JPH0629207B2 - Method for hydrogenating aliphatic unsaturated ketone - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of hydrogenating an aliphatic unsaturated ketone to selectively obtain an aliphatic unsaturated ketone.

[Conventional technology]

The reaction of hydrogenating a carbon-carbon multiple bond such as an olefin or acetylene compound to convert it into a compound having a low degree of unsaturation is an industrially important reaction, and many studies have been conducted so far. Many metals, oxides, sulfides, etc. have been proposed as effective catalysts for these groups of reactions, and precious metal catalysts such as platinum, rhodium, palladium, ruthenium, etc., nickel, cobalt, copper, etc. as main active ingredients. The contained catalyst system has remarkably high activity and is widely used. In addition to carbon-carbon multiple bonds in the molecule, carbon-
When a saturated carbonyl compound is produced by selectively hydrogenating only a carbon-carbon unsaturated bond in a compound (aldehyde, ketone) having an oxygen unsaturated bond, particularly a carbonyl group, palladium is particularly preferable among the above-mentioned active ingredients. Is well known to be effective. For example, the same amount of 4-methyl-3-pentene-based on various noble metal catalysts (platinum, ruthenium and palladium) by the present inventors in an atmospheric pressure reaction.
The measurement results of the hydrogen absorption rate between 2-one and 4-methyl-2-pentanone are shown in Table 1 below.
The selectivity characteristics for hydrogenation of carbon unsaturated bonds are shown.

Also, Choi Sungbom, Kazunori Tanaka et al. Reported that hydrogenation ability of palladium for carbonyl bond was low (Bull.Chem.Soc.Japan 55 , 2275 (198
2)).

In addition, "Practical catalysts for each reaction" (published by Kagaku Kogyo Co., Ltd., edited by Kimio Tarama, 1970), page 184, 4-methyl-2-pentanone was used at room temperature and atmospheric pressure using 5% Pd / activated carbon catalyst When hydrogenating in various solvents at 0.5N, the reaction does not proceed in water, methanol, methyl acetate and 0.5N HCl.
-It is described that hydrogenation to 4-methyl-2-pentanol gradually proceeds in NaOH. That is, the alkali in the solution causes a decrease in the selectivity to the target product, a saturated carbonyl compound. Also, in the liquid phase hydrogenation reaction, the reactivity is affected by the solvent.

Therefore, in the case of producing a saturated carbonyl compound from an unsaturated carbonyl compound by hydrogenating a carbon-carbon unsaturated bond, palladium is the most effective catalyst component, and platinum and ruthenium further hydrogenate the carbonyl group to give alcohol (4 -Methyl-2-pentanol) is not preferable because hydrogenation proceeds even to (methyl-2-pentanol).

USP 3,736,266 is a method for producing a palladium catalyst supported on activated carbon. A basic substance is added to a soluble palladium salt aqueous solution containing powdered activated carbon carrier slurry to adjust the pH to 12 or more, and palladium is deposited in the form of hydroxide. We are proposing a way to give back. At this time, a hydroxide of alkali or alkaline earth as a basic substance, preferably Li, Na,
It is advisable to use a 5 to 50% aqueous solution of hydroxides of K, Ba, and Cs, and the use of carbonates and bicarbonates is disadvantageous because the pH increases only to 9 to 10. Then
After reduction in an aqueous medium, the catalyst is isolated by filtration, washing and drying. It is described that this preparation method increases the activity as a hydrogenation catalyst.

In addition, USP 3,804,779, like USP 3,736,266, shows resistance to sulfur by reducing, separating and washing a carbon carrier slurry in an acidic aqueous palladium salt solution in a more basic environment (pH 5.0 to 6.0). A method for producing large supported palladium catalysts is reported. The basic compounds used here are alkali or alkaline earth metal hydroxides, ammonium hydroxide and quaternary ammonium compounds, alkali metal carbonates, bicarbonates and the like, with sodium carbonate being particularly preferred. It is said that.

In these catalysts, the alkali is separated and removed in the process of washing, so that it is generally hardly left in the catalyst, but when washing with an alkali-containing aqueous solution, or when washing is insufficient, etc. It is possible that some of the alkali remains. However, these patent specifications only describe the general hydrogenation activity of palladium catalysts or the improvement of resistance to sulfur, and the selection of saturated coubonyl compounds in the hydrogenation of olefinic unsaturated carbonyl compounds. There is no suggestion of increasing sex.

[Problems to be solved by the invention]

Several proposals have been made in the past for improving the selective hydrogenation of carbon-carbon unsaturated bonds with the palladium catalyst. However, none of them are satisfactory because they have a drawback in that a large amount of solvent is used or an excessive hydride such as alcohol is still by-produced. For example, the above-mentioned "Practical catalysts for each reaction", Chapter 2
11-338), hydrogenation of mesityl oxide using 1.3% Pd / alumina catalyst was carried out at 200 ° C. to obtain methyl isobutyl ketone in a yield of 97%. In terms of yield, there still existed inconveniences such as requiring a high rectification column reflux ratio for removing impurities during purification.

