JPS591438A - Preparation of 4,4'-dihydroxybenzophenone - Google Patents

Abstract

PURPOSE:To obtain the titled substance useful as an intermediate for dye, a raw material for synthetic resins, etc. efficiently, by reacting bis(4-trichloromethylphenyl)carbonate with phenol in the presence of a Lewis acid catalyst, hydrolyzing the reaction product with an alkali. CONSTITUTION:A compound shown by the formula I is reacted with phenol in the presence of a Lewis acid catalyst (e.g., AlCl3, or FeCl3) in an amount to give 2.0-3.0 times the molar amount of the compound shown by the formula I at -5-15 deg.C to give a compound shown by the formula II, which is hydrolyzed with an alkali at 10-30 deg.C to give a compound shown by the formula III. In the second process, it is important that water is used in combination with a water- soluble organic solvent (e.g., methanol, dioxane, or THF), and the compound shown by the formula II is brought into contact with the alkali well in a homogeneous system or suspension state. The first process is carried out using a solvent such as CS2, dichloromethane, etc. in an amount to give 5-10 times as much as that of the compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new method for producing 4,4'-dihydroxybenzophenone, which is useful as a synthetic raw material for dye intermediate 1 synthetic resin.

The method for producing 4.4'-dihydroxybenzophenone is described in Soviet Patent No. 529.149.
A method for alkaline hydrolysis of lopenzophenone is described.

However, this method requires equipment costs due to the high temperature reaction, making it difficult to supply inexpensive products industrially.

Additionally, U.S. Pat. No. 4,566,691 describes a method for synthesizing 4,4'-bis(phenoxy)benzophenone by reacting diphenyl ether with phosgene in the presence of an AICIB catalyst, followed by alkaline hydrolysis. be. However, the use of harmful phosgene gas and the need for hydrolysis at high temperatures similar to the above method pose major obstacles to industrialization.

In view of the above-mentioned problems, the present inventors have overcome the drawbacks of the conventional methods, and have made it possible to efficiently and industrially produce 4,4'
- As a result of intensive studies to develop a method for producing dihydroxybenzophenone, a new method for producing it from a biscarbonate compound and phenol was discovered, and the present invention was completed.

That is, the present invention provides bis(4-
) IJ Chloromethylphenyl) carbonate and phenol are reacted in an organic solvent to obtain bis(4(4'-hydroxybenzoyl)phenyl)carbonate, and then the compound is subjected to alkaline hydrolysis. This is a method for producing 4,4'-dihydroxybenzophenone.

The method of the present invention consists of two steps, and the reaction formula is as follows. It can be produced almost quantitatively by chlorinating the side chain of bis(4-methylphenyl) carbonate obtained by reacting with .

Phenol can be added dropwise in a molten state, but since it is solid at room temperature, it is preferable to dilute it with an organic solvent before adding it dropwise. There is no particular restriction on the dilution ratio, and a needle that allows easy dropping of phenol is sufficient.

The amount of phenol used is 2.0 to 50 times, preferably 2.0 to 2.2 times, the molar ratio of the theoretical calculation lid to the raw material carbonate (1).

The catalysts used in the method of the present invention include M port 8, F port 8,
Known Lewis acid catalysts such as ectl, 5bcts, etc. are used.

Although the catalyst can be added in portions, it is preferable to add it all at once. The amount of catalyst is 1.8 to 4.0 times mole, preferably 2.0 to 50 times mole relative to (1).

Examples of the organic solvent used in step (1) of the method of the present invention include carbon disulfide, dichloromethane, dichloroethane, and tetrachloroethane.

The amount of solvent used varies depending on the solubility of bis(4-trichloromethylphenyl) carbonate (■). In order to facilitate reaction control and decompose the complex with luic acid produced in the reaction to facilitate the extraction of bis(4(4'-hydroxybenzoyl)phenyl fucarbonate (■)), which is an intermediate of the present invention. Appropriate children are (11 to 2-2
0 times by weight, preferably 5 to 10 times.

The reaction temperature in step (1) is carried out at 50°C or lower, preferably from -5 to 15°C.

The reaction time depends on the scale and capacity of the reactor. The dropwise addition rate of phenol can also be freely controlled, and is selected within the range of 1 to 10 hours.

