JPS61180738A - Production of alkyl(dihydroxyphenyl)ketone - Google Patents

Abstract

PURPOSE:To obtain the titled compound by a simple operation efficiently in high quality in high yield, by reacting a resorcin compound and a lower carboxylic acid halide as raw materials in the presence of a zinc halide and an inert solvent in a heterogeneous state. CONSTITUTION:A resorcin compound shown by the formula (R1-R3 are H, or <=5C alkyl) such as resorcin, etc., is reacted with <=5C monocarboxylic acid halide such as acetic acid chloride, etc., in an inert solvent such as nitrobenzene, etc., in the presence of a zinc halide such as zinc chloride, etc., at -10-100 deg.C for 0.1-5hr, the reaction mixture is subjected to solid-liquid separation, and the prepared solid substance is washed with water, to give the aimed high- quality compound such as 2,4-dihyroxyacetophenone, etc. EFFECT:Complicated operations such as distillation, recrystallization, etc., after the reaction are not required, and separating operation can be simplified. USE:An intermediate for fine chemicals, and a raw material for drugs, agricultural chemicals, photosensitive materials, perfume, resins, etc.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing alkyl (dihydroxyphenyl) ketones, and more specifically, the present invention relates to a method for producing alkyl (dihydroxyphenyl) ketones, and more specifically, to efficiently produce alkyl (dihydroxyphenyl) ketones by simple operations using a resorcinol compound and lower calgenic acid halide as raw materials. The present invention relates to a method for producing 2,4-dihydroxyphenyl)ketone.

(Prior Art) A method for producing an alkyl (2,4-dihydroxyphenyl) ketone by reacting a resorcin compound and a lower carboxylic acid in the presence of zinc halide is described.

It is conventionally known. For example, as a specific example.

A method of heating and dissolving a mixture of acetic acid and zinc chloride to 140°C, adding resorcin to it, and heating it to 159°C (0
RGANIC5YNTHKSES Co11@ctiv
e Vol, 3゜761), a method of reacting resorcin and acetic acid at 100 to 130°C in the presence of zinc chloride (%
1983-65039) etc. are known.

However, in both methods, the reaction is carried out at a high temperature of 100° C. or higher, so the products tend to be colored.

Furthermore, the yield was not always satisfactory.

Generally, if a lower carboxylic acid halide is used instead of a lower carboxylic acid, the reaction can be carried out at low temperatures.

Therefore, we tried a method in which resorcinol was dissolved in acetic acid and acetic acid chloride was added at room temperature to cause a homogeneous reaction.1.The problem of coloration was avoided, but large amounts of other by-products were produced.2. There were problems in that the yield of 4-dihydroxyacetophenone was low and furthermore, the separation operation of 2,4-dihydroxyacetophenone after the reaction was complicated.

(Problems to be Solved by the Invention) Therefore, as a result of intensive research in order to solve the above-mentioned drawbacks seen in the prior art, the present inventors found that when the reaction between a resorcin compound and a lower calgenic acid halide is carried out in a heterogeneous state, It was discovered that the yield of alkyl (2,4-dihydroxyphenyl) ketone can be dramatically improved, and that the separation operation after step (i) can be simplified.

Based on these findings, we have completed the present invention.

(Means for Solving the Problems) Thus, according to the present invention, a resorcinol compound and a lower caldenic acid halide are reacted in a heterogeneous state in the presence of a zinc halide and an inert solvent to form an alkyl (2,4-dihydroxyphenyl) compound. ) A method for producing an alkyl (2,4-dihydroxyphenyl) ketone is provided, which comprises producing a ketone, performing solid-liquid separation, and then washing the obtained solid with water.

Hereinafter, the present invention will be specifically explained in detail.

The resorcinol compound, lower carboxylic acid halide, zinc halide, and inert solvent used in the reaction must all be substantially anhydrous! is necessary.

The resorcinol compound used as a reaction raw material in the present invention includes not only resorcinol itself but also resorcinol derivatives having a substituent on the aromatic nucleus, and is preferably represented by the following general formula.

General formula: [However, R,, R2, R3 are hydrogen atoms or have 5 carbon atoms
It means the following alkyl group. On the other hand, the lower carboxylic acid halide used is usually a monocarboxylic acid halide having 5 or less carbon atoms, and specific examples thereof include acetic acid chloride, zolopionic acid chloride, butyric acid chloride, acetic bromide, acetic acid iodide, and the like.

