Preparation method of 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid

Abstract

The invention discloses a preparation method of 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, which comprises the following steps: taking 2-nitro-2 '-hydroxy-3'-tert-butyl-5 '-(2-propionyl) azobenzene as a raw material, taking isopropanol as a hydrogen donor, and taking 2-nitro-2'-hydroxy-3 '-tert-butyl-5'-(2-propionyl) azobenzene as a hydrogen donor; the 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid is prepared by a one-pot method in the presence of a catalyst under an alkaline condition. The preparation method has the advantages of simple process, convenience in operation, low cost, mild reaction condition, low equipment requirement, safety in operation, high preparation efficiency, environmental friendliness and the like, the reaction yield is more than 90%, the purity is more than 95%, large-scale preparation can be realized, and the method is suitable for industrial production. The method is of great significance in realizing industrial production of the ultraviolet light absorber UV1130 and promoting wide application of the ultraviolet light absorber UV1130.

Description

Technical Field

[0001] The invention relates to a method for preparing a key intermediate of an ultraviolet light absorber UV1130, and in particular to a method for preparing 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid. Background Art

[0002] 3-[3-(Benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid is a key intermediate for preparing ultraviolet light absorber UV1130. According to the known preparation method of 3-[3-(Benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, it is as follows:

[0003] Method 1: 3-(3-tert-butyl-4-hydroxy)phenylpropionic acid methyl ester is used as a raw material, and reacted with o-chloroaniline diazonium salt to obtain an azo intermediate, and the intermediate reacts with sodium azide under the catalysis of cuprous bromide to synthesize 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid methyl ester. This method requires the use of hazardous reagents such as NaN 3 .

[0004]

[0005] Method 2: Using o-diphenylamine and 3-(3-tert-butyl-4-hydroxy-5-nitrosobenzene) propionate as raw materials, triethyl borate is used to obtain an azo intermediate, which is reduced with copper sulfate and ammonia to obtain the target product 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionate. Although this method has a shorter route, the nitroso raw materials used are difficult to prepare.

[0006]

[0007] Method 3: Using 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as raw material, 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid was obtained by two-step reduction using hydrazine hydrate and hydrosulfite as reducing agents respectively.

[0008]

[0009] Method 4: Using 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionyl)azobenzene as raw material, 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid was obtained by two-step reduction using glucose and zinc powder as reducing agents respectively.

[0010]

[0011] Method 5: 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionyl)azobenzene is directly reduced to 3-[3-(benzotriazol-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid methyl ester in one step under cobalt catalyst, 220°C, and 6MPa H2. The reaction conditions of this method are relatively harsh, which will cause excessive reduction of the raw materials, poor selectivity, low product yield, and low purity.

[0012]

[0013] In the above-mentioned prior art, the preparation method of 3-[3,3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid and the corresponding ester still has the following shortcomings: (1) hazardous reagents are required; (2) raw materials are not easy to obtain; (3) a two-step method is adopted, which is cumbersome to operate; (4) metal reducing agents are used, which are relatively expensive; (5) a large amount of wastewater and metal by-products are generated; and (6) the reaction conditions are harsh, the selectivity is poor, and the product purity is low. Summary of the invention

[0014] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for preparing 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, which has the advantages of simple process, convenient operation, low cost, mild reaction conditions, low equipment requirements, safe operation, high preparation efficiency and environmental friendliness.

[0015] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0016] A method for preparing 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, which uses 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as a raw material and isopropanol as a hydrogen donor, and is prepared by a one-pot process under a catalyst and alkaline conditions. The reaction formula is as follows:

[0017]

[0018] The above preparation method is further improved and comprises the following steps:

[0019] Step S1, mixing 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene, isopropanol, a catalyst, and a solid base, and stirring to obtain a mixed solution;

[0020] Step S2, heating the mixed solution obtained in step S1 to 40°C to 60°C for reaction for 1h to 2h, and further heating to 80°C to 90°C for reaction for 1h to 2h to obtain a reaction product solution;

[0021] Step S3, filtering the reaction product liquid to remove the catalyst, adjusting the pH value of the reaction product liquid to be acidic, precipitating crystals, filtering, washing, and drying to obtain a crude product;

[0022] Step S4, recrystallizing the crude product to obtain 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid.

