JPH10175887A - Method for cyclodimerization of conjugated diolefin - Google Patents

Abstract

(57) [Problem] To be stable and easy to handle in a reaction for cyclizing and dimerizing a conjugated diolefin in the presence of a catalyst, and
Provides a highly active catalyst system. SOLUTION: A method of using an onium tricarbonylnitrosylferrate and a strong protonic acid as a catalyst precursor when cyclizing and dimerizing a conjugated diolefin in the presence of a catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for cyclizing and dimerizing a conjugated diolefin. More specifically,
The present invention relates to a method for producing vinylcyclohexenes by cyclodimerization of a conjugated diolefin.

[0002]

2. Description of the Related Art Methods for producing vinylcyclohexenes by catalytic cyclization and dimerization of conjugated diolefins such as 1,3-butadiene and isoprene are well known, and various catalyst systems have been proposed. . For example, Japanese Patent Publication No. 44-29451 discloses an iron compound such as tris (acetylacetonato) iron and bis (diphenylphosphino) iron.
A ternary catalyst comprising a phosphorus compound such as ethane and an alkylaluminum such as triethylaluminum has been proposed. However, the selectivity of 4-vinylcyclohexene, which is the target compound, is low, and the use of expensive phosphorus compounds and alkyl aluminum which is unstable in air and moisture has been a problem in industrial production.

[0003] US Pat. No. 5,329,057 discloses silica-
A catalyst system characterized by moderately adjusting the water content of a catalyst obtained by impregnating and calcining a Cu salt on an alumina carrier has been disclosed.However, a highly active ion-exchange-calcined catalyst has a problem in terms of life and regeneration. Industrialization is problematic and necessitates the use of impregnated-calcined catalysts that have low activity but are advantageous for life and catalyst regeneration. In this patent, a multi-stage reaction or a high temperature reaction is required to achieve a high conversion. Also, according to the description of the patent, there is a problem that impurities are generated with a slightly lower selectivity.

A zero-valent dinitrosyl iron compound is known as a catalyst species having high activity and high selectivity in the cyclization dimerization reaction of a conjugated diolefin.
atalysis 24 (1986) 1-15), and various methods for preparing iron dinitrosyl halide have been studied mainly as preparation methods thereof. French Patent 1,502,141 discloses a catalyst system comprising a combination of iron dinitrosyl halide and a reducing agent as an advantageous catalyst system capable of achieving cyclodimerization of butadiene. In the presence of this catalyst, butadiene is quantitatively converted to 4-vinylcyclohexene at temperatures below 30 ° C. However, this catalyst system requires the use of an expensive reducing agent such as allyl magnesium bromide, and cannot be an industrially advantageous method for preparing a catalyst.

[0005] French Patent 1,535,936 describes a catalyst system in which dihalo (πallyldinitrosyliron) tin or germanium is prepared and used in the system for cyclodimerization of butadiene. However, this catalyst system also has the disadvantage of requiring the use of expensive organometallic tin or germanium compounds. US Patent 4,238,301
Discloses a method for reducing dinitrosyl iron halide by electrolytic reduction, but electrolytic reduction is not an industrially advantageous reduction method and has not yet been commercialized.

As a method using an inexpensive reducing agent, US Pat. No. 4,234,454 discloses a method using metallic zinc or metallic tin as a reducing agent. However, the amount of 4-vinylcyclohexene produced per catalyst is not sufficient, and it has not been industrialized. Further, as is common to all the above catalyst systems, the instability of dinitrosyl iron halide is also a problem, and storage is industrially difficult. As a method for solving this problem, WO9410110
No. describes the storage and reaction of dinitrosyl iron halides as N
A method characterized by performing under O gas pressure is proposed.
However, this patent method is extremely complicated as an industrial production method such as the necessity of an auxiliary facility using NO gas and the centrifugal recovery of metal zinc excessively used as a reducing agent.

As a method for producing a zero-valent dinitrosyl iron compound by a method other than the reduction of dinitrosyl iron halide, M ⁺ [Fe (CO) ₃
NO] ^- (where M is an alkali metal) and a metal halide are disclosed. However, alkali metal tricarbonylnitrosylferrate proposed in Japanese Patent Publication No. 57-19086 is a compound which is unstable and difficult to handle, and requires special attention such as handling at a relatively low temperature in an inert gas. As those skilled in the art know, industrial use is disadvantageous. According to this patent, the amount of 4-vinylcyclohexene produced per catalyst in the butadiene dimerization reaction is not satisfactory.

