Method for synthesizing ultraviolet absorbent through alcohol reduction reaction

Abstract

The invention relates to the technical field of fine chemical engineering, and discloses a method for synthesizing an ultraviolet absorbent through reduction reaction of alcohols, which comprises the following steps: heating an azo compound (I) or an intermediate nitrogen oxide (II) with alcohol R-(OH) n in a reaction kettle under the action of an MOF-derived copper-nickel-cerium trimetal catalyst to generate reduction reaction; and the benzotriazole compound (III) is prepared. According to the method, the reduction characteristic of alcohol is utilized, the MOF-derived copper-nickel-cerium three-metal catalyst is adopted, the porosity regulated and controlled by the structure-directing agent and the metal synergistic effect are combined, the catalytic reduction efficiency and the reaction selectivity are effectively improved, and the synthesis method has the advantages of being free of sewage, low in cost, high in safety, high in yield and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fine chemical industry, and in particular to a method for synthesizing ultraviolet absorber by alcohol reduction reaction. BACKGROUND

[0002] In the ultraviolet absorber industry, benzotriazole compounds have been widely used as anti-aging additives for plastics, coatings and daily chemical products due to their wide spectrum absorption, thermal oxygen stability and moderate molecular weight. However, the existing industrial preparation routes of benzotriazole ultraviolet absorbers mainly focus on two categories: one is to first perform diazotization on substituted aniline, and then perform ring closure under a copper salt or iron salt catalytic system; the other is to use nitrile or halogenated benzotriazole as an intermediate, and then obtain the final product through multi-step substitution-reduction. The former usually uses high-concentration inorganic acid and nitrite, and generates a large amount of inorganic salt waste in the reaction and separation process, and has many reaction steps and long reaction time; the latter can avoid the high-risk diazotization operation, but needs to introduce toxic solvents or expensive nucleophilic reagents, and also has prominent economic and environmental burdens. For products with high-performance substituent groups, the above processes also have problems such as poor selectivity, many by-products, limited one-step yield, etc. SUMMARY

[0003] Based on the technical problems existing in the background art, the present application provides a method for synthesizing ultraviolet absorber by alcohol reduction reaction, which has the advantages of no wastewater, low cost, high safety and high yield.

[0004] The method for synthesizing ultraviolet absorber by alcohol reduction reaction provided by the present application has the following steps: reacting an azo compound (I) or an intermediate nitroxide (II) with an alcohol R-(OH) n in a reaction kettle under the action of a MOF-derived copper-nickel-cerium trimetallic catalyst to generate a reduction reaction, and obtaining a benzotriazole compound (III); The reaction formula of the azo compound (I) or the intermediate nitroxide (II) with the alcohol is as follows: wherein R1 and R2 are one of -H, -CH3, -CH2CH3, -CH(CH3)2, -CH2CH2CH3, -CH2CH2CH2CH3, -C(CH3)2Ar and -C(CH3)2CH2C(CH3)3.

[0005] Preferably, the preparation method of the MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: S1: dissolving a nickel source, a copper source, a cerium source and an organic ligand in dimethylformamide; S2: adding a structure directing agent to the solution of S1, and obtaining a precursor solution after mixing; S3: the precursor solution is reacted in a reactor, and after reaction, the MOF derived copper-nickel-cerium trimetallic catalyst is obtained through washing, drying and calcination.

[0006] Preferably, the nickel source is one or more of nickel nitrate and its hydrate, nickel acetate and its hydrate, nickel chloride and its hydrate, and nickel sulfate and its hydrate.

[0007] Preferably, the copper source is one or more of copper nitrate and its hydrate, copper acetate and its hydrate, copper chloride and its hydrate, and copper sulfate and its hydrate.

[0008] Preferably, the cerium source is one or more of cerium nitrate and its hydrate, cerium acetate and its hydrate, cerium chloride and its hydrate, and cerium sulfate and its hydrate.

