JP3802087B2 - Process for producing lactones and process for producing esters - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for producing lactones and a method for producing esters. Specifically, the present invention 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]
[Prior art]
Lactones and acyclic esters are useful substances used in various industrial chemicals such as solvents, functional resins and pharmaceuticals, and synthetic intermediates thereof. As a method for producing such lactones and acyclic esters, a buyer's billiard reaction of ketones is common. However, since this reaction is a homogeneous reaction, it is difficult to separate the products, and it is economically disadvantageous because expensive peracid is used.
[0003]
Further, as a reaction similar to the Bayer-Billiger reaction, Japanese Patent Publication No. 39-5921 discloses a reaction of a cyclic ketone such as cyclohexanone in the presence of a catalyst, an oxygen-containing gas and aldehydes, and a lactone such as ε-caprolactone. And a method for simultaneously producing carboxylic acids. However, this method uses a heavy metal compound such as cobalt, manganese, platinum, palladium, vanadium, ruthenium, zirconium, aluminum, antimony, beryllium or copper as a catalyst because the yield of lactones is low. There are problems of toxicity and separation of the reaction product from the catalyst. Japanese Patent Application Laid-Open No. 53-25516 is characterized in that a chromium compound is dissolved in the reaction system as a catalyst, but as described above, it is unsatisfactory in terms of yield and toxicity of lactones. Japanese Patent Publication No. 55-36667 is characterized in that peracid is added in the liquid phase oxidation of cyclic ketones in the presence of aldehydes and molecular oxygen. However, since peracid is used, it is safe to use. There are disadvantages in terms of costs and economics. JP-A-5-65245 adopts a production condition using a non-catalytic system or a known cobalt catalyst described in JP-B-39-5921, and reacts cyclic ketones and aldehydes under limited conditions. Although it has been described that by-products can be suppressed by using a non-catalytic system, the yield is not sufficient.
[0004]
In addition, all the above publications limit the final target product to lactones, and do not describe any method for synthesizing corresponding esters from acyclic ketones having an aromatic ring.
[0005]
[Problems to be solved by the invention]
The present invention provides a novel production method capable of obtaining lactones or acyclic esters having an aromatic ring in high yield from ketones under mild reaction conditions and in the absence of a metal catalyst. With the goal.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the problems of the prior art, the present inventors have added acid chlorides to the reaction system in the liquid phase oxidation of raw material ketones in the presence of aldehydes and oxygen. It has been found that the problems of the prior art can be solved. The present invention has been completed based on such new findings.
[0007]
That is, the present invention relates to a method for producing a lactone by liquid phase oxidation of an alicyclic ketone in the presence of an aldehyde and oxygen, wherein an acid chloride is added to the reaction system. In the production method and the method of producing acyclic esters having an aromatic ring by liquid phase oxidation of an acyclic ketone having an aromatic ring in the presence of an aldehyde and oxygen, an acid chloride is added to the reaction system. The present invention relates to a method for producing an acyclic ester having an aromatic ring.
[0008]
As the alicyclic ketones which are raw materials in the present invention, various known ones can be used without particular limitation. Specific examples thereof include, for example, 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.
[0009]
In addition, as the acyclic ketone having an aromatic ring, various known ones can be used without particular limitation. Specific examples thereof include, for example, 4-methoxyacetophenone, 4-methylacetophenone, 2-ethoxy-2-phenylacetophenone, benzoylacetone, o-benzoylbenzoic acid, 2-benzoylpyridine, benzophenone, propiophenone, pentanophenone, Examples include 4-methoxyphenylcyclopropyl ketone, cyclopentylphenylbutanone, myristophenone, butyrophenone, chlorophenylethanone, bromophenylbutanone, 1-phenyldodecaffeone, and heptanophenone.
[0010]
As the acid chloride used in the present invention, various known ones can be used without particular limitation. Specific examples thereof include benzoyl chloride, propionyl chloride, pentyl chloride, p-methoxybenzoyl chloride, p-chlorobenzoyl chloride and the like. Of these, aromatic acid chlorides such as benzoyl chloride are preferred.
[0011]
The amount of the acid chloride used is usually about 0.5 to 25% by weight, preferably 1 to 15% by weight, based on raw material ketones such as alicyclic ketones or acyclic ketones having an aromatic ring. It is. When the amount is less than 0.5% by weight, a sufficient reaction rate cannot be obtained due to a low addition effect. On the other hand, if it exceeds 25% by weight, it is disadvantageous in terms of cost and work. In addition, although the mechanism of action by addition of an acid chloride is not clarified, it is considered that the generation of peracid radicals generated as a radical donor is promoted.
[0012]
Various known aldehydes can be used, and aromatic aldehydes are particularly preferable. Examples of aromatic aldehydes include benzaldehyde, dimethylbenzaldehyde, trimethylbenzaldehyde, ethylbenzaldehyde, butylbenzaldehyde, methoxybenzaldehyde, phenoxybenzaldehyde, hydroxybenzaldehyde, cyclohexylbenzaldehyde, and biphenylbenzaldehyde.
[0013]
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 the following solvent system is used in view of the yield of the obtained lactones or acyclic esters having an aromatic ring. preferable. As the solvent, at least one selected from aromatic hydrocarbons, alkyl halides, halogenated carbons and esters can be used.
