JPS58203936A - Preparation of oxocarboxylic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound, e.g. adipaldehydic acid, etc., which is a useful synthetic intermediate in improve yield, by adding a cyclohexanone to water and an iron compound, and oxidizing the cyclohexanone with oxygen in the presence of sulfur and/or an organic sulfur compound. CONSTITUTION:A compound expressed by formula I (R is H or alkyl) is oxidized with oxygen in the presence of (i) water, (ii) an iron compound preferably soluble in water, e.g. ferric chloride, and (iii) sulfur and/or an organic sulfur compound to give a compound expressed by formula II in high yield. The amounts of the raw materials are as follows: the component (i) in an amount of 0.05- 1,000 times, preferably about 0.1-100 times, of the weight of the compound expressed by formula I , and the amount of the component (ii) is 0.1-100mol%, preferably about 1-30mol%, expressed in terms of iron based on the compound expressed by formula I . The amount of the component (iii) is 0.1-100mol%, preferably about 5-100mol%, specifically equivalent weight or more, expressed in terms of sulfur based on the iron. The reaction temperature is 0-200 deg.C, preferably about 30-90 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing oxocarboxylic acids. Azibaldehyde acid, which is a synthetically useful intermediate, is known as a representative compound of oxocarboxylate/acids, but conventionally, as for the production method of this product, for example, cyclohexanone is mixed in the presence of water and a copper compound. A method of oxidizing with molecular oxygen (Japanese Patent Publication No. 26-26-63) has been reported. However, Kempo has the drawback that both the conversion rate of raw materials and the yield of the target product are not high.

On the other hand, the present inventors have found that when cyclohexanone is first subjected to an oxidation reaction in the presence of water and an iron or iridium compound, azibaldehyde acid is rapidly produced. The present inventors continued their studies in order to further increase the yield of the target product, and found that by oxidizing cyclohexanone with oxygen in the presence of water and iron compounds, as well as sulfur or sulfur compounds, The present invention was accomplished by discovering that the yield of oxocarboxylic acids, including azibaldehyde acid, can be improved.

1'J, a detailed description of the present invention is given below.

In the present invention, cyclohexanones represented by the following general formula (1) are oxidized with oxygen in the presence of (0 water, ■ an iron compound, and ■ sulfur and/or an organic sulfur compound).
) Oxocarvone type 1 represented by the formula % ([1) is produced.

R in general formulas (1) and (II) have the same meaning,
Indicates hydrogen or an alkyl group. Although the alkyl group is not limited to %, it is practically preferable that the number of alkyl groups is 6 or less.

The iron compound is preferably one that is soluble in water, and specific examples include ferrous chloride, ferric chloride, ferric bromide, ferrous sulfate, and ferric iron.

Examples include inorganic acid salts such as ferric nitrate and organic acid salts such as acetate. It may also be something that dissolves in the raw material, such as iron acetylacetonate.

The amount of the iron compound to be used can be varied over a wide range, but for example, for cyclohexanones, the amount of iron is preferably about θ, 1 to /θO, more preferably about / to JO.

In the present invention, it is essential to use sulfur or organic sulfur compounds in addition to iron compounds. Specific examples include elemental sulfur, dicarboxylic acid, mercaptans such as ether mercaptan, komerkabutoethanol,
2-mercaptoethylamine 1. 2-mercaptopyridine, tei-mercaptopyridine, thioglycolic acid, nsuaine I, etc., thiophenols, ttf thiophenol, thiocresol, p-nitrothiophenol, etc., sulfides such as diethylsulf(de, diphenyl) Sulfide, thiazolidine, methionine, etc., disulfides such as Schiff↑ enyl disulfide, thioamides such as thiourea,
Examples include thioacetamide, sulfoxides such as evadimethyl sulfoxide, sulfones such as hasiphenyl sulfone, thiocyanate esters such as ethyl thiocyanate, and a wide range of other compounds such as sulfonium compounds, thiuronium compounds, thiocarboxylic acids, dithiocarbamic acids, and xanthogenic acids. . The amount of these used is
The range of sulfur relative to iron is 0.1 to ioθ moles, more preferably 3 to ioo moles. It is preferable not to use more than the equivalent amount to the special trap iron.

