JPH08198788A - Production of alpha-phenylethyl alcohol - Google Patents

Abstract

PURPOSE: To suppress the amount of ethylbenzene formed as a by-product to a sufficiently low level and obtain α-phenylethyl alcohol useful as a raw material for styrene and various perfumes in high selectivity using a readily preparable catalyst by hydrogenating acetophenone in the presence of the specific supported catalyst. CONSTITUTION: (B) Acetophenone is hydrogenated in the presence of (A) a supported catalyst containing 2-9wt.% CuO and 2-9wt.% Cr2 O3 supported on a carrier such as silica or diatomaceous earth to afford the objective compound. Furthermore, the component (A) is prepared by adding the powdery silica carrier to a solution obtained by dissolving, e.g. cupric carbonate and ammonium dichromate in aqueous ammonia, then stirring and kneading the resultant mixture, providing a homogeneous pasty form, drying the obtained paste at 80-150 deg.C temperature under 10-300mHg reduced pressure, then washing the dried material with water, etc., several tithes, affording a cake, drying the resultant cake, calcining and thermally decomposing the dried cake at 100-500 deg.C temperature in air for 1-2hr.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing α-phenylethyl alcohol. More specifically, the present invention is characterized in that α is obtained by hydrogenating acetophenone.
-A method for producing phenylethyl alcohol, comprising:
It suppresses the by-product of ethylbenzene to a sufficiently low level, and thus has a high selectivity for the target α-phenylethyl alcohol, and does not have a complicated step for preparing the catalyst, which is extremely preferable from the viewpoint of industrial implementation. The present invention relates to an excellent method for producing α-phenylethyl alcohol.

Α-Phenylethyl alcohol is useful, for example, as a raw material for styrene production and as a raw material for various flavors.

[0003]

2. Description of the Related Art By hydrogenating acetophenone, α
It is known that phenylethyl alcohol can be produced.

For example, in Japanese Patent Publication No. 25730/1989, α-phenylethyl alcohol is converted from acetophenone using an unsupported hydrogenation catalyst containing CuO, Cr ₂ O ₃ , BaO, ZnO, MgO and the like. A method of manufacturing is disclosed. However, this method has a problem that excessive hydrogenation of acetophenone produces a considerable amount of ethylbenzene as a by-product, and the selectivity to α-phenylethyl alcohol which is the target is lowered. .

Further, in Japanese Patent Publication No. 59-216216, a catalyst obtained by impregnating a solution containing a zinc component into a pyrolyzed product of barium copper ammonium chromate and recalcining the mixture is used. A method for producing α-phenylethyl alcohol while suppressing by-products is disclosed. However, this method is still insufficient in the effect of suppressing the by-product of ethylbenzene, and the components constituting the catalyst are complicated, so that the catalyst preparation process becomes complicated, which is disadvantageous in terms of cost and production efficiency. I have a problem.

[0006]

In view of the above situation, the problem to be solved by the present invention is a method for producing α-phenylethyl alcohol by hydrogenating acetophenone, and the by-product of ethylbenzene is sufficiently produced. Is extremely low from the viewpoint of industrial implementation, that is, the selectivity to the target α-phenylethyl alcohol is high, and there is no complicated step for preparing the catalyst. The point is to provide a method for producing alcohol.

[0007]

That is, the present invention is a method for producing α-phenylethyl alcohol by hydrogenating acetophenone, which comprises _{2 to} 9% by weight of CuO and _{2 to} 9% by weight of Cr ₂ O _3. The present invention relates to a method for producing α-phenylethyl alcohol using a supported catalyst containing

The details will be described below.

In the present invention, the catalyst used for hydrogenating acetophenone is 2 to 9% by weight of CuO and Cr.
It is a supported catalyst containing 2 to 9% by weight of ₂ O ₃ .

CuO contained in the catalyst is copper oxide (I
I), i.e. cupric oxide. The content of CuO in the catalyst is 2 to 9% by weight based on the total weight of the supported catalyst (amount based on oxide. The same applies hereinafter). If the content is too small, the hydrogenation reaction may not proceed sufficiently, while if the content is too large, the amount of ethylbenzene by-product may increase.

