JP5130957B2 - Platinum fixed carbon catalyst for catalytic hydrogenation of aliphatic ketones and process for producing aliphatic secondary alcohols from aliphatic ketones using the same - Google Patents

Description

  The present invention relates to a platinum-fixed carbon catalyst useful for the production of aliphatic secondary alcohols by catalytic hydrogenation of aliphatic ketones, and catalytic hydrogenation of aliphatic ketones in the presence of hydrogen at atmospheric pressure using the catalyst. The present invention relates to a method for producing an aliphatic secondary alcohol.

A process for producing an aliphatic secondary alcohol by catalytic hydrogenation of an aliphatic ketone using a catalyst in the presence of hydrogen is known. For example, an example of producing isopropyl alcohol by catalytic hydrogenation of acetone using a ruthenium carbon catalyst in the presence of hydrogen at a pressure of 90 kgf / cm ² (Patent Document 1), hydrogen at a pressure of 3.5 to 7 kgf / cm ² Is known in which 1,1,1-3,3,3-hexafluoro-2-propanol is produced by catalytic hydrogenation of hexafluoroacetone using a palladium-carbon catalyst in the presence of water (Patent Document 2) Yes. In these examples, there is the disadvantage that pressurized hydrogen must be present.

  Also known is a method for producing an aliphatic secondary alcohol by catalytic hydrogenation of an aliphatic ketone using a catalyst in the presence of hydrogen at normal pressure. For example, an example in which an aliphatic secondary alcohol is produced by catalytic hydrogenation of an aliphatic ketone using a sponge nickel catalyst in the presence of atmospheric pressure (Non-Patent Document 1) is known. In this example, spontaneously ignitable sponge nickel must be used, which is dangerous to handle and 0.5 g for 0.72 g (10 mmol) of 2-butanone (69% by weight based on reactive groups) Therefore, there is a disadvantage that a large amount of catalyst is used.

  Also known is a method for producing an aliphatic secondary alcohol by catalytic hydrogenation using a platinum catalyst in the presence of hydrogen at normal pressure. For example, an example in which an aliphatic secondary alcohol is produced by catalytic hydrogenation of an aliphatic ketone using a platinum oxide (Adams) catalyst in the presence of hydrogen at normal pressure is known (Non-Patent Document 2). In this example, it is necessary to add hydrochloric acid to the reaction system, and due to its corrosiveness, it is not possible to use a reaction vessel made of metal such as stainless steel, and it is necessary to use a catalyst metal of 5% by weight of the substrate weight. Although it is not as good as nickel, it has the disadvantage that the amount of catalyst used is large.

  There is also known a method for producing an aliphatic secondary alcohol by catalytic hydrogenation using a platinum catalyst without adding a corrosive substance such as hydrochloric acid to the reaction system in the presence of hydrogen at normal pressure. For example, an example in which ethyl 2-hydroxybutyrate is produced by catalytic hydrogenation of ethyl acetoacetate using a platinum oxide (Adams) catalyst in the presence of hydrogen at normal pressure is known (Non-patent Document 3). In this example, the applicable substrate is limited to a beta keto ester such as ethyl acetoacetate that is susceptible to hydrogenation of a carbonyl group, and a secondary alcohol is produced by catalytic hydrogenation of an aliphatic ketone having only one carbonyl group. As a disadvantage, it is not applicable.

Japanese Patent Laid-Open No. 2-279634 Shoko 61-25694 S. Nishimura, “Handbook of Heterogeneous Catalytic Hydrogenation for Organic Syntheses”, p.186 (2001) John Wiley & Sons Inc. S. Nishimura, “Handbook of Heterogeneous Catalytic Hydrogenation for Organic Syntheses”, p.189 (2001) John Wiley & Sons Inc. P. Rylander, “Catalytic Hydrogenation in Organic Syntheses”, p.86 (1979) Academic Press

  Therefore, catalytic hydrogenation of aliphatic ketones with only one carbonyl group is carried out with a small amount of catalytic metal used under normal pressure and in the presence of hydrogen, without using corrosive substances such as hydrochloric acid or dangerous substances such as sponge nickel. Thus, development of a method for producing an aliphatic secondary alcohol has been desired.

