JPH07242575A - Method for linearly dimerizing alpha-alkylstyrenes - Google Patents

Abstract

PURPOSE:To efficiently obtain a linear dimer of alpha-alkylstyrenes useful as a monomer for polymerization, a polymerization modifier, a synthetic intermediate, etc., in high selectivity and yield by dimerizing the alpha-alkylstyrenes under specific conditions. CONSTITUTION:This method for linearly dimerizing alpha-alkylstyrenes expressed by the formula [R<1> and R<2> each is a 1-6C alkyl; (n) is 0-5] such as alpha- methylstyrene is to react the alpha-alkylstyrenes at 80-140 deg.C or 30-140 deg.C in the absence or presence of a solvent without dissolving a catalyst using a heteropoly acid such as silicomolybdic acid as the catalyst in an amount of 1-100wt.% or 1-200wt.% based on the raw material alpha-alkylstyrenes in a heterogeneous system of the solid phase-liquid phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear dimerization method for .alpha.-alkylstyrenes. The linear dimers of α-alkylstyrenes are not only useful as monomers for polymerization, polymerization regulators, and synthetic intermediates for various compounds, but are also attracting attention as raw materials for synthetic lubricating oils. It is important as a raw material for the base material of the working fluid.

[0002]

2. Prior Art When α-alkylstyrenes such as α-methylstyrene are reacted in the presence of an acid catalyst, a linear dimer of 2,4-diphenyl-4-methyl-1-pentene (1-pentene) is obtained. Body), 2,4-diphenyl-4-methyl-2-pentene (2-pentene body), 1,1,3-trimethyl-3-phenylindane (cyclic body) which is a cyclic dimer, and trimer or more The polymer of

As described above, the linear dimers of α-alkylstyrenes such as α-methylstyrene, that is, the 1-pentene compound and the 2-pentene compound, are intermediates for the synthesis of monomers for polymerization, polymerization regulators and various compounds. Not only is it useful as a body, it is also useful as a raw material for synthetic lubricating oils, and is particularly important as a raw material for a base material for traction drive fluids. On the other hand, the cyclic body is not only unsuitable as a monomer for polymerization and a raw material for synthetic lubricating oil,
Not only is it poor in usefulness as it causes the performance of the traction drive fluid to deteriorate, but it is linear when present.
It is an undesirable ingredient that reduces the value of the monomer. However, since it is difficult to separate the cyclic body from the linear dimer by distillation or the like, it is desired to develop a method for reducing the formation of the cyclic body and increasing the selectivity of the linear dimer, and Various proposals have been made.

For example, JP-A-50-117754 discloses that α
-When producing a dimer of an alkyl styrene, it is characterized by using a heteropolyacid, but in reality, it is dimerized by a homogeneous reaction using a solvent capable of dissolving a heteropolyacid such as acetone. Is to do. That is, 0.02 to 1 wt% of the heteropoly acid (weight ratio to the raw material) is dissolved in acetone and reacted at 50 ° C. for 60 minutes or more (usually about 60 minutes, the shortest one is 30 minutes) to carry out the dimerization It is carried out. However, in this method, the ratio of undesired components other than the linear dimer in the product is as high as about 20%, and washing with water is required to remove the heteropolyacid that is the catalyst from the reaction solution after the reaction. In particular, when the heteropolyacid removed by washing with water is reused, there is a problem that it is difficult to recover it from the aqueous phase.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to improve the conversion of a linear dimer into a linear dimer of α-alkylstyrenes which is easy to recover and reuse an expensive catalyst. Is provided.

