JP2003334450A - Telomerization catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a palladium complex catalyst that is heat stable, does not require an excessive amount of a ligand and exhibits an excellent catalytic activity in the telomerization of conjugated diene compounds. <P>SOLUTION: The palladium complex catalyses the telomerization of conjugated diene compounds and has a nitrogen-containing heterocyclic carbene coordinated with palladium. The telomerization process using the palladium complex is presented. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel telomerization reaction catalyst and a telomerization reaction method using the catalyst.

[0002]

2. Description of the Related Art The telomerization reaction of a conjugated diene compound is a reaction in which a conjugated diene takes in a nucleophilic reactive agent to form an oligomer. For example, two molecules of butadiene react with one molecule of an active hydrogen compound such as acetic acid to produce 1-
Examples include reactions that produce products such as acetoxy-2,7-octadiene [Industrial Applications of Homogeneous Catalysis (Ind
custom Applications of H
Omogeneous Catalysis), 141
Pp. 155 (1988)]. A wide variety of telomerization reaction products are known, including plasticizers, pesticides,
It is useful as a raw material for medicines, fragrances, polymer compounds and the like.

It is known that a palladium complex, particularly a palladium complex coordinated with phosphine, exhibits excellent activity as a catalyst [Palladium Reagents and Catalysts (Palladium Reagent).
s and Catalysts), 422-446 (1995)].

It is known that a palladium complex coordinated with a nitrogen-containing heterocyclic carbene has a catalytic action such as a Heck reaction or a Suzuki coupling reaction [Advances.
In Organometallic Chemistry (Advan
ces in Organometallic Che
), 48, 1-69 (2001)]. These reactions are reactions of an aromatic halide with a heteroatom compound such as an olefin compound, an organometallic compound or an amine, and are different from the telomerization reaction of a conjugated diene compound.

[0005]

When industrially carrying out the telomerization reaction of a conjugated diene compound, a conventionally known phosphine-coordinated palladium complex (hereinafter referred to as a phosphine-coordinated palladium complex) is used as a catalyst. If so, there are the following problems. (1) The phosphine-coordinated palladium complex has poor thermal stability, and palladium metal is deposited in the step of evaporating and separating the telomerization reaction product and the catalyst component. Therefore, it is difficult to reuse the catalyst, and the deposited metal causes problems such as pipe clogging. (2) In order to maintain the stability of the phosphine-coordinated palladium complex, it is necessary to allow an excess amount of phosphine ligand to exist in the reaction solution, but the presence of an excessive amount of phosphine ligand essentially causes catalytic activity. Will be lowered.

An object of the present invention is to have high thermal stability and
An object of the present invention is to provide a palladium complex that does not require an excessive amount of ligand and exhibits excellent catalytic activity for the telomerization reaction of a conjugated diene compound. Another object of the present invention is to provide a telomerization reaction method using the above palladium complex as a catalyst.

[0007]

The present inventors have found that a palladium complex having a nitrogen-containing heterocyclic carbene as a ligand has a catalytic action for the telomerization reaction of a conjugated diene compound,
The present inventors have found that the palladium complex has excellent thermal stability, and that the palladium complex exhibits good stability even when an excess amount of ligand is not present, and has completed the present invention.

The present invention has a function of catalyzing the telomerization reaction of a conjugated diene compound and is characterized in that a nitrogen-containing heterocyclic carbene is coordinated with palladium. It is referred to as a heterocyclic carbene coordination palladium complex]. Further, the present invention is a telomerization reaction method characterized by using a nitrogen-containing heterocyclic carbene coordinated palladium complex as a catalyst when carrying out the telomerization reaction of a conjugated diene compound.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The nitrogen-containing heterocyclic carbene coordinated palladium complex of the present invention can be synthesized from a nitrogen-containing heterocyclic carbene and a palladium compound by a known method [advances in organometallic chemistry]. (Advances in Organomet
allic Chemistry), 48, 1-69
Page (2001)]. The nitrogen-containing heterocyclic carbene coordination palladium complex can be synthesized by a method of mixing a nitrogen-containing heterocyclic carbene and a palladium compound, or a method of generating a nitrogen-containing heterocyclic carbene in the presence of a palladium compound. it can.

