阅读说明：本技术 一种催化合成紫外线吸收剂bp-2的方法 (Method for catalytically synthesizing ultraviolet absorbent BP-2 ) 是由 汪敦佳 殷国栋 胡艳军 方辉明 刘建军 *** 于 2020-08-31 设计创作，主要内容包括：本发明公开了一种催化合成紫外线吸收剂BP-2的方法,包括下述步骤：(1)向反应器中加入卤代烃溶剂和复合催化剂,搅拌混合均匀,升温至90~120℃,再向混合物中加入2,4-二羟基苯甲酸和间二苯酚,搅拌溶解,保温反应2~3小时,反应完毕,趁热过滤回收催化剂石墨,向滤液中加入适量水,升温至90~100℃,搅拌溶解完全,静置分层,有机层蒸馏回收溶剂,水层冷却至10~20℃,析出大量红色晶体,抽滤、水洗,得到粗产品；(2)将粗产品用适量热水溶解,加入活性炭脱色,煮沸30~60min,趁热过滤,冷却结晶,得到浅黄绿色晶体紫外线吸收剂BP-2产品,产品的熔点为199~200℃,纯度≥99.8%；本发明方法合成产率高,生产工艺简单,产品纯度高,且成本较低,适合工业化生产。(The invention discloses a method for catalytically synthesizing an ultraviolet absorbent BP-2, which comprises the following steps: (1) adding a halogenated hydrocarbon solvent and a composite catalyst into a reactor, stirring and mixing uniformly, heating to 90-120 ℃, adding 2, 4-dihydroxybenzoic acid and resorcinol into the mixture, stirring and dissolving, carrying out heat preservation reaction for 2-3 hours, filtering and recovering catalyst graphite while the mixture is hot after the reaction is finished, adding a proper amount of water into filtrate, heating to 90-100 ℃, stirring and dissolving completely, standing and layering, distilling an organic layer to recover the solvent, cooling a water layer to 10-20 ℃, separating out a large amount of red crystals, carrying out suction filtration and washing to obtain a crude product; (2) dissolving the crude product with a proper amount of hot water, adding activated carbon for decolorization, boiling for 30-60 min, filtering while the crude product is hot, and cooling and crystallizing to obtain a light yellow green crystal ultraviolet absorbent BP-2 product, wherein the melting point of the product is 199-200 ℃, and the purity of the product is more than or equal to 99.8%; the method has the advantages of high synthesis yield, simple production process, high product purity and lower cost, and is suitable for industrial production.)

1. A method for catalytically synthesizing an ultraviolet absorbent BP-2 is used for preparing the BP-2 by carrying out catalytic synthesis on 2, 4-dihydroxybenzoic acid and resorcinol as raw materials, and is characterized by comprising the following steps: adding a halohydrocarbon solvent and a composite catalyst into a reactor, stirring and mixing uniformly, heating to 90-120 ℃, adding 2, 4-dihydroxybenzoic acid and resorcinol into the mixture, stirring and dissolving, carrying out heat preservation reaction for 2-3 hours, filtering and recovering catalyst graphite while the mixture is hot after the reaction is finished, adding a proper amount of water into filtrate, heating to 90-100 ℃, stirring and dissolving completely, standing and layering, distilling an organic layer to recover the solvent, cooling a water layer to 10-20 ℃, precipitating a large amount of red crystals, carrying out suction filtration and washing to obtain a BP-2 crude product, wherein the product purity of the crude product is more than or equal to 80%;

the composite catalyst is composed of A, B raw materials, wherein the A raw material is selected from any one of graphite and diatomite, the B raw material is selected from any one of methanesulfonic acid and p-toluenesulfonic acid, and the mass ratio of A to B is 6-10: 6-10.

2. The method for catalytically synthesizing the ultraviolet absorbent BP-2 according to claim 1, wherein: dissolving the prepared BP-2 crude product in a proper amount of hot water, adding activated carbon for decolorization, boiling for 30-60 min, filtering while hot, cooling and crystallizing to obtain a light yellow green crystal ultraviolet absorbent BP-2 product, wherein the melting point of the product is 199-200 ℃; the purity of the obtained ultraviolet absorbent BP-2 product is more than or equal to 99.8 percent through liquid chromatography detection.

3. The method for catalytically synthesizing the ultraviolet absorbent BP-2 according to claim 1, wherein: the mass ratio of the 2, 4-dihydroxy benzoic acid to the resorcinol is 10: 7-9.

4. The method for catalytically synthesizing the ultraviolet absorbent BP-2 according to claim 1, wherein: the halogenated hydrocarbon solvent is any one selected from dichloroethane, trichloroethane, trichloroethylene and tetrachloroethylene; the mass ratio of the 2, 4-dihydroxybenzoic acid to the halogenated hydrocarbon solvent is 10: 35-65.

