KR950005378B1 - Preparation of 2,3,4-trihydroxy benzo phenane - Google Patents

Abstract

The preparation method of 2,3,4-tri-hydroxy-benzophenone (I) consists of reacting benzotrichloride and pyrogallol in a solvent mixture of water, lower alcohol and organic solvent in the ratio of 1:0.8-6:4-8. The 3,4,5-tri-hydroxy- benzophenone and red color-forming materials as byproduct can be migrated into the polar solvent and this makes simple process. (I) is useful for uv shielding agents in photo-resist resin.

Description

Method for preparing 2,3,4-trihydroxy benzophenone

The present invention relates to an improved process for the preparation of 2,3,4trihydroxy benzophenone. 2,3,4trihydroxy benzophenone is known to be used as a raw material for photoresist resin used in the microcircuit processing of flat printing plates and semiconductors as well as a sunscreen due to its excellent ultraviolet absorption effect. Compound.

Conventional methods for producing 2,3,4trihydroxy benzophenone are known from Japanese Patent Laid-Open Nos. 63-264543 and USP 3639483.

According to Japanese Patent Publication No. 63-264543, benzoic acid and pyrogallol are reacted at 140 ° C. for about 22 hours using various sulfonic acid catalysts in xylene, and then cooled, filtered and dissolved in an aqueous alcohol solution. The catalyst is removed and recrystallized to produce 2,3,4trihydroxy benzophenone in about 52% yield. However, this method is too economical because the reaction temperature is too high, the energy consumption is high, the yield is low, and because of the cumbersome manufacturing process of three steps, it is difficult to apply to actual production.

The process according to USP 3639483 provides crude 2,3,4trihydroxy benzophenone by reacting benzotrichloride with pyrogaltol for 6 hours at 60-80 ° C. in water and isopropanol solvents to give the crude product. Toluene was treated with a solvent at 110 ° C. under activated clay and filtered to prepare a tablet. However, this method uses 2,3,4 trihydroxy benzophenone as a photoresist raw material by using activated clay in the purification process, and it is difficult to lower the content of metal components and must be purified to remove color (red color). There is a problem in that the energy cost increase and the manufacturing process is complicated accordingly.

When the benzotrichloride is reacted with pyrogaltol, the present invention is carried out in a mixed solvent composed of incompatible organic solvents (hereinafter referred to as organic solvents) such as lower alkanols, water and aliphatic hydrocarbons, aromatic hydrocarbons or derivatives thereof. After the reaction, or reacted with a lower alkanol aqueous solution, and then secondly treated with the organic solvent, the acylation process and purification process can be carried out in one reactor in one reactor (2,3) as a high yield. , 4 trihydroxy benzophenone.

When the organic solvent used in the present invention is described in detail, aliphatic hydrocarbons include C ₁ -C ₁₅ alkanes such as pentane, hexane, isooctane and the like and halogenated derivatives thereof such as chloroform, methylene chloride and dichloroethane. And nitrated derivatives thereof, such as nitromethane, nitroethane and the like, and in the case of C ₁ -C ₄ , those substituted with halogen or nitro group are preferable. Aromatic hydrocarbons include benzene, toluene, ethylbenzene, xylene, mesitylene, cumene and the like and halogenated derivatives thereof such as chlorobenzene and nitrated derivatives thereof such as nitrobenzene, and the lower alkanols are methanol, Ethanol, propanol and isopropanol.

The present invention is represented by the following scheme.

Scheme 1

As shown in the above reaction, the reaction result is about 90% of 2,3,4trihydroxy benzophenone is produced, but due to the nature of the reaction, the following structural formula 3,4,5-trihydroxy benzophenone is added 2-4% Is generated.

Scheme 2

However, this 3,4,5-trihydroxy benzophenone can be easily removed by adding the aforementioned organic solvents. That is, since 3,4,5-trihydroxy benzophenone is more polar than 2,3,4 trihydroxy benzophenone, it is easily dissolved into a relatively polar aqueous solution of alcohol and is mostly 2,3,4 trihydroxy. Benzophenone precipitates as a slurry with an organic solvent and can be easily removed by filtration.

In addition, the reactions generated during the reaction should be removed because the reddish component, which is assumed to be an intermediate, degrades the product quality and adversely affects the physical properties in the end use, which is also effectively removed as an organic solvent. That is, the affinity between organic solvents and 2,3,4-trihydroxy benzophenone is greater than the affinity between colored components and 2,3,4-trihydroxy benzophenone. Exchange of components and organic solvent takes place and the liberated color components are dissolved in an aqueous alcohol solution and easily removed.

In the present invention, in the preparation of 2,3,4trihydroxy benzophenone by reacting benzotrichloride and pyrocalcol, water and lower alcohols are used as a reaction solvent and another organic solvent is mixed as a cosolvent, Or secondary use. When used in combination, the volume ratio of the solvent is water: lower alkanol = 1: 0.1-2, water: organic solvent = 1: 0.1-4, but preferably water: lower alkanol = 1: 0.8-1.2, water: organic. Solvent = 1.5-2.5. When the reaction solvent = 1: 1.5 or less, as the reaction proceeds, the solid precipitates, so the stirring effect is less, and when the reaction is finished, the stirring is impossible and it is difficult to discharge the target substance from the reactor.

In the case of using the organic solvent secondarily after the reaction, the volume ratio of the reaction solvent may be a lower alkanol aqueous solution containing water equivalent to or more than the pyrogaltol used in the reaction, but preferably water: lower alkanol = 1: 0.8-6, The volume ratio of organic solvent can be up to water: organic solvent = 1: 1.5-8, but water: organic solvent = 1: 4-8 is most suitable.

