JPH0421644A - Production of alkylarylcarbinol - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high selectivity by reacting an aromatic ketone in the presence of ruthenium, an organic phosphine and a specific phosphorus compound in a homogeneous liquid phase when the aromatic ketone is hydrogenated to produce the title compound useful as a raw material for medicine and agricultural chemical. CONSTITUTION:An aromatic ketone expressed by formula I (R1 is H, 1-5C linear or branched chain alkyl, OH or lower alkoxy; R2 is lower alkyl) is made to react in a homogeneous liquid phase at normally 50-250 deg.C, preferably 100-200 deg.C in hydrogen partial pressure of normally 0.1-200kg/cm<2>, preferably 1-150kg/cm<2> in the presence of (A) ruthenium, (B) organic phosphine and (C) a phosphours compound expressed by formula II (X and Y are H, OH, halogen, alkoxy, aryloxy, alkyl or aryl) to provide the objective compound expressed by formula III in extremely mild conditions and good selectivity.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing alkylaryl carbinol by hydrogenating aromatic ketones.

The alkylaryl carbinol produced by the method of the present invention can be used as a raw material for medicines and agricultural chemicals.

<Prior Art> Conventionally, methods using various metal catalysts or metal oxide catalysts have been investigated for the catalytic hydrogenation reaction of aromatic ketones.

In particular, much research has been done on solid catalysts;
Not only carbinol is produced by hydrogenation of the carbonyl group in the aromatic ketone, but also the aromatic ring participates in the reaction.Furthermore, since the hydrogenated product carbinol has a benzyl alcohol type hydroxyl group, the hydroxyl group continues to be produced. It is susceptible to hydrogenolysis and the reaction is complex.

For example, copper-chromium oxide catalysts require high temperature and high pressure reaction conditions and are therefore prone to hydrogenolysis, while palladium catalysts are not only highly active for hydrogenolysis but also for nuclear hydrogenation. There were problems such as high price.

On the other hand, a method using a homogeneous complex catalyst is also known. In particular, reactions using Ru complex catalysts are examples.

A, ORO, J, Mo 1. Cat, Sat 51 (1
98B) or W, Strohmeier.

J, Organometallic Chem.

171, 121 (1979), etc.

However, although the reaction selectivity was high, there was a problem in that the reaction activity was low.

Means for Solving the Problems The present inventors have conducted intensive research on an industrially advantageous method for obtaining alkylaryl carbinol in good yield by catalytic hydrogenation of aromatic ketones, and have arrived at the present invention. It is something.

That is, the present invention provides a formula (I): (wherein, Ro represents a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, a hydroxyl group, or a lower alkoxy group, and R2 represents a lower alkyl group. The aromatic ketone represented by (A) ruthenium, (B)
Organic phosphine and (C) general formula (■): HO-P −
Y...(II)1
] (wherein, X and Y are a hydrogen atom, a hydroxyl group,
It represents a halogen atom, an alkoxy group, an aryloxy group, an alkyl group, or an aryl group, and may be different from each other. ) By carrying out a hydrogenation reaction in a homogeneous liquid phase in the presence of a phosphorus compound represented by the general formula (■): (where R,
and R2 have the same meanings as in general formula (I).

According to the method of the present invention, the desired product can be obtained with good selectivity under extremely mild conditions.

The present invention will be explained in more detail below.

The aromatic ketone used as a raw material of the present invention is represented by the above general formula (I). Among them, when R2 is a lower alkoxy group, the alkoxy group having 1 to 2 carbon atoms is
Further, R2 is preferably an alkyl group having 1 to 2 carbon atoms.

Specifically, acetophenone, 4-methylacetophenone, 4-ethylacetophenone, 4-isobutylacetophenone, 4-methoxyacetophenone, 4-hydroxyacetophenone, propiophenone, 4-methylpropiophenone, 4-ethylpropiophenone, Examples include 4-hydroxyplubiophenone.

As the ruthenium catalyst used in the present invention, both metal ruthenium and ruthenium compounds can be used. As the ruthenium compound in this case, ruthenium oxides, hydroxides, inorganic acid salts, organic acid salts, complex compounds, etc. are used, and specifically, for example, ruthenium dioxide, ruthenium tetroxide, ruthenium trihydroxide, Ruthenium chloride, ruthenium bromide, ruthenium iodide, ruthenium nitrate, ruthenium acetate, tris(acetylacetone)ruthenium, sodium hexachlororuthenate, dipotassium tetracarbonylruthenate, pentacarbonylruthenium, cyclopentadienyldicarbonylruthenium, dibromotricarbonylruthenium, chlorotris (triphenylphosphine) hydridoruthenium,
Examples include bis(tri-n-butylphosphine)tricarbonylruthenium, dodecacarbonyltriruthenium, tetrahydridodecacarbonyltetraruthenium, dicesium octadecacarbonylhexarthenate, and tetraphenylphosphonium undecacarbonylhydridotriruthenate.

