h ^-1 or less. This range of LHSV is an exceptionally large value as compared with ordinary flow-type catalytic reaction conditions, but by selecting the above range, it is possible to improve the selectivity of the bond of the naphthalene ring to the second position on the alkyl chain. You can

From the viewpoint of suppressing the formation of a dialkylated product in which the naphthalene ring is substituted with two or more alkyl groups derived from linear α-olefins, the ratio of the naphthalene which is the reaction raw material to the linear α-olefin is in excess. However, on the other hand, if naphthalene compounds are used in a too large excess, the efficiency of product recovery decreases. Therefore, the above-mentioned feed ratio is naphthalenes: linear α-olefin = 1.
It is preferably 2: 1 to 10: 1 (molar ratio).

The reaction temperature is determined depending on the balance with other reaction conditions, but is usually 80 to 350 ° C, preferably 100 to 300 ° C.

In the present invention, the type and amount of catalyst, LH
It is necessary to control the upper limit of the conversion rate of the linear α-olefin to 99% or less by adjusting SV, temperature, the type and amount of the reaction raw material, or other reaction conditions, and it is preferable to keep the upper limit of 90% or less. On the other hand, it is necessary to control the lower limit to 50% or more, and it is preferable to keep it at 70% or more.
Under the reaction conditions in which the conversion exceeds 99% and the linear α-olefin is quantitatively consumed, the rearrangement reaction proceeds and a product having an undesired isomer composition is produced. On the other hand, if the conversion rate is less than 50%, it is not economically preferable.

In the method of the present invention, a naphthalene compound and a linear α-olefin can be reacted without using a solvent, and a solvent which does not participate in the reaction, such as decane, decalin, kerosene, etc., can be used, if necessary. It can also be used. However, if the amount of the solvent used is unnecessarily large, the alkylation rate is lowered by the dilution and the isomerization of the olefin is relatively promoted, which is not preferable.

According to the method of the present invention, the above formula (VIIa) and / or
Or an alkylnaphthalene compound represented by (VIIb), that is, a structure in which only one 1-methylalkyl group having the same carbon number as the starting linear α-olefin is introduced on the naphthalene ring (1-methylalkyl) The naphthalene compound can be selectively produced, and the selectivity of the bond of the naphthalene ring to the second carbon of the alkyl chain can be 35% or more.

The crude reaction liquid obtained by the method of the present invention contains a high concentration of the objective alkylnaphthalenes, but in addition to this, unreacted naphthalene and linear α-olefin, and a small amount of Contains by-products. These impurities can be separated by an ordinary separation means such as distillation, and the desired product (1-methylalkyl) naphthalene can be easily obtained from the crude reaction solution. The (1-methylalkyl) naphthalene thus obtained is excellent in oxidation stability and various physical properties and can be suitably used as a lubricating oil, a heat carrier oil, a plastic raw material, and the like. Further, in the method of the present invention, if 1-methylnaphthalene, 2-methylnaphthalene or a mixture thereof is used as the naphthalene, and the linear α-olefin having 10 to 24 carbon atoms is used as the linear α-olefin to carry out the reaction, The above-mentioned synthetic oil of the present invention can be produced.

[0049]

EXAMPLES The present invention will be described more specifically by the following experimental examples. The following experimental examples consist of Examples 1 to 15 and Comparative Examples 1 to 15, of which Examples 1 to 6 and Comparative Examples 1 to 1
11 mainly relates to the synthetic oil of the present invention, and Examples 7 to 15
And Comparative Examples 12 to 15 mainly relate to the production method of the present invention. Table 1 is a summary of the results of the oxidation resistance test, Table 2 is a summary of the results of the thermal stability test, and Table 3 is a summary of the measurement results of the electrical characteristics.

Example 1 A reaction tube made of stainless steel having an internal volume of 60 ml was filled with activated clay and heated to 125 ° C. in a constant temperature bath. A mixture of 2-methylnaphthalene and 1-decene in a weight ratio of 5: 1 was fed into the reaction tube at a rate of 3.5 ml / min (LHSV = 3.5 h ⁻¹ ) using a pump to react. I went.
When the reaction solution was analyzed by gas chromatography, the conversion rate of olefin was 93%. Unreacted 2-methylnaphthalene and olefin were removed from the obtained reaction solution by distillation under reduced pressure, and further distilled under reduced pressure to produce 2-methyl- (second
A mixture of grade C ₁₀ alkyl) naphthalene was obtained. The product was analyzed by gas chromatography to find that it was 2-methyl-1- (1-methylnonyl) naphthalene, 2-methyl-3- (1-methylnonyl) naphthalene, 2-methyl-
4- (1-methylnonyl) naphthalene, 2-methyl-5
-(1-Methylnonyl) naphthalene, 2-methyl-6-
(1-Methylnonyl) naphthalene, 2-methyl-7-
(1-Methylnonyl) naphthalene, and 2-methyl-8
-(1-Methylnonyl) naphthalene is 39 mol% in total
The substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 39%. The properties of this product were as follows. [Property] Viscosity: 16.18 cSt (40 ° C) Pour point: -45 ° C Flash point: 178 ° C

This 2-methyl- (secondary C ₁₀ alkyl)
The oxidation test of the naphthalene mixture is performed by the rotary cylinder type oxidation stability test (RBOT) specified in JIS K2514.
The test was performed under the following conditions. [Test conditions] Temperature: 150 ° C. Oxygen pressure: 620 kPa (6.3 kgf / cm ² ) Catalyst: Copper wire, 1.6 mmφ × 3 m And from the maximum pressure, 175 kPa (1.8 kgf / c)
The time showing the pressure drop of m ² ) was taken as the oxidation end point, and the time (minute) from the start of the test to the end point was adopted as the test value, and the oxidation resistance was evaluated by this value. The test results are shown in Table 1.