[0006]

Means for Solving the Problems JP-A-50-11775
In 4, the main purpose is to improve the reactivity by making a homogeneous system using an organic solvent that dissolves the heteropolyacid, but in order to carry out the reaction in a homogeneous system, separation of the catalyst,
It was difficult to reuse. The inventors of the present invention have earnestly studied for the purpose of developing a method for easily separating and reusing a catalyst without lowering the selectivity to a linear dimer, and as a result, α-alkylstyrenes were used as a heteropolyacid catalyst. In the presence of, a solvent is not used, or a solvent that does not dissolve the heteropolyacid catalyst (forms a heterogeneous system with the catalyst) is used to carry out the reaction in a solid-liquid heterogeneous system, thereby facilitating the reaction. Catalyst separation,
We have found that they can be collected and reused. At this time, as described in the above-mentioned JP-A-50-117754, when the amount of the catalyst used is small, there are problems that the reaction time becomes long or the conversion rate becomes low. If the dimerization reaction is carried out under a heterogeneous solid-liquid phase condition with a relatively high reaction temperature and a large amount of catalyst, conversion will occur without decreasing the selectivity of the linear dimer in the dimer. They have also found that the rate can be improved and the reaction time can be significantly shortened, and have completed the present invention.

That is, the gist of the first invention is to use α-alkylstyrenes in an amount of 1 to 100% by weight of a heteropolyacid based on the starting α-alkylstyrenes, without a solvent, in a solid-liquid phase inhomogeneity. The present invention resides in a linear dimerization method of α-alkylstyrenes, which comprises dimerizing at 80 to 140 ° C., and the gist of the second invention is to convert α-alkylstyrenes into a raw material α-alkylstyrene. 1 to 200 wt% based on styrene
Of the heteropoly acid of 1., in the presence of a solvent that does not dissolve the catalyst, in a solid-liquid heterogeneous system, dimerization at 30 to 140 ° C.
It exists in the quantification method.

The α-alkylstyrenes used as raw materials have the following general formula:

[Chemical 1] (In the formula, R ¹ and each R ² are independently selected from an alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, and t.
A butyl group, an amyl group, a cyclohexyl group, etc., and n
Indicates 0 to 5. ). Among them, compounds in which R ¹ and R ² are an alkyl group having 1 to 3 carbon atoms are preferable, and among them, R ¹ is an alkyl group having 1 to 3 carbon atoms and n is 0. Those are preferable.

Typical examples thereof are α-methylstyrene, methyl-α-methylstyrene, ethyl-α-methylstyrene, i-propyl-α-methylstyrene, t-butyl-α-methylstyrene and methyl-α-. There are ethylstyrene, ethyl-α-ethylstyrene, α-i-propylstyrene and methyl-α-n-propylstyrene, and α-methylstyrene is particularly preferable.

In the present invention, a mixture of two or more kinds of the compounds represented by the above general formula can be used, and the dimer of the present invention is used in the sense of including a codimer.

In the present invention, the catalyst used is a heteropoly acid containing at least one kind or more of molybdenum, tungsten and vanadium, such as silicomolybdic acid, phosphomolybdic acid, cerium molybdic acid and chromium. Molybdic acid, cobalt molybdic acid, nickel molybdic acid, borotungstic acid, silicotungstic acid, germanotungstic acid, phosphotungstic acid, vanadotungstic acid, cobalt tungstic acid, phosphovanadic acid, uravanadic acid, manganese vanadic acid, phosphovanad Molybdic acid,
Cobalt silicotungstic acid, siliconickel tungstic acid, germanocobalt tungstic acid, phosphovanadotungstic acid, phosphomolybdotungstic acid, phosphomanganese tungstic acid, phosphonickel tungstic acid, etc. Phosphomolybdic acid, borotungstic acid, silicotungstic acid, phosphotungstic acid and the like are preferable. These plural types can be used in combination.

Regarding the various conditions of the reaction in the case of the batch system, the first invention will be described first. The amount of the catalyst used is 1 to 100 wt% with respect to the raw material, preferably 2 to 8
0 wt%, particularly preferably 5 to 50 wt%. If it is less than the above range, the reaction time becomes long, the production of cyclic dimers increases, and the selectivity of linear dimers decreases. On the other hand, if the amount is larger than this, the amount of polymer of trimer or more increases and the yield of dimer decreases.

