JPS60112736A - Production of cinnamic acid - Google Patents

Abstract

PURPOSE:To obtain a cinnamic acid of high quality useful as a raw material for perfumes, medicines, pressure-sensitive paper and industrial chemicals easily at a low cost, by hydrolyzing a cinnamic acid ester in the presence of an acid having a specific acid strength as a catalyst. CONSTITUTION:A cinnamic acid ester of the formula (R<1> is H, halogen, 1-4C alkyl and alkoxyl; R<2> is H or 1-6C alkyl; R<3> is 1-4C alkyl), e.g. methyl cinnamate, as a raw material is hydrolyzed with water in the presence of an acid catalyst having <=2pKa value if necessary in a solvent at 50-140 deg.C under ordinary pressure to afford the aimed cinnamic acid. An acid catalyst, e.g. p-toluenesulfonic acid, benzenesulfonic acid, sulfuric acid or a solid acid catalyst such as ''Diaion PK-208'' (manufactured by Mitsubishi Chemical Industries Limited) which is a strongly acidic cation exchange resin having <=2pKa value and sulfonic acid functional groups may be used as the above-mentioned acid catalyst. The amount of the acid to be used is 0.001-10mol based on 1mol raw material of the formula.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of cinnamic acids by the hydrolysis reaction of cinnamic acid esters, and more specifically, to the production of cinnamic acids from cinnamic acid esters efficiently in the presence of an acid catalyst. It is about the method.

Cinnamic acid is used as a raw material for perfumes, medicines, pressure-sensitive papers, and other useful industrial chemicals. Conventional methods for producing cinnamic acid include the Perkin reaction or the condensation of benzaldehyde and ketene.

The present inventors first conducted an oxidative carbonylation (alkoxycarbonylation) reaction of styrenes in the presence of a catalyst consisting of palladium metal or its compound, copper or iron salts, and alkali metal or alkaline earth metal salts. As a result of further intensive research into a method for industrially advantageous production of cinnamic acids by decomposing cinnamate, we found that if cinnamic acid esters are brought into contact with water in the presence of an acid with a specific acid strength, the hydrolysis reaction can be prevented. The present invention was achieved by discovering that scales can be advantageously advanced.

In other words, today, as long as cinnamic acid esters can be hydrolyzed efficiently and economically, it is possible to use these cinnamic acid esters as raw materials instead of the conventional method of directly producing cinnamic acid, which is cheaper and of higher quality. This means that cinnamic acids can be obtained.

Therefore, the object of the present invention is to provide a method for carrying out the hydrolysis reaction for obtaining cinnamic acids from cinnamic acid esters in an industrially advantageous manner. is easily achieved by hydrolyzing cinnamic acid esters using an acid of λ or less as a catalyst.

The present invention will be explained in detail below.

The raw material used in the method of the present invention has the general formula (wherein R1 represents hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 1 carbon atoms, and R2 represents hydrogen or a carbon number /-A represents an alkyl group, and R1 represents an alkyl group having a carbon atom number/~g. Examples include butyl, α-methyl, ethyl β-phenylacrylate, methyl α-propyl β-chlorophenylacrylate.

The hydrolysis reaction according to the method of the present invention is carried out in the presence of an acid catalyst having a pKa value of 2 or less. Specifically, acid catalysts with an acid strength of 2 or less in pKa value include organic carboxylic acids such as trifluoroacetic acid; Sulfonic acid; mineral acids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, hexafluorophosphoric acid, fluorosulfonic acid, chlorosulfonic acid;
Examples include heteropolyacids such as phosphomolybdic acid and silicotungstic acid, and so-called solid acids such as acidic cation exchange resins, clay minerals, and zeolites are also useful.

The acidic cation exchange resin used as the solid acid catalyst is a strongly acidic cation exchange resin having a sulfonic acid functional group with a pKa value of 2 or less, and may be in either gel form or porous form and may be selected from various commercially available products. You can choose. Specifically, Diaion @ 5KIA, 5xrB, px-
xor, PK-2rr, Diamondion HPK-
Those with a styrene-divinylbenzene copolymer skeleton such as JJF (manufactured by Mitsubishi Chemical Industries, Ltd.), 7/Bar Phyto +200 (manufactured by Rohm and Haas), and tetracarbons such as Nafion Roi (manufactured by DuPont). Examples include those having a fluoroethylene polymer skeleton.

It is also preferable to have a hydrogen ion exchange capacity exceeding 1 milliequivalent/S't-.

As inorganic solid acids, natural or synthetic products such as acid-treated minerals or zeolites have pK values useful in the method of the present invention.
a has an acidity of λ or less, and specific clay minerals and zeolites include montmorillonite, kaolinite, and bent. The amount of acid used is 0.00/~10 mol per 1 mol of cinnamic acid ester, preferably 0.01N1
It is in the molar range.

Although the use of a solvent is not essential in the method of the present invention,
In order to carry out the reaction more smoothly, it is preferable to use a solvent.

Examples of such solvents include ethers such as diethyl ether, diphenyl ether, dioxane, tetrahydrofuran, and ethylene glycol dimethyl ether, ketones such as acetone, ethyl methyl ketone, dibutyl ketone, and acetophenone, acetonitrile, and propionitrile.

Nitriles such as benzonitrile, benzene, toluene,
Examples include aromatic hydrocarbons such as xylene and ethylbenzene, but alcohols such as methanol, ethanol and butanol can also be used.

The hydrolysis reaction in the method of the present invention can be carried out in any of a homogeneous phase system, a suspended bed system, and a fixed bed system, and can also be carried out in a batch reaction system or a continuous flow system.

The appropriate amount of water relative to the raw material cinnamic acid ester is o, 1-xoo times, preferably 1 to 100 times, in mole.

The reaction temperature is suitably 0.1 aoc., preferably 0.1 aoc. Although the operation is usually carried out at normal pressure, it may also be advantageous to operate at slightly reduced or increased pressure.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 Methyl cinnamate 11 and water 207 were introduced into a 100 ml glass Mitsuroh flask equipped with a reflux condenser, together with Diaion [F] PK-2 or (manufactured by Mitsubishi Chemical Corporation) 1, and the flask was heated. Temperature in oil path / 10C
The reaction was carried out for 3 hours while maintaining the temperature. Analysis of the product by gas chromatography revealed that the conversion rate of methyl cinnamate to cinnamic acid was 4%.

Example In Example 1, diamond ion [F]px-2or%t
The reaction and analysis were conducted under the same conditions except that he-paratoluenesulfonic acid and 31 were used. The conversion rate of methyl cinnamate was 3r, 0%.

Example 3 The reaction and analysis were carried out under the same conditions as in Example λ except that the reaction temperature was changed from /20C to 120C for 2 hours. The conversion rate of methyl cinnamate was II/, 2%.

Example ≠ Methyl cinnamate/1 and water λ01 were placed in a glass-slit Mitsuro flask equipped with a 100 t reflux condenser, and 31 sulfuric acid was added.
Introduce the temperature of the flask with an oil bath.
The reaction was carried out for 3 hours while maintaining the temperature at 20C. The conversion rate of methyl cinnamate to cinnamic acid is 23. He was in charge.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - (7 others)

Claims (1)

[Claims] (1) A method for producing cinnamic acids, which comprises hydrolyzing cinnamic acid esters using an acid having a pKa value of λ or less as a catalyst.