The nitrogen-containing heterocyclic carbene is a general term for carbene consisting of a heterocycle containing at least one nitrogen atom, and is also called N-heterocyclic carbene.
The nitrogen-containing heterocyclic carbene in the present invention is not limited in its ring structure and the like as long as the palladium complex to which it has a ligand catalyze the telomerization reaction of the conjugated diene compound.

As the nitrogen-containing heterocyclic carbene, for example,
5 containing at least one nitrogen atom represented by the following formula:
To those having a 7-membered ring structure. A hetero atom such as an oxygen atom or a sulfur atom may be present in the ring structure, or a double bond may be present.

[0012]

[Chemical 1]

As long as the nitrogen-containing heterocyclic carbene-coordinated palladium complex provided by the nitrogen-containing heterocyclic carbene has a catalytic action for the telomerization reaction, a hydrogen atom is added to a carbon atom constituting a ring other than the carbene-like carbon atom. It may have an atom other than an atom or a substituent. Examples of atoms other than hydrogen atoms include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom. Examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and an aralkyl group. Further, the nitrogen-containing heterocyclic carbene has a hydrogen atom or a substituent on the nitrogen atom constituting the ring as long as the nitrogen-containing heterocyclic carbene coordination palladium complex provided by it has a catalytic action for the telomerization reaction. May be. Examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and an aralkyl group.

Examples of the above-mentioned alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, octyl group, dodecyl group, octadecyl group, cyclopentyl group. , An alkyl group having 1 to 20 carbon atoms such as a cyclohexyl group, a cyclooctyl group and a cyclododecyl group is preferable,
The alkenyl group is preferably an alkenyl group having 2 to 20 carbon atoms such as a vinyl group, an allyl group, a crotyl group, a prenyl group, a 7-octenyl group and a cyclohexenyl group, and examples of the alkynyl group include an ethynyl group and a propynyl group. An alkynyl group having 2 to 20 carbon atoms such as a propargyl group is preferable. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diisopropylphenyl group, a naphthyl group,
An aryl group having 6 to 20 carbon atoms such as an indenyl group, a biphenyl group, a binaphthyl group and a phenanthryl group is preferable, and an aralkyl group having 7 to 20 carbon atoms such as a benzyl group and a naphthylmethyl group is preferable.

As long as the nitrogen-containing heterocyclic carbene-coordinated palladium complex provided by the nitrogen-containing heterocyclic carbene has a catalytic action for the telomerization reaction, it can be present on the carbon atoms constituting the ring other than the carbene carbon atom and on the nitrogen atom. It may have a functional group. Further, the substituents on the carbon atoms and the nitrogen atoms constituting the ring other than the carbene carbon atoms may have a halogen atom or a functional group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the functional group include a hydroxyl group; a methoxy group, an ethoxy group, a propoxy group,
Butoxy group, isobutoxy group, s-butoxy group, t-butoxy group, cyclopentyloxy group, cyclohexyloxy group, 2-methoxyethoxy group, 2-ethoxyethoxy group, furyl group, tetrahydrofuryl group, tetrahydropyranyl group, phenoxy group , Ether groups such as benzyloxy group, biphenyloxy group and naphthyloxy group; ketone groups such as acetyl group and benzoyl group; aldehyde groups such as formyl group; carboxylic acid group and its metal salt or amine salt; acetoxy group, benzoyloxy group A carboxylic acid ester group such as a group; a methoxycarbonyloxy group,
Carbonic acid ester group such as phenoxycarbonyloxy group;
Amino group, N-methylamino group, N, N-dimethylamino group, N-ethylamino group, N, N-dibutylamino group, Nt-butylamino group, N-cyclohexylamino group, N, N-dioctyl Amino group, piperidinyl group,
An amino group such as a pyrrolidinyl group, a pyridyl group, and an anilyl group;