Cr ₂ O ₃ contained in the catalyst is chromium (III) oxide, that is, chromic oxide (also called dichromium trioxide or chromium trioxide). The content of Cr ₂ O _{3 in} the catalyst is 2 to 9% by weight based on the total weight of the supported catalyst. If the content is too small, the hydrogenation reaction may not proceed sufficiently, while if the content is too large, the amount of ethylbenzene by-product may increase.

The catalyst used in the present invention is a supported catalyst. When a non-supported catalyst is used without the present invention, a considerable amount of ethylbenzene is by-produced due to excessive hydrogenation of acetophenone, and the selectivity to α-phenylethyl alcohol, which is the target product, is high. descend.

Examples of the carrier include metal oxides such as silica, alumina, titania, zirconia, magnesia, and silica-alumina, and complex oxides thereof; bentonite, montmorillonite, diatomaceous earth, acid clay and the like. Of these, silica and diatomaceous earth are preferred.

Next, a method for producing the catalyst used in the present invention will be described.

As a copper raw material for supplying CuO, a water-soluble salt containing cupric acid is preferable, and for example, a mineral acid salt such as nitrate or sulfate containing cupric acid or carbonate is preferably used. To be

As a chromium raw material for supplying Cr ₂ O ₃ , a water-soluble salt containing chromic acid or dichromic acid is preferable, and for example, a mineral acid such as nitrate or sulfate containing chromic acid or dichromic acid. Alkali metal salts such as salts, carbonates, ammonium salts and sodium salts are preferably used.

The above-mentioned copper raw material and chromium raw material are usually 0.1% or less.
It is dissolved in ammonia water of 01 to 30% by weight. When cupric carbonate is used as the copper raw material, ammonium carbonate having a molar ratio of 1 to 5 times that of cupric carbonate is usually added to aqueous ammonia before dissolving cupric carbonate.

The order of melting the copper raw material and the chromium raw material is
There is no particular limitation. When the raw material is dissolved in ammonia water, the sum of copper salt and chromium salt is 0.01 to 50% by weight,
It is preferably 0.1 to 30% by weight.

In preparing the catalyst, an alkali metal salt, an alkaline earth metal salt, or a transition metal oxide may be used as a co-catalyst component in addition to the above copper raw material and chromium raw material. In this case, the amount of the co-catalyst component is 0.1 to 50% by weight based on the total weight of the supported catalyst. The co-catalyst component is dissolved in aqueous ammonia together with the copper raw material and the chromium raw material.

Thus, a uniform solution of aqueous ammonia containing the obtained cupric and chromic chromium and, if necessary, the promoter component added is obtained. In the present invention, cupric and chromic chromium used in obtaining the homogeneous solution, and the cocatalyst component added as necessary, are substantially all in the final supported catalyst. Contained.

Next, a powdery carrier (the kind of carrier is as described above) is added to the above-mentioned homogeneous solution, and a homogeneous paste is prepared by stirring and / or kneading. If the stirring and / or kneading at this time is insufficient,
The composition of the prepared catalyst may be non-uniform, resulting in a decrease in activity and a considerable amount of ethylbenzene as a by-product. This paste-like substance is usually subjected to a reduced pressure of 10 to 300 mmHg,
Dry at a temperature of 80-150 ° C. From the viewpoint of obtaining stable catalytic activity, it is preferable to remove the metal cations and the anions derived from the mineral acid by washing the dried product a plurality of times with water or the like. However, caution is required because the copper ammonium complex may flow out and the activity of the prepared catalyst may be reduced by excessive washing. Thus, a cake after washing is obtained. The cake is subjected to pyrolysis.

The above cake is dried at 100 to 100%.
At 500 ° C, preferably 250-400 ° C, in air
It is pyrolyzed by baking. Calcination is usually 1-10
Done on time. Thus, the supported catalyst used in the present invention
Is obtained. In addition, in the catalyst of the present invention, CuO and
Cr₂O₃Is copper chromite (CuO ・ CuCr
₂O _Four).

Next, a hydrogenation reaction method for obtaining α-phenylethyl alcohol by hydrogenating acetophenone will be described.

As the hydrogenation reaction method, any of a suspension bed reaction method, a fixed bed reaction method and a fluidized bed reaction method can be adopted.