  Therefore, the present invention provides an aliphatic group having only one carbonyl group in the presence of hydrogen under normal pressure and without using a corrosive substance such as hydrochloric acid or a dangerous substance such as sponge nickel and using a small amount of catalytic metal. An object of the present invention is to provide a method for producing an aliphatic secondary alcohol by catalytic hydrogenation of a ketone.

  As a result of intensive studies on the production of aliphatic secondary alcohols by catalytic hydrogenation of aliphatic ketones under normal pressure and in the presence of hydrogen, the present inventors have completed the present invention.

  That is, the present invention provides a catalyst comprising carbon particles and platinum fixed to the carbon particles, and has only a carbonyl group in which the platinum content in the catalyst is 7% by weight or more. The platinum-fixed carbon catalyst used in the reaction to convert to an aliphatic secondary alcohol by catalytic hydrogenation of an aliphatic ketone having the same is provided.

Second, the present invention is a method for producing an aliphatic secondary alcohol by hydrogenating the carbonyl group of an aliphatic ketone having only one carbonyl group,
Contacting the aliphatic ketone with hydrogen in the presence of a catalyst under normal pressure and wet;
As the catalyst, a catalyst comprising carbon particles and platinum fixed to the carbon particles, wherein the platinum content in the catalyst is 7% by weight or more,
A method for producing the above-mentioned aliphatic secondary alcohol is provided.

  According to the method for producing an aliphatic secondary alcohol using the platinum-fixed carbon catalyst for catalytic hydrogenation of aliphatic ketones of the present invention, a carbonyl group is merely used in a small amount of catalytic metal in the presence of hydrogen under normal pressure. An aliphatic secondary alcohol can be produced in high yield by catalytic hydrogenation of one aliphatic ketone. In this method, it is not necessary to use corrosive substances such as hydrochloric acid or dangerous substances such as sponge nickel.

  Hereinafter, the present invention will be described in more detail.

<Platinum fixed carbon catalyst>
The platinum-fixed carbon catalyst used in the present invention is obtained by fixing platinum to carbon particles so that the platinum content is 7% by weight or more, preferably 7 to 50% by weight, more preferably 8 to 20% by weight. .

-Carrier-
The carbon particles are the platinum carrier, and a particularly suitable example is activated carbon.

Is not particularly limited specific surface area of the carbon particles is preferably 700-2000 m ² / g, particularly preferably 900~1500 m ² / g. The specific surface area is a value measured by the BET method.

  In addition, the shape of the carbon particles is not particularly limited, but a powder form or a granular form is preferable, and a powder form is particularly preferable.

-Catalyst preparation method (Platinum fixation on carbon particles)-
The platinum can be fixed to the carbon particles by bringing the carbon particle carrier into contact with a solution containing platinum.

  Specifically, the platinum-fixed carbon catalyst used in the present invention is performed, for example, by dissolving a platinum compound in a solvent, putting a carbon carrier into the solution, and adsorbing or impregnating the platinum compound on the carbon carrier. When the platinum compound is water-soluble such as hexachloroplatinic (IV) acid, water can be used as a solvent. Further, when the platinum compound is water-soluble and can be fixed as a hydroxide by neutralization, a neutralization treatment may be performed. Examples include neutralizing an alkaline solution of hexahydroxoplatinum (IV) acid with hydrochloric acid, and neutralizing tetrachloroplatinum (II) acid with sodium hydroxide. When the platinum compound is water-insoluble such as bis (2,4-pentanedionato) platinum (II), it can be adsorbed or impregnated on the carbon support using an organic solvent that dissolves the platinum compound. The catalyst in which platinum is fixed to the support by a method such as adsorption or impregnation may be subjected to a reduction treatment as necessary. In the case of reduction in a wet manner, gaseous hydrogen can be used in addition to a reducing agent such as methanol, formaldehyde, formic acid or the like. When the reduction is performed in a dry manner, gaseous hydrogen is used, but it is also possible to dilute the hydrogen gas with an inert gas such as nitrogen. In this way, a platinum fixed carbon catalyst in which platinum is fixed to the carbon support is obtained.