In the alkaline hydrolysis step (second step) of the present invention, it is important to dissolve the intermediate (It) and improve contact with the alkali. Therefore, it is better to react K in a homogeneous system using a water-soluble organic solvent, rather than reacting in an aqueous system. However, sufficient reaction can be achieved even in a suspended state, which is not necessarily a homogeneous system.

Examples of water-soluble solvents include methanol, ethanol,
Examples include dioxane and tetrahydrofuran.

Further, as a solvent insoluble in water, toluene, monochlorobenzene, dichloroethane, etc. can be used.

The use of these organic solvents is 10 times higher than that of the intermediate (in). In addition, the violet of water to be used in combination is used at a molar ratio of at least twice the theoretical amount to the intermediate (11). When reacting in an aqueous system, use a violet with an alkaline concentration of 60% or less.

Examples of the alkali used in step (2) of the present invention include aqueous ammonia, hydroxides and carbonates of alkali metals and alkaline earth metals.

Examples of alkali metal hydroxides and carbonates include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, and the like.

As alkaline metal hydroxides and carbonates.

Examples include magnesium hydroxide, calcium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, and the like. Generally, it is preferable in the present invention to select an alkali that is easily dissolved in water or a water-soluble solvent.

The alkaline lid used has a molar ratio of 2 to 8 times, preferably 3 to 5.5 times, that of intermediate (n).

The reaction temperature is usually 50°C or lower, preferably 10 to 60°C.

To carry out the process of the invention, bis(4-trichloromethylphenyl)carbonate (I) is dissolved or suspended in the organic solvent and then a Lewis acid catalyst is added. Phenol diluted with a portion of the organic solvent is added dropwise to this mixture to carry out the reaction in step (1).

After the reaction is completed, the reaction contents are poured into ice water, and the reaction complex with Lewis acid and unreacted Lewis acid are hydrolyzed,
The precipitated intermediate (It) is separated.

Next, this intermediate (If) is dissolved in an organic solvent and hydrolyzed by force with an alkaline aqueous solution. The reaction solution is distilled to recover the organic solvent and recycled. Add water and mineral acid to the distillation residue to neutralize excess alkali and dissolve the formed inorganic salts. The precipitated 4,4'-dihydroxybenzophenone can be separated in high yield.

EXAMPLES The present invention will be specifically explained below using examples.

Example 1 Bis(4-trichloromethylphenyl)carbonate 4
49 parts were dissolved in 2tK of dichloromethane.

While stirring, 3547 parts of Atct were added.

Next, add 188 parts of phenol to this and 1 part of dichloromethane.
A solution containing tK was added dropwise over 1 hour. After the dropwise addition was completed, the temperature was gradually raised to room temperature, and the reaction was completed by stirring for 1 hour.

This reaction solution was poured into ice water to decompose the generated reaction complex and unreacted AICLB, and the precipitated crystals were washed door to door with water and dried.
425 parts of 4'-hydroxybenzoyl) phenyl fucarbonate (n) (yield 96% based on the theoretical yield) was obtained.

Next, this was dissolved in 3.5 t of ethanol, 625 parts of 28% aqueous ammonia was added, and the mixture was stirred at room temperature for 6 hours. After distilling the reaction solution to remove the solvent, add 100 parts of water, neutralize with 1% by weight of hydrochloric acid, cool, filter, wash with cold water and dry to obtain 4.4'-4. 390 parts of dihydroxybenzophenone (yield 98% based on (n)) was obtained.

Example 2 Bis(4(4'-human) obtained in the same manner as in Example 1.

Roxybenzoyl) phenyl fucarbonate (n) 4
Dissolve 25 parts in 6.5 L of ethanol and add 6'0% NaO
976 parts of H aqueous solution was added, and the mixture was stirred at room temperature for 4 hours. The reaction solution was distilled to remove the solvent, then 100 parts of water was added, neutralized with 1% by weight hydrochloric acid, cooled, filtered, washed with cold water and dried to obtain 4.4'-4. 390 parts of dihydroxybenzophenone was obtained in a yield of 98%.

Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] Bis(4-trichloromethylphenyl) carbonate and phenol are reacted in an organic solvent in the presence of a Lewis acid catalyst to obtain bis(4(4'-hydroxybenzoyl)phenyl cicarbonate). A method for producing 4,4'-dihydroxybenzophenone, which comprises then subjecting the compound to alkaline hydrolysis.