On the other hand, (C ₄ H ₉ ) ₄ N ⁺ [Fe (CO)
₃ NO] ^- tricarbonyl nitrosyl ferrate tetrabutylammonium represented by is a soluble in an organic solvent, the aqueous phase /
It is known that it can be easily synthesized in a two-phase system of an organic phase and is a stable substance (Journal of the Chemical Society of Japan, 1985, N.
o. 3, p271-281). However, its reactivity is said to be significantly lower than the corresponding alkali metal salts. (J. Organomet. Chem. 376 (1
989) C20-C22)

[0009]

As described above, although a zero-valent dinitrosyl iron-based catalyst has high activity, its precursor is unstable and its industrial use is severely restricted. Therefore, an object of the present invention is to provide a catalyst system for a cyclized dimerization reaction of a conjugated diolefin, which has satisfactory reactivity and selectivity as an industrial production method, is easy to handle, and is advantageous in the production process. It is to provide.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies for the above purpose, and as a result, have conducted a cyclization dimerization reaction with a catalyst prepared in a system from onium tricarbonylnitrosylferrate and a strong protonic acid. As a result, it has been found that even if the amount of the catalyst is significantly reduced, the desired product can be obtained in a short time with a high yield and a high selectivity. That is, the gist of the present invention is to provide an onium tricarbonylnitrosylferrate and a strong protonic acid represented by the following general formula (1) as a catalyst precursor when cyclizing and dimerizing a conjugated diolefin in the presence of a catalyst. The present invention relates to a method for cyclizing and dimerizing a conjugated diolefin, which is characterized in that it is used.

Embedded image A ⁺ [Fe (CO) ₃ NO] ⁻ (1) (where A ⁺ represents an onium ion)

Hereinafter, the present invention will be described in detail. The diolefin used in the present invention is not particularly limited, but preferred specific examples are 1,3-butadiene, isoprene (2-methyl-1,3-butadiene),
Examples include chain conjugated dienes such as chloroprene and piperylene, and cyclic conjugated dienes such as norbornadiene. These diolefins may be used for the reaction as it is, or may be used for the reaction together with a suitable solvent. The reaction can also be carried out by supplying a mixture containing these as a diolefin source to the reaction.

The onium tricarbonylnitrosylferrate represented by the general formula (1) used in the method of the present invention is not particularly limited.
⁺ , Ie, the onium ion of the onium tricarbonylnitrosylferrate, is preferably R ₁ R ₂ R ₃ R
_{^{4 N +, R 1 R 2}} R 3 R 4 P + (R 1, R 2, R 3, R
₄ represents any alkyl group, aralkyl group, aryl group and the like), specifically, tetraalkylammonium, tetraalkylphosphoniums, specifically, tetramethylammonium, tetraethylammonium, tetrabutylammonium, tetraphenylammonium, benzyltrimethyl Ammonium, phenyltrimethylammonium, benzyltriethylammonium, methyltriphenylammonium, and phosphonium analogs thereof, and R ₁ 1N ⁺ ＲR ₂ (R ₁ and R ₂ have the same meanings as described above) Examples include iminium-based oniums, specifically, bis (triphenylphosphine) iminium and the like, but are not limited thereto. The method for producing onium tricarbonylnitrosylferrate is not limited, and any method produced by any method can be used. In addition, a plurality of them may be present on the same molecule, and more specifically, those which are immobilized on a resin such as an anion exchange resin may be used.

The strong protic acid used in the method of the present invention is not particularly limited, but preferably has an acid dissociation index pka value (in water at 25 ° C.) of 0.5 or less,
More preferably, the protic acid is 0.3 or less. Such protic acids include, for example, perfluorocarboxylic acids such as trifluoroacetic acid, organic sulfonic acids such as trifluoromethanesulfonic acid, p-toluenesulfonic acid and its hydrate or benzenesulfonic acid and its hydrate, Hydrochloric acid, sulfuric acid, perchloric acid and the like can be mentioned, and particularly preferred are at least one selected from perfluorocarboxylic acids, organic sulfonic acids and hydrates thereof, and most preferred are trifluoroacetic acid and methanesulfonic acid. It is at least one selected from an acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid and its hydrate, and benzenesulfonic acid and its hydrate.

In the present invention, the molar ratio of the protonic acid to the onium tricarbonylnitrosylferrate used as the catalyst precursor is in the range of 0.1 to 2, preferably 0.3 to 1.5. Range. In addition, these catalyst precursors may be independently supplied to the reactor as a solid if solid or a liquid if liquid, or may be supplied to the reactor as a solution or suspension of an appropriate solvent. It can also be supplied.