  The solvent used for the catalyst preparation is not particularly limited as long as it dissolves a platinum compound, but water is preferable when a water-soluble platinum compound is used. In the case of a platinum compound that is water-insoluble and soluble in an organic solvent. For this, an organic solvent such as ethanol, acetone or chloroform which dissolves the platinum compound is suitable.

  The platinum compound is not particularly limited as long as it is soluble in a solvent used in the catalyst preparation step, but platinum (IV) nitrate, platinum (IV) sulfate, tetraammine platinum (II) chloride, tetraammine platinum (II) bromide. , Tetraammineplatinum (II) nitrate, tetraammineplatinum (II) acetate, hexachloroplatinum (IV) acid, tetrachloroplatinic acid (II), sodium hexahydroxoplatinate (IV), hexahydroxoplatinum (IV) acid (2- In addition to water-soluble compounds such as hydroxyethylammonium), dinitrodiammine platinum (II) nitric acid solution, dinitrodiammine platinum (II) aqueous ammonia solution, bis (2,4-pentanedionato) platinum (II), dichloro (1,5 -Cyclooctadiene) platinum (II), dichlorobis (triphenylphosphite) ) Platinum (II), can be tetrakis (triphenylphosphine) platinum (II), tris (dibenzylideneacetone) dipalladium (0) soluble complexes in an organic solvent such as may be used. Among them, tetraammineplatinum (II) acetate, hexachloroplatinic (IV) acid, tetrachloroplatinic acid (II), sodium hexahydroxoplatinum (IV), hexahydroxoplatinum (IV) acid (2-hydroxyethylammonium), dinitro Diammine platinum (II) nitric acid solution and bis (2,4-pentanedionato) platinum (II) are preferred.

  The platinum fixed carbon catalyst used in the present invention can also be obtained, for example, under the trade name SGH-10MR (manufactured by NV Chemcat Co., Ltd.).

<Method for producing aliphatic secondary alcohol by catalytic hydrogenation of aliphatic ketone>
According to the present invention, an aliphatic ketone having only one carbonyl group is contacted with hydrogen under atmospheric pressure in the presence of the above platinum-fixed carbon catalyst to convert the carbonyl group to a hydroxyl group. Aliphatic secondary alcohols can be produced. Here, “wet” usually means “in the presence of a solvent”, preferably “in a solvent”.

  As the aliphatic ketone having only one carbonyl group used as a substrate in the method of the present invention, the following general formula (I):

（Ｉ）
（式中、R₁及びR₂は、異なっていても同じでもよい一価脂肪族炭化水素基を表し、相互に結合して一体化して２価の脂肪族炭化水素基を形成してもよく、該一価炭化水素基の炭素原子に結合している１つ以上の水素原子がハロゲン原子および／または水酸基で置換されていてもよい。）
で表される化合物が挙げられる。
該一般式（Ｉ）で表される脂肪族ケトンとしては、具体的には、例えば、アセトン、２−ブタノン、４−メチルブタン−２−オン、２−デカノン、４−デカノン、１，１，１−
トリフルオロアセトン、ヒドロキシアセトンなどが挙げられる。

(I)
(In the formula, R ₁ and R ₂ represent a monovalent aliphatic hydrocarbon group which may be the same or different, and may be bonded together to form a divalent aliphatic hydrocarbon group. And one or more hydrogen atoms bonded to the carbon atom of the monovalent hydrocarbon group may be substituted with a halogen atom and / or a hydroxyl group.)
The compound represented by these is mentioned.
Specific examples of the aliphatic ketone represented by the general formula (I) include acetone, 2-butanone, 4-methylbutan-2-one, 2-decanone, 4-decanone, 1,1,1. −
Examples thereof include trifluoroacetone and hydroxyacetone.

  By applying the method of the present invention to the aliphatic ketone represented by the above general formula (I), the following general formula (II):

（ＩＩ）
（式中、R₁及びR₂は、前記と同じ意味を表す）
で表される脂肪族第２アルコールが得られる。

(II)
(Wherein R ₁ and R ₂ represent the same meaning as described above)
The aliphatic secondary alcohol represented by these is obtained.