5. The method for catalytically synthesizing the ultraviolet absorbent BP-2 according to claim 1, wherein: the mass ratio of the 2, 4-dihydroxybenzoic acid to the composite catalyst is 10: 12-20.

6. The method for catalytically synthesizing the ultraviolet absorbent BP-2 according to claim 1, wherein: the water for dissolving the filtrate is 5-8 times of the volume of the filtrate.

7. The method for catalytically synthesizing the ultraviolet absorbent BP-2 according to claim 2, wherein: the temperature of hot water for dissolving the BP-2 crude product is 80-100 ℃, and the using amount of the hot water is 3-5 times of the mass of the crude product.

Technical Field

The invention relates to the technical field of preparation methods of ultraviolet absorbers, in particular to a method for catalytically synthesizing an ultraviolet absorber BP-2.

Background

The ultraviolet absorbent BP-2 has an ultraviolet absorption peak of 320-400 nm, has strong absorption on ultraviolet rays in the whole UVA waveband, has a chemical name of 2, 2 ', 4, 4' -tetrahydroxybenzophenone, is low in toxic and side effects and good in water solubility, is a class I sunscreen agent approved by the American FDA, can be used as a pharmaceutical intermediate, a photosensitive material, a cosmetic ultraviolet-proof additive and the like, and is widely applied to products such as the cosmetic industry, the photosensitive material, printing ink and the like.

The synthesis methods of the ultraviolet absorbent BP-2(2, 2 ', 4, 4' -tetrahydroxybenzophenone) reported at home and abroad at present mainly comprise the following two types.

(I): U.S. Pat. No. 3,2694729 and U.S. Pat. No. 2016, 201511004771.9 in 1954 report that resorcinol derivatives and phosgene are used as raw materials, anhydrous aluminum trichloride is used as a catalyst to perform acylation reaction, and then dilute hydrochloric acid is added to perform hydrolysis to obtain the ultraviolet absorbent BP-2 product. The synthetic route is as follows:

(II): journal of daily chemical industry (2004, phase 1, pages 34-36) in 2004 reports that 2, 4-dihydroxybenzoic acid and resorcinol are used as raw materials, anhydrous zinc chloride and phosphorus oxychloride are used as composite catalysts, sulfolane is used as a solvent, and an ultraviolet absorbent BP-2 is synthesized through an acylation reaction. The synthetic route is as follows:

2. the advantages and disadvantages of the currently reported process

1) In the method (I), the American patent US2694729 is that m-phenyl dimethyl ether and phosgene are subjected to acylation reaction under the catalysis of anhydrous aluminum trichloride, but methoxy benzophenone in the process is difficult to hydrolyze, the synthesis yield is low and is only about 35-40%, and therefore, the method is not suitable for industrial production. The Chinese patent ZL201511004771.9 takes resorcinol as a raw material, a target product is obtained through esterification, acylation and hydrolysis reactions, the synthesis yield is about 80%, and the method is suitable for industrial production, but the process increases the raw material cost and the industrial cost through two-step reaction, and the three wastes of aluminum salt are more in treatment.

2) In the method (II), the catalyst anhydrous zinc chloride and the phosphorus oxychloride are used in large amounts, and the sulfolane solvent is used in large amounts, so that although the synthesis yield can reach more than 80%, the raw material unit consumption is high, the sulfolane solvent is expensive, the recycling energy consumption is high, the process production cost is high, and the method is not suitable for industrial production.

In conclusion, the two existing synthesis processes of the ultraviolet absorbent BP-2 have the problems of difficulty in industrial production or high production cost, so that the development of a new synthesis process route of the ultraviolet absorbent BP-2 is very important for reducing the production cost of the ultraviolet absorbent BP-2.

Disclosure of Invention

The invention aims to provide a method for catalytically synthesizing an ultraviolet absorbent BP-2, aiming at the problems that the two existing methods for producing the ultraviolet absorbent BP-2 are difficult to industrially produce or have higher production cost.