The reaction temperature is 80 to 140 ° C, preferably 100 to 140 ° C, particularly preferably 120 to 140 ° C. The reaction pressure is atmospheric pressure to 100 kg / cm ² , preferably atmospheric pressure to 10 kg / cm ² . Reaction time is about 0.5
It is about 1 minute to 1 hour.

The second invention will be described. In the present invention, the solvent used is not particularly limited as long as it is a hydrocarbon that does not dissolve the heteropolyacid. For example, n-pentane,
i-pentane, n-hexane, i-hexane, dimethylbutane, n-heptane, i-heptane, dimethylpentane, n-octane, i-octane, dimethylhexane,
Ethylhexane, 2,2,4-trimethylpentane, n
-Chain saturated hydrocarbons such as nonane, n-decane, cyclic saturated hydrocarbons such as cyclohexane, methylcyclohexane, dimethylcyclohexane, cyclopentane, methylcyclopentane, cycloheptane, cyclooctane, benzene, toluene, xylene. Ethers such as various aromatic hydrocarbons, diethyl ether, dipropyl ether and dibutyl ether are preferably used.

The reaction temperature is 30 to 140 ° C., preferably 50 to 120 ° C., particularly preferably 60 to 100 ° C. The reaction time is about 5 minutes to 5 hours, preferably 30 minutes or more. The amount of catalyst is 1-2 with respect to the raw material.
00 wt%, preferably 5 to 150 wt%, particularly preferably 10 to 100 wt%. The amount of solvent is solvent / raw material = 0.5 to 30, preferably 1 to 20 in weight ratio. The reaction pressure is atmospheric pressure to 100 kg / cm ² , preferably atmospheric pressure to
It is carried out at 10 kg / cm ² .

Usually, the reaction is carried out batchwise, and the heteropolyacid is used as it is without being molded. But alumina,
It can also be carried out by a fixed bed flow system (continuous method) by molding using an inorganic binder such as silica or diatomaceous earth. In that case, the content rate of the heteropolyacid is 5 to 15
WHSV is 10 in the case of the first invention by using a molded product of wt%.
~ 200h ^-1 , reaction temperature 80 ~ 140 ℃, the second invention, WHSV 0.5 ~ 20h ^-1 , reaction temperature 30 ~ ¹
Perform at 40 ° C. The pressure is from normal pressure to 100 kg / cm ² ,
It is preferably carried out at atmospheric pressure to 10 kg / cm ² . However, it is necessary to precisely control the temperature of the catalyst bed.

If the process according to the invention is carried out at a temperature lower than the temperature specified above, the reaction time will be longer, which leads to higher yields of trimers and higher and lower yields of dimers. Also,
When the reaction is carried out at a temperature higher than the above-specified temperature, only a ring is formed. The reaction can be carried out in the presence or absence of a coexisting gas, but when using the coexisting gas, an inert gas such as nitrogen gas is used.

In the first and second inventions, a high boiling substance of a trimer or more is also produced in a small amount, but a by-product of a trimer or more is easily produced by distillation to obtain a linear product which is the object of the present invention. It can be separated and removed from the dimer. If desired, by selecting the reaction conditions (catalyst amount, reaction temperature, reaction time, etc.), a large amount of trimer can be produced, or the reaction rate and conversion rate are sacrificed to some extent. Thus, it is possible to suppress the formation of high boiling substances of these trimers or higher.

[0019]

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

Example 1 30 ml of α-methylstyrene was added to a 100 ml autoclave.
g, 12-tungstophosphoric acid 3.3 g was put and sealed.
After heating at 130 ° C. for 5 minutes, stirring and reacting, the autoclave was cooled in a 20 ° C. water bath. The autoclave was opened, the solid catalyst was removed by filtration, and the reaction liquid was analyzed by gas chromatography. The equipment used was GC-14A manufactured by Shimadzu Corporation, and the column was HE.
A PONA column manufactured by WLET PACKARD, and the carrier gas is helium (the same applies to the following examples and comparative examples). As a result, the conversion rate of α-methylstyrene was 9
5.1 wt%, yield of linear dimer is 84.9 wt%, cyclic 2
The yield of the trimer was 3.86 wt% and the yield of the high boiling point trimer or higher was 6.28 wt%. At this time, linear dimer / annular 2
The monomer (linear dimer selectivity) = 22.0.

