JPH07247240A - Production of lactones and esters - Google Patents

Abstract

PURPOSE:To provide a method capable of producing a lactone or a noncyclic ester containing an aromatic ring from a raw material ketone in the absence of a catalyst and even under a mild condition in high yield. CONSTITUTION:In producing a lactone by oxidizing an alicyclic ketone in a liquid phase in the presence of both an aldehyde and oxygen or producing a noncyclic ester containing an aromatic ring by oxidizing a noncyclic ketone containing an aromatic ring in a liquid phase, 0.5-25wt.%, preferably 1-15wt.% based on the raw material ketone of an acid chloride, preferably an aromatic acid chloride (especially benzoyl chloride) is added to the reaction system and the reaction is carried out usually at 0-65 deg.C, preferably 10-40 deg.C. The reaction is preferably done in a solvent system selected from among an aromatic hydrocarbon, an alkyl halide, a halogenated hydrocarbon and an ester in terms of yield of the prepared lactone or ester. Since a metal catalyst is not used, side reactions of the formed product will not occur and after-treatment is simple.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing lactones and a method for producing esters. Specifically, it relates to a method for producing a lactone by liquid-phase oxidation of an alicyclic ketone and a method for producing an acyclic ester having an aromatic ring by liquid-phase oxidation of an acyclic ketone having an aromatic ring.

[0002]

BACKGROUND OF THE INVENTION Lactones and acyclic esters are
It is a useful substance used for various industrial chemicals such as solvents, functional resins, and pharmaceuticals, and their synthetic intermediates. As a method for producing such lactones and acyclic esters, the Bayer-Villiger reaction of ketones is generally used. However, since this reaction is a homogeneous reaction, it is difficult to separate products, and an expensive peracid is used, which is economically disadvantageous.

As a reaction similar to the Bayer-Villiger reaction, Japanese Patent Publication No. 39-5921 discloses that cyclic ketones such as cyclohexanone are reacted in the presence of a catalyst, an oxygen-containing gas and aldehydes to obtain ε-caprolactone. The method for simultaneously producing the lactones and the carboxylic acids is disclosed. However, the method has a low yield of lactones, and further uses a heavy metal compound such as cobalt, manganese, platinum, palladium, vanadium, ruthenium, zirconium, aluminum, antimony, beryllium or copper as a catalyst. There are problems of toxicity and separation of the reaction product and the catalyst. Further, in JP-A-53-25516, a chromium compound is dissolved in a reaction system as a catalyst,
Similar to the above, it is unsatisfactory in terms of yield and toxicity of lactones. Further, JP-B-55-36667 is characterized by adding a peracid when liquid-phase oxidizing cyclic ketones in the presence of aldehydes and molecular oxygen, but is safe because peracid is used. There are disadvantages both economically and economically. Further, in Japanese Unexamined Patent Publication (Kokai) No. 5-65245, manufacturing conditions using a catalyst-free system or a known cobalt catalyst described in JP-B-39-5921 are adopted, and a cyclic ketone and an aldehyde are reacted under limited conditions. Although it is described that by-products can be suppressed by doing so, the yield is not sufficient in the non-catalyst system.

Further, all of the above publications limit the final product to lactones, and do not describe any method for synthesizing corresponding esters from acyclic ketones having an aromatic ring.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a high yield of a lactone or an acyclic ester having an aromatic ring from a ketone under a mild reaction condition and in the absence of a metal catalyst. The purpose of the present invention is to provide a new production method that can be used.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that in the liquid-phase oxidation of starting material ketones in the coexistence of aldehydes and oxygen, It has been found that the above-mentioned problems of the prior art can be solved by adding an acid chloride into the reaction system. The present invention has been completed based on this new finding.

That is, the present invention is characterized in that an acid chloride is added to the reaction system in a method for producing a lactone by liquid phase oxidation of an alicyclic ketone in the presence of aldehydes and oxygen. A method for producing a lactone and a method for producing an acyclic ester having an aromatic ring by subjecting an acyclic ketone having an aromatic ring to liquid phase oxidation in the coexistence of an aldehyde and oxygen to produce an acid chloride in the reaction system. And a method for producing an acyclic ester having an aromatic ring.