Ammonium group, methylammonium group,
Dimethyl ammonium group, trimethyl ammonium group,
Ammonium groups such as tetramethylammonium group, triethylammonium group, tetrabutylammonium group, octylammonium group; amide groups such as formamide group, acetamide group, N-methylacetamide group, N-phenylacetamide group; cyano group; N-methylimino Group, imino group such as N-phenylimino group; imide group such as succinimide group, phthalimido group; carbamine such as N-methylaminocarbonyloxy group, N, N-dimethylaminocarbonyloxy group, N-phenylaminocarbonyloxy group Acid ester group; sulfide group such as methylsulfanyl group and phenylsulfanyl group; sulfoxide group such as methylsulfinyl group and phenylsulfinyl group; sulfone such as methylsulfonyl group and phenylsulfonyl group Sulfonic acid groups and metal salts or amine salts thereof; silyl groups such as trimethylsilyl group and triphenylsilyl group; phosphino groups such as dimethylphosphino group, dibutylphosphino group and diphenylphosphino group; oxodimethylphosphino group, oxo Examples thereof include phosphine oxide groups such as dibutylphosphino group and oxodiphenylphosphino group; phosphonic acid groups and metal salts or amine salts thereof.

The nitrogen-containing heterocyclic carbene may be a monodentate ligand or a polydentate ligand. In the case of a multidentate ligand, the bridging group connecting the nitrogen-containing heterocyclic carbene is any of the above-mentioned substituents, and the bridging group may have the above functional group.

As a typical example of the nitrogen-containing heterocyclic carbene,
1,3-dimethylimidazoline-2-ylidene, 1,3
-Dimethylimidazolidine-2-ylidene, 1,3-diethylimidazoline-2-ylidene, 1,3-diethylimidazolidine-2-ylidene, 1,3-diisopropylimidazoline-2-ylidene, 1,3-diisopropylimidazolidine -2-ylidene, 1,3-dibutylimidazoline-2-ylidene, 1,3-dibutylimidazolidine-2-ylidene, 1,3-di-t-butylimidazoline-2-ylidene, 1,3-di-t -Butylimidazolidin-2-ylidene, 1,3-diphenylimidazoline-2-ylidene, 1,3-diphenylimidazolidine-2-ylidene, 1,3-di-o-tolylulyimidazoline-2-ylidene, 1,3 -Di-o-tolylimidazolidin-2-ylidene, 1,3-di-m-tolylimidazolin-2-ylidene , 1,3-di-m-tolylimidazolidin-2-ylidene, 1,3-di-p-tolylimidazoline-2-ylidene, 1,3-di-p-tolylimidazolidin-2-ylidene, 1, 3-di-o-methoxyphenylimidazoline-2-ylidene, 1,3-di-o-
Methoxyphenylimidazolidin-2-ylidene, 1,
3-di-p-methoxyphenylimidazoline-2-ylidene, 1,3-di-p-methoxyphenylimidazolidine-2-ylidene, 1,3-dimesitylimidazoline-
2-ylidene, 1,3-dimesityl imidazolidine-2
-Yiliden and the like.

The palladium compound may be 0-valent or 2-valent.
It has a valent palladium atom and may have a ligand other than the nitrogen-containing heterocyclic carbene. Examples of the zero-valent palladium compound include tris (dibenzylideneacetone) dipalladium, tetrakis (triphenylphosphine) palladium, and bis (tri-o-tolylphosphine).
Examples include palladium and bis (tricyclohexylphosphine) palladium. Examples of the divalent palladium compound include palladium chloride, palladium bromide, palladium iodide, dilithium tetrachloroparadate, disodium tetrachloroparadate, ammonium tetrachloroparadate, bis (acetonitrile) palladium dichloride, and dichloride. Bis (benzonitrile) palladium, bis (triphenylphosphine) palladium dichloride, bis (cyclooctadiene) palladium dichloride, allylpalladium chloride dimer, palladium acetate, bis (triphenylphosphine) palladium diacetate, palladium acetylacetate And palladium trifluoroacetate.