[0014]
Among the above solvents, examples of the aromatic hydrocarbons include various known ones such as benzene, toluene, xylene, ethylbenzene, propylbenzene, isobutylbenzene, methylethylbenzene, diethylbenzene, and tetralin. Among them, benzene is preferable. Known alkyl halides can be used, but those having about 1 to 5 carbon atoms are preferred, and dichloromethane, trichloromethane, dichloroethane, trichloroethane, dichloropropane, dichlorobutane, trichloropropane, trichlorobutane, tetrachloropropane, tetra And chlorobutane. Examples of the halogenated carbon 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.
[0015]
Any of the above solvents can be used alone or in combination of two or more. In view of the yield of lactones or acyclic esters having an aromatic ring, aromatic hydrocarbons and alkylyl halides are preferable among the above solvents, and benzene and dichloroethane are particularly preferable.
[0016]
What is necessary is just to determine suitably the usage-amount of the aldehyde and the solvent used arbitrarily with respect to raw material ketones according to the kind of raw material ketones. Usually, the amount of aldehydes is 1 mol part or more, preferably 1 to 50 mol parts, relative to 1 mol part of the raw material ketones. If the amount of aldehyde is less than 1 mole part, the reaction does not proceed sufficiently. The usage-amount of a solvent is 1 weight part or more normally with respect to 1 weight part of aldehydes, Preferably it is 2-125 weight part. When the amount of solvent used is less than 1 part by weight, the reaction rate decreases.
[0017]
In the production method of the present invention, a predetermined amount of aldehydes and acid chlorides are dissolved in the solvent, and the aldehydes are auto-oxidized in an oxygen atmosphere to generate peroxides. A two-stage method in which a predetermined amount is added and lactonized (or esterified), or a one-stage method in which a predetermined amount of raw material ketones is lactonized (or esterified) simultaneously with the generation of a peroxide as an intermediate. Can be adopted. A one-step method is preferable from the viewpoint of reaction efficiency.
[0018]
In the production method of the present invention, there is no particular limitation on the method for forming an oxygen atmosphere. For example, an oxygen atmosphere can be easily prepared by supplying an oxygen flow to the gas phase of the reaction system or bubbling oxygen directly into the liquid phase. . Since the oxygen supply amount correlates with the amount of peracid generated in the reaction system, it must be carefully determined. Usually, the supply amount of the reaction solution per unit volume unit time is 0.1 to 1200 liters hr ^−1. -About ¹ liter, preferably 25-200 liters-hr ^-1 -liter ^-1 .
[0019]
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 normal pressure, but does not exclude pressurization conditions. The reaction temperature is preferably set to a temperature at which peracid generated from aldehydes is not decomposed, and is usually about 0 to 65 ° C, preferably 10 to 40 ° C. By using the acid chloride, The reaction can be sufficiently performed even at room temperature. Further, since the optimum reaction temperature varies depending on the type of the solvent, it is preferable to carry out by selecting the optimum temperature appropriately. In addition, when it exceeds 65 degreeC, there exists a tendency for the yield of the acyclic ester which has lactones or an aromatic ring to fall. Moreover, when making it react at normal pressure using a solvent, it is good to set it as the temperature within the said temperature range and below the boiling point of a solvent. The reaction time varies depending on the type of raw material ketones and the reaction temperature, but is usually about 2 to 36 hours.
[0020]
【The invention's effect】
According to the present invention, acyclic esters having a lactone or an aromatic ring can be produced in high yield from raw material ketones under non-catalytic and mild conditions. In the present invention, since no metal catalyst is used, the side reaction of the product does not occur, the post-treatment is simple, and there is no problem of catalyst toxicity. In addition, since the reaction proceeds sufficiently at room temperature, the safety is good and there is an economical effect.
[0021]
【Example】
EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to these examples.
[0022]
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 and 68 mg (0.484 mmol) of benzoyl chloride as an aldehyde compound were added, and then room temperature (18-22 ° C.) was reached. Then, oxygen was bubbled for 30 minutes at a supply rate of 45 to 55 ml / min. Next, a solution obtained by dissolving 393 mg (4 mmol) of cyclohexanone as a raw material ketone in 5 ml of dichloroethane in advance was added dropwise over 10 minutes, and further reacted for 4.5 hours to obtain a lactone as a target product. The lactone was analyzed by gas chromatography. Table 1 shows the conversion and selectivity. Note that the selectivity refers to the proportion of the target product in the converted raw material.
[0023]
Examples 2-15
The same procedure as in Example 1 except that at least one of the types of raw material ketones, the addition rate of the amount of benzoyl chloride (% by weight with respect to the raw material ketones), the type of solvent and the reaction temperature was changed as shown in Table 1. It was. Table 1 shows the conversion and selectivity.
[0024]
Comparative Examples In each example, the same procedure as in each example was performed except that benzoyl chloride was not added. Table 1 shows the conversion and selectivity.
[0025]
[Table 1]

Claims (5)

A method for producing a lactone, wherein an acid chloride is added to a reaction system in a method for producing a lactone by liquid phase oxidation of an alicyclic ketone in the presence of an aldehyde and oxygen. A method for producing an acyclic ester having an aromatic ring by liquid phase oxidation of an acyclic ketone having an aromatic ring in the presence of an aldehyde and oxygen, characterized in that an acid chloride is added to the reaction system. A method for producing acyclic esters. The production method according to claim 1 or 2, wherein an organic solvent is present in the reaction system. The process according to claim 3, wherein the organic solvent is at least one selected from aromatic hydrocarbons, alkyl halides, halogenated carbons and esters. The method according to claim 1 or 2, wherein the aldehyde is an aromatic aldehyde.