The amount of these metal ruthenium and ruthenium compounds to be used is such that the concentration in the reaction solution is 0.01 to 100 moles of ruthenium in 1 liter of the reaction solution, preferably 0.0
The amount is 0.01 to 10 moles.

In the present invention, the use of an organic phosphine together with ruthenium is an essential condition, and it is believed that this substance controls the electronic state of ruthenium, which is the main catalyst, and contributes to stabilizing the active state of ruthenium. It will be done. Specific examples of such organic phosphine include trialkylphosphines such as trioctylphosphine, tri-n-butylphosphine, triisopropylphosphine, and dimethyl-n-octylphosphine, tricycloalkylphosphines such as tricyclohexylphosphine, and triphenylphosphine. triarylphosphines such as, alkylarylphosphine such as dimethylphenylphosphine,
1.2-Bis(diphenylphosphino)ethane, bis(
Examples include polyfunctional phosphines such as diphenylphosphino)butane.

The amount of these organic phosphines used is in the range of 0.1 to 1000 mol, preferably 1 to 100 mol, per 1 mol of ruthenium as the main catalyst. Further, these organic phosphines can be supplied to the reaction system either alone or in the form of a complex with ruthenium.

In addition, by using a phosphorus compound represented by the general formula (n) above as an additional promoter for ruthenium constituting the main catalyst, the hydrogenation reaction can proceed under mild conditions by taking advantage of the advantages of ruthenium. In particular, the hydrogenation catalyst activity can be improved.

Specific examples of such phosphorous compounds include phosphoric acid, phosphorous acid, hypophosphorous acid, fluorophosphoric acid, dimethyl phosphate, diphenyl phosphate, phenyl phosphite, methyl phosphite, and dimethylphosphinic acid. , diphenylphosphinic acid, methylphosphonic acid, phenylphosphonic acid and the like.

Similar effects can also be expected if phosphorus pentoxide or polyphosphoric acid, which is thought to generate phosphoric acid with a small amount of water present in the reaction system, is used instead of phosphoric acid.

The above phosphorus compounds may be used in the form of alkali metal salts or ammonium salts.

The amount of these phosphorus compounds used is 0.01 to 1000 mol, preferably 0.1 to 10 mol, per 1 mol of ruthenium atom.
It is in the range of 0 mol.

The method of the present invention can be carried out in the absence of a solvent, that is, the reaction raw material or the reaction product itself can be used as a solvent, but other solvents can also be used.

Examples of such solvents include ethers such as diethyl ether, anisole, ethylene glycol, dimethyl ether, dioxane, and tetraethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, and acetophenone, methanol, ethanol, n
-Alcohols such as butanol, benzyl alcohol, phenol, ethylene glycol, diethylene glycol, carboxylic acids such as formic acid, acetic acid, propionates, toluic acid, esters such as methyl acetate, n-butyl acetate, hensyl benzoate, benzene, toluene , aromatic hydrocarbons such as xylene, ethylhenzene, and tetralin; aliphatic hydrocarbons such as n-hexane, n-octane, and cyclohexane; halogenated hydrocarbons such as dichloromethane, trichloroethane, and chlorobenzene; nitro compounds such as nitromethane and nitrobenzene; - Carboxylic acid amides such as dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, N.

Other amides such as N,N'N'-tetraethylsulfamide, N,N'-dimethylimidazolitone, N,
Ureas such as N,N,N-tetramethylurea, sulfones such as dimethylsulfone and tetramethylenesulfone, sulfoxides such as dimethylsulfoxide and diphenylsulfoxide, polyethers such as tetraglyme, 18 to crown-6, acetonitrile , nitriles such as benzonitrile, and carbonic esters such as dimethyl carbonate and ethylene carbonate.

In order to carry out the hydrogenation reaction according to the method of the present invention, a reaction vessel is charged with a reaction raw material, a catalyst component and, if desired, a solvent.
Hydrogen may be introduced into this. Hydrogen may be diluted with a gas inert to the reaction, such as nitrogen or carbon dioxide.