Specific examples of zinc halides that can be used include zinc fluoride, zinc chloride, zinc bromide, and zinc iodide, with zinc chloride being particularly preferred.゛The inert lysate used in the present invention is a product alkyl (zohydrocyphenyl)ketone &lt; which has low solubility and is inert to the reaction + reed; Nitrobenzene, chlorobenzene, carbon tetrachloride, diesel oil, carbon disulfide, ethylene chloride, methylene chloride, cyclohexane,
Examples include hexane, chloroform, etc. □ The amount of the lower carboxylic acid halide to be used is usually 1 to 5 imol per mole of the resorcinol compound, but preferably from the same mole to 2 times the mole.

The amount of zinc halide used can also be selected as appropriate.

Usually, the amount is 0.5 to 3 times the mole of the resorcinol compound, and it is particularly preferable to use the amount of 0.5 to 3 times the mole of the resorcinol compound. The amount of the inert solvent used is usually 1 to 20 times the molar equivalent to the resorcinol compound.

Resorcinol compounds, lower calgenic acids, de.

For information on how to prepare zinc halide and inert solvent,
Not subject to any restrictions. For example, a resorcin compound, a lower calgenic acid nitride, a zinc chloride, and an inert solvent may be mixed together at a low temperature and then reacted at a predetermined temperature, or a resorcin compound.

After mixing zinc halide and an inert solvent and bringing the mixture to a predetermined temperature, lower caldic acid halide may be added.

The required reaction temperature is usually -10 to 100°C.

Preferably the temperature is 0 to 60°C and one reaction time is 0.1 to 5 hours.

In the present invention, solid-liquid separation of the reaction mixture is performed after completion of one reaction. The solid-liquid separation method is not particularly limited, and examples thereof include a filtration separation method and a static separation method.

The solid content obtained by solid-liquid separation contains unreacted solcin compounds and zinc halide, so washing with water is performed to remove them, thereby producing high-quality alkyl (dihydroxyphenyl). Ketones are obtained. When washing with water, it is preferable to use an acid aqueous solution such as an aqueous hydrochloric acid solution, thereby further improving the purity.

(Effects of the Invention) Thus, according to the present invention, complicated operations such as post-reaction distillation and recrystallization can be avoided, and high-quality alkyl (dihydroxyphenyl) ketones can be obtained in good yield.

The alkyl (dihydroxyphenyl) ketone obtained in this way is a fine chemical intermediate.

It is an important substance as a raw material for medicines, agricultural chemicals, photosensitive materials, fragrances, resins, etc.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and parts in the examples are key 9 unless otherwise specified.
It is based on weight.

Example 1 44 parts of resorcinol, 80 parts of zinc chloride, and 300 parts of nitrobenzene were charged into a four-bottle flask equipped with a stirrer, a thermometer, and a cooling tube, heated to 40'C, and heated at that temperature for 0.5 hours. Add 40 parts of acetic acid chloride, then add 0.
Stirring was carried out in an uneven state for 5 hours.

Thereafter, it was cooled to room temperature and filtered, washed with 150 parts of 18-thihydrochloric acid aqueous solution, filtered, and then dried to produce 2,4-dihydroxyacetophenone with very little coloring.
I got 6 copies. The yield based on resorcinol was 8 parts and 1 mole, and the selectivity was 99 mole. The purity of the obtained 2,4-dihydroxyacetophenone was 99% or higher, and the melting point was 146-147°C.

Example 2 The same operation as in Example 1 was performed except that 280 parts of chlorobenzene was used in place of the nitrobenzene used in Example 1, and 51.7 parts of 2,4-dihydroxyacetophenone with very little coloring was obtained. . The yield based on resorcinol was 85.1 mol and the selectivity was 99 mol. The purity of the obtained 2,4-dihydroxyacetophenone was 9
At 9% or higher, the melting point was 146-147°C.

Example 3 An experiment was conducted in the same manner as in Example 1 except that 150 parts of water was used instead of the 18-thihydrochloric acid aqueous solution for washing. 2,4
The yield of -dihydroxyacetophenone was 86.8 mol.

Claims (1)

[Claims] 1. A resorcinol compound and a lower carboxylic acid halide are reacted in a heterogeneous state in the presence of zinc halide and an inert solvent to produce an alkyl (2,4-dihydroxyphenyl) ketone, followed by solid-liquid separation. The alkyl (2,4-
Method for producing (dihydroxyphenyl)ketone.