[0023] The above preparation method is further improved, in step S1, the molar ratio of the 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to the solid base is 1:7-10.

[0024] The above preparation method is further improved, in step S1, the molar ratio of the isopropanol to the solid base is 1 to 4:1.

[0025] The above preparation method is further improved, in step S1, the solid base is solid sodium hydroxide and / or solid potassium hydroxide.

[0026] The above preparation method is further improved, in step S1, the mass ratio of the 2-nitro-2'-hydroxy-3'-tert-butyl-5'-(2-propionic acid)azobenzene to the catalyst is 1:0.005-0.2.

[0027] The above preparation method is further improved, in step S1, the catalyst is a nickel-aluminum oxide composite and / or a nickel-magnesium-aluminum composite oxide.

[0028] The above preparation method is further improved, in step S3, when adjusting the pH value of the reaction product liquid, the temperature of the reaction product liquid is maintained at 60°C to 80°C.

[0029] The above preparation method is further improved in that in step S3, a hydrochloric acid solution is used to adjust the pH value of the reaction product liquid; the mass concentration of the hydrochloric acid solution is 10%.

[0030] The above preparation method is further improved in that in step S4, the crude product is recrystallized using isopropanol.

[0031] Compared with the prior art, the advantages of the present invention are:

[0032] (1) In view of the shortcomings of the synthesis method, such as low safety factor, harsh reaction conditions and high equipment requirements, complicated operation, low preparation efficiency, high preparation cost, and easy generation of a large amount of wastewater and by-products, the present invention creatively proposes a preparation method of 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, which uses 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as a raw material, and uses a mild and highly selective hydrogen transfer reduction method with isopropanol as a raw material to obtain 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid. The method is a hydrogen donor and is prepared by a one-pot method under a catalyst and alkaline conditions. The method has the advantages of simple process, convenient operation, low cost, mild reaction conditions, low equipment requirements, safe operation, high preparation efficiency, environmental friendliness, etc. The reaction yield is greater than 90%, and 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid can be prepared on a large scale. The method is of great significance for realizing the industrial production of the ultraviolet light absorber UV1130 and promoting the widespread use of the ultraviolet light absorber UV1130.

[0033] (2) In the present invention, cheap and easily available isopropanol is used as a hydrogen transfer donor, and no dangerous reducing agents such as hydrazine hydrate and hydrogen are required; at the same time, in the present invention, no separation is required, and the target product is obtained by a "one-pot method", the operation is simple and efficient, and has good social and economic benefits.

[0034] (3) In the present invention, the mixed solution of each raw material is heated to 40°C to 60°C for reaction for 1h to 2h, and then further heated to 80°C to 90°C for reaction for 1h to 2h. By performing the reaction in stages, excessive reduction of the raw materials can be prevented, the reaction selectivity can be reduced, and the product purity can be higher.

[0035] (4) In the present invention, by optimizing the molar ratio of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to the solid base to 1:7-10, the amount of the solid base used can be reduced while ensuring the normal reaction.

[0036] (5) In the present invention, by optimizing the molar ratio of isopropanol to solid base to 1-4:1, the reaction rate can be increased and the isopropanol hydrogen transfer efficiency can be increased. In particular, reducing the amount of base or isopropanol will result in incomplete reaction and reduce the product yield and purity.