[0009] Preferably, the organic ligand is one or more of 2,5-dihydroxyterephthalic acid, pyrimidine-4,6-dicarboxylic acid, and terephthalic acid.

[0010] Preferably, the structure directing agent in S2 is composed of cetyltrimethylammonium bromide and non-ionic fluorocarbon surfactant at a mass ratio of 2:1-4.

[0011] Preferably, the mass ratio of the nickel source, the copper source, the cerium source, the organic ligand, and the structure directing agent is 1:0.5-1:0.5-1:0.8-1.2:0.5-1.

[0012] Preferably, the temperature of the reaction in S3 is 100-150℃, and the time is 6-12h; the calcination temperature is 300-400℃, and the time is 1-5h.

[0013] Preferably, R in the alcohol R-(OH)n represents a saturated hydrocarbon group (carbon chain), which can be an alkyl group, a cycloalkyl group, etc., and the carbon atoms in the carbon chain are connected by single bonds (saturated state); n is the number of hydroxyl groups (-OH), when n=1, it is a monohydric alcohol, such as methanol, ethanol, etc., when n=2, it is a dihydric alcohol, such as ethylene glycol, etc., and when n≥3, it is a polyhydric alcohol, such as glycerol, etc.

[0014] Preferably, the molar ratio of the azo compound (I) or the intermediate nitroxide (II) and the alcohol R-(OH) n is 1:1-2.2; the amount of the catalyst is 0.5-1.5% of the mass of the azo compound (I) or the intermediate nitroxide (II).

[0015] Preferably, in the two-step heating reaction, the temperature of the first step of heating reaction is 42-120℃, and the time is 2-4h; the temperature of the second step of heating reaction is 120-230℃, and the time is 1-3h.

[0016] The beneficial technical effects of the present application are: (1) The synthesis of benzotriazole compounds is realized by two-step heating under the action of alcohol as a reducing agent and a catalyst, has the advantages of no sewage, low cost, high safety, conforms to the green chemistry concept, and reduces the environmental protection treatment burden.

[0017] (2) The MOF-derived copper-nickel-cerium three-metal catalyst is combined with the porosity and metal synergistic effect controlled by the structure directing agent to effectively improve the catalytic reduction efficiency and reaction selectivity; in addition, the structure directing agent is composed of cetyltrimethylammonium bromide and a non-ionic fluorocarbon surfactant, can realize the control of the pore size, grain size and distribution of the catalyst, can also form a large number of mesoporous channels to enhance the specific surface area of the catalyst and make the metal active sites fully exposed, and ensure the synergistic catalytic ability of the multi-metal center, thereby significantly improving the catalytic performance of the catalyst. DETAILED DESCRIPTION

[0018] The application will be further described below in combination with specific examples.

[0019] The non-ionic fluorocarbon surfactant of the application is F-6000, and the structural formula is CF3CF2(CF2CF2) n CH2CH2O(CH2CH2O) m H, wherein n is approximately 2 and m is 6-8, and is purchased from Sichuan Ruikai Bang Chemical Material Co., Ltd.

[0020] Example 1 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol are heated and reacted in a reaction kettle under the action of the MOF-derived copper-nickel-cerium three-metal catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0021] The molar ratio of the azo compound to the alcohol is 1:2.1, the amount of the catalyst is 1% of the mass of the azo compound, the temperature of the first heating reaction in the two-step heating reaction is 100 DEG C, and the time is 3h, and the temperature of the second heating reaction is 190 DEG C, and the time is 2h.

[0022] The preparation method of the MOF-derived copper-nickel-cerium three-metal catalyst is as follows: Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O and 2,5-dihydroxyterephthalic acid are dissolved in dimethylformamide (DMF); then the structure directing agent is added, and the precursor solution is obtained after mixing; the precursor solution is reacted in a reaction kettle at 125 DEG C for 8h, and after reaction, it is washed, dried and calcined at 350 DEG C for 3h to obtain the MOF-derived copper-nickel-cerium three-metal catalyst.