The production method according to the present invention is as follows.

Into a 500 ml four-necked flask equipped with a mechanical stirrer and thermometer, pure water and lower alkanol (ethanol) are dissolved. Next, add an organic solvent and benzotricloid and stir for several hours at room temperature. The reaction was filtered, washed with pure water and benzene, and then vacuum dried at 70 ° C. or below for 5 hours to obtain 2,3,4trihydroxy benzophenone in a yield of 75-88%.

Alternatively, the lower alkanol aqueous solution (ethanol aqueous solution) is added to the same apparatus to dissolve pyrogallol. The benzotrichloride is added dropwise for several hours at 20-100 ° C., preferably 20-80 ° C., followed by several hours of reaction at 50-70 ° C. Then, an organic solvent was added, followed by further filtration of pure water by ethanol, filtration, washing with pure water and benzene, and vacuum drying to obtain the same result as described above.

The invention is described in detail by the following examples.

Example 1

In a 500 ml four-necked flask equipped with a mechanical stirrer and thermometer, 60 ml of pure water and 60 ml of ethanol are dissolved, and 31.5 g of pyrogaltol is dissolved. 100 ml of benzene and 100 ml of benzotrichloride were added thereto, stirred at 25 ° C. for 16 hours, filtered, washed with 100 ml of pure water and 50 ml of benzene, and vacuum-dried at 70 ° C. for 4 hours to give 2,3,4 trihydroxybenzophenone. Was prepared.

Example 2-3

In Example 1, the reaction was carried out while changing the volume ratio of the reaction solvent.

Comparative Example 1

In a 500 ml four-necked flask equipped with a mechanical stirrer and thermometer, 60 ml of pure water and 60 ml of ethanol are dissolved, and 31.5 g of pyrogaltol is dissolved. 240 ml of benzene and 100 ml of benzotrichloride were added thereto, stirred at 25 ° C. for 16 hours, filtered, washed with 100 ml of pure water and 50 ml of benzene, and dried under vacuum at 70 ° C. for 4 hours to obtain 2,3,4 trihydroxy benzophenone. Prepared.

Comparative Example 2-3

In Comparative Example 1, the reaction was carried out while changing the volume ratio of the reaction solvent and the reaction temperature.

TABLE 1

BTCl: Benzotrichloride

1.7% is the residual% of 3,4,5-trihydroxy benzophenone.

[Example 4-9 and Comparative Example 4]

In Example 1, the reaction was carried out while changing the type of reaction solvent.

TABLE 2

Example 10

In a 500 ml four-necked flask equipped with a mechanical stirrer and thermometer, 20 ml of pure water and 60 ml of methanol were dissolved, 31.5 of pyrogaltol was dissolved, and the temperature was 30 ° C., benzotrichloride was added dropwise for 2 hours, and the temperature was raised to 60 ° C. for 1 hour. Stir. 120 ml of toluene was added thereto, cooled to 30 ° C. or lower, 40 ml of water was added thereto, stirred for 30 minutes, filtered, washed with 100 ml of pure water and 50 ml of toluene, and vacuum-dried at 70 ° C. for 4 hours to give 2,3,4 trihydroxy benzophenone. Prepared.

Example 11-14 and Comparative Example 5-6

In Example 10, the reaction was carried out while changing the volume ratio, reaction temperature, and reaction time of the reaction solvent.

TABLE 3

Claims (10)

A process for producing 2,3,4trihydroxy benzophenone, wherein benzotrichloride and pyrogallol are reacted in a mixed solvent of lower alkanol, water, and an organic solvent. The method for producing 2,3,4trihydroxy benzophenone according to claim 1, wherein a mixed solvent of water: lower alkanol: organic solvent is mixed at a ratio of 1: 0.8-1.2: 1.5-3. A process for producing 2,3,4trihydroxy benzophenone, characterized in that the reaction of claim 1 or 2 at room temperature. The method for producing 2,3,4trihydroxy benzophenone according to claim 1 or 2, wherein the lower alkanol is an alkanol having 1-3 carbon atoms. The organic solvent according to claim 1 or 2, wherein the organic solvent is selected from an aliphatic hydrocarbon having 5 to 15 carbon atoms, a halogen or nitro group derivative of aliphatic hydrocarbon having 1 to 4 carbon atoms, an aromatic hydrocarbon having 6 to 15 carbon atoms, or a halogen or nitro group derivative thereof. Method for producing 2,3,4trihydroxy benzophenone, characterized in that the solvent. A process for producing 2,3,4trihydroxy benzophenone, wherein benzotrichloride and pyrogallol are reacted under a mixed solvent of water and lower alkanol, and the organic solvent is secondarily treated. The method for producing 2,3,4trihydroxy benzophenone according to claim 6, wherein the ratio of water: lower alkanol: organic solvent is 1: 0.8-6: 4-8. The process for producing 2,3,4trihydroxy benzophenone according to claim 6 or 7, wherein the reaction is carried out at room temperature to 80 degrees. The process for producing 2,3,4trihydroxy benzophenone according to claim 6 or 7, wherein the lower alkanol is an alkanol having 1-3 carbon atoms. The organic solvent according to claim 6 or 7, wherein the organic solvent is selected from aliphatic hydrocarbons having 5 to 15 carbon atoms, halogen or nitro group derivatives of aliphatic hydrocarbons having 1 to 4 carbon atoms, aromatic hydrocarbons having 6 to 15 carbon atoms, or halogen or nitro group derivatives thereof. Method for producing 2,3,4, trihydroxy benzophenone, characterized in that the solvent.