  Specific examples of the aliphatic secondary alcohol represented by the general formula (II) include 2-propanol, 2-butanol, 4-methyl-2-butanol, 2-decanol, 4-decanol, 1 , 1,1-trifluoro-2-propanol, 1,2-propanediol and the like.

  For example, 2-decanone, which is an aliphatic ketone compound, is an aliphatic alcohol by reacting for 3 hours at room temperature by contacting hydrogen under normal pressure in a cyclohexane solvent using a platinum-fixed carbon catalyst. 2-decanol can be obtained with a yield of 100% based on 2-decanone.

In the above general formulas (I) and (II), R ₁ and R ₂ are aliphatic hydrocarbon groups, which may be different or the same, and are bonded together to form a divalent aliphatic hydrocarbon. A group may be formed, and one or more hydrogen atoms bonded to a carbon atom may be substituted with a halogen atom and / or a hydroxyl group. As an independent example where R ₁ and R ₂ are not bonded, an alkyl group having 1 to 20 carbon atoms or an ω-cycloalkylalkyl group, and one or more hydrogen atoms bonded to the carbon atom are halogen atoms. And / or may be substituted with a hydroxyl group, preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, etc. An alkyl group having 1 to 16 carbon atoms; a 2-cyclopentylethyl group or a 3-cyclohexylpropyl group;

Examples of the divalent aliphatic hydrocarbon group formed by combining R ₁ and R ₂ together include, for example, 1,3-propanediyl group, 1,5-pentanediyl group, 1,4-butanediyl. Group, 1,11-undecanediyl group, methyltetradecane-1,14-diyl group, 1,2,2-trimethyl-3-methylene-cyclopentan-1-yl group, bicyclo- [3,3,1]- Nonane-3,7-diyl group and the like can be mentioned.

When R ₁ and R ₂ are combined to form a divalent aliphatic hydrocarbon group, an aliphatic group containing a carbon atom to which R ₁ and R ₂ are bonded in general formula (I) as a ring member A ring is formed and the compound of general formula (I) becomes an alicyclic ketone. Examples of such alicyclic ketones are cycloalkanones having 3 to 16 carbon atoms, bicycloalkanones having 6 to 16 carbon atoms, tricycloalkanones having 8 to 16 carbon atoms, and carbon atoms. One or more hydrogen atoms bonded to may be substituted with an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a halogen atom and / or a hydroxyl group. Preferred are cyclobutanone, cyclohexanone, cyclopentanone, cyclododecanone, methylcyclopentadecanone, camphor, and adamantanone.

  The catalyst used in the present invention is usually used in an amount of 0.001 to 10% by weight, preferably 0.01 to 5% by weight, more preferably 0.05 to 2% by weight as platinum metal with respect to the aliphatic ketone compound as a reactant. % Range. In the reaction, particles such as activated carbon, alumina, or diatomaceous earth to which platinum is not fixed may be mixed.

  The solvent used in the catalytic hydrogenation reaction is not particularly limited, but is preferably water; alkanol having 1 to 6 carbon atoms such as methanol, ethanol, 2-propanol; alkane having 5 to 10 carbon atoms, and 5 carbon atoms. 10 to 10 cycloalkanes; chlorinated hydrocarbons having 1 to 2 carbon atoms such as chloroform and dichloromethane; or a combination thereof, and 2-propanol, cyclohexane and chloroform are particularly preferable.

  This catalytic hydrogenation reaction is carried out under normal pressure and in the presence of hydrogen. Hydrogen may be pure hydrogen gas, but may be a mixed gas obtained by diluting hydrogen with an inert gas such as nitrogen as necessary. Usually, the reaction is carried out in the temperature range of 0 to 40 ° C. for about 1 to 48 hours. Operation at room temperature where the reactor is not heated or cooled is allowed.

  Examples of the present invention are shown below, but the present invention is not limited to the following examples.

