JPS6046103B2 - Method for producing unsaturated carbonyl compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of unsaturated carbonyl compounds.

More specifically, the present invention relates to a method for producing an unsaturated carbonyl compound by reacting a carbonyl compound and/or acetal with an unsaturated alcohol. The unsaturated carbonyl compound that is the object of the present invention is a compound that has been conventionally useful in the terpene chemical industry, and is particularly an industrially valuable compound as a fragrance, a medicine, an agricultural chemical, or an intermediate thereof.

Conventionally, methods for producing such unsaturated carbonyl compounds include, for example, first producing acetylene alcohols using a carbonyl compound and acetylene as raw materials;
A known method is to reduce this and then react the resulting alcohol with diketene, acetoacetate, isopropenyl ether, or the like. This conventional method not only requires numerous reaction steps in order to add five carbon atoms to the starting carbonyl compound, but also
As a reaction reagent, a difficult-to-handle compound such as acetylene must be used under pressure, which is unavoidable from an industrial standpoint.

As a result of research on a method that does not have the drawbacks of the conventional methods described above, the present inventors have determined that an acetal having at least three carbon atoms having a substituent at least at the γ-position is reacted with allyl alcohol or a substituted derivative thereof. It was found that an unsaturated carbonyl compound having the following skeleton could be obtained all at once.

According to the present invention, the following general formula [1] [wherein R is an alkyl group having 1 to 4 carbon atoms, R1 to R3]
are the same or different hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and R4 is a hydrogen atom.

In addition, -R'' and RO are the same or different alkyl groups having 1 to 4 carbon atoms, or one of them is a hydrogen atom.] The acetals represented by the following general formula [■] [
However, in the formula, R is an alkyl group having 1 to 4 carbon atoms, R1 to R8
are the same or different hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and R4 is a hydrogen atom.

] The aldehyde represented by the following general formula [■] [wherein R5 to R8 are the same or different hydrogen atoms or hydrogen atoms having 1 carbon number]
-4 alkyl group, R9 is a hydrogen atom or has 1 to 40 carbon atoms
represents a hydrocarbon group. ] By heating and reacting with an unsaturated alcohol represented by the following general formula [■] [
However, an unsaturated carbonyl compound represented by the formula (R, Rl to R9 are the same as defined above) is obtained in one step.

According to the present invention, at least 5
carbon atoms can be bonded.

In the present invention, in the compound represented by the formula [1], it is necessary that γ be substituted with at least a substituent R in order to obtain the desired unsaturated carbonyl compound. R is an alkyl group having 1 to 4 carbon atoms, examples of which include methyl group, ethyl group, propyl group,
A butyl group may be mentioned.

Further, R1 to R3 are the same or different hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and R4 is a hydrogen atom.

Furthermore, R'' and R'' may be the same or different, and both are alkyl groups having 1 to 4 carbon atoms, or one of them is a hydrogen atom. Specific examples of the compounds of the above formula [1] are as follows.

In the present invention, the acetal represented by the above formula [1] and the unsaturated alcohol represented by the above formula [■] are reacted.

To explain the unsaturated alcohol of formula [■] as shown below, the unsaturated alcohol has at least carbons at the β and γ positions forming a double bond with each other based on the alcoholic hydroxyl group. It is something that exists.

In the above formula [■], R and -R8 may be the same or different.

R and ~R6 are hydrogen atoms or alkyl groups having 1 to 4 carbon atoms. Further, R represents a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms, and may be either saturated or unsaturated. The following unsaturated alcohols include [■]-(a
) to (f) can be mentioned as specific examples.

[Above [■] In (a) to (f), n is 1 to 101
Preferably it shows 1-5.

] Among these [■]-(a) to (f), preferred is [
■] 1 (a), [■] - (b), [■] - (e) and [
■] - (f).

An example of an industrially advantageous embodiment of the method of the present invention is as follows: When m is 0, citral is obtained, and when m is 1, farnesal is obtained.

In another example, when (m is O to 10) is used instead of the alcohol in the above reaction, when m is 1, it is a compound represented by the formula dihydrofarnesal, and when m is 2, it is a compound represented by the formula: It is a precursor of phytol.

In the present invention, the ratio of the unsaturated alcohol represented by the general formula [formerly] to the acetals represented by the general formula [1] is not particularly limited, but is usually 100 moles or less of the latter per 1 mole of the former, preferably 1 mole or less of the latter. is suitably 50 mol or less, and the lower limit is advantageously 0.2 mol or more, preferably 0.3 mol or more.

The reaction of the present invention can be carried out either in the presence or absence of a catalyst, but when an acid catalyst is used as a catalyst, it is possible to obtain an unsaturated carbonyl compound in good yield in some cases.

The acid catalyst used in this case may be any catalyst as long as it exhibits acidity, and includes various catalysts such as inorganic acids, organic acids, solid acids, and strong acid salts of weakly basic substances.