[0023] The structural directing agent is composed of hexadecyl trimethyl ammonium bromide and non-ionic fluorocarbon surfactant in a mass ratio of 1:1; the mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxy terephthalic acid and the structural directing agent is 1:0.8:0.8:1:0.8.

[0024] Example Two 2-(2'-hydroxy-3',5'-dicumylphenyl)azobenzene and isopropanol are heated and reacted in a reaction kettle under the action of the MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole.

[0025] The molar ratio of the azo compound and the alcohol is 1:2.2; the amount of the catalyst is 0.8% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction is 90°C, and the time is 4h; the temperature of the second heating reaction is 200°C, and the time is 2h.

[0026] The MOF-derived copper-nickel-cerium trimetallic catalyst is prepared as follows: Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O and 2,5-dihydroxy terephthalic acid are dissolved in dimethylformamide (DMF); then the structural directing agent is added, and after mixing, a precursor solution is obtained; the precursor solution is reacted in a reaction kettle at 125°C for 8h, and after the reaction, it is washed, dried and calcined at 350°C for 3h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0027] The structural directing agent is composed of hexadecyl trimethyl ammonium bromide and non-ionic fluorocarbon surfactant in a mass ratio of 1:1; the mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxy terephthalic acid and the structural directing agent is 1:0.8:0.8:1:0.8.

[0028] Example Three 2-(2'-hydroxy-5'-tert-octylphenyl)azobenzene and butanediol are heated and reacted in a reaction kettle under the action of the MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole.

[0029] The molar ratio of the azo compound and the alcohol is 1:2.1; the amount of the catalyst is 1.2% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction is 110°C, and the time is 3h; the temperature of the second heating reaction is 180°C, and the time is 3h.

[0030] The preparation method of the MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O and 2,5-dihydroxyterephthalic acid are dissolved in dimethylformamide (DMF); then a structure directing agent is added, and a precursor solution is obtained after mixing; the precursor solution is reacted in a reaction kettle at 125°C for 8h, and after the reaction, it is washed, dried and calcined at 350°C for 3h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0031] The structure directing agent is composed of cetyltrimethylammonium bromide and non-ionic fluorocarbon surfactant in a mass ratio of 1:1; the mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid and the structure directing agent is 1:0.8:0.8:1:0.8.

[0032] Comparative Example 1 2-(2'-hydroxy-5'-methylphenyl)benzotriazole is prepared by heating and reacting 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol in a reaction kettle in the presence of the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0033] The molar ratio of the azo compound and the alcohol is 1:2.1; the amount of the catalyst is 1% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction is 100°C, and the time is 3h; the temperature of the second heating reaction is 190°C, and the time is 2h.

[0034] The preparation method of the MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: Ni(NO3)2·6H2O and 2,5-dihydroxyterephthalic acid are dissolved in dimethylformamide (DMF); then a structure directing agent is added, and a precursor solution is obtained after mixing; the precursor solution is reacted in a reaction kettle at 125°C for 8h, and after the reaction, it is washed, dried and calcined at 350°C for 3h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0035] The structure directing agent is composed of cetyltrimethylammonium bromide and non-ionic fluorocarbon surfactant in a mass ratio of 1:1; the mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid and the structure directing agent is 1:0.8:0.8:1:0.8.

[0036] Comparative Example 2 2-(2'-hydroxy-5'-methylphenyl)benzotriazole is prepared by heating and reacting 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol in a reaction kettle in the presence of the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0037] The molar ratio of the azo compound to the alcohol is 1:2.1; the amount of the catalyst is 1% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction is 100°C and the time is 3 hours; the temperature of the second heating reaction is 190°C and the time is 2 hours.

[0038] The preparation method of the MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: Cu(NO3)2·3H2O and 2,5-dihydroxyterephthalic acid are dissolved in dimethylformamide (DMF); then a structure-directing agent is added and mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125°C for 8 hours, and after the reaction, the MOF-derived copper-nickel-cerium trimetallic catalyst is obtained by washing, drying and calcining at 350°C for 3 hours.