Example 2 In the same apparatus and operation as in Example 1, the reaction temperature was set to 12
The reaction was carried out at 5 ° C., with the raw material being a mixture of 2-methylnaphthalene and 1-tetradecene in a weight ratio of 2.5: 1, and the raw material supply rate being 3.5 ml / min (LHSV = 3.5 h ⁻¹ ). I went. The olefin conversion rate during the reaction was 90%. The obtained reaction liquid was treated in the same manner as in Example 1 to obtain a 2-methyl- (secondary C ₁₄ alkyl) naphthalene mixture. When this product was analyzed by gas chromatography, 2-methyl-1- (1-methyltridecyl) naphthalene, 2-methyl-3- (1-methyltridecyl) naphthalene, 2-methyl-4- (1 -Methyltridecyl)
Naphthalene, 2-methyl-5- (1-methyltridecyl) naphthalene, 2-methyl-6- (1-methyltridecyl) naphthalene, 2-methyl-7- (1-methyltridecyl) naphthalene, and 2- A total of 37 mol% of methyl-8- (1-methyltridecyl) naphthalene was contained, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 37%. The properties of this product were as follows. [Properties] Viscosity: 28.16 cSt (40 ° C.) Pour point: -42.5 ° C. Flash point: 222 ° C. The oxidation test of this 2-methyl- (secondary C ₁₄ alkyl) naphthalene mixture was conducted as in Example 1. The same method was used. The test results are shown in Table 1.

Example 3 In the same apparatus and operation as in Example 1, the reaction temperature was adjusted to 15
The reaction was carried out at 0 ° C., with the raw material being a mixture of 2-methylnaphthalene and 1-hexadecene in a weight ratio of 2: 1 and the raw material supply rate being 7.2 ml / min (LHSV = 7.2 h ⁻¹ ). It was The olefin conversion rate during the reaction was 78%.
The obtained reaction liquid was treated in the same manner as in Example 1 to obtain a 2-methyl- (secondary C ₁₆ alkyl) naphthalene mixture (I). When this product was analyzed by gas chromatography, 2-methyl-1- (1-methylpentadecyl) naphthalene, 2-methyl-3- (1-methylpentadecyl) naphthalene, 2-methyl-4- (1 -Methylpentadecyl) naphthalene, 2-methyl-5- (1-methylpentadecyl) naphthalene, 2-methyl-6- (1-methylpentadecyl) naphthalene, 2-methyl-7- (1-
Methylpentadecyl) naphthalene, and 2-methyl-8
-(1-Methylpentadecyl) naphthalene in total 43
It was contained by mol%, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 43%. The properties of this product were as follows. [Properties] Viscosity: 34.65 cSt (40 ° C.) Pour point: −45 ° C. Flash point: 240 ° C. This 2-methyl- (secondary C ₁₆ alkyl) naphthalene mixture (I) was tested for oxidation in Example 1. The same method was used. The test results are shown in Table 1.

Example 4 In the same apparatus and operation as in Example 1, the reaction temperature was adjusted to 15
At 0 ° C., the raw materials were 2-methylnaphthalene, 1-hexadecene and 1-octadecene in a weight ratio of 2: 0.65: 0.5.
5, and the raw material feed rate is 7.2 ml / min (L
The reaction was carried out by changing the HSV to 7.2 h ^-1 ). The olefin conversion rate during the reaction was 81%. The obtained reaction liquid was treated in the same manner as in Example 1 to obtain a mixture (I) of 2-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₈ alkyl) naphthalene. . When this product was analyzed by gas chromatography, 2-methyl-
1- (1-methylpentadecyl) naphthalene, 2-methyl-3- (1-methylpentadecyl) naphthalene, 2-
Methyl-4- (1-methylpentadecyl) naphthalene,
2-methyl-5- (1-methylpentadecyl) naphthalene, 2-methyl-6- (1-methylpentadecyl) naphthalene, 2-methyl-7- (1-methylpentadecyl)
Naphthalene, 2-methyl-8- (1-methylpentadecyl) naphthalene, 2-methyl-1- (1-methylheptadecyl) naphthalene, 2-methyl-3- (1-methylheptadecyl) naphthalene, 2-methyl -4- (1-Methylheptadecyl) naphthalene, 2-methyl-5- (1-
Methylheptadecyl) naphthalene, 2-methyl-6-
(1-Methylheptadecyl) naphthalene, 2-methyl-
7- (1-methylheptadecyl) naphthalene, and 2-
A total of 42 mol% of methyl-8- (1-methylheptadecyl) naphthalene was contained, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 42%. The properties of this product were as follows. [Properties] Viscosity: 36.53 cSt (40 ° C.) Pour point: −32.5 ° C. Flash point: 252 ° C. This 2-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C) The oxidation test for the mixture (I) of ₁₈ alkyl) naphthalene was carried out in the same manner as in Example 1. The test results are shown in Table 1.