In the nitrogen-containing heterocyclic carbene coordination palladium complex of the present invention, the palladium atom may have either zero valence or two valence. If the valence is divalent,
Before the telomerization reaction or in the telomerization reaction system, it is necessary to reduce to 0-valent palladium having a catalytic activity for the telomerization reaction. As the reducing agent, known reducing agents can be used, and examples thereof include hydride compounds such as sodium borohydride and lithium tri-s-butylhydroborate; phosphine compounds such as triphenylphosphine and tributylphosphine; butadiene and isoprene. And other conjugated diene compounds. When the counter ion of divalent palladium is a halogen atom, it is preferable to carry out the reduction in the presence of a basic compound such as sodium methoxide, potassium t-butoxide, sodium carbonate, potassium carbonate and cesium carbonate.

The nitrogen-containing heterocyclic carbene coordination palladium complex of the present invention may have a ligand other than the nitrogen-containing heterocyclic carbene. As such a ligand, for example,
Olefinic ligands such as cyclooctadiene and norbornadiene; Nitrogen-containing ligands such as acetonitrile, benzonitrile, pyridine and 2,6-lutidine; triphenylphosphine, tri-o-tolylphosphine, tributylphosphine, tricyclohexylphosphine , Trimethylphosphite, triphenylphosphite, and other phosphorus-containing ligands.

Next, the telomerization reaction of the conjugated diene compound will be described. The telomerization reaction is a reaction in which a conjugated diene compound takes in a nucleophilic reactive agent and oligomerizes. Examples of the conjugated diene compound include butadiene, isoprene, piperylene, 1,3,7-octatriene,
Examples thereof include 1,3-cyclohexadiene and 1,3-cyclooctadiene. As a nucleophilic reactant,
For example, a compound having a carboxyl group such as formic acid, acetic acid, and propionic acid; a compound having a hydroxyl group such as water, methanol, ethanol, cyclohexanol, ethylene glycol, 1,4-butanediol, glycerin, phenol, and cresols; ammonia, Compounds having amino groups such as hydrazine, methylamines, ethylamines, butylamines, pyrrolidine, piperidine, morpholine; compounds having amide groups such as acetamide, benzenesulfonamide; acetylacetone, methyl acetoacetate, dimethyl malonate, nitromethane, etc. A compound having active hydrogen bonded to the carbon atom of hydride; a hydride compound such as sodium borohydride, lithium tri-s-butylhydroborate, lithium tri-t-butoxyaluminohydride , It may be mentioned enol equivalent compound such as pyrrolidine enamine, trimethylsilyl enol ether of cyclohexanone cyclohexanone.

In the telomerization reaction method of the present invention,
A nitrogen-containing heterocyclic carbene coordination palladium complex prepared and isolated in advance may be used for the telomerization reaction, and a nitrogen-containing heterocyclic carbene coordination prepared from a nitrogen-containing heterocyclic carbene and a palladium compound. The reaction mixture containing the palladium complex may be used as it is for the telomerization reaction. In the telomerization reaction system, a nitrogen-containing heterocyclic carbene coordination palladium complex may be generated. When a nitrogen-containing heterocyclic carbene coordinated palladium complex is generated in the telomerization reaction system, the molar ratio of the palladium compound and the nitrogen-containing heterocyclic carbene is preferably 4: 1 to 1: 4, and 1: 1. More preferably, it is in the vicinity.

The amount of the nitrogen-containing heterocyclic carbene coordination palladium complex used is 0.0001 with respect to the conjugated diene compound.
It is preferably in the range of 10 to 10 mol%, and 0.001 to
The range of 0.1 mol% is more preferable. Also, the molar ratio of the conjugated diene compound and the nucleophilic reactant is 50: 1 to
The range is preferably 1:50, preferably 10: 1 to 1: 1.
The range of 0 is more preferable.