In the present invention, the amount of the catalyst precursor to be used with respect to the starting diolefin is not particularly limited, and a wide range of ratio is used. There is no restriction on the concentration of the diolefin and the mixture containing the diolefin. However, from the viewpoint of economy, generally, the molar ratio of diolefin / onium tricarbonylnitrosylferrate is 500
Preferably, the concentration of onium tricarbonylnitrosylferrate is 0.01 mmol / l or more, more preferably 0.1 mmol / l or more. In the present invention, the two kinds of catalyst precursors are independently supplied to the reactor, and are heated and stirred at a predetermined temperature in the presence of diolefin to become catalytically active species in the system, whereby cyclization and dimerization of diolefin is performed. proceed. In other words, the reaction can be performed after all the raw materials, catalyst precursors, etc. are charged at once.

In the present invention, it is not necessary to use a solvent. However, in order to supply onium tricarbonylnitrosylferrate to a reactor without industrial difficulty, the onium tricarbonylnitrosylferrate is dissolved in a suitable solvent, and Supplying the solution or suspension to the reactor is advantageous in terms of the production process. Also, a diolefin as a raw material,
When the solubility of the catalyst precursor in the mixture containing the catalyst precursor and the diolefin is low, the use of a solvent for the purpose of dissolving the catalyst precursor in the reaction mixture is advantageous in terms of the reaction yield. Examples of usable solvents include aromatic compounds such as benzene, toluene, ethylbenzene, xylene, and mesitylene; tetrahydrofuran (THF);
Examples thereof include ethers such as diethyl ether, but are not particularly limited as long as the catalyst precursor and the raw materials can be dissolved. Also,
Optionally, the cyclized dimerization product itself can be used as a solvent. In this case, there is an advantage that the step of separating the solvent can be omitted.

The reaction can be carried out at a temperature in the range of 20 ° C. to 150 ° C .; The reaction is carried out under a pressure sufficient to maintain the diolefin as a liquid phase or, when a solvent is used, at a pressure sufficient to maintain the diolefin in the liquid phase. There is no particular limitation on the reaction pressure,
An inert gas may be used to maintain the diolefin in the liquid phase to increase the internal pressure of the reactor, or if the reaction is not required, the inert gas need not be pressurized. The reaction pressure varies depending on the reaction temperature, the composition of the mixture containing the diolefin compound, and the like. Generally, the internal pressure of the reactor at room temperature is selected from the range of the vapor pressure of diolefin to 20 MPa, preferably the vapor pressure of diolefin to 5 MPa. Is done. According to the method for cyclizing and dimerizing a conjugated diolefin of the present invention described above, a special process at a low temperature for the production of active species of the catalyst in the reaction system is not required. Shortening is also possible.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded. Example 1 In a 100 cc stainless steel autoclave, tetrabutylammonium tricarbonylnitrosylferrate {(C ₄ H ₉ ) ₄ N ⁺ [Fe (CO) ₃ N
O] ^- @ 4.12 mg (0.010 mmol) and 1.90 mg (0.010 mmol) of p-toluenesulfonic acid monohydrate were charged under a nitrogen atmosphere. After 30 g of liquid butadiene was pressurized there, the butadiene injection amount was adjusted to 0.50 mol (about 27.05 g) by operating a valve. At this time, the internal pressure was about 0.15 MPa, which is the vapor pressure of butadiene at room temperature. Then, add 1
The mixture was heated and stirred at 00 ° C. for 2 hours to be reacted. After the reaction, the autoclave was cooled, and 34.60 g of toluene was added as an internal standard. The product was identified by gas chromatography analysis of the reaction mixture, and the product and unreacted butadiene were quantified. The yield of 4-vinylcyclohexene (hereinafter referred to as 4-VCH), which is a cyclized dimerization product, is 96.9.
%, 4-VCH selectivity was 100%.

[Examples 2 and 3] Reactions were carried out in the same manner as in Example 1 using the solvents shown in Table 1. After the reaction, the solvent used was used as an internal standard substance, and the results of quantifying 4-VCH are shown in Table 1.