When the synthetic oil of the present invention is used as a high temperature lubricating oil or heat carrier oil, heat resistance is required in addition to oxidation resistance. Therefore, 2-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₈ alkyl)
The heat resistance test of the mixture (I) of naphthalene was conducted according to JIS K
According to the rotary thermal stability test specified in 2540, the test was performed under the following conditions. [Test Conditions] Temperature × time: 150 ° C. × 24 hours Sample amount: 20 g Equipment and instruments: The ones specified in JIS K2540 were used. At the same time, a heat resistance test was also performed on the conventionally used high temperature synthetic oil materials shown in Comparative Examples 5 to 8 to compare the test results. Further, a heat resistance test was conducted on the synthetic oil of Comparative Example 1. The results of these heat resistance tests are summarized in Table 2.

When the synthetic oil of the present invention is used as an electric insulating oil, good electrical characteristics are required in addition to oxidation resistance. Therefore, the electrical characteristics of the mixture (I) of 2-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₈ alkyl) naphthalene were examined. At the same time, the electrical characteristics of the conventionally used synthetic insulating oils shown in Comparative Examples 9 to 11 were examined and the electrical characteristics were compared. The test results of this example and Comparative Examples 9 to 11 are summarized in Table 3.

Example 5 In the same apparatus and operation as in Example 1, the reaction temperature was adjusted to 15
The reaction was carried out at 0 ° C., with the raw material being a mixture of 2-methylnaphthalene and 1-eicosene in a weight ratio of 2: 1 and the raw material supply rate being 7.2 ml / min (LHSV = 7.2 h ⁻¹ ). It was The olefin conversion rate during the reaction was 82%. The obtained reaction solution was treated in the same manner as in Example 1 to give 2-methyl-
A (secondary C ₂₀ alkyl) naphthalene mixture was obtained. When this product was analyzed by gas chromatography, it was found to be 2
-Methyl-1- (1-methylnonadecyl) naphthalene,
2-Methyl-3- (1-methylnonadecyl) naphthalene, 2-methyl-4- (1-methylnonadecyl) naphthalene, 2-methyl-5- (1-methylnonadecyl) naphthalene, 2-methyl-6- (1-methylnonadecyl) Naphthalene, 2-methyl-7- (1-methylnonadecyl)
Naphthalene and 2-methyl-8- (1-methylnonadecyl) naphthalene are contained in a total amount of 40 mol%,
The substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain is 4
It was 0%. The properties of this product were as follows. [Properties] Viscosity: 42.25 cSt (40 ° C.) Pour point: −15 ° C. Flash point: 268 ° C. An oxidation test of this 2-methyl- (secondary C ₂₀ alkyl) naphthalene mixture was conducted in the same manner as in Example 1. Made by way. The test results are shown in Table 1.

Example 6 In the same apparatus and operation as in Example 1, the reaction temperature was adjusted to 15
At 0 ° C., the raw material is 0.2: 1. By weight ratio of 1-methylnaphthalene, 2-methylnaphthalene, and 1-hexadecene.
8: 1 mixture and feed rate 7.2 ml / min
The reaction was carried out by changing to (LHSV = 7.2 h ⁻¹ ). The olefin conversion rate during the reaction was 83%. The obtained reaction solution was treated in the same manner as in Example 1 to give 1-methyl- (secondary C
A mixture of ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₆ alkyl) naphthalene was obtained. When this product was analyzed by gas chromatography, 1-methyl-2
-(1-methylpentadecyl) naphthalene, 1-methyl-3- (1-methylpentadecyl) naphthalene, 1-methyl-4- (1-methylpentadecyl) naphthalene, 1
-Methyl-5- (1-methylpentadecyl) naphthalene, 1-methyl-6- (1-methylpentadecyl) naphthalene, 1-methyl-7- (1-methylpentadecyl)
Naphthalene, 1-methyl-8- (1-methylpentadecyl) naphthalene, 2-methyl-1- (1-methylpentadecyl) naphthalene, 2-methyl-3- (1-methylpentadecyl) naphthalene, 2-methyl -4- (1-methylpentadecyl) naphthalene, 2-methyl-5- (1-
Methylpentadecyl) naphthalene, 2-methyl-6-
(1-Methylpentadecyl) naphthalene, 2-methyl-
7- (1-methylpentadecyl) naphthalene, and 2-
Methyl-8- (1-methylpentadecyl) naphthalene was contained at 42 mol% in total, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 42%. The properties of this product were as follows. [Properties] Viscosity: 34.32 cSt (40 ° C.) Pour point: −45 ° C. Flash point: 242 ° C. This 1-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₆ alkyl). ) The oxidation test on the mixture of naphthalene was carried out in the same manner as in Example 1. The test results are shown in Table 1.

