A method for synthesizing ultraviolet absorbers by alcohol reduction reaction

Abstract

The application relates to the fine chemical technology field and discloses a method for synthesizing an ultraviolet absorber through an alcohol reduction reaction, and the method steps are as follows: under the action of a MOF-derived copper-nickel-cerium trimetallic catalyst, an azo compound (I) or an intermediate nitroxide (II) is reacted with alcohol R-(OH) n A reduction reaction is generated by heating in a reaction kettle, and a benzotriazole compound (III) is prepared. The application utilizes the reduction characteristics of alcohol, adopts the MOF-derived copper-nickel-cerium trimetallic catalyst, combines the porosity and metal synergistic effect regulated by a structure directing agent, effectively improves the catalytic reduction efficiency and reaction selectivity, and the synthesis method has the advantages of no sewage, low cost, high safety and high yield.

Description

Technical Field

[0001] This invention relates to the field of fine chemical technology, and in particular to a method for synthesizing ultraviolet absorbers by alcohol reduction reaction. Background Technology

[0002] In the UV absorber industry, benzotriazole compounds are widely used as anti-aging additives in plastics, coatings, and daily chemical products due to their broad-spectrum absorption, thermo-oxidative stability, and moderate molecular weight. However, existing industrial preparation routes for benzotriazole UV absorbers mainly fall into two categories: one is to first diazotize substituted anilines and then close the ring under a copper or iron salt catalytic system; the other is to use nitriles or halobenzotriazoles as intermediates to obtain the final product through multiple substitution-reduction steps. The former typically uses high-concentration inorganic acids and nitrites, generating a large amount of inorganic salt waste during the reaction and separation process, and involves many reaction steps and a long reaction time; the latter, although avoiding the high-risk diazotization operation, requires the introduction of toxic solvents or expensive nucleophiles, resulting in significant economic and environmental burdens. For products requiring high-performance substituents, the above processes also face problems such as poor selectivity, numerous byproducts, and limited one-step yields. Summary of the Invention

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

[0004] This invention proposes a method for synthesizing ultraviolet absorbers via alcohol reduction reaction. The method comprises the following steps: reacting an azo compound (Ⅰ) or an intermediate oxynitride (Ⅱ) with an alcohol R-(OH) in the presence of a MOF-derived copper-nickel-cerium trimetallic catalyst. n A reduction reaction was carried out by heating in a reaction vessel to obtain benzotriazole compounds (III).

[0005] The reaction equations for azo compounds (Ⅰ) or intermediate nitrogen oxides (Ⅱ) with alcohols are as follows:

[0006]

[0007] Among them, R1 and R2 are one of -H, -CH3, -CH2CH3, -CH(CH3)2, -CH2CH2CH3, -CH2CH2CH2CH3, -C(CH3)2Ar and -C(CH3)2CH2C(CH3)3.

[0008] Preferably, the preparation method of the MOF-derived copper-nickel-cerium trimetallic catalyst is as follows:

[0009] S1: Dissolve nickel source, copper source, cerium source and organic ligand in dimethylformamide;

[0010] S2: Add a structure-directing agent to the S1 solution and mix to obtain a precursor solution;

[0011] S3: The precursor solution is reacted in a reactor. After the reaction, the catalyst is washed, dried and calcined to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] Preferably, the organic ligand is one or more of 2,5-dihydroxyterephthalic acid, pyrimidine-4,6-dicarboxylic acid, and terephthalic acid.

[0016] Preferably, the structure directing agent in S2 is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a mass ratio of 2:1-4.

[0017] Preferably, the mass ratio of nickel source, copper source, cerium source, organic ligand and structure directing agent is 1:0.5-1:0.5-1:0.8-1.2:0.5-1.

[0018] Preferably, the reaction temperature in S3 is 100-150℃, and the time is 6-12h; the calcination temperature is 300-400℃, and the time is 1-5h.

[0019] Preferably, R in alcohol R-(OH)n represents a saturated hydrocarbon group (carbon chain), which can be alkyl, cycloalkyl, 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., when n≥3 it is a polyhydric alcohol, such as glycerol, etc.