<Example 1>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10% by weight platinum fixed carbon catalyst)
2-Decanone 78 mg (0.5 mmol) was dissolved in cyclohexane 2 ml. To the resulting solution, 10% platinum-fixed carbon powder catalyst (trade name: SGH-10MR, manufactured by N.E. Chemcat Co., Ltd.) was added as platinum metal in an amount equivalent to 1% by weight of the reaction substrate. The reaction was allowed to stir at 25 ° C. for 3 hours. Thereafter, the catalyst was separated by filtration, and the product obtained by ¹ H-NMR was analyzed. As a result, it was 2-decanol. The yield of 2-decanol relative to the charged 2-decanone was 100%.

<Example 2>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10% by weight platinum fixed carbon catalyst)
In Example 1, 2-decanol was obtained in the same manner as in Example 1 except that 2 ml of 2-propanol was used instead of cyclohexane. The yield was 98%.

<Example 3>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10% by weight platinum fixed carbon catalyst)
In Example 1, 2-decanol was obtained in the same manner as in Example 1 except that 2 ml of chloroform was used instead of cyclohexane. The yield was 93%.

<Example 4>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10% by weight platinum fixed carbon catalyst)
In Example 1, 2-decanol was obtained in the same manner as in Example 1 except that the reaction time was 1 hour instead of 3 hours. The yield was 98%.

<Example 5>
(Synthesis of 4-decanol by catalytic hydrogenation of 4-decanone using 10 wt% platinum fixed carbon catalyst)
In Example 1, 4-decanol was obtained like Example 1 except having used 4-decanone 78 mg (0.5 mmol) instead of 2-decanone 78 mg (0.5 mmol). The yield was 98%.

<Example 6>
(Synthesis of 4-tert-butyl-1-cyclohexanol by catalytic hydrogenation of 4-tert-butyl-1-cyclohexanone using 10 wt% platinum-fixed carbon catalyst)
In Example 1, 4-tert-butyl was carried out in the same manner as in Example 1, except that 77 mg (0.5 mmol) of 4-tert-butyl-1-cyclohexanone was used instead of 78 mg (0.5 mmol) of 2-decanone. −1-cyclohexanol was obtained. The yield was 90%.

<Example 7>
(Synthesis of 2-adamantanol by catalytic hydrogenation of 2-adamantanone using 10 wt% platinum fixed carbon catalyst)
In Example 1, 2-adamantanol was obtained like Example 1 except having used 2-adamantanone 75 mg (0.5 mmol) instead of 2-decanone 78 mg (0.5 mmol). The yield was 90%.

<Comparative Example 1>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 5 wt% platinum-fixed carbon catalyst In Example 1, instead of 10 wt% platinum-fixed carbon catalyst, 5 wt% platinum-fixed carbon catalyst (trade name: 2-decanol was produced by catalytic hydrogenation of 2-decanone in the same manner as in Example 1 except that 5% Pt carbon powder K type (manufactured by N.E. Chemcat Co., Ltd.) was used. The yield of 2-decanol based on decanone was 74%.

<Comparative example 2>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 5 wt% platinum-fixed carbon catalyst In Example 1, instead of 10 wt% platinum-fixed carbon catalyst, 5 wt. : 2-decanol was produced by catalytic hydrogenation of 2-decanone in the same manner as in Example 1 except that platinum on carbon (5 wt% supported activated carbon) manufactured by Aldrich was used. The yield of 2-decanol was 77%.

<Comparative Example 3>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10 wt% rhodium fixed carbon catalyst In Example 1, instead of 10 wt% platinum fixed carbon catalyst, 10 wt% rhodium fixed carbon powder catalyst (trade name : 10% Rh carbon powder K type, manufactured by N.E. Chemcat Co., Ltd.) and contact with 2-decanone in the same manner as in Example 1 except that an amount corresponding to 1% by weight of the reaction substrate was added as rhodium metal. The hydrogenation produced 2-decanol, and the yield of 2-decanol relative to the charged 2-decanone was 21%.

<Comparative example 4>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10% by weight palladium fixed carbon catalyst In Example 1, instead of 10% by weight platinum fixed carbon catalyst, 10% by weight palladium fixed carbon powder catalyst (trade name) : 10% Pd carbon powder K type, manufactured by N.E. Hydrogenation was attempted and the product was analyzed, and the yield of 2-decanol relative to the 2-decanone charged was 0%.

