KR940010887B1 - Process for preparing optical brightener of 4,4-bis-benz-0x-(thi,imid)-azol-2-yl-stilbenes - Google Patents

Abstract

Title compound is a useful fluorescense-increasing agent for plastics, synthetic fiber and synthetic rubber. The compound (II) such as o-aminophenol, o- aminothiophenol or o-phenylene diamine and 4-(halomethyl)benzoic acid (III) are reacted with thionylchloride in N-methyl pyrollidone solvent at 120-180 deg.C to give 2-benz-ox-(-ty,-imide)-azolyl-4-halomethyl-benzene (IV), which is reacted with sodium t-butoxide, potasium t-butoxide, KOH or NaOH in polar solvent such as N,N'-dimethyl formamide at -10 - 50 deg.C to give title compound(I).

Description

Preparation of fluorescent 4,4'-bis-benz-ox (-T, -imide) -azol-2-yl-stilbene

The present invention is a fluorescent 4,4'-bis-benz- used as a fluorescent brightener useful for almost all plastics and synthetic fibers and synthetic rubbers such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene It relates to a process for the preparation of oxi (-T, -imide) -azol-2-yl-stilbene.

The present invention relates to o-aminophenol, o-aminothiophenol or o-phenylenethiamine of formula (II) and 4- (halomethyl) -benzoic acid of formula (III) under N-methylpyrrolidone solvent. 2-benz-ox (-thi, -imide) -azolyl-4-halomethyl-benzene of the following formula (IV) obtained by reaction with onyl chloride was dissolved in sodium t-butoxide, potassium t-butoxide, hydroxide Reacting with potassium and sodium hydroxide in a polar aprotic solvent to prepare 4,4'-bis-benz-ox (-thi, -imide) -azol-2-yl-stilbene of formula (I) It is about. More specifically, N-methylpyrrolidone is used as a reaction solvent, and thionyl chloride, 4- (halomethyl) benzoic acid, o-aminophenol, o-aminothiophenol or o-phenylenediamine of formula (II) After the reaction, the compound of formula (IV) was prepared in high yield in a short time, and was poured into water to reflux to crystallize and recrystallized from a mixture of water and aliphatic alcohol, followed by polar aprotic solvent such as N, N-dimethylformamide. 4,4'-bis-benzox (-T, -imide) -azole- of the following formula (I) which is reacted with sodium t-butoxide, potassium t-butoxide, potassium hydroxide and sodium hydroxide After preparing 2-yl-stilbene, it is poured into water, acidified with hydrochloric acid or acetic acid, filtered and washed with lower alcohol and water to obtain a final fluorescent brightener.

In the general formula, R, R ₁ , R ₂ , R ₃ are the same as or different from each other, hydrogen, C ₁ ~ C ₄ alkyl, C ₁ ~ C ₄ alkoxy, C ₁ ~ C ₄ alkoxycarbonyl, chlorine, bromine, fluorine, sia Furnace, nitro or sulfo, Z represents oxygen, sulfur or NH and X represents chlorine or bromine.

R ₁ is independently hydrogen, methyl, ethyl, normalpropyl, isopropyl, t-butyl, isobutyl and other C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, C ₁ -C ₄ alkoxycarbonyl , Chlorine, bromine, fluorine, nitro, cyano or sulfo.

4,4'-bis-benz-ox (-ti, -imide) -azol-2-yl-stilbene represented by the above formula (I) is a known optical optical brightener and is a polyolefin such as polyethylene / polypropylene. Of course, it is used to increase the whiteness of polyurethane polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene and synthetic rubber, and the following methods are already known as a prior art for preparing the same.

The method proposed in US Pat. No. 3,260,715 (hereinafter referred to as “method 1”) synthesizes 4,4′-stilbene dicarboxylic acid by reacting p-tolucin at high temperature in sulfur and synthesized with thionyl chloride. Synthesis of 4'-styrene dicarboxylic acid chloride is performed. The synthesized reactant was reacted with o-aminophenol to obtain 4,4'-bis (benzoxa), the final material at a high temperature of 320-340 ° C. via 4,4'-bis (2-phenylcarbamoyl) stilbene. Zol-2-yl) -Stilbene was synthesized.

U.S. Patent No. 4921964 (hereinafter referred to as Method 2) synthesizes dimethyl 4,4'-steelbendicarboxylate, and then 260-265 under a titanium tetraisopropoxide catalyst in o-aminophenol and a higher aromatic hydrocarbon solvent. It is synthesized by reacting at a high temperature of ℃.

In US Patent No. 3935195 (hereinafter referred to as 3 method), 4,4'-steelbendicarboxylic acid and o-aminophenol are reacted at a high temperature of 200 ° C or higher using polyphosphoric acid as a solvent.