[0020] Preferably, the azo compound (Ⅰ) or the intermediate nitride (Ⅱ) and the alcohol R-(OH) n The molar ratio is 1:1-2.2; the amount of catalyst used is 0.5-1.5% of the mass of azo compound (Ⅰ) or intermediate nitrous oxide (Ⅱ).

[0021] Preferably, in the two-step heating reaction, the temperature of the first heating reaction is 42-120℃ and the time is 2-4h; the temperature of the second heating reaction is 120-230℃ and the time is 1-3h.

[0022] Beneficial technical effects of the present invention:

[0023] (1) The present invention uses alcohols as reducing agents and achieves the synthesis of benzotriazole compounds through two-step heating under the action of catalysts. It has the advantages of no wastewater, low cost and high safety, which is in line with the concept of green chemistry and reduces the burden of environmental treatment.

[0024] (2) The present invention uses a copper-nickel-cerium trimetallic catalyst derived from MOF, combined with the porosity controlled by the structure-directing agent and the metal synergistic effect, to effectively improve the catalytic reduction efficiency and reaction selectivity. In addition, the structure-directing agent of the present invention is composed of hexadecyltrimethylammonium bromide and nonionic fluorocarbon surfactant, which can realize the control 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. Detailed Implementation

[0025] The present invention will be further explained below with reference to specific embodiments.

[0026] The nonionic fluorocarbon surfactant of this invention is designated F-6000, with the structural formula CF3CF2(CF2CF2). n CH2CH2O(CH2CH2O) m H, where n≈2, m=6-8, was purchased from Sichuan Ruikaibang Chemical Materials Co., Ltd.

[0027] Example 1

[0028] 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were reacted in a reactor under heating in the presence of an MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0029] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 100℃ and the time is 3h; the temperature of the second heating reaction is 190℃ and the time is 2h.

[0030] The preparation method of 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 the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0031] The structure-directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a 1:1 mass ratio; 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] Example 2

[0033] 2-(2'-hydroxy-3',5'-dicumylphenyl)azobenzene and isopropanol were reacted in a reactor under heating in the presence of a MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole.

[0034] The molar ratio of azo compounds to alcohols was 1:2.2; the amount of catalyst was 0.8% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first step was 90℃ and the time was 4h; the temperature of the second step was 200℃ and the time was 2h.

[0035] The preparation method of 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 the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0036] The structure-directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a 1:1 mass ratio; 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.

[0037] Example 3

[0038] 2-(2'-hydroxy-5'-tert-octylphenyl)azobenzene and butanediol were reacted in a reactor under heating in the presence of a MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole.

[0039] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1.2% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 110℃ and the time is 3h; the temperature of the second heating reaction is 180℃ and the time is 3h.

[0040] The preparation method of 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 the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0041] The structure-directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a 1:1 mass ratio; 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.

[0042] Comparative Example 1

[0043] 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were reacted in a reactor under heating in the presence of an MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0044] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 100℃ and the time is 3h; the temperature of the second heating reaction is 190℃ and the time is 2h.

[0045] The preparation method of 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 the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0046] The structure-directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a 1:1 mass ratio; the mass ratio of Ni(NO3)2·6H2O, 2,5-dihydroxyterephthalic acid and the structure-directing agent is 2.6:1:0.8.

[0047] Comparative Example 2

[0048] 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were reacted in a reactor under heating in the presence of an MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0049] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 100℃ and the time is 3h; the temperature of the second heating reaction is 190℃ and the time is 2h.

[0050] The preparation method of 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 the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0051] The structure-directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a 1:1 mass ratio; the mass ratio of Cu(NO3)2·3H2O, 2,5-dihydroxyterephthalic acid and the structure-directing agent is 2.6:1:0.8.

[0052] Comparative Example 3

[0053] 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were reacted in a reactor under heating in the presence of an MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0054] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 100℃ and the time is 3h; the temperature of the second heating reaction is 190℃ and the time is 2h.

[0055] The preparation method of 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 the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0056] The structure-directing agent is composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant in a 1:1 mass ratio; the mass ratio of Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid and the structure-directing agent is 2.6:1:0.8.