When the suspension bed reaction system is adopted, a powdery catalyst is used, and the catalyst amount is usually 0.0 relative to acetophenone.
It is 1 to 20% by weight, preferably 0.1 to 10% by weight. The reaction temperature is usually 50 to 300 ° C., preferably 90.
~ 200 ° C. If the reaction temperature is too low, the hydrogenation reaction may not proceed sufficiently, while if the reaction temperature is too high, ethylbenzene by-product may increase. The hydrogen pressure is usually 1 to 350 kg / cm ² , preferably 10
It is 200 kg / cm ² . If the pressure is too low, the hydrogenation reaction may not proceed sufficiently. From the viewpoint of reaction efficiency, it is preferable to perform sufficient stirring during the reaction. When the reaction is carried out in a continuous suspension bed system, the space velocity (LHSV) of the reaction raw material liquid in the reaction vessel is usually 0.1 to 10 hr ⁻¹ . When the reaction is carried out in a suspension bed batch system, the reaction time is 0.
5 to 5 hours.

When the hydrogenation reaction is carried out in a fixed bed reaction system,
A shaped catalyst is used. Reaction temperature is 50-300
C., preferably 90 to 200.degree. Pressure is 1 to 35
0 kg / cm ² , preferably 10 to 200 kg / cm ²
Is. When the reaction is carried out in a fixed bed continuous system, the amount of the catalyst used is 0.0
It is ¹ to 50 hr ^-1 , preferably 0.1 to 20 hr ^-1 . The amount of hydrogen is usually 1.0 to 30 times the amount of acetophenone in the raw material liquid to be fed. When the reaction is carried out in a fixed bed batch system, the amount of the catalyst is 1 to 100% by weight, preferably 5 to 50% by weight, based on acetophenone. The reaction time depends on the reaction temperature, the amount of catalyst, and the pressure,
There is no particular limitation. It is preferable that the reaction is sufficiently stirred from the viewpoint of reaction efficiency. The reason for setting the reaction conditions as described above is the same as the reason explained in the section of the suspension bed reaction system.

The hydrogenation reaction can be carried out in the presence of a solvent. Examples of the solvent include alcohols such as methanol, ethanol, propanol, ethylene glycol monomethyl ether and α-phenylethyl alcohol, ethers such as diethyl ether, tetrahydrofuran, dioxane and ethylene glycol dimethyl ether, carbonization such as hexane, heptane, toluene and ethylbenzene. Examples thereof include hydrogens and mixed solvents thereof. When a solvent is used, the amount used is usually 0.5 to 10 times by weight that of acetophenone.

[0028]

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

Catalyst Preparation Example 1 Ammonium carbonate 0.75 g, 20 in distilled water 200 ml
After 20% by weight of aqueous ammonia was dissolved, 1.23 g of basic copper carbonate was added little by little with stirring to dissolve the aqueous solution. Next, 1.22 g of ammonium dichromate was added, and the mixture was stirred at 25 ° C for 30 minutes. The solution thus prepared was added to 19.0 g of Aerosil silica and then evaporated to dryness with a rotary evaporator, and further 20 mmHg
20. By drying and pulverizing at 80 ° C. under reduced pressure of 20.
5 g of a light brown solid was obtained. 20.0 g of this product was molded at 400 Kg / cm ² using a tablet molding machine, and then 7-9
Crushed into mesh. Then, this is put under an air stream,
After heating at 0 ° C. for 4 hours, it was cooled to room temperature to obtain 7.0% by weight of catalyst A with a carrier as copper chromite (CuO.CuCr ₂ O ₄ ).

Catalyst Preparation Example 2 Ammonium carbonate used in Catalyst Preparation Example 1.
5 g, 20 wt% ammonia water 40 ml, basic copper carbonate 2.46 g, ammonium dichromate 2.44 g
Catalyst B with a carrier of 13.0% by weight was obtained as copper chromite.