In addition, Japanese Patent Publication No. 47-15,809 discloses the use of a palladium-carbon catalyst having an alkali metal acetate attached thereto as a method for selectively synthesizing methyl isobutyl ketone by hydrogenating mesityl oxide. There is. This catalyst is produced by a method of impregnating and adhering a soluble alkali metal acetate as a solution to a palladium-carbon catalyst prepared in advance. The reaction is carried out in the gas phase, and the conversion rate is 99%, methyl isobutyl ketone selectivity is 99.8% (Example-1), or selectivity is 99.7% (Example-2). However, this is still insufficient in terms of conversion rate and selectivity (industrial it is desirable that the concentrations of the raw material and the impurities are both 1000 ppm or less), and it cannot be said that the performance is industrially satisfactory. . According to the study by the present inventors, the cause of such performance deficiency is considered to be both that the reaction is carried out in the gas phase and that the amount of alkali used is inappropriate. However, considering that the alkali metal acetate is soluble in an organic solvent, it seems that it was impossible to use a catalyst containing a high concentration of alkali in a liquid phase reaction in the first place.

Further, when the conventional general palladium-supported catalyst as described above is used, impurities due to hydrogenation of the unsaturated carbonyl compound, that is, unreacted raw material unsaturated carbonyl compound and saturated alcohol which is an excess hydride, are 50% respectively.
0-10,000ppm and 1,000-50,000ppm
However, there is still a problem in terms of selectivity because it is generated to some extent.

For example, the reaction results according to Example 1 described in JP-B-47-15,809 are 99% conversion (unreacted mesityl oxide 10,000 ppm), methyl isobutyl ketone selectivity 99.8%, low boiling point. Decomposition product and methyl isobutyl carbinol (saturated alcohol) total 0.2%
It is said to have been given below. Japanese Patent Publication No.47-15,809
According to the first table of the publication, the amount of the low-boiling compound below the boiling point of acetone is 0.02% or less, so that the amount of matylisobutylcarbinol is 0.1 to 0.2% (1,000
~ 2,000 ppm).

[Means for solving problems]

The present inventors have aimed to improve the method for selectively hydrogenating an aliphatic unsaturated ketone by using a palladium catalyst, and have a high selectivity for the aliphatic unsaturated ketone under mild conditions. As a result of diligent search for a catalyst that hydrogenates to
The catalyst is remarkably effective on activated carbon carrying palladium and alkali metal as active ingredients, and the conversion rate is 99.9%.
The present invention has been completed by finding that high selectivity is maintained even when the above-mentioned extremely high level is used.

That is, the object of the present invention is to further improve the selectivity of the reaction when hydrogenating an aliphatic unsaturated ketone to produce an aliphatic saturated ketone, and to suppress the secondary formation of an aliphatic saturated alcohol to the utmost. In the method, hydrogenation of an aliphatic unsaturated ketone in the liquid phase in the presence of a catalyst to obtain an aliphatic saturated ketone, wherein the catalyst comprises palladium and an alkali metal supported on activated carbon as active components. Before being subjected to hydrogenation reaction, the alkali metal / palladium atomic ratio of the catalyst surface up to about 50 Å in the depth direction is determined by X-ray photoelectron spectroscopy.
A method for hydrogenating an aliphatic unsaturated ketone, which comprises subjecting a material in the range of 3.5 to a hydrogenation reaction.

The present invention will be described in more detail below.

In the method for hydrogenating an aliphatic unsaturated ketone of the present invention, a catalyst containing palladium and an alkali metal supported on a carrier as an active component is used.

Activated carbon is used as the carrier. Powder, blob,
Although it may be in the form of granules or the like, powdered activated carbon is the most common.

The catalyst, for example, a soluble palladium salt as a palladium component, for example, palladium chloride, palladium nitrate, a palladium amine complex or the like supported on a carrier, after reduction to produce a palladium-supported catalyst, an alkali metal salt as an alkali metal component, It is prepared by additionally supporting a hydroxide or the like from a solution. Further, both components may be supported on the carrier at the same time.

The catalyst used in the method of the present invention contains palladium and an alkali metal as active components supported thereon, and in particular, it is effective to make the supported palladium catalyst coexist in an amount within a certain range. Target.

For example, when sodium or lithium is used as the alkali metal, a suitable atomic ratio range of alkali metal / palladium is 0.15 to 4, more preferably 0.2 to 3.5 in bulk composition. For other potassium, cesium, etc., the bulk composition is preferably in the range of 0.2 to 1.5. Of the alkali metals, sodium is the most effective.

The above palladium and alkali metal are preferably supported on the surface of the catalyst particles. In the above bulk composition, the carrier itself may contain a small amount of alkali metal, and the surface supported amount is not always clearly expressed. The amount of surface supported is estimated by surface composition analysis by X-ray photoelectron spectroscopy (ESCA). According to the study by the present inventors,
In the catalyst surface composition analysis up to about 50 Å in the depth direction by ESCA, the atomic ratio of alkali metal / palladium is 0.7-
When it is 3.5, it is particularly effective when it is 1.0 to 2.0, and high activity and high selectivity can be stably achieved.