Specific examples of acid catalysts include inorganic acids such as hydrochloric acid,
Sulfuric acid, perchlorate, phosphoric acid, boric acid, titanic acid, hypophosphorous acid, metaboric acid, etc.; examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, stearic acid , aliphatic carboxylic acids such as palmitic acid, acrylic acid, oxalic acid, tartaric acid, maleic acid, etc., alicyclic carboxylic acids such as hexahydrobenzoic acid, naphthenic acid, etc., benzoic acid, o-, m-, or p-toluyl. Aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, alpha- or beta-naphthoic acid, anisic acid, benzoic acid, cyanobenzoic acid, brobenzoic acid, etc.; e.g. methane Aliphatic acids such as sulfonic acid, ethanesulfonic acid, cyclohexane sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.
Aliphatic mono- or aromatic-sulfonic acids; e.g. methylphos,
phosphinic acids or phosphonic acids such as finic acid, ethylphosphinic acid, phenylphosphinic acid, methylphosphonic acid, ethylphosphonic acid, benzylphosphonic acid, etc.;
Examples of solid acids include silica gel, silica alumina,
In addition to oxide-based solid acids such as alumina, titanium oxide, germanium oxide, and boron oxide, salts or acid-supported solid acids such as NH4Ce-supported silica alumina and zinc chloride-supported silica alumina; as strong acid salts of weak basic substances , Examples include ammonium chloride, ammonium nitrate, ammonium sulfate,
Examples include ammonium phosphate, ferric chloride, zinc chloride, aluminum chloride, calcium chloride, tin chloride, ammonium p-toluenesulfonate, and tetraethylammonium p-toluenate.

The various acid catalysts described above are merely exemplified, and the present invention is not limited thereto in any way.
The acid catalyst used in the present invention is characterized by its acid strength (P
Preference is given to those with ka) in the range from 0 to 10, preferably in the range from 0 to 7, particularly preferably in the range from O to 5.

The amount of the acid catalyst to be used is desirably 500 mol% or less, preferably 250 mol% or less, particularly preferably 100 mol% or less, based on 1 mol of the acetal [1].

The lower limit is 1 x 10-6% or more, preferably 1 x 10-6%
A suitable amount is 5 mol% or more. According to the research of the present inventor,
The yield of the desired unsaturated carbonyl compound mainly depends on the reaction temperature and reaction time, which are interrelated, and if an acid catalyst is used, it is also related to the type and amount used. It has been found that unsaturated carbonyl compounds can be obtained in high yield by appropriately selecting them.

That is, it is preferable to carry out the reaction at a temperature of generally 100 DEG C. or higher, particularly 150 DEG C. or higher, for a period of 1 minute to 5 hours, particularly 5 minutes to 2 m, within the range of reaction temperature and reaction time described below. In addition, as an acid catalyst, the acid strength (Pka) is 0 to
7, preferably a relatively strong acid to a strong acid in the range of 0 to 5, to the acetals [1] as the raw material,
in the range of 1 x 10-6 to 250 mol%, especially 1 x 10-5
When used in a range of 100 mol %, an unsaturated carbonyl compound can be obtained in high yield. Although the reaction of the present invention can be carried out in either a gas phase or a liquid phase, it is generally preferable to carry out the reaction in a liquid phase.

At that time, a solvent may or may not be used. When using a solvent, any solvent may be used as long as it does not adversely affect the reaction, and for example, the following solvents can be used. (1) Aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, etc. (Ii) Alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane, decalin, etc. (111) Aromatic hydrocarbons such as benzene, toluene , xylene (oxo, meta,
(IV) Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, chloroform,
Dichloroethane, trichloroethane, tetrachloroethane, chlorobenzene, dichlorobenzene, etc. (v) Ethers such as diethyl ether, tetrahydrofuran, dioxane, etc. (Vi) Esters such as ethyl acetate, butyl acetate, methyl benzoate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate Among these solvents, particularly preferred are solvents having 1 to 20 carbon atoms (
1) Aliphatic hydrocarbon, (IiO aromatic hydrocarbon having 1 to 20 carbon atoms).

When using the above solvents, the starting materials, acetals [
1] A molar ratio of 0.01 to 200, preferably 0.1 to 100 is used per 1 mole.

The heating reaction of the present invention is preferably carried out at a temperature in the range of 100 to 350°C, particularly preferably 150 to 300°C, and the pressure may be reduced, normal pressure, or increased pressure. .

The reaction time varies depending on the reaction temperature, gas phase, liquid phase, etc., but is generally 1 minute or more.

In particular, in the case of a liquid phase, 1 minute to 5 hours, particularly 5 minutes to 2 hours is preferable. The method of the present invention can be carried out either batchwise or continuously. EXAMPLES Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Examples 1 to 7 3-Methyl-3-butenal diethyl acetal
When reacted with methyl-2-butenol (prenol) in a sealed tube, the following results were obtained.

In the table, 3-methyl-3-butenal-1-diethyl acetal is abbreviated as acetal, and the product citral is abbreviated as CT.

Note that the CT selectivity is the CT selectivity for the converted acetal.
is the mole% of

Claims (1)

[Claims] 1 The following general formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. are included▼...[I] [However, in the formula, R is an alkyl group having 1 to 4 carbon atoms, and R_1 to R_3 are the same or different hydrogen atoms. an atom or an alkyl group having 1 to 4 carbon atoms,
R_4 represents a hydrogen atom. Further, R' and R'' are the same or different alkyl groups having 1 to 4 carbon atoms, or one of them is a hydrogen atom.
] The acetals represented by the following general formula [II] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... [II] [However, R_ in the formula
5 to R_6 are the same or different hydrogen atoms or carbon atoms 1 to 4
The alkyl group R_9 represents a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms. ] The following general formula [III] ▲ mathematical formula, chemical formula,
There are tables, etc. ▼… [III] [However, in the formula R, R_1 ~ R
_9 is the same as the above definition] A method for producing an unsaturated carbonyl compound.