The telomerization reaction method of the present invention is carried out in the presence or absence of a solvent. In the absence of a solvent, the conjugated diene compound and / or the nucleophilic reagent acts as a solvent. Examples of the solvent include hydrocarbons such as butane, isobutane, pentane, hexane, cyclohexane, benzene, toluene, xylene; isopropyl ether, butyl ether, t-
Ethers such as butyl methyl ether, tetrahydrofuran, dioxane, anisole, ethylene glycol dimethyl ether, diethylene glycol diethyl ether; methyl acetate, ethyl acetate, isopropyl acetate,
Esters such as dimethyl carbonate, diethyl carbonate, and ethylene carbonate; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; dichloromethane, 1,2
-Halogenated hydrocarbons such as dichloroethane and chloroform; nitrogen-containing compounds such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and acetonitrile; sulfur-containing compounds such as dimethyl sulfoxide and sulfolane; Phosphorus-containing compounds such as trimethyl phosphate and tributyl phosphate; 1-butyl-3
-Methyl-1H-imidazolium tetrafluoroborate, 1-butyl-3-methyl-1H-imidazolium hexafluorophosphate, 1-ethyl-3-methyl-1H-imidazolium trifluoromethanesulfonate, 1-butylpyridinium nitrate, etc. Ionic liquids of. These solvents may be used alone or
You may mix and use 1 or more types. The amount of solvent used is not particularly limited, but if the amount used is large, it is economically disadvantageous.

In the telomerization reaction method of the present invention, known reaction accelerators can be used. For example, in the telomerization reaction of butadiene and methanol, the reaction rate can be increased by the presence of a basic compound such as sodium methoxide, sodium carbonate, potassium carbonate, cesium carbonate. In the telomerization reaction between butadiene and water, a reaction accelerator such as carbon dioxide, triethylamine carbonate or bicarbonate is used.
In the telomerization reaction of butadiene with acetic acid or formic acid, a reaction accelerator such as sodium salt of acetic acid or formic acid, potassium salt of acetic acid or formic acid, triethylamine, trioctylamine, etc. is used.

The reaction temperature is preferably in the range of 0 to 150 ° C, more preferably in the range of 20 to 100 ° C. When the reaction temperature is low, the reaction time becomes long, and when it is high, the by-products increase. The reaction pressure is not particularly limited, and the reaction is usually performed under a pressure generated according to the reaction temperature.

The telomerization reaction method of the present invention can be carried out batchwise or continuously. In the case of the continuous system, either a piston flow type reactor or a complete mixing tank type reactor can be used, or a combination thereof can be used.

After the reaction is completed, the telomerization reaction product can be separated from the obtained reaction mixture by a usual method. For example, the solvent and unreacted raw materials are separated by distillation, and if necessary, the residue is distilled, recrystallized, reprecipitated or purified by column chromatography to obtain the desired product. These separation methods may be used alone or in combination. In addition to the above-mentioned purification operation, a catalyst separation operation is carried out if necessary. As a method for separating the catalyst, an evaporation method, a thin film evaporation method, a layer separation method, an extraction method, an adsorption method, or the like is adopted. These methods may be used alone or in combination.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples.
In Examples and Comparative Examples, reaction yield, regioselectivity,
Telomerization selectivity, TOF is defined as follows. Reaction yield: yield of 1-methoxy-2,7-octadiene Regioselectivity: [(yield of 1-methoxy-2,7-octadiene) / {(yield of 1-methoxy-2,7-octadiene ) + (Yield of 3-methoxy-1,7-octadiene)}] × 100 Telomerization selectivity: [{(yield of 1-methoxy-2,7-octadiene) + (3-methoxy-1,7) -Yield of octadiene)} / {(yield of 1-methoxy-2,7-octadiene) + (yield of 3-methoxy-1,7-octadiene) + (yield of 1,3,7-octatriene rate)}]
× 100 TOF: {(yield of 1-methoxy-2,7-octadiene) + (yield of 3-methoxy-1,7-octadiene)
+ (Yield of 1,3,7-octatriene)} / 100x
92,000 (molar ratio of butadiene and palladium before reaction) / 4 (hours)