The presence of water is a fee for carrying out the method of the present invention, and the amount used is o, o
It is good to set it to about r times to /,000 times, more preferably about 0.1 times to 100 times. Depending on the amount of water used,
The reaction system can be a homogeneous phase or a Fi suspended phase, and either of these can be used to carry out the method of the present invention. Moreover, a solvent can also be used to promote homogenization of the reaction system. As the solvent, aprotic polar solvents such as dioxa/tetrahydrofuran are preferred.

The reaction temperature when carrying out this reaction can be varied over a wide range, but to give one example, it is preferably from oc to θOC1, preferably from JOc to deoc. Although the reaction can proceed sufficiently at normal pressure, it may be pressurized.

#'i Pure oxygen can be used as acid JA#, but it may also be used in a diluted form such as air.

Although the conversion rate of cyclohexanones can be arbitrarily selected, a high conversion rate tends to increase overoxidation products, so if the conversion rate is kept at 1, for example, 200 or less, the selectivity of the target oxocarboxylic acids will be better.

The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as they do not exceed the gist of the invention.

Comparative Example Cyclohexanone 1t (to, commimole), water lθ,
A mixture of 6t1 anhydrous ferric chloride o, t A z v (commmol) was heated to toc and stirred vigorously to absorb oxygen at normal pressure. The reaction was stopped when the amount of absorbed oxygen reached approximately commimolar, and the product was analyzed by gas chromatography. The results were as follows.

Reaction time Cyclohexa Adiboaldenone conversion rate Human selectivity (min) (Sword (4) 40 2!, 9 A9.7 Example/
~/j Under the same reaction conditions as in the comparative example, sulfur compounds of each orange were added to the reaction system in the amounts shown in Table 1 to carry out the reaction. The results are shown in Table-/.

-'' Example 76~I Under the same conditions as Example/~is, using a dioxa/-water mixture C, t:s (weight ratio))/jd instead of water as a solvent, the reaction fraction was determined. The results are shown in Table 1.

EXAMPLE - The same reaction as in Example 1 was carried out in the same manner as in Example 1, except that the amount of Komelkabutoviridine added was reduced to 0.0/mmol.

The results are shown below.

Reaction time Cyclohexa Adiboaldeno/conversion rate Human rice selectivity (min) (chi) (chi) 40
Ko4.4! 73. Meng Example, 23 Anhydrous ferric bromide in place of ferric chloride 0. ．． 30t(/
The same reaction as in Example 1 was carried out except that 0 commimol) was used. The results are shown below.

Reaction time Cyclohexa Adiboaldenone conversion rate Selectivity to human # (min) (H) (4) 7! I 20. &
Kda, 9 Examples Koda Same Methylcyclohexanone/l (z, qtti mol)
, water/O, J f, anhydrous ferric chloride 0. /'I da f(
θ, t de mmol), thiourea 0.03 daf (o, ti
s Mi! 7 mol) was reacted under the same conditions as in Example 1. The results are shown below.

Reaction time Kometelcyclo 4-ketoheptanehexanone conversion rate Acid selectivity (Feng) (%) (Chi)
/10 2t,E ri7.
[Representative of Mitsubishi Chemical Industries, Ltd. Patent attorney Hase - and 1 other person]

Claims (1)

[Claims] (1) Cyclohexanones represented by the general formula (1) (wherein R represents hydrogen or an alkyl group) are mixed with ■ water, ■ an iron compound, and ■
General formula (n) characterized in that it is oxidized by oxygen in the presence of sulfur and /' or an organic sulfur compound A method for producing oxocarboxylic compounds represented by