[0020]

Table 1 Example 1 Solvent 4-VCH yield 4-VCH selectivity ────── 2 Toluene 20 ml 96.1 100 3 THF 20 ml 93.3 100

Example 4 In a 100 cc stainless steel autoclave, 10.3 mg (0.025 mmol) of tetrabutylammonium tricarbonylnitrosylferrate, 2.85 mg (0.025 mmol) of trifluoroacetic acid, and 17.3 g of toluene ( About 20 ml) was charged under a stream of nitrogen. After 30 g of liquid butadiene was pressurized there, the butadiene injection amount was adjusted to 0.50 mol (about 27.05 g) by operating a valve. At this time, the internal pressure is about 0.15MPa, which is the vapor pressure of butadiene at room temperature.
a. The contents were heated and stirred at 100 ° C. for 2 hours to cause a reaction. After the reaction, the autoclave was cooled, toluene was used as a reaction solvent as an internal standard substance, and the product was identified by gas chromatography analysis of the reaction mixture, and the product and unreacted butadiene were quantified. The yield of 4-VCH, a cyclized dimerization product, was 97.5%,
The VCH selectivity was 100%.

Example 5 In a 100 cc stainless steel autoclave, 10.3 mg (0.025 mmol) of tetrabutylammonium tricarbonylnitrosyl ferrate, 2.4 mg (0.025 mmol) of methanesulfonic acid, and 17.3 g of toluene ( About 20 ml) was charged under a stream of nitrogen. After 30 g of liquid butadiene was pressurized there, the butadiene injection amount was adjusted to 0.50 mol (about 27.05 g) by operating a valve. At this time, the internal pressure is about 0.15MPa, which is the vapor pressure of butadiene at room temperature.
a. The contents were heated and stirred at 100 ° C. for 2 hours to cause a reaction. After the reaction, the autoclave was cooled, toluene was used as a reaction solvent as an internal standard, and the product was identified by gas chromatography analysis of the reaction mixture, and the product and unreacted butadiene were quantified. The yield of 4-VCH, a cyclized dimerization product, was 93.6%,
The VCH selectivity was 100%.

[Comparative Example 1-5] The same operation as in Example 4 was performed using the acids and acid amounts shown in Table 2 instead of trifluoroacetic acid. Table 2 shows the results.

[0024]

Table 2 Comparative Example Acid Amount of acid (mmol) 4-VCH yield (%) １ 1 acetic acid 0.025 0.8 2 acetic acid 2.50 2.8 3 acetic acid 250 0.6 4 chloroacetic acid 0.025 1.65 trichloroacetic acid 0.025 0.5

[0025]

According to the method of the present invention, it is possible to prepare a catalyst precursor using an easy-to-handle and stable onium salt of tricarbonylnitrosylferrate, and it is possible to prepare an active species of the catalyst in a reaction system. The catalyst can be used as a highly active catalyst without requiring a special process at a low temperature. Since the catalyst precursor of the present invention can be supplied to the reactor as an organic solvent solution, it is preferable from the viewpoint of process design.

Claims (8)

[Claims] 1. A cyclized dimerization of a conjugated diolefin in the presence of a catalyst, wherein an onium tricarbonylnitrosylferrate and a strong protonic acid represented by the following general formula (1) are used as a catalyst precursor. A method for cyclizing and dimerizing a conjugated diolefin, the method comprising: Embedded image A ⁺ [Fe (CO) ₃ NO] ^- (1) (where A ⁺ represents an onium ion) 2. The cyclization of a conjugated diolefin according to claim 1, wherein the onium ion of the onium tricarbonylnitrosylferrate is at least one selected from the group consisting of ammonium ion, iminium ion and phosphonium ion. Dimerization method. 3. The cyclized diolefin of a conjugated diolefin according to claim 1, wherein the strong protonic acid is an acid having an acid dissociation index (pka value) of 0.5 or less in water at 25 ° C. Quantification method. 4. The conjugated diene according to claim 3, wherein the strong protonic acid is at least one selected from perfluorocarboxylic acid, organic sulfonic acid and hydrate thereof, hydrochloric acid, sulfuric acid and perchloric acid. A method for cyclizing and dimerizing olefins. 5. The strong protonic acid is trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, p-
5. The method for cyclizing and dimerizing a conjugated diolefin according to claim 4, wherein the method is at least one selected from toluenesulfonic acid and its hydrate, and benzenesulfonic acid and its hydrate. 6. The conjugated diolefin ring according to claim 1, wherein the conjugated diolefin is at least one selected from 1,3-butadiene, isoprene and norbornadiene. Dimerization method. 7. The cyclization dimerization reaction is carried out in the presence of at least one solvent selected from benzene, toluene, ethylbenzene, xylene, mesitylene, tetrahydrofuran and diethyl ether. 7. The method for cyclizing and dimerizing a conjugated diolefin according to any one of 6. 8. The conjugate according to claim 1, wherein the amount of the protic acid used is 0.1 to 2 in a molar ratio to the onium tricarbonylnitrosylferrate. A method for cyclizing and dimerizing a diolefin.