[0039] The structure directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a mass ratio of 1:1; the mass ratio of Cu(NO3)2·3H2O, 2,5-dihydroxyterephthalic acid and the structure directing agent is 2.6:1:0.8.

[0040] Comparative Example 3 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol are heated and reacted in a reactor under the action of a MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0041] The molar ratio of the azo compound to the alcohol is 1:2.1; the amount of the catalyst is 1% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction is 100°C and the time is 3 hours; the temperature of the second heating reaction is 190°C and the time is 2 hours.

[0042] The preparation method of the MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: Ce(NO3)3·6H2O and 2,5-dihydroxyterephthalic acid are dissolved in dimethylformamide (DMF); then a structure-directing agent is added and mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125°C for 8 hours, and after the reaction, the MOF-derived copper-nickel-cerium trimetallic catalyst is obtained by washing, drying and calcining at 350°C for 3 hours.

[0043] The structure directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a mass ratio of 1:1; the mass ratio of Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid and the structure directing agent is 2.6:1:0.8.

[0044] Comparative Example 4 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were heated in a reaction kettle in two steps to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole under the action of the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0045] The molar ratio of the azo compound to the alcohol was 1:2.1; the amount of the catalyst was 1% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction was 100°C, and the time was 3h; the temperature of the second heating reaction was 190°C, and the time was 2h.

[0046] The MOF-derived copper-nickel-cerium trimetallic catalyst was prepared as follows: Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and 2,5-dihydroxyterephthalic acid were dissolved in dimethylformamide (DMF); then non-ionic fluorocarbon surfactant was added, and a precursor solution was obtained after mixing; the precursor solution was reacted in a reaction kettle at 125°C for 8h, and after the reaction, the product was washed, dried, and calcined at 350°C for 3h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0047] The mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid, and non-ionic fluorocarbon surfactant was 1:0.8:0.8:1:0.8.

[0048] Comparative Example Five 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were heated in a reaction kettle to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole under the action of the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0049] The molar ratio of the azo compound to the alcohol was 1:2.1; the amount of the catalyst was 1% of the mass of the azo compound; the temperature of the first heating reaction in the two-step heating reaction was 100°C, and the time was 3h; the temperature of the second heating reaction was 190°C, and the time was 2h.

[0050] The MOF-derived copper-nickel-cerium trimetallic catalyst was prepared as follows: Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and 2,5-dihydroxyterephthalic acid were dissolved in dimethylformamide (DMF); then cetyltrimethylammonium bromide was added, and a precursor solution was obtained after mixing; the precursor solution was reacted in a reaction kettle at 125°C for 8h, and after the reaction, the product was washed, dried, and calcined at 350°C for 3h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0051] The mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid and hexadecyltrimethylammonium bromide is 1:0.8:0.8:1:0.8.

[0052] The yields of the benzotriazole compounds synthesized in Examples 1 to 3 and Comparative Examples 1 to 5 were measured, and the results are shown in Table 1.

[0053] Table 1 Yield of compounds Group Yield (%) Example 1 92.1 Example 2 91.6 Example 3 92.8 Comparative Example 1 72.3 Comparative Example 2 64.7 Comparative Example 3 59.1 Comparative Example 4 78.4 Comparative Example 5 83.7 As can be seen from the test results of Examples 1 to 3 in Table 1, the yield of synthesizing benzotriazole compounds by reducing azo compounds to alcohols under two-step temperature increase catalysis is as high as more than 90% with the process of the present invention, and the synthesis method of the present invention has the advantages of no sewage, low cost and high safety, conforms to the green chemistry concept, and reduces the burden of environmental protection treatment. As can be seen from the test results of Examples 1 to 3, the catalyst performance of the MOF derived from the three metals of copper, nickel and cerium prepared by the present invention is significantly improved compared to the catalytic performance of the catalyst prepared by a single metal. As can be seen from the test results of Example 1 and Comparative Examples 4 to 5, the structure-directing agent of the present invention is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant, which is also a key factor in making the prepared catalyst have excellent performance, because the structure-directing agent of this combination can realize the regulation of the pore size, grain size and distribution of the catalyst, and can also form a large number of mesoporous channels to enhance the specific surface area of ​​the catalyst and fully expose the metal active sites, and ensure the synergistic catalytic ability of the multi-metal center, thereby significantly improving the catalytic performance of the catalyst.