In U.S. Pat.Nos. 4,515,033 and 4585875 (hereinafter referred to as method 4), (4-chloromethyl) -imino-benzoic acid alkylester or hydrochloride thereof synthesized from p-cyanobenzylchloride is reacted with o-aminophenol. To give 2-benz-ox-azolyl-4-chloromethyl-benzene and the obtained material is reacted with sodium hydroxide or sodium t-butoxide in a polar aprotic solvent.

However, the conventional methods have the following problems.

In the first method, the yield of 4,4'-stilbendicarboxylic acid obtained by reacting at high temperature in sulfur is specifically low and difficult to purify. The subsequent reactions are also long and inefficient in terms of reaction conditions and yield.

In the second method, too, it is difficult to prepare a starting material, and the reaction solvent is a higher aromatic hydrocarbon such as chloronaphthalene or diphenyl ether, which is not an aromatic hydrocarbon normally used, and the reaction temperature is 260 to 265 ° C.

In the third method, it is also difficult to prepare 4,4'-steelbendicarboxylic acid, which is a starting material, and the solvent used in the reaction is very viscous polyphosphoric acid, which is difficult to stir and the reaction temperature is high. And treatment of polyphosphate after the reaction is difficult.

In the fourth method, the starting material, p-cyanobenzyl chloride is expensive, and the time required for preparing the hydrochloride salt of (4-chloromethyl) -imino-benzoic acid alkyl ester is over 20 hours. In addition, a large amount of acetic acid is required even when reacting with o-aminophenol, which causes a problem in the treatment of excess acetic acid.

In order to solve the above problems, the present inventors conducted extensive research to find a method with mild reaction conditions, easy to process by-products, and high yields. As a result, o-aminophenol and 4- (halomethyl) benzoic acid It was found that the benzyl halide group remained stable, the reaction time was short, and the yield was high when reacting with thionyl chloride to dissolve and dissolve in the N-methylpyrrolidone to form the benzoxazole ring.

The present invention provides a slightly excess N-methylpyrrolidone solvent of o-aminophenol, o-aminothiophenol or o-phenylenediamine of formula (II) and 4- (halomethyl) benzoic acid of formula (III) 2-benz-ox (-thi, -imide) -azolyl-4-halomethyl-benzene of the following formula (IV) under mild conditions under participation in thionyl chloride reaction was synthesized and sodium t-butoxide was synthesized. 4,4'-bis-benz-ox (-T, -imide) -azole-2- of formula (I) by reacting with cation, potassium t-butoxide, potassium hydroxide and sodium hydroxide in a polar aprotic solvent It relates to the production of yl-steelbene.

In the general formula, R, R ₁ , R ₂ , R ₃ are the same as or different from each other, hydrogen, C ₁ ~ C ₄ alkyl, C ₁ ~ C ₄ alkoxy, C ₁ ~ C ₄ alkoxycarbonyl, chlorine, bromine, fluorine, nitro , Cyano or sulfo, Z represents oxygen, sulfur or NH and X represents chlorine or bromine.

R ₁ is independently hydrogen, methyl, ethyl, normalpropyl, isopropyl, t-butyl, isobutyl and other C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, C ₁ -C ₄ alkoxycarbonyl , Chlorine, bromine, fluorine, nitro, cyano or sulfo.

Further advantages and methods of the present invention will be described below.

The present invention is a simple manufacturing method that the reaction step is dramatically reduced compared to the prior art. In other words, by reacting 4- (halomethyl) benzoic acid with o-aminophenol, the benzoxazole ring is produced in high yield under mild conditions, and then stilbene group is easily introduced. It is an efficient way. Introduction reaction of stilbene group 4,4′-bis-benz-ox (-T, -imide) -azole- of formula (I) as a final product in high yield under mild conditions of 0 ° C. to 20 ° C. It is a very good process for producing 2-yl-steelbene.

More specifically, the method of the present invention will be described.

Disperse and dissolve 4- (halomethyl) benzoic acid in N-methylpyrrolidone, and then slowly add thionyl chloride at 0 ° C. to 20 ° C., preferably at 10 ° C. to 15 ° C., and add the reaction solution to 30 Stir for 2 hours at minutes and preferably at room temperature for 1 hour. In this case, N-methylpyrrolidone used as a solvent and a reactant is used in an amount of 8 to 20 equivalents, preferably 10 equivalents based on 4- (halomethyl) benzoic acid, and thionyl chloride is used in an amount of 1.0 to 1.5 equivalents. .