Comparative Example 1 In the same apparatus and operation as in Example 1, the reaction temperature was adjusted to 10
At 0 ° C., the raw material was a mixture of naphthalene and 1-hexadecene in a weight ratio of 2: 1, and the raw material supply rate was 14 ml / min.
The reaction was performed by changing to (LHSV = 14 h ⁻¹ ). The olefin conversion rate during the reaction was 84%. The obtained reaction liquid was treated in the same manner as in Example 1 to obtain a (secondary C ₁₆ alkyl) naphthalene mixture having the following composition and properties. [Composition] 1- (1-methylpentadecyl) naphthalene 24 mol% 1- (1-ethyltetradecyl) naphthalene 12 mol% 1- (1-propyltridecyl) naphthalene 6 mol% 1- (1-butyldodecyl) Naphthalene 5 mol% 1- (1-pentylundecyl) naphthalene 3 mol% 1- (1-hexyldecyl) naphthalene and 1- (1-heptylnonyl) naphthalene 4 mol% 2- (1-methylpentadecyl) naphthalene 19 mol % 2- (1-Ethyltetradecyl) naphthalene 10 mol% 2- (1-Propyltridecyl) naphthalene 5 mol% 2- (1-Butyldodecyl) naphthalene 4 mol% 2- (1-Pentylundecyl) naphthalene 3 Mol% 2- (1-hexyldecyl) naphthalene and 2- (1-heptylnonyl) naphthalene Mol% [Properties] Viscosity: 24.92cSt (40 ℃) pour point: -40 ° C. Flash point: 238 ° C. performed at the (secondary C ₁₆ alkyl) same manner as in Example 1 oxidation test naphthalene mixture A thermal stability test was conducted in the same manner as in Example 4. The test results are shown in Table 1 and Table 2.
Each is shown in the table.

[0060]Comparative example 2 Four-necked 2 liter capacity equipped with reflux condenser and stirrer
1000 g of naphthalene, 1-hexadecene in the flask
65:55 by weight of 1 and octadecene 5
00g, and 200g of activated clay, put at 170 ℃ 1
The reaction was carried out for 5 minutes. Gas chromatographic reaction mixture
When analyzed, the olefin conversion was 80%. Got
The reaction mixture was filtered to remove the catalyst, and then the same procedure as in Example 1 was performed.
And have the following composition and properties (secondary C₁₆A
Rukiru) Naphthalene and (Secondary C ₁₈Alkyl) naphthale
A mixture of

[Composition] 1- (1-methylpentadecyl) naphthalene 18 mol% 1- (1-ethyltetradecyl) naphthalene 6 mol% 1- (1-propyltridecyl) naphthalene 4 mol% 1- (1- Butyldodecyl) naphthalene 2 mol% 1- (1-pentylundecyl) naphthalene 1 mol% 1- (1-hexyldecyl) naphthalene and 1- (1-heptylnonyl) naphthalene 1 mol% 2- (1-methylpentadecyl) Naphthalene 11 mol% 2- (1-ethyltetradecyl) naphthalene 7 mol% 2- (1-propyltridecyl) naphthalene 3 mol% 2- (1-butyldodecyl) naphthalene 2 mol% 2- (1-pentylundecyl) ) Naphthalene 1 mol% 2- (1-hexyldecyl) naphthalene and 2- (1-heptylnonyl) na Thallene 3 mol% 1- (1-methylheptadecyl) naphthalene 7 mol% 1- (1-ethylhexadecyl) naphthalene 5 mol% 1- (1-propylpentadecyl) naphthalene 3 mol% 1- (1-butyltetra Decyl) naphthalene 3 mol% 1- (1-pentyltridecyl) naphthalene 2 mol% 1- (1-hexyldecyl) naphthalene and 1- (1-heptylundecyl) naphthalene and 1- (1-octyldecyl) naphthalene 4 Mol% 2- (1-methylheptadecyl) naphthalene 4 mol% 2- (1-ethylhexadecyl) naphthalene 3 mol% 2- (1-propylpentadecyl) naphthalene 2 mol% 2- (1-butyltetradecyl) Naphthalene 2 mol% 2- (1-pentyltridecyl) naphthalene 2 mol% 2- (1-hexyl) Decyl) naphthalene and 2- (1-heptylundecyl) naphthalene and 2- (1-octyldecyl) naphthalene 4 mol%

[Properties] Viscosity: 28.88 cSt (40 ° C.) Pour point: −30 ° C. Flash point: 248 ° C. This (secondary C ₁₆ alkyl) naphthalene and (secondary C ₁₈
An oxidation test on a mixture of alkyl) naphthalene,
The same method as in Example 1 was used. The test results are shown in Table 1.