Catalyst Preparation Example 3 Ammonium carbonate used in Catalyst Preparation Example 1
0.5 g, 20 wt% ammonia water 10 ml, basic copper carbonate 0.82 g, ammonium dichromate 0.81 g
Catalyst C with a carrier of 5.0% by weight as copper chromite by carrying out according to Catalyst Preparation Example 1 except that
I got

Catalyst Preparation Example 4 Ammonium carbonate used in Catalyst Preparation Example 1.
Catalyst Preparation Example 1 except that 0 g, 20 wt% ammonia water 80 ml, basic copper carbonate 4.92 g, ammonium dichromate 4.88 g, and Aerosil silica 24.7 g were used.
By carrying out according to
0.0% by weight of a catalyst D with a carrier was obtained.

Example 1 A stainless wire cage made of 200 ml of stainless steel replaced with nitrogen was charged with 24 ml of the supported catalyst A (fill specific gravity = 0.43) which had been reduced in advance at 180 ° C. for 5 hours under a hydrogen stream. Fix, then add acetophenone 8
0.0g was charged. The temperature was raised to 130 ° C. with stirring, and then hydrogen was introduced at a pressure of 20.0 Kg / cm ² . After reacting for 2 hours under stirring, the mixture was cooled to room temperature, and the reaction liquid was analyzed by gas chromatography. As a result, the composition was 24.3% by weight of acetophenone, 75.1% by weight of α-phenylethyl alcohol, and 0.6% of ethylbenzene. The conversion was 75.4% for acetophenone, the selectivity for α-phenylethyl alcohol was 99.1%, and the selectivity for ethylbenzene was 0.9%.

Example 2 The procedure of Example 1 was repeated except that the catalyst used was the supported catalyst B (filling specific gravity = 0.43). As a result of analyzing the reaction liquid by gas chromatography, the composition was 26.7% by weight of acetophenone and 72.
0% by weight, ethylbenzene 1.3% by weight, acetophenone conversion 73.0%, α-phenylethyl alcohol selectivity 98.0%, ethylbenzene selectivity 2.0.
%Met.

Example 3 The procedure of Example 1 was repeated, except that the catalyst used was the supported catalyst C (filling specific gravity = 0.47). As a result of analyzing the reaction liquid by gas chromatography, the composition was 61.7% by weight of acetophenone and 38.
2% by weight, ethylbenzene 0.1% by weight, acetophenone conversion 62.1%, α-phenylethyl alcohol selectivity 99.7%, ethylbenzene selectivity 0.3.
%Met.

Comparative Example 1 The procedure of Example 1 was repeated, except that the catalyst used was the supported catalyst D (filling specific gravity = 0.49). As a result of analyzing the reaction liquid by gas chromatography, the composition was 26.4% by weight of acetophenone and 71.
6% by weight, 2.0% by weight of ethylbenzene, conversion of acetophenone 72.9%, α-phenylethyl alcohol selectivity 96.9%, ethylbenzene selectivity 3.1.
%Met.

The following can be seen from the results. That is, all the examples using the catalyst of the present invention showed satisfactory reaction results, while Comparative Example 1 using the catalyst having an excessive CuO and Cr ₂ O ₃ content showed ethylbenzene. Is a by-product, and the selectivity to the target product, α-phenylethyl alcohol, is low.

[0038]

[Table 1]

* 1 Catalyst wt%: amount of CuO and Cr ₂ O ₃ contained in the supported catalyst (amount based on oxide) * 2 Reaction result APH conversion: [consumed acetophenone (mol) /
Acetophenone supplied (mol)] × 100 PEA selectivity: [α-phenylethyl alcohol produced (mol) / acetophenone consumed (mol)] × 1
00 EBZ selectivity: [Ethylbenzene produced (mol) / Acetophenone consumed (mol)] × 100

[0040]

As described above, according to the present invention, there is provided a method for producing α-phenylethyl alcohol by hydrogenating acetophenone, which suppresses the by-product of ethylbenzene to a sufficiently low level. Is α
It was possible to provide a very excellent method for producing α-phenylethyl alcohol, which has a high selectivity to phenylethyl alcohol and does not have a complicated step for preparing a catalyst, from the viewpoint of industrial implementation.

Claims (1)

[Claims] 1. A method comprising hydrogenating acetophenone to obtain α
-A method for producing phenylethyl alcohol, comprising:
A method for producing α-phenylethyl alcohol using a supported catalyst containing 2 to 9% by weight of CuO and _{2 to} 9% by weight of Cr ₂ O ₃ .