As the alicyclic ketones used as the raw material in the present invention, various known ones can be used without particular limitation.
Specific examples thereof include cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-
Methylcyclohexanone, 2-ethylcyclohexanone, 2-isopropyl-5-methylcyclohexanone,
2-methoxycyclohexanone, 4-methoxycyclohexanone, 3,3,5-trimethylcyclohexanone,
4-t-butylcyclohexanone, 2,5-methanocyclohexanone, cycloheptanone, 2-adamantanone and the like can be mentioned.

As the acyclic ketone having an aromatic ring, various known ones can be used without particular limitation. Specific examples thereof include 4-methoxyacetophenone,
4-methylacetophenone, 2-ethoxy-2-phenylacetophenone, benzoylacetone, o-benzoylbenzoic acid, 2-benzoylpyridine, benzophenone, propiophenone, pentanophenone, 4-methoxyphenylcyclopropylketone, cyclopentylphenylbutanone, Myristophenone, butyrophenone, chlorophenylethanone, bromophenylbutanone, 1-
Examples include phenyl dodecaphenone and heptanophenone.

The acid chloride used in the present invention may be any known one without any particular limitation. As a concrete example,
Examples thereof include benzoyl chloride, propionyl chloride, pentylyl chloride, p-methoxybenzoyl chloride and p-chlorobenzoyl chloride. Among these, aromatic acid chlorides such as benzoyl chloride are preferable.

The acid chloride is used in an amount of usually about 0.5 to 25% by weight, preferably 1 to 25% by weight based on the starting ketones such as alicyclic ketones or acyclic ketones having an aromatic ring. It is 15% by weight. If it is less than 0.5% by weight, the effect of addition is low and a sufficient reaction rate cannot be obtained.
If it exceeds 25% by weight, it is disadvantageous in terms of cost and work. Although the mechanism of action by the addition of the acid chloride has not been clarified, it is considered that it promotes the generation of peroxy acid radicals generated as a radical donor.

Various known aldehydes can be used, but aromatic aldehydes are particularly preferable. Examples of aromatic aldehydes include benzaldehyde, dimethylbenzaldehyde, trimethylbenzaldehyde, ethylbenzaldehyde, butylbenzaldehyde, methoxybenzaldehyde, phenoxybenzaldehyde, hydroxybenzaldehyde, cyclohexylbenzaldehyde and biphenylbenzaldehyde.

In the production method of the present invention, it is not always necessary to carry out the reaction in the presence of a solvent, but from the viewpoint of the yield of the obtained lactone or acyclic ester having an aromatic ring, the following solvent system is used. It is preferable to carry out. As the solvent, at least one selected from aromatic hydrocarbons, alkyl halides, halogenated carbons and esters can be used.

Among the above solvents, aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene,
Various known compounds such as propylbenzene, isobutylbenzene, methylethylbenzene, diethylbenzene, and tetralin can be exemplified, but among them, benzene is preferable.
Known alkyl halides can be used, but those having about 1 to 5 carbon atoms are preferable, and dichloromethane, trichloromethane, dichloroethane, trichloroethane, dichloropropane, dichlorobutane, trichloropropane, trichlorobutane, tetrachloropropane,
Examples include tetrachlorobutane. Examples of the carbon halide include carbon tetrachloride, hexachloroethane, octachloropropane and the like. Examples of the esters include methyl acetate, ethyl acetate, isobutyl acetate, methyl propionate, ethyl propionate, isobutyl propionate and the like.

Each of the above solvents may be used alone or in combination.
A combination of two or more species can be used. From the viewpoint of the yield of lactones or acyclic esters having an aromatic ring, aromatic hydrocarbons and alkyl halides are preferable among the above solvents, and benzene and dichloroethane are particularly preferable.

The amounts of the aldehydes and the optionally used solvent used with respect to the raw material ketones may be appropriately determined according to the type of the raw material ketones. Usually, the amount of aldehydes is 1 part by mole or more, preferably 1 to 50 parts by mole, relative to 1 part by weight of the starting ketones. When the amount of aldehydes is less than 1 part by mole, the reaction is difficult to proceed sufficiently. The amount of the solvent used is usually 1 part by weight or more, preferably 2 to 125 parts by weight, relative to 1 part by weight of the aldehyde. If the amount of solvent used is less than 1 part by weight, the reaction rate will decrease.