Comparative Example 3 In the same apparatus and operation as in Example 1, the reaction temperature was set to 12
The reaction was carried out at 5 ° C., with the raw material being a mixture of 2-methylnaphthalene and 1-hexadecene in a weight ratio of 2: 1 and the raw material supply rate being 2.2 ml / min (LHSV = 2.2 h ⁻¹ ). It was The olefin conversion rate during the reaction was 87%.
The obtained reaction liquid was treated in the same manner as in Example 1 to obtain a 2-methyl- (secondary C ₁₆ alkyl) naphthalene mixture (II). When this product was analyzed by gas chromatography, 2-methyl-1- (1-methylpentadecyl) naphthalene, 2-methyl-3- (1-methylpentadecyl) naphthalene, 2-methyl-4- (1 -Methylpentadecyl) naphthalene, 2-methyl-5- (1-methylpentadecyl) naphthalene, 2-methyl-6- (1-methylpentadecyl) naphthalene, 2-methyl-7- (1-
Methylpentadecyl) naphthalene, and 2-methyl-8
-(1-Methylpentadecyl) naphthalene is 33 in total
It was contained at a mol%, and the substitution selectivity of the naphthalene ring at the 2-position of the alkyl chain was 33%. The properties of this product were as follows. [Properties] Viscosity: 34.05 cSt (40 ° C.) Pour point: −45 ° C. Flash point: 246 ° C. Oxidation test of this 2-methyl- (secondary C ₁₆ alkyl) naphthalene mixture (II) was conducted according to Example 1 The same method was used. The test results are shown in Table 1.

Comparative Example 4 1000 g of 2-methylnaphthalene and 65:55 by weight ratio of 1-hexadecene and 1-octadecene were placed in a two-liter four-necked flask equipped with a reflux condenser and a stirrer.
Add 500g of mixture and 400g of activated clay 1
The reaction was carried out at 80 ° C for 30 minutes. The olefin conversion rate during the reaction was 95%. The obtained reaction solution was filtered to remove the catalyst, and then treated in the same manner as in Example 1 to prepare 2-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₈ alkyl). A mixture (II) of naphthalene was obtained. When this product was analyzed by gas chromatography, it was found to be 2
-Methyl-1- (1-methylpentadecyl) naphthalene, 2-methyl-3- (1-methylpentadecyl) naphthalene, 2-methyl-4- (1-methylpentadecyl)
Naphthalene, 2-methyl-5- (1-methylpentadecyl) naphthalene, 2-methyl-6- (1-methylpentadecyl) naphthalene, 2-methyl-7- (1-methylpentadecyl) naphthalene, 2-methyl -8- (1-methylpentadecyl) naphthalene, 2-methyl-1- (1-
Methylheptadecyl) naphthalene, 2-methyl-3-
(1-Methylheptadecyl) naphthalene, 2-methyl-
4- (1-methylheptadecyl) naphthalene, 2-methyl-5- (1-methylheptadecyl) naphthalene, 2-
Methyl-6- (1-methylheptadecyl) naphthalene,
2-Methyl-7- (1-methylheptadecyl) naphthalene, and 2-methyl-8- (1-methylheptadecyl)
The total content of naphthalene was 30 mol%, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 30%. The properties of this product were as follows. [Properties] Viscosity: 37.69 cSt (40 ° C.) Pour point: −35 ° C. Flash point: 238 ° C. This 2-methyl- (secondary C ₁₆ alkyl) naphthalene and 2-methyl- (secondary C ₁₈ alkyl). ) An oxidation test was conducted on the mixture (II) of naphthalene in the same manner as in Example 1. The test results are shown in Table 1.

Comparative Examples 5 to 8 The thermal stability test of the following synthetic oils conventionally used as a high temperature synthetic oil material was conducted in the same manner as in Example 4. Table 2 shows the results. In addition, Table 2 also shows the results of the oxidation resistance test conducted in the same manner as in Example 1. [Test Synthetic Oil] Comparative Example 5: Diester (Dioctyl sebacate) Comparative Example 6: Polyether (Polyoxypropylene glycol monoalkyl ester) Comparative Example 7: Hindered ester (Pentaerythritol tetracapryate) Comparative Example 8: Poly α-olefin (1-decene oligomer)

Comparative Examples 9 to 11 Various electrical characteristics of the following synthetic oil conventionally used as a synthetic insulating oil were examined and compared with the synthetic oil of Example 4. The test results are summarized in Table 3. [Test Synthetic Oil] Comparative Example 9: Alkylbenzene shown in JIS C2320 Comparative Example 10: Polybutene shown in JIS C2320 Comparative Example 11: Alkyldiphenylethane shown in JIS C2320

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

[Table 3]

From the test results summarized in Table 1, the dialkylnaphthalene mixture which is the synthetic oil of the present invention has extremely excellent oxidation resistance and is said to be excellent in oxidation resistance. It can be seen that it has remarkably excellent oxidation resistance even when compared with. Also,
It can be seen that even in the case of the dialkylnaphthalene mixture, the dialkylnaphthalene mixture of the present invention in which the substitution position selectivity of the naphthalene ring to the second position of the long alkyl chain is 35% or more is excellent in oxidation resistance. From the test results summarized in Table 2, it is understood that the dialkylnaphthalene mixture which is the synthetic oil of the present invention has heat resistance higher than that of the conventionally used high temperature synthetic oil material. From the test results summarized in Table 3, it can be seen that the dialkylnaphthalene mixture which is the synthetic oil of the present invention has electric characteristics comparable to those of the conventionally used synthetic insulating oils. From the above results, it can be seen that the synthetic oil of the present invention has particularly excellent oxidation resistance and performance required for industrial oils for various applications.