<Comparative Example 5>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10 wt% ruthenium-fixed carbon catalyst In Example 1, instead of 10 wt% platinum-fixed carbon catalyst, 10 wt% ruthenium-fixed carbon powder catalyst (trade name) : 10% Ru carbon powder K type, manufactured by N.E. Chemcat Co., Ltd.) and contact with 2-decanone in the same manner as in Example 1 except that an amount corresponding to 1% by weight of the reaction substrate was added as ruthenium metal. Hydrogenation was attempted and the product was analyzed, and the yield of 2-decanol relative to the 2-decanone charged was 0%.

<Comparative Example 6>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10 wt% iridium fixed carbon catalyst In Example 1, instead of 10 wt% platinum fixed carbon catalyst, 10 wt% iridium fixed carbon powder catalyst (trade name : 10% Ir carbon powder K type, manufactured by N.E. Chemcat Co., Ltd.) and contact with 2-decanone in the same manner as in Example 1 except that an amount corresponding to 1% by weight of the reaction substrate was added as iridium metal. Hydrogenation was attempted and the product was analyzed, and the yield of 2-decanol relative to the 2-decanone charged was 0%.

<Comparative Example 7>
(Synthesis of 2-decanol by catalytic hydrogenation of 2-decanone using 10 wt% gold fixed carbon catalyst In Example 1, instead of 10 wt% platinum fixed carbon catalyst, 10 wt% gold fixed carbon powder catalyst (trade name : Catalytic hydrogenation of 2-decanone in the same manner as in Example 1 except that 10% Au carbon powder K type, manufactured by N.E. Chemcat Co., Ltd.) was used as a gold metal in an amount corresponding to 1% by weight of the reaction substrate. Attempts were made to analyze the product, and the yield of 2-decanol relative to the charged 2-decanone was 0%.

The method for producing an aliphatic secondary alcohol of the present invention is useful in research, development and production in the fine chemical industry and petrochemical industry such as pharmaceutical intermediate production and functional material production.

Claims (7)

An aliphatic ketone having only one carbonyl group as a catalyst comprising carbon particles and platinum fixed to the carbon particles, wherein the platinum content in the catalyst is 8 to 20% by weight. A platinum carbon catalyst used in a reaction to convert to an aliphatic secondary alcohol by catalytic hydrogenation of. The platinum carbon catalyst according to claim 1, wherein the carbon particles used for the support have a specific surface area of 700 to 2000 m ² / g by BET method. The aliphatic ketone is represented by the following general formula (I):

(I)
(In the formula, R ₁ and R ₂ represent a monovalent aliphatic hydrocarbon group which may be the same or different, and may be bonded together to form a divalent aliphatic hydrocarbon group. And one or more hydrogen atoms bonded to the carbon atom of the monovalent hydrocarbon group may be substituted with a halogen atom and / or a hydroxyl group.)
A compound represented by
The aliphatic secondary alcohol is represented by the following general formula (II):

(II)
(Wherein R ₁ and R ₂ represent the same meaning as described above)
The platinum carbon catalyst according to claim 1 or 2 , which is a compound represented by A process for producing an aliphatic secondary alcohol by hydrogenating the carbonyl group of an aliphatic ketone having only one carbonyl group,
Contacting the aliphatic ketone with hydrogen under atmospheric pressure in the presence of a catalyst in a wet manner;
As the catalyst, a catalyst comprising carbon particles and platinum fixed to the carbon particles, wherein the platinum content in the catalyst is 8 to 20% by weight ,
A process for producing the above-mentioned aliphatic secondary alcohol. The aliphatic ketone is a compound represented by the general formula (I) according to claim 3 ,
Aliphatic secondary manufacturing process of alcohol according to claim 4, wherein the aliphatic secondary alcohol is of the general formula (II) compounds represented by claim 3. The method for producing an aliphatic secondary alcohol according to claim 4 or 5 , wherein a ratio of platinum in the catalyst to the aliphatic ketone as a reaction substrate is 0.001 to 10% by weight. The method for producing an aliphatic secondary alcohol according to any one of claims 4 to 6 , wherein the contact between the aliphatic ketone and hydrogen is performed at 0 to 40 ° C.