Example 2 Example 1 except that 10 g of 12-tungstophosphoric acid is used.
I went the same way. As a result, the conversion rate of α-methylstyrene was 99.5 wt%, the yield of the linear dimer was 76.7 wt%,
The yield of the cyclic dimer was 4.7 wt% and the yield of the high boiling point trimer or higher was 18.1 wt%. At this time, the linear dimer / cyclic dimer = 16.3.

Example 3 Example 1 except 3.3 g of 12-molybdophosphoric acid is used.
I went the same way. As a result, the conversion rate of α-methylstyrene was 99.3 wt%, the yield of the linear dimer was 87.5 wt%,
The yield of cyclic dimer was 4.27 wt% and the yield of high boiling point trimer or higher was 7.53 wt%. At this time, linear dimer /
Cyclic dimer = 20.5.

Comparative Example 1 50 ml of α-methylstyrene was placed in a 100 ml autoclave.
g, 0.01 g of 12-tungstophosphoric acid 2.
The solution dissolved in 5 g was put and sealed. After heating at 50 ° C for 40 minutes, stirring and reacting, the autoclave is heated for 20 minutes.
Cooled in a water bath at ℃. The autoclave was opened, the reaction solution was washed with water to remove the catalyst and acetone, and then the reaction solution was analyzed by gas chromatography. As a result, α-
The conversion rate of methylstyrene was 81.0 wt%, the yield of linear dimer was 61.8 wt%, the yield of cyclic dimer was 3.3 wt%,
The yield of high boiling point trimers and above was 15.7 wt%. At this time, the linear dimer / cyclic dimer = 19.0.

Example 4 30 ml of α-methylstyrene was added to a 200 ml autoclave.
g, cyclohexane 30 g, 12-tungstophosphoric acid 1
0 g was put and sealed. After heating at 80 ° C. for 30 minutes, stirring and reacting, the autoclave was cooled in a water bath at 20 ° C. The autoclave was opened, the solid catalyst was removed by filtration, and the reaction liquid was analyzed by gas chromatography. As a result, the conversion rate of α-methylstyrene was 8
2.5 wt%, yield of linear dimer is 64.5 wt%, cyclic 2
The yield of the monomer was 1.5 wt% and the yield of the high boiling point trimer or higher was 16.5 wt%. At this time, the linear dimer / cyclic dimer = 43.0.

[0025]

According to the first aspect of the present invention, while maintaining the selectivity of the conventional linear dimer, it is 95 to 100 wt% higher than that of the conventional one.
It is possible to obtain such a conversion rate and to shorten the reaction time significantly. Further, since the catalyst and the raw material (the product after the reaction) are in a solid-liquid phase heterogeneous system, the catalyst can be separated from the reaction liquid simply by filtering, and the filtered catalyst can be reused as it is. . Therefore, it is possible to easily remove, recover and reuse the catalyst, which has been difficult with the conventional method.

Further, according to the second invention, by using a solvent which forms a heterogeneous system with the catalyst, the selectivity of the linear dimer in the dimer can be improved as compared with the conventional one. Like the above, the catalyst can be reused easily.

Claims (2)

[Claims] 1. An α-alkyl styrene is used in an amount of 1 to 100 wt% of a heteropoly acid based on the starting α-alkyl styrene, in a solid phase-liquid phase heterogeneous system in the absence of solvent.
A linear dimerization method for α-alkylstyrenes, which comprises dimerizing at 40 ° C. 2. An α-alkyl styrene is used in a solid-liquid heterogeneous system in the presence of a solvent that does not dissolve the catalyst, using 1 to 200 wt% of a heteropoly acid based on the starting α-alkyl styrene. A linear dimerization method for α-alkylstyrenes, which comprises dimerizing at 30 to 140 ° C.