Example 7 A stainless steel reaction tube having an inner diameter of 10 mm was filled with 10 ml of activated clay as a catalyst and heated to 110 ° C. in a constant temperature bath. A mixture of naphthalene and 1-hexadecene in a molar ratio of 3.5: 1 was introduced into the reaction tube at a rate of 2.6 ml / min (LHSV = 15.6) using a plunger pump.
The reaction was carried out by feeding in h ^-1 ). When the reaction solution was analyzed by gas chromatography, the conversion rate of olefin was 8
It was 7%. Unreacted naphthalene and olefin are removed from the obtained reaction solution by distillation, and further distilled under reduced pressure to remove C
₁₆ alkylnaphthalene (bp185-210 ° C / 1mm
Hg). When this product was analyzed by gas chromatography, it was found to contain 24 mol% of 1- (1-methylpentadecyl) naphthalene and 19 mol% of 2- (1-methylpentadecyl) naphthalene, and the secondary alkyl chain
The substitution selectivity of the naphthalene ring to the position was 43%.

Example 8 The catalyst was silica-alumina, the reaction temperature was 160 ° C., and the raw material feed rate was 2.1 ml / min (LHSV = 12.6 h).
^The reaction was carried out under the same conditions and operating methods as in Example 7, except that the above was changed to ^-1 ). When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 85%. The C ₁₆ alkylnaphthalene obtained by distillation under reduced pressure was analyzed by gas chromatography to find that it contained 23 mol% of 1- (1-methylpentadecyl) naphthalene and 19 mol% of 2- (1-methylpentadecyl) naphthalene. The substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain is 42
%was.

Example 9 The catalyst was HY type zeolite, the reaction temperature was 150 ° C.,
The feed rate of the raw material is 1.7 ml / min (LHSV = 10.2
The reaction was carried out under the same conditions and operating methods as in Example 7, except that h ^-1 ) was used. When the reaction solution was analyzed by gas chromatography, the conversion rate of olefin was 78%. The C ₁₆ alkylnaphthalene obtained by vacuum distillation was analyzed by gas chromatography to find that it contained 24 mol% of 1- (1-methylpentadecyl) naphthalene and 18 mol% of 2- (1-methylpentadecyl) naphthalene. And
The substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain is 4
It was 2%.

Example 10 The same conditions and conditions as in Example 7 were used except that the catalyst was changed to acid clay, the reaction temperature was changed to 240 ° C., and the feed rate of the raw materials was changed to 3.8 ml / min (LHSV = 22.8 h ⁻¹ ). The reaction was performed according to the operating method. When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 89%. The C ₁₆ alkylnaphthalene obtained by distillation under reduced pressure was analyzed by gas chromatography to find that it contained 20 mol% of 1- (1-methylpentadecyl) naphthalene and 21 mol% of 2- (1-methylpentadecyl) naphthalene. The substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 41%.

Example 11 A reaction tube made of stainless steel having an inner diameter of 20 mm was filled with 60 ml of activated clay as a catalyst, and this was heated to 150 ° C. in a constant temperature bath. In the reaction tube, a mixture of 2-methylnaphthalene and 1-decene in a molar ratio of 5: 1 was used at a rate of 7.2 ml / min (LHSV = 7.2 h) by using a plunger pump.
^-1 ) to carry out the reaction. When the reaction solution was analyzed by gas chromatography, the conversion rate of olefin was 92.
%was. The unreacted 2-
Methylnaphthalene and olefin were removed and further distilled under reduced pressure to obtain 2-methyl- (C ₁₀ alkyl) naphthalene. When this product was analyzed by gas chromatography, 2-methyl-1- (1-methylnonyl) naphthalene, 2-methyl-3- (1-methylnonyl) naphthalene, 2-methyl-4- (1-methylnonyl) naphthalene , 2-methyl-5- (1-methylnonyl) naphthalene, 2-methyl-6- (1-methylnonyl) naphthalene, 2-methyl-7- (1-methylnonyl) naphthalene, and 2-methyl-8- (1- It contained 43 mol% of methylnonyl) naphthalene in total, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 43%.

Example 12 The reaction was carried out under the same conditions and operating method as in Example 11 except that the raw material was changed to a mixture of 2-methylnaphthalene and 1-tetradecene in a molar ratio of 3.5: 1 (LHSV = 7.
2h ^-1 ). When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 82%. When 2-methyl- (C ₁₄ alkyl) naphthalene obtained by distillation under reduced pressure was analyzed by gas chromatography, 2-methyl-1- (1-methyltridecyl) naphthalene and 2-methyl-3- (1- Methyltridecyl) naphthalene, 2-
Methyl-4- (1-methyltridecyl) naphthalene, 2
-Methyl-5- (1-methyltridecyl) naphthalene,
2-Methyl-6- (1-methyltridecyl) naphthalene, 2-methyl-7- (1-methyltridecyl) naphthalene, and 2-methyl-8- (1-methyltridecyl)
The total content of naphthalene was 42 mol%, and the substitution selectivity of the naphthalene ring to the second position of the alkyl chain was 42%.