To the reaction solution o-aminophenol, o-aminothiophenol or o-phenylenediamine is slowly added at room temperature and the reaction solution is about 120 ~ 180 ℃, preferably about 140 ℃ 10 minutes to 1 hour, more preferably The temperature is raised over 30 minutes, stirred at that temperature for 2-4 hours, preferably for 2 hours 30 minutes. After the reaction solution was cooled to room temperature, poured into water and crystallized, the acidity was neutralized to 7.0 with sodium hydroxide or potassium hydroxide, followed by stirring for 30 minutes. The product obtained by stirring was filtered and dried under reduced pressure, and then recrystallized from an aliphatic alcohol mixture of 10 to 80% hydrous, preferably recrystallized from an aliphatic alcohol mixture of 30 to 50% hydrous to recover the product of formula (IV). . At this time, the yield was maintained at 91%.

Herein, the aliphatic alcohol is methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, sec-butyl alcohol, t-butyl alcohol and a mixture thereof, and higher aliphatic hydrocarbons such as ligroine are also used. I use it. Then, sodium hydride or potassium hydride is dispersed and dissolved in a polar aprotic solvent such as dimethyl formamide (DMF), blown with nitrogen to block air, and then t-butanol is added. After stirring for about 1 hour, it is cooled to -10 ~ 50 ℃, preferably about 20 ℃ and 2-benz-ox (-thy, -imide) -azolyl-4-halomethyl of formula (IV) Add benzene. At this time, in the case of using sodium t-butoxide and potassium t-butoxide, which have already been prepared, disperse and dissolve the corresponding substances in N and N-dimethylformamide, and then stir for 10 to 20 minutes, and cool down to about 20 ° C. 2-benz-ox (-thi, -imide) -azolyl-4-halomethyl-benzene is added. Sodium hydroxide and potassium hydroxide are used in the same manner.

The reaction solution is then stirred at -10 to 50 ° C., preferably at 15 ° C., wherein X in formula (IV) is Cl, and 5 to 6 hours is required when sodium and potassium t-butoxide are used. When using potassium hydroxide, the stirring time is about 7 to 12 hours. After the reaction was completed, the reaction solution was poured into water and acidified with hydrochloric acid or acetic acid solution to acidity of about 5-6, and the resulting product was filtered, washed 2-3 times with distilled water and methanol and dried under reduced pressure or N, N -Dimethylformamide or an aqueous solution thereof, or recrystallized from aromatic hydrocarbons such as benzene, toluene, and xylene to obtain the optical brightener of formula (I) in a yield of 90% or more.

Example 1

190 ml of N-methylpyrrolidone was added to a 500 ml well-dried flask equipped with a thermometer, a hydrochloric acid gas treatment system, and a stirring device. 34.12 g of 4- (chloromethyl) benzoic acid was dispersed and dissolved. Slowly add at a temperature of about ℃ and stirred at room temperature for 30 minutes to 1 hour. 33.05 g of 2-amino-4-t-butyl-phenol are added at room temperature and the reaction solution is heated to 140 ° C. over 30 minutes and stirred for 2 to 2 hours 30 minutes. After cooling to room temperature, poured into 700 ml of water, neutralized with sodium hydroxide or potassium hydroxide solution to about acidity 7.0 degree, stirred for about 30 minutes, filtered and dried under reduced pressure, and recrystallized from 20% aqueous isopropyl alcohol solution. 55g of yellowish brown 2- (5-t-butyl) benz-ox-azolyl-4-chloromethyl-benzene was obtained.

Yield: 92%, Melting point: 148.6 ℃

Example 2

4- (Bromomethyl) benzoic acid is used instead of 4- (chloromethyl) benzoic acid and the reaction conditions are the same as those of Example 1, where 2- (5-t-butyl) benz-ox-azolyl-4-chloromethyl Obtain 60 g of benzene.

Yield: 90% Melting point: Light yellowish brown solid at 168.2 ° C

Example 3

Fill a well-dried 500 ml flask with a thermometer with nitrogen, dissolve and dissolve 9.0 g of t-butanol and 4.0 g of sodium hydride (80%) in 200 ml of N, N-dimethylformamide and stir for about 1 hour. Cool to 20 ° C. 30 g of 2- (5-t-butyl) benz-ox-isozolyl-4-chloromethyl-benzene was slowly added to the reaction solution, stirred at about 20 ° C. for about 6 hours, poured into 800 ml of water, and had an acidity of 5-6. After adjusting with hydrochloric acid solution, filtered under pressure, washed with distilled water and methanol 2 ~ 3 times, dried under reduced pressure and recrystallized from toluene to obtain 4,4'-bis- (5-t-butyl) ) 25 g of benz-ox-azol-2-yl-stilbene is obtained.