In the production method of the present invention, a predetermined amount of an aldehyde and an acid chloride are dissolved in the solvent, and the aldehyde is automatically oxidized in an oxygen atmosphere to generate a peroxide. A two-step method in which a predetermined amount of ketones is added and lactonized (or esterified), or a predetermined amount of raw material ketones is lactonized (or esterified) simultaneously with the generation of a peroxide as an intermediate 1. A step method can be adopted. From the viewpoint of reaction efficiency, the one-step method is preferable.

In the production method of the present invention, there is no particular limitation on the method of forming an oxygen atmosphere, and for example, if an oxygen stream is supplied to the gas phase of the reaction system or oxygen is bubbled directly into the liquid phase, the oxygen atmosphere can be easily obtained. Can be prepared. Oxygen supply is
It must be carefully determined because it correlates with the amount of peracid generated in the reaction system. Normally, the supply amount of the reaction solution per unit volume per unit time is 0.1 to 1200 liters hr ^-1 liters.
⁻¹ , preferably 25 to 200 liters · hr ⁻¹ · liter ⁻¹ .

The reaction in the production method of the present invention can yield lactones or acyclic esters having an aromatic ring in good yield even at atmospheric pressure, but it does not exclude pressurized conditions. The reaction temperature is preferably such that the peracid generated from the aldehydes is not decomposed, usually about 0 to 65 ° C, preferably 10 to 40 ° C. The reaction can be sufficiently performed even at room temperature. Since the optimum reaction temperature varies depending on the type of solvent, it is preferable to select the optimum temperature as appropriate. If the temperature exceeds 65 ° C, the yield of lactones or acyclic esters having an aromatic ring tends to decrease. When using a solvent and reacting under normal pressure,
It is preferable that the temperature is within the above temperature range and not higher than the boiling point of the solvent. The reaction time varies depending on the kind of the starting ketones, the reaction temperature, etc., but is usually about 2 to 36 hours.

[0020]

EFFECTS OF THE INVENTION According to the present invention, lactones or acyclic esters having an aromatic ring can be produced in high yield from raw material ketones under mild conditions without catalyst. In the present invention, since no metal catalyst is used, side reaction of the product does not occur, post-treatment is easy, and there is no problem of catalyst toxicity. In addition, since the reaction proceeds sufficiently at room temperature, the safety is good and the economical effect is achieved.

[0021]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

Example 1 To a 100 ml three-necked flask equipped with a reflux tube, 15 ml of benzene as a solvent, 1.27 ml (12 mmol) of benzaldehyde as an aldehyde compound and 68 mg (0.484 mmol) of benzoyl chloride were added.
Oxygen was bubbled for 30 minutes at room temperature (18-22 ° C.) with a supply rate of 45-55 ml / min. Then, a solution prepared by dissolving 393 mg (4 mmol) of cyclohexanone as a raw material ketone in 5 ml of dichloroethane in advance was used.
The mixture was added dropwise over 1 minute, and the reaction was continued for 4.5 hours to obtain the desired product, lactone. The lactone was analyzed by gas chromatography. Table 1 shows the conversion rate and the selectivity. The selectivity refers to the ratio of the target product in the converted raw materials.

Examples 2 to 15 At least one of the raw material ketones, the addition ratio of the amount of benzoyl chloride (% by weight relative to the raw material ketones), the type of solvent and the reaction temperature was changed as shown in Table 1. Was performed in the same manner as in Example 1. Table 1 shows the conversion rate and the selectivity.

Comparative Example In each example, the same procedure as in each example was performed except that benzoyl chloride was not added. Table 1 shows the conversion rate and the selectivity.

[0025]

[Table 1]

Claims (5)

[Claims] 1. A method for producing a lactone by subjecting an alicyclic ketone to liquid phase oxidation in the presence of an aldehyde and oxygen to produce a lactone, wherein an acid chloride is added to the reaction system. Manufacturing method. 2. A method for producing an acyclic ester having an aromatic ring by subjecting an acyclic ketone having an aromatic ring to liquid phase oxidation in the presence of aldehydes and oxygen to produce an acyclic ester having an aromatic ring, and adding an acid chloride to the reaction system. A method for producing an acyclic ester, comprising: 3. An organic solvent is present in the reaction system.
Or the production method described in 2. 4. The method according to claim 3, wherein the organic solvent is at least one selected from aromatic hydrocarbons, alkyl halides, halogenated carbons and esters. 5. The method according to claim 1 or 2, wherein the aldehydes are aromatic aldehydes.