Example 13 The reaction was carried out under the same conditions and operating method as in Example 11 except that the raw material was changed to a mixture of 2-methylnaphthalene and 1-hexadecene in a molar ratio of 3.2: 1 (LHSV = 7.
2h ^-1 ). When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 95%. When 2-methyl- (C ₁₆ alkyl) naphthalene (bp 190-215 ° C./1 mmHg) obtained by distillation under reduced pressure was analyzed by gas chromatography, 2-methyl-1- (1-
Methylpentadecyl) naphthalene, 2-methyl-3-
(1-Methylpentadecyl) naphthalene, 2-methyl-
4- (1-methylpentadecyl) naphthalene, 2-methyl-5- (1-methylpentadecyl) naphthalene, 2-
Methyl-6- (1-methylpentadecyl) naphthalene,
2-methyl-7- (1-methylpentadecyl) naphthalene, and 2-methyl-8- (1-methylpentadecyl)
The total content of naphthalene was 37 mol%, and the substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 37%.

Example 14 The reaction was carried out under the same conditions and operating procedures as in Example 11 except that the starting material was changed to a mixture of 2-methylnaphthalene and 1-eicosene in a molar ratio of 3.9: 1 (LHSV = 7.2
h ^-1 ). When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 85%. When 2-methyl- (C ₂₀ alkyl) naphthalene obtained by distillation under reduced pressure was analyzed by gas chromatography, 2-methyl-1- (1-methylnonadecyl) naphthalene and 2-methyl-3- (1-methylnonadecyl) were obtained. Naphthalene, 2-methyl-4- (1-methylnonadecyl) naphthalene, 2-
Methyl-5- (1-methylnonadecyl) naphthalene, 2
-Methyl-6- (1-methylnonadecyl) naphthalene,
2-Methyl-7- (1-methylnonadecyl) naphthalene and 2-methyl-8- (1-methylnonadecyl) naphthalene are contained in a total amount of 40 mol%, and the substitution selection of the naphthalene ring to the second position of the alkyl chain is selected. The rate was 40%.

Example 15 The starting material was a mixture of 1-methylnaphthalene and 1-hexadecene in a molar ratio of 3.2: 1, and the reaction temperature was 150 ° C.
The feed rate of the raw material is 1.2 ml / min (LHSV =
The reaction was carried out under the same conditions and operating methods as in Example 7, except that the reaction rate was changed to 7.2 h ^-1 ). When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 82%. 1-Methyl- (C ₁₆ alkyl) naphthalene obtained by distillation under reduced pressure (bp 190 to 210 ° C./1 mmHg)
Was analyzed by gas chromatography to find that 1-methyl-2- (1-methylpentadecyl) naphthalene, 1-
Methyl-3- (1-methylpentadecyl) naphthalene,
1-methyl-4- (1-methylpentadecyl) naphthalene, 1-methyl-5- (1-methylpentadecyl) naphthalene, 1-methyl-6- (1-methylpentadecyl)
It contains naphthalene, 1-methyl-7- (1-methylpentadecyl) naphthalene, and 1-methyl-8- (1-methylpentadecyl) naphthalene in a total amount of 40 mol%, and is in the second position of the alkyl chain. The substitution selectivity of the naphthalene ring was 40%.

Comparative Example 12 524 g (3.69) of 2-methylnaphthalene was placed in a 1-liter four-necked flask equipped with a reflux condenser and a stirrer.
Mole), 1-hexadecene 220 g (0.98 mole),
Then, 85 g of activated clay was added, and the mixture was heated to 180 ° C. and reacted for 25 minutes while stirring. When the reaction solution was analyzed by gas chromatography, the olefin conversion rate was 87%. The resulting reaction solution was filtered to remove the catalyst, and then unreacted 2-methylnaphthalene and olefin were removed by distillation, and further distilled under reduced pressure to remove 2-methyl- (C
₁₆ alkyl) naphthalene was obtained. When this product was analyzed by gas chromatography, it was found to be 2-methyl-1-
(1-Methylpentadecyl) naphthalene, 2-methyl-
3- (1-methylpentadecyl) naphthalene, 2-methyl-4- (1-methylpentadecyl) naphthalene, 2-
Methyl-5- (1-methylpentadecyl) naphthalene,
32-Methyl-6- (1-methylpentadecyl) naphthalene, 2-methyl-7- (1-methylpentadecyl) naphthalene, and 2-methyl-8- (1-methylpentadecyl) naphthalene in total of 32 moles %, The selectivity of substitution of the naphthalene ring at the 2-position of the alkyl chain is 32%.
was.

Comparative Example 13 The reaction was carried out under the same conditions and operating method as in Example 7 except that the reaction temperature was changed to 110 ° C. and the feed rate of the raw materials was changed to 0.35 ml / min (LHSV = 2.1 h ⁻¹ ). went. When the reaction solution was analyzed by gas chromatography, the conversion rate of olefin was 87%. C obtained by distillation under reduced pressure
_{When 16} alkylnaphthalene was analyzed by gas chromatography, it was found to contain 21 mol% of 1- (1-methylpentadecyl) naphthalene and 10 mol% of 2- (1-methylpentadecyl) naphthalene, and the second alkyl chain The substitution selectivity of the naphthalene ring to the position was 31%.