On the other hand, the preferable loading rate of palladium is 0.
It is 2 to 10 wt%, more preferably 1 to 5 wt%. The carrying rate of the alkali metal is determined by the amount of palladium carried as described above.

By the method of the present invention, various aliphatic unsaturated ketones can be selectively hydrogenated to obtain aliphatic saturated ketones. For example, cyclohexenone to cyclohexanone, 4-
Methyl-3-penten-2-one to 4-methyl-2-
Pentanone is obtained.

The process according to the invention is carried out in the liquid phase. Although a suitable reaction solvent such as alcohol, ester, ether, aromatic compound can be used, the reaction is preferably carried out without solvent. The reaction temperature is usually in the range of 40 to 200 ° C. As the pressure condition, normal pressure to 50 kg / cm is adopted.

Furthermore, since the desired aliphatic saturated ketone is obtained in extremely high purity in the product liquid obtained by hydrogenating the aliphatic unsaturated ketone according to the method of the present invention, by simple distillation or the like,
The desired product can be taken out.

〔Example〕

Next, the present invention will be described more specifically with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist.

The alkali metal / palladium atomic ratio on the surface of the catalyst of the present invention was determined by the surface composition analysis by X-ray photoelectron spectroscopy (ESCA) according to the following method.

Preparation of sample to be measured The catalyst powder is directly dried under reduced pressure at room temperature. After drying, fix the catalyst powder to the sample holder using double-sided adhesive tape,
Use the following measurements.

Measurement and analysis method Equipment: KRATOS XSAM 800 Excitation source: AlKα ray (14KV × 20mA) Measurement mode: Fixed reduction ratio (Fixed Retarding Ratio) C _1S , Pd _3d , Na _2S , K _2P scanning width Measured by computer control at 20 eV. The peak area of the obtained spectrum is determined by subtracting the linear baseline. The obtained peak area is corrected by the element sensitivity ratio and the molar ratio (atomic number ratio)
Ask for. (Analytical values for surfaces up to approximately 50 Å in the depth direction are obtained by this method.) Elemental sensitivity ratio (C _1S value is 1.00) Pd _3d 14.1 Na _2S 0.649 K _2P 0. 259 atomic ratio Examples 1-2 and Comparative Examples 1-3 Aqueous solution containing palladium chloride, aqueous sodium carbonate solution,
An activated carbon catalyst containing sodium ions and atomic palladium was prepared using activated carbon powder and a reducing agent. The catalyst was washed with demineralized water and the sodium component was gradually extracted and removed to prepare catalysts having various sodium contents. The amount of sodium component supported on the obtained catalyst (bulk composition), Na / Pd atomic ratio (bulk composition), and Na / Pd atomic ratio on the catalyst surface determined by X-ray photoelectron spectroscopy are shown in Table 2. It was. The palladium loading rate (based on dry catalyst) was 2 wt%. 30 g of 4-methyl-3-penten-2-one and 0.6 g of the prepared catalyst (about 50% content) in a 200 ml autoclave with stirring.
Was charged and hydrogenation was carried out by reacting at 150 ° C. and hydrogen pressure of 0.9 MPa for 2 hours. The product was allowed to stand to separate the catalyst by sedimentation, and then the supernatant component was analyzed. The results are shown in Table-2.

Examples 3 to 6 Catalysts were prepared in the same manner as in Example 1 except that the type and amount of the aqueous alkali carbonate solution used were changed to change the alkali metal / palladium atomic ratio as shown in Table 3.

Using the prepared catalyst, a reaction was carried out under the same conditions as in Example-1. The results are shown in Table-3.

[Effect] When the aliphatic unsaturated ketone is hydrogenated by the method of the present invention, the composition in the resulting reaction product liquid is, for example, as shown below, since the aliphatic saturated ketone has an extremely high purity, it can be easily distilled. The product can be taken out with high purity. In saturated aliphatic ketones (target product)

Claims (2)

[Claims] 1. A method for hydrogenating an aliphatic unsaturated ketone in a liquid phase in the presence of a catalyst to obtain an aliphatic saturated ketone, wherein the catalyst contains palladium and an alkali metal supported on activated carbon as active components. Before the hydrogenation reaction, the atomic ratio of alkali metal / palladium on the catalyst surface up to about 50Å in the depth direction is determined by X-ray photoelectron spectroscopy, and the atomic ratio is within the range of 0.7 to 3.5. A method for hydrogenating an aliphatic unsaturated ketone, which comprises subjecting a certain substance to a hydrogenation reaction. 2. The method for hydrogenating an aliphatic unsaturated ketone according to claim 1, wherein the aliphatic unsaturated ketone is 4-methyl-3-penten-2-one. how to.