[0037] (6) In the present invention, by optimizing the mass ratio of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to the catalyst to 1:0.005-0.2, the generation of more products can be promoted and the generation of impurities can be reduced. In particular, when the amount of catalyst is too high, the nitrogen-nitrogen double bond in the raw material will be broken, reducing the reaction selectivity; while when the amount of catalyst is too small, the reaction will be incomplete and the yield will be reduced. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0039] In the following examples of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0040] Example 1

[0041] A method for preparing 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, which uses 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as a raw material and isopropanol as a hydrogen donor, and is prepared by a one-pot process under a catalyst and alkaline conditions. The reaction formula is as follows:

[0042]

[0043] In this embodiment, the preparation method of 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid comprises the following steps:

[0044] Step S1, 0.4 mol (148.4 g) of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene, 280 g of isopropanol, 15 g of nickel aluminum oxide complex (commercially available product), and 2.8 mol (116.7 g) of sodium hydroxide solid were mixed, and stirred at room temperature for 0.5 h to obtain a mixed solution.

[0045] Step S2, heating the mixed solution obtained in step S1 to 55°C and reacting for 1 hour, the reaction solution changes from purple-black to yellow-brown, evaporating part of the solvent to raise the temperature to 80°C, keeping the temperature for 2 hours, the reaction solution turns dark brown, and obtaining a reaction product liquid.

[0046] Step S3, filtering the reaction product liquid to remove the catalyst, evaporating part of the isopropanol in the reaction product liquid (filtrate after filtration), and adding a hydrochloric acid solution with a mass concentration of 10% at a temperature of 60° C. to 80° C. to adjust the pH value of the reaction product liquid to acidic, precipitating crystals, filtering, washing with water, and drying to obtain a crude product in black.

[0047] Step S4, recrystallizing the crude product with isopropanol to obtain an off-white product, namely 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid.

[0048] After testing, the mass of the off-white product was 122 g, and the yield was 90%.

[0049] Example 2

[0050] A method for preparing 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, which uses 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as a raw material and isopropanol as a hydrogen donor, and is prepared by a one-pot process under a catalyst and alkaline conditions. The reaction formula is as follows:

[0051]

[0052] In this embodiment, the preparation method of 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid comprises the following steps:

[0053] Step S1, 0.4 mol (148.4 g) of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene, 280 g of isopropanol, 15 g of nickel-magnesium-aluminum composite oxide (commercially available), and 2.8 mol (116.7 g) of sodium hydroxide solid were mixed, and stirred at room temperature for 0.5 h to obtain a mixed solution.

[0054] Step S2, heating the mixed solution obtained in step S1 to 55°C and reacting for 1 hour, the reaction solution changes from purple-black to yellow-brown, evaporating part of the solvent to raise the temperature to 80°C, keeping the temperature for 2 hours, the reaction solution turns dark brown, and obtaining a reaction product liquid.

[0055] Step S3, filtering the reaction product liquid to remove the catalyst, evaporating part of the isopropanol in the reaction product liquid (filtrate after filtration), and adding a hydrochloric acid solution with a mass concentration of 10% at a temperature of 60° C. to 80° C. to adjust the pH value of the reaction product liquid to acidic, precipitating crystals, filtering, washing with water, and drying to obtain a crude product in black.

[0056] Step S4, recrystallizing the crude product with isopropanol to obtain an off-white product, namely 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid.

[0057] After testing, the mass of the off-white product was 124.7 g, and the yield was 92%.

[0058] In this example, the effect of different molar ratios of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to solid base on the product yield was also investigated. Other conditions were the same as in Example 2. The results are shown in Table 1.

[0059] Table 1 Comparison of product yield and purity data under different molar ratios of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to solid base

[0060]

[0061] As can be seen from Table 1, when the molar amount of the base is reduced to 5 times of the raw material, the reaction will be incomplete, greatly reducing the reaction yield and product purity. When the molar amount of the base is increased to 8 times and 10 times of the raw material, the reaction yield is equivalent to 7 times, with no obvious improvement. Therefore, the molar amount of the base is selected to be 7 times of the raw material as the final amount.

[0062] In this example, the effect of different molar ratios of isopropanol to solid base on the product yield was also investigated. Other conditions were the same as in Example 2. The results are shown in Table 2.