The reaction temperature is usually 50 to 250°C, preferably 100°C.
~200°C. The hydrogen partial pressure in the reaction system is usually 0.
1 to 200 kg/d, preferably 1 to 150 kg/aj
It is. Of course, it is not impossible to carry out the process under lower or higher pressures, but it is not industrially advantageous.

The reaction can also be carried out either batchwise or continuously. In the case of batch method, the required reaction time is usually 1
~20 hours.

The target product, alkylaryl carbinol, can be recovered from the reaction product liquid by conventional separation and purification means such as distillation and extraction.

The resulting alkylaryl carbinol is represented by the general formula (I[[).

Further, the above-mentioned distillation residue can be recycled to the reaction system as a catalyst component.

<Example> Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 Ruthenium acetylacetonate 0.0625 mmj2. 0.625 ttrmol of trioctylphosphine and 0.156 mmof of phosphoric acid were charged, 200 mmof of acetophenone as an aromatic ketone and 80 mf of tetraethylene glycol dimethyl ether as a reaction solvent were added, the autoclave was closed, the autoclave was replaced with nitrogen, and the temperature was raised to 200°C. . When the temperature reaches 200°C, hydrogen is added at 30)cg/
When the dG pressure was increased and the reaction was carried out at a constant pressure for 2 hours, the conversion of acetophenone was 95.9% and the selectivity of α-hydroxyethylenebenzene was 98.7%. The by-product rate of styrene was less than 1%, and only trace amounts of ethylbenzene were observed.

Comparative Example 1 and Examples 2-9 0.05 mmoj of ruthenium acetylacetonate in a 70-l spinner-stirred microautoclave! , trioctylphosphine 0.5m+*ojl! , 80 mmf of acetophenone, 10 mf of tetraethylene glycol dimethyl ether, and 0.125 vwof of the phosphorus compound shown in Table 1 were charged, and 30 kg/C of hydrogen was added at room temperature.
IaG was charged and the reaction was carried out at 200°C for 2 hours.

The results are summarized in Table-1.

Examples 9 to 11 The same reactions as in Example 2 were carried out except that the reaction solvents shown in Table 2 were used instead of tetraethylene glycol dimethyl ether.

The results are shown in Table-2.

Comparative Example 2 Ruthenium chloride 0.05 mmol, trioctylphosphine 0.5 m+woj2, acetophenone 4Qmn+o11 in a 70 ml spinner-stirred microautoclave.
．． , tetraethylene glycol dimethyl ether 16m
I! Prepare 30kg/cdG of hydrogen at room temperature and prepare 20
The reaction was carried out at 0°C for 2 hours, and 13.3 mmof of α-hydroxyethylbenzene was produced.

Example 12 Phosphoric acid at 0.125 mmol! When the same reaction as in Comparative Example 2 was carried out except that .

Comparative Example 3 The same reaction as in Example 1 was carried out except that 0.156 n+mol of ammonium hexafluorophosphate was charged in place of the phosphoric acid used in Example 1, and the conversion rate of acetophenone was 95.8. %, the selectivity of α-hydroxyethylbenzene was 92.3%, styrene was produced as by-products with a selectivity of 6.7%, and ethylhenzene with a selectivity of 0.5%.

Examples 13-16 In Example 2, instead of trioctylphosphine,
The reaction was carried out in the same manner except that various organic phosphines shown in 3 were used.

The results are shown in Table 3.

Example 17 When the same reaction as in Example 2 was carried out using 80111 m01 of 4-methylacetophenone instead of acetophenone, 61.4 mmof of p-methylphenylmethyl carbinol was produced.

<Effects of the Invention> According to the present invention, when aromatic ketones are hydrogenated to produce alkylaryl carbinol, a specific catalyst is used to carry out the reaction in a homogeneous liquid phase reaction, resulting in higher yields than conventional methods. The target object can be obtained with selectivity.

Claims (1)

[Claims] (1) General formula (I): ▲Mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R_1 is a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, or a hydroxyl group. or a lower alkoxy group, and R_2 represents a lower alkyl group), (A) ruthenium, (B)
Organic phosphine and (C) general formula (II): ▲Mathematical formula, chemical formula, table, etc.▼...(II) (In the formula, X and Y are a hydrogen atom, a hydroxyl group,
It represents a halogen atom, an alkoxy group, an aryloxy group, an alkyl group, or an aryl group, and may be different from each other. ) By carrying out a hydrogenation reaction in a homogeneous liquid phase in the presence of a phosphorus compound represented by the formula (III): ▲Mathematical formula, chemical formula, table, etc.▼...(III) (In the formula, R_1 and R_2 have the same meanings as in general formula (I).