Yield: 95%, Melting point: pale yellow solid at 299.2 ° C

Example 4

A well-dried 500 ml flask equipped with a thermometer was charged with nitrogen, 13.5 g of potassium-t-butoxide was dispersed and dissolved in 200 ml of DMF, stirred for about 10 minutes, and cooled to 20 ° C. 30 g of 2- (5-t-butyl) benz-ox-azolyl-4-chloromethyl-benzene was slowly added to the reaction solution, stirred at 10-20 ° C. for about 4 hours, poured into 800 ml of distilled water, and acidic acid of 5˜. Setting to 6 followed by filtration under pressure yielded the same product as in Example 3 in 96% yield.

Example 5

Disperse 16 g (0.4 mol) of sodium hydroxide in 200 ml of N, N-dimethylformamide, and slowly add 30 g of 2- (5-t-butyl) benz-ox-azolyl-4-chloromethyl-benzene in the presence of nitrogen. After stirring for about 7 to 12 hours, poured into 800 ml of water, acidified with acetic acid solution, and filtered under reduced pressure to obtain 4,4'-bis- (5-t-butyl) benz-ox-azole-2 of formula (I). 20 g of -yl-steelbene were obtained (yield = 85%).

Accordingly, the present invention aims to provide a process for preparing Formula (I) under mild conditions and high yield using 4- (halomethyl) benzoic acid as a starting material. In more detail, 2-benz-ox (-) of formula (IV) in 2-hour under mild conditions of 140 ° C. or less with 4- (halomethyl) benzoic acid and o-aminophenol as a solvent of N-methylpyrrolidone. Thi, -imide) -azolyl-4-halomethyl-benzene was prepared and purified and reacted with potassium hydroxide, sodium hydroxide, sodium t-butoxide and potassium t-butoxide in a polar aprotic solvent. There is an excellent effect that 4,4'-bis-benz-ox-(-ti, -imide) -azol-2-yl-stilbene of I) can be produced in high yield and in a short time.

Claims (6)

2-benz of the following formula (IV) using o-aminophenol, o-aminothiophenol or o-phenylenediamine of formula (II) and 4- (halomethyl) benzoic acid of formula (III) as starting materials -Ox (-T, -imide) -azolyl-4-halomethyl-benzene was synthesized, and the synthesized formula (IV) was reacted to form 4,4'-bis-benz-ox of formula (I) In the method for producing (-ti, -imide) -azol-2-yl-stilbene, o-aminophenol, o-aminothiophenol or o-phenylenediamine of the following formula (II) and the following formula ( 4- (halomethyl) benzoic acid of III) was reacted with thionyl chloride in an N-methylpyrrolidone solvent at 120-180 ° C to give 2-benz-ox (-ti, -imide)-of formula (IV)- Azolyl-4-halomethyl-benzene was synthesized, and the following formula (IV) was synthesized with the same polarity as sodium t-butoxide, potassium t-butoxide, potassium hydroxide and sodium hydroxide and N, N'-dimethylformamide. Reaction at a temperature of -10 to 50 ° C in aprotic A process for preparing 4,4′-bis-benz-ox (-ti, -imide) -azol-2-yl-stilbene of I). In the general formula, R, R ₁ , R ₂ , R ₃ are the same as or different from each other, hydrogen, C ₁ ~ C ₄ alkyl, C ₁ ~ C ₄ alkoxy, C ₁ ~ C ₄ alkoxycarbonyl, chlorine, bromine, fluorine, nitro , Cyano or sulfo, Z represents oxygen, sulfur or NH and X represents chlorine or bromine. A compound according to claim 1, wherein R ₁ is independently hydrogen, methyl, ethyl, normalpropyl, isopropyl, t-butyl, isobutyl and other C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, C ₁ -C ₄ alkoxycarbonyl, chlorine, bromine, fluorine, nitro, cyano or sulfo. The method according to claim 1, wherein the recrystallization of formula (IV) is made into a 30-50% aqueous aliphatic alcohol solution, wherein the aliphatic alcohol is methanol, ethanol, propanol, isopropanol, butanol, sec-butanol, t-butanol and mixtures thereof. In the form or using aliphatic hydrocarbons such as ligroine. The method according to claim 1, wherein when synthesizing the compound of formula (I) from the compound of formula (IV), the use of N, N-dimethylformamide as a polar aprotic solvent and t-butanol / sodium hydride, A process characterized by the use of t-butanol / potassium hydride. The method according to claim 1, wherein N, N-dimethylformamide or an aqueous solution thereof is used to purify the compound of formula (I), or aromatic hydrocarbons such as benzene, toluene and xylene are used. The method of claim 1, wherein when purifying the compound of formula (I), washing with water and aliphatic alcohol.