Example 1 1.4 mg (3.8 μmol) of 1,3-dimesityl imidazolium chloride at 20 ° C. under an argon atmosphere.
And 2.1 mg (18.7 μmol) of potassium t-butoxide were dissolved in 3 mL of tetrahydrofuran.
After stirring the resulting solution for 15 minutes, 2.2 mg (3.8 μmol) of bis (dibenzylideneacetone) palladium was added to the solution and further stirred for 1 hour to prepare a catalyst solution. In a stainless steel autoclave, the above catalyst solution, 30 mL of methanol (0.74 mol) and 1,
After adding 2,4-trimethylbenzene (internal standard solution), 30 mL (0.35 mol) of butadiene was fed and stirred at 80 ° C. for 4 hours. The obtained reaction liquid was subjected to gas chromatography (GC-14, manufactured by Shimadzu Corporation).
B type), and the results are shown in Table 1.

A thermal stability test of the catalyst was carried out using the above reaction solution. After distilling off methanol under reduced pressure, the solution was heated under an argon atmosphere. When the solution temperature reached 150 ° C., precipitation of palladium was observed.

Example 2 In an autoclave made of stainless steel, under an argon atmosphere, 2
At 0 ° C., [(1,3-dimesitylimidazoline-2-ylidene) chloropalladium (μ-chloro)] ₂ 2.4 m
g (2.5 μmol), triphenylphosphine 1.3 mg (5.0 μmol), cesium carbonate 16
1.6 mg (0.5 mmol), 1,2,4-trimethylbenzene (internal standard solution) and methanol 32 mL
(0.79 mol) was added and stirred for 30 minutes to prepare a catalyst solution. 32 mL of butadiene (0.3
7 mol) was fed and the mixture was stirred at 80 ° C. for 4 hours. Gas chromatography of the resulting reaction liquid (as described above)
The results are shown in Table 1.

Comparative Example 1 2.2 mg (3.8 μmol) of bis (dibenzylideneacetone) palladium at 20 ° C. under an argon atmosphere.
22.5 mg (3.8 μmol) of a 2% by weight toluene solution of triethylphosphine was added to a solution of 3 mL of tetrahydrofuran in, and the mixture was stirred for 1 hour to prepare a catalyst solution. In a stainless steel autoclave, the above catalyst solution,
30 mL (0.74 mol) of methanol and 1,2,4
-After adding trimethylbenzene (internal standard solution), 30 mL (0.35 mol) of butadiene was fed, and the temperature was 80 ° C.
It was stirred for 4 hours. The resulting reaction liquid was analyzed by gas chromatography (as described above), and the results are shown in Table 1.
It was shown to.

A thermal stability test of the catalyst was carried out using the above reaction solution. After distilling off methanol under reduced pressure, the solution was heated under a nitrogen atmosphere. When the solution temperature reached 123 ° C, precipitation of palladium was observed.

Comparative Example 2 The same reaction and operation were carried out as in Comparative Example 1, except that triphenylphosphine was used instead of triethylphosphine. The analysis results of the obtained reaction liquid by gas chromatography (as described above) are shown in Table 1.

[0037]

[Table 1]

[0038]

EFFECTS OF THE INVENTION According to the present invention, there is provided a palladium complex which has high thermal stability, does not require an excessive amount of ligand, and exhibits excellent catalytic activity for the telomerization reaction of a conjugated diene compound. . Further, according to the present invention, by using the above palladium complex as a telomerization reaction catalyst,
The corresponding telomerization reaction product can be produced industrially advantageously from the conjugated diene compound.

Continued front page    F-term (reference) 4G069 AA06 BA27A BA27B BC72A                       BC72B BE13B CB48 DA02                 4H006 AA02 AC21 AC43 AC92 BA25                       BA47 GN21 GP01                 4H039 CA20 CA61 CF10

Claims (2)

[Claims] 1. A palladium complex having a function of catalyzing a telomerization reaction of a conjugated diene compound, wherein a nitrogen-containing heterocyclic carbene is coordinated with palladium. 2. A telomerization reaction method, which comprises using the palladium complex according to claim 1 as a catalyst when carrying out the telomerization reaction of a conjugated diene compound.