[0054] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application. n The scope of the synthetic route of the ultraviolet absorber as a reducing agent is defined by the appended claims and their equivalents, and should all be included in the scope of protection of this application.

Claims

1. A method for synthesizing an ultraviolet absorber by reduction reaction of alcohols, characterized in that: The method steps are as follows: an azo compound (I) or an intermediate nitrogen oxide (II) is reacted with an alcohol R-(OH) in the presence of a MOF-derived copper-nickel-cerium trimetallic catalyst. n The product is heated in a reaction vessel to undergo a reduction reaction to obtain a benzotriazole compound (III); The reaction formula of azo compound (Ⅰ) or intermediate nitrogen oxide (Ⅱ) with alcohol is as follows: Wherein, R1 and R2 are one of -H, -CH3, -CH2CH3, -CH(CH3)2, -CH2CH2CH3, -CH2CH2CH2CH3, -C(CH3)2Ar and -C(CH3)2CH2C(CH3)3.

2. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 1, characterized in that: The preparation method of MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: S1: dissolving nickel source, copper source, cerium source and organic ligand in dimethylformamide; S2: Add a structure-directing agent to the S1 solution and mix to obtain a precursor solution; S3: reacting the precursor solution in a reactor, washing, drying and calcining after the reaction to obtain a MOF-derived copper-nickel-cerium trimetallic catalyst.

3. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 2, characterized in that: The nickel source is one or more of nickel nitrate and its hydrate, nickel acetate and its hydrate, nickel chloride and its hydrate, and nickel sulfate and its hydrate; the copper source is one or more of copper nitrate and its hydrate, copper acetate and its hydrate, copper chloride and its hydrate, and copper sulfate and its hydrate; the cerium source is one or more of cerium nitrate and its hydrate, cerium acetate and its hydrate, cerium chloride and its hydrate, and cerium sulfate and its hydrate; and the organic ligand is one or more of 2,5-dihydroxyterephthalic acid, pyrimidine-4,6-dicarboxylic acid, and terephthalic acid.

4. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 2, characterized in that: The structure directing agent in S2 is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a mass ratio of 2:1-4.

5. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 2, characterized in that: The mass ratio of the nickel source, the copper source, the cerium source, the organic ligand and the structure directing agent is 1:0.5-1:0.5-1:0.8-1.2:0.5-1.

6. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 2, characterized in that: The reaction temperature in S3 is 100-150°C, and the reaction time is 6-12 hours; the calcination temperature is 300-400°C, and the reaction time is 1-5 hours.

7. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 1, characterized in that: R in the alcohol R-(OH)n is a saturated hydrocarbon group, which may be an alkyl group or a cycloalkyl group; n is the number of hydroxyl groups in the alcohol R-(OH)n, and n≥1.

8. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 1, characterized in that: Azo compounds (Ⅰ) or intermediate nitrogen oxides (Ⅱ) and alcohols R-(OH) n The molar ratio is 1:1-2.2; the amount of the catalyst is 0.5-1.5% of the mass of the azo compound (I) or the intermediate nitrogen oxide (II).

9. The method for synthesizing an ultraviolet absorber by alcohol reduction reaction according to claim 1, characterized in that: In the two-step heating reaction, the temperature of the first heating reaction is 42-120° C. and the time is 2-4 hours; the temperature of the second heating reaction is 120-230° C. and the time is 1-3 hours.

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