[0063] Table 2 Comparison of product yield and purity data under different molar ratios of isopropanol to solid base

[0064] Molar ratio of isopropanol to solid base Product yield (%) Product purity (%) 1∶1 88 97 1.66∶1 92 98 2∶1 92 98 4∶1 92 98

[0065] As shown in Table 2, reducing the amount of isopropanol will result in incomplete reaction, lower reaction yield, and lower product purity; increasing the amount of isopropanol will not significantly improve product yield and purity. Therefore, the final molar ratio of isopropanol to solid base is 1.66:1.

[0066] In this example, the effect of different mass ratios of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to the catalyst on the product yield was also investigated. Other conditions were the same as in Example 2. The results are shown in Table 3.

[0067] Table 3 Comparison of product yield and purity data under different mass ratios of 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to catalyst

[0068]

[0069] As shown in Table 3, increasing the amount of catalyst will reduce the reaction yield, increase impurities, produce over-reduction products, and reduce product purity. Therefore, it is best to select a catalyst mass of 1% of the raw material.

[0070] It can be seen from the above results that, compared with the conventional method, the preparation method of 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid of the present invention uses 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as a raw material and isopropanol as a hydrogen donor, and is prepared by a one-pot process under catalyst and alkaline conditions. It has the advantages of simple process, convenient operation, low cost, mild reaction conditions, low equipment requirements, safe operation, high preparation efficiency, and environmental friendliness, and the reaction yield is greater than 90%. 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid can be prepared on a large scale, which is of great significance for realizing the industrial production of ultraviolet absorber UV1130 and promoting the widespread use of ultraviolet absorber UV1130.

[0071] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid, characterized in that: It is prepared by a one-pot method using 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene as raw material and isopropanol as hydrogen donor under catalyst and alkaline conditions. The reaction formula is as follows:

2. The preparation method according to claim 1, characterized in that: The following steps are involved: Step S1, mixing 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene, isopropanol, a catalyst, and a solid base, and stirring to obtain a mixed solution; Step S2, heating the mixed solution obtained in step S1 to 40°C to 60°C for reaction for 1h to 2h, and further heating to 80°C to 90°C for reaction for 1h to 2h to obtain a reaction product solution; Step S3, filtering the reaction product liquid to remove the catalyst, adjusting the pH value of the reaction product liquid to be acidic, precipitating crystals, filtering, washing, and drying to obtain a crude product; Step S4, recrystallizing the crude product to obtain 3-[3-(benzotriazole-2-yl)-4-hydroxy-5-tert-butylphenyl]-propionic acid.

3. The preparation method according to claim 2, characterized in that: In step S1, the molar ratio of the 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to the solid base is 1:7-10.

4. The preparation method according to claim 3, characterized in that: In step S1, the molar ratio of the isopropanol to the solid base is 1-4:

1.

5. The preparation method according to claim 4, characterized in that: In step S1, the solid alkali is solid sodium hydroxide and / or solid potassium hydroxide.

6. The preparation method according to claim 3, characterized in that: In step S1, the mass ratio of the 2-nitro-2′-hydroxy-3′-tert-butyl-5′-(2-propionic acid)azobenzene to the catalyst is 1:0.005-0.

2.

7. The preparation method according to claim 6, characterized in that: In step S1, the catalyst is a nickel-aluminum oxide composite and / or a nickel-magnesium-aluminum composite oxide.

8. The preparation method according to any one of claims 2 to 7, characterized in that In step S3, the temperature of the reaction product liquid is maintained at 60°C to 80°C when adjusting the pH value of the reaction product liquid.

9. The preparation method according to claim 8, characterized in that: In step S3, a hydrochloric acid solution is used to adjust the pH value of the reaction product liquid; the mass concentration of the hydrochloric acid solution is 10%.

10. The preparation method according to any one of claims 2 to 7, characterized in that: In step S4, the crude product is recrystallized using isopropanol.

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