The invention discloses a method for catalytically synthesizing an ultraviolet absorbent BP-2, which takes 2, 4-dihydroxy benzoic acid and resorcinol as raw materials to prepare the BP-2 by catalytic synthesis and comprises the following steps: adding a halohydrocarbon solvent and a composite catalyst into a reactor, stirring and mixing uniformly, heating to 90-120 ℃, adding 2, 4-dihydroxybenzoic acid and resorcinol into the mixture, stirring and dissolving, carrying out heat preservation reaction for 2-3 hours, filtering and recovering catalyst graphite while the mixture is hot after the reaction is finished, adding a proper amount of water into filtrate, heating to 90-100 ℃, stirring and dissolving completely, standing and layering, distilling an organic layer to recover the solvent, cooling a water layer to 10-20 ℃, precipitating a large amount of red crystals, carrying out suction filtration and washing to obtain a BP-2 crude product, wherein the product purity of the crude product is more than or equal to 80%; in the process, the water for dissolving the filtrate is 5-8 times of the volume of the filtrate.

The composite catalyst is composed of A, B raw materials, wherein the A raw material is selected from any one of graphite and diatomite, the B raw material is selected from any one of methanesulfonic acid and p-toluenesulfonic acid, and the mass ratio of A to B is 6-10: 6-10.

Preferably, the method for refining the prepared BP-2 crude product comprises the steps of firstly dissolving the crude product in a proper amount of hot water, then adding activated carbon for decolorization, boiling for 30-60 min, filtering while the crude product is hot, and cooling and crystallizing to obtain a light yellow green crystal ultraviolet absorbent BP-2 product, wherein the melting point of the product is 199-200 ℃; the purity of the obtained ultraviolet absorbent BP-2 product is more than or equal to 99.8 percent through liquid chromatography detection; in the process, the temperature of hot water for dissolving the crude product is 80-100 ℃, and the using amount of the hot water is 3-5 times of the mass of the crude product.

The mass ratio of the 2, 4-dihydroxy benzoic acid to the resorcinol is 10: 7-9.

The halogenated hydrocarbon solvent is any one selected from dichloroethane, trichloroethane, trichloroethylene and tetrachloroethylene; the mass ratio of the 2, 4-dihydroxybenzoic acid to the halogenated hydrocarbon solvent is 10: 35-65.

The mass ratio of the 2, 4-dihydroxybenzoic acid to the composite catalyst is 10: 12-20.

The method takes 2, 4-dihydroxy benzoic acid and m-diphenol as raw materials, and synthesizes the ultraviolet absorbent BP-2 product through one-step reaction catalysis in a solvent of halogenated hydrocarbon (dichloroethane, tetrachloroethylene and the like), the method adopts graphite (or diatomite) and methanesulfonic acid (or p-toluenesulfonic acid) to carry out mixed catalytic acylation reaction, the synthesis yield can also reach more than 80%, and the catalyst of graphite and the like and the halogenated hydrocarbon solvent can be recycled, thereby not only reducing the environmental pollution, but also reducing the production cost, being more suitable for industrial production, and having the following synthesis route:

the ultraviolet absorbent BP-2 product prepared by the method has the following quality standard:

inspection item	Index of product quality
		Appearance of the product	Light yellow-green crystalline powder
Melting Point	195～203℃
		Solubility in water	Transparent and insoluble-free
Turbidity of water	≤12NTU
		Gardner color number	≤3.0
Chromatographic purity (HPLC)	≥99.0％
		Loss on drying	≤0.5％
Heavy metals	≤5ppm
		Ultraviolet absorption coefficient (1%, 1cm)	E345≥580

As can be seen from the above table, the UV absorbent BP-2 product produced by the method of the present invention meets the quality standards of products in the cosmetic industry.

The ultraviolet absorbent BP-2 (with the chemical name of 2, 2 ', 4, 4' -tetrahydroxybenzophenone) prepared by the invention has the ultraviolet absorption peak of 320-400 nm, has strong absorption to ultraviolet rays in the whole UVA waveband, low toxic and side effects and good water solubility, is a class I sunscreen approved by the American FDA, can be used as a pharmaceutical intermediate, a photosensitive material, a cosmetic ultraviolet-proof additive and the like, and is widely applied to products such as the cosmetic industry, the photosensitive material, printing ink and the like.

Compared with the prior art, the invention has the following characteristics:

(1) the method adopts graphite (diatomite) and methanesulfonic acid (p-toluenesulfonic acid) to carry out mixed catalytic acylation reaction, so that the synthesis yield is high, and the production process is simple;

(2) the catalyst graphite (diatomite) can be recycled, so that the solid waste pollution is reduced, and the industrial cost is reduced.

(3) The product purity is high: the ultraviolet absorbent BP-2 product produced by the method has the chromatographic purity of over 99.0 percent, can be dissolved in water to form a transparent solution, completely meets the industrial requirements of cosmetics and the like, and is widely applied to the fields of skin care cosmetics, photosensitive materials and the like.

Drawings

FIG. 1 is a high performance liquid chromatogram of an ultraviolet absorbent BP-2 product obtained in example 1 of the present invention.

Detailed Description