Comparative Example 14 The starting material was a mixture of 2-methylnaphthalene and 1-hexadecene in a molar ratio of 3.2: 1, and the reaction temperature was 140 ° C.
The feed rate of the raw material is 0.3 ml / min (LHSV =
The reaction was carried out under the same conditions and operating methods as in Example 7, except that the reaction time was changed to 1.8 h ⁻¹ ). When the reaction liquid was analyzed by gas chromatography, the conversion rate of olefin was 89%. When 2-methyl- (C ₁₆ alkyl) naphthalene obtained by distillation under reduced pressure was analyzed by gas chromatography, 2-methyl-1- (1-methylpentadecyl) naphthalene and 2-methyl-3- (1- Methylpentadecyl) naphthalene, 2-methyl-4- (1-methylpentadecyl) naphthalene, 2-methyl-5- (1-methylpentadecyl) naphthalene, 2-methyl-6- (1-methylpentadecyl) naphthalene , 2-methyl-7- (1-
Methylpentadecyl) naphthalene, and 2-methyl-8
-(1-Methylpentadecyl) naphthalene in total 30
It was contained in an amount of mol%, and the substitution selectivity of the naphthalene ring at the 2-position of the alkyl chain was 30%.

Comparative Example 15 The reaction was carried out under the same conditions and operating method as in Example 7 except that the reaction temperature was changed to 140 ° C. and the raw material supply rate was changed to 1.7 ml / min (LHSV = 10.2 h ⁻¹ ). went. When the reaction liquid was analyzed by gas chromatography, the olefin had disappeared. When C ₁₆ alkylnaphthalene obtained by distillation under reduced pressure was analyzed by gas chromatography, 15 mol% of 1- (1-methylpentadecyl) naphthalene and 14- (2-methylpentadecyl) naphthalene 14 were obtained.
The substitution selectivity of the naphthalene ring to the 2-position of the alkyl chain was 29%.

The above Examples 7 to 15 and Comparative Examples 12 to 15
Comparing the above, it can be seen that according to the method for producing an alkylnaphthalene compound of the present invention, an alkylnaphthalene compound having a structure in which the second carbon of the alkyl chain is bonded to the naphthalene ring can be selectively produced. In particular, in the comparative example, the selectivity of the bond of the naphthalene ring to the second carbon of the alkyl chain was 35.
Nothing exceeded%, while Examples 7-15
In the above, since the selectivity is 35% or more, it can be seen that the method of the present invention has very excellent selectivity.

[0085]

INDUSTRIAL APPLICABILITY The synthetic oil of the present invention can be suitably used as various industrial oils, but since it has particularly excellent oxidation resistance, it has a long life and is used in an atmosphere that promotes oxidation. It is also possible to use it for a long period of time. Also,
According to the method for producing an alkylnaphthalene compound of the present invention, it is possible to selectively produce a (1-methylalkyl) naphthalene compound useful as a lubricating oil, a medium oil, a plastic raw material, or the like. In particular, even when a long-chain alkyl group is substituted on the naphthalene ring, rearrangement of the carbocation derived from the alkyl source does not easily occur, so that the product does not have a complicated isomer composition and the post-treatment is easy. Further, since the substitution selectivity of the naphthalene ring to the second carbon of the alkyl chain can be set to 35% or more, the synthetic oil of the present invention can be efficiently produced by a one-step reaction.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07C 15/24 9546-4H C07C 15/24 // C07B 61/00 300 C07B 61/00 300 C10N 30 : 10 40:04 40:08 40:16 40:20 40:25 (72) Inventor, Mitsuki Yasuhara, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor, Hiroaki Taniguchi Tokyo 1-2 1-2 Marunouchi, Chiyoda-ku Nihon Kokan Co., Ltd. (72) Inventor Takamasa Takahashi 4-1, Kudankita, Chiyoda-ku, Tokyo 3-4 Adchemco Co., Ltd. (72) Inventor Teruo Yamamoto Osaka, Kita, Osaka 2-8-5 Nishi-Tenma-ku, Matsumura Oil Co., Ltd. (72) Inventor Jouji Imafuku 2-8-5 Nishi-Tenma, Kita-ku, Osaka City, Osaka Prefecture Matsumura Oil Co., Ltd.

Claims (4)

[Claims] 1. At least one dialkylnaphthalene compound having a structure in which one methyl group and one secondary alkyl group having 10 to 24 carbon atoms are substituted on the naphthalene ring is contained, and all the dialkylnaphthalene compounds are present. A synthetic oil characterized in that the ratio of the amount of the dialkylnaphthalene compound in which the secondary alkyl group is a 1-methylalkyl group to the amount thereof is 35% or more in terms of molar ratio. 2. The synthetic oil according to claim 1, wherein the dialkylnaphthalene compound has a methyl group substituted at the 2-position on the naphthalene ring. 3. In the method for producing an alkylnaphthalene compound, at least one naphthalene selected from the group consisting of naphthalene, 1-methylnaphthalene and 2-methylnaphthalene and a linear α-olefin are subjected to a flow-type catalytic reaction. , In the presence of a solid acid catalyst, reaction temperature 80-350
A method for producing a (1-methylalkyl) naphthalene compound, which comprises reacting at 0 ° C., a liquid hourly space velocity (LHSV) of 3 to 50 h ⁻¹ and a linear α-olefin conversion rate of 50 to 99%. 4. The (1-methyl) according to claim 3, wherein the selectivity of the bond of the naphthalene ring to the second carbon on the alkyl chain is 35% or more with respect to the position of the carbon in the alkyl chain bonded to the naphthalene ring. Process for producing alkyl) naphthalene compound.