[0057] Comparative Example 4

[0058] 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were reacted in a reactor in two steps with an MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0059] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 100℃ and the time is 3h; the temperature of the second heating reaction is 190℃ and the time is 2h.

[0060] The preparation method of 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 nonionic fluorocarbon surfactant is added, and the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8 h, and after the reaction, it is washed, dried and calcined at 350℃ for 3 h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0061] The mass ratio of Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, 2,5-dihydroxyterephthalic acid, and nonionic fluorocarbon surfactant is 1:0.8:0.8:1:0.8.

[0062] Comparative Example 5

[0063] 2-(2'-hydroxy-5'-methylphenyl)azobenzene and ethanol were reacted in a reactor under heating in the presence of an MOF-derived copper-nickel-cerium trimetallic catalyst to prepare 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0064] The molar ratio of azo compounds to alcohols is 1:2.1; the amount of catalyst used is 1% of the mass of azo compounds; in the two-step heating reaction, the temperature of the first heating reaction is 100℃ and the time is 3h; the temperature of the second heating reaction is 190℃ and the time is 2h.

[0065] The preparation method of 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 hexadecyltrimethylammonium bromide is added, and the mixture is mixed to obtain a precursor solution; the precursor solution is reacted in a reactor at 125℃ for 8h, and after the reaction, it is washed, dried and calcined at 350℃ for 3h to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst.

[0066] 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.

[0067] The yields of benzotriazole compounds synthesized in Examples 1 to 3 and Comparative Examples 1 to 5 were determined, and the results are shown in Table 1.

[0068] Table 1. Compound Yields

[0069] 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

[0070] As can be seen from the experimental results of Examples 1 to 3 in Table 1, the yield of benzotriazole compounds synthesized by the process of the present invention through two-step heating catalysis via alcohol reduction of azo compounds is as high as 90%. Furthermore, the synthesis method of the present invention has advantages such as no wastewater, low cost, and high safety, conforming to the concept of green chemistry and reducing the burden of environmental treatment. The experimental results of Examples 1 to 3 show that the MOF-derived catalyst prepared by the present invention using three metals—copper, nickel, and cerium—significantly improves the catalytic performance compared to catalysts prepared using a single metal. The experimental results of Examples 1 and Comparative Examples 4 to 5 show that the structure-directing agent of the present invention, composed of hexadecyltrimethylammonium bromide and a nonionic fluorocarbon surfactant, is also a key factor in the excellent performance of the prepared catalyst. This is because this combination of structure-directing agents can control the pore size, grain size, and distribution of the catalyst, while also forming a large number of mesoporous channels to enhance the specific surface area of ​​the catalyst and fully expose the metal active sites, ensuring the synergistic catalytic ability of the multi-metal centers, thereby significantly improving the catalytic performance of the catalyst.

[0071] Although embodiments of this 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 this application, including the use of alcohol R-(OH) under different catalysts. n The synthetic routes for ultraviolet absorbers that act as reducing agents are defined by the appended claims and their equivalents, and should all be included within the scope of protection of this application.

Claims

1. A method for synthesizing ultraviolet absorbers via alcohol reduction reaction, characterized in that, The method steps are as follows: Azo compound (Ⅰ) or intermediate oxynitride (Ⅱ) is reacted with alcohol R-(OH) in the presence of a MOF-derived copper-nickel-cerium trimetallic catalyst. n A reduction reaction was carried out by heating in a reaction vessel to obtain benzotriazole compounds (III). The reaction equations for azo compounds (Ⅰ) or intermediate nitrogen oxides (Ⅱ) with alcohols are as follows: Among them, R1 and R2 are one of -H, -CH3, -CH2CH3, -CH(CH3)2, -CH2CH2CH3, -CH2CH2CH2CH3, -C(CH3)2Ar and -C(CH3)2CH2C(CH3)3; The preparation method of MOF-derived copper-nickel-cerium trimetallic catalyst is as follows: S1: Dissolve 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: The precursor solution is reacted in a reactor. After the reaction, it is washed, dried and calcined to obtain the MOF-derived copper-nickel-cerium trimetallic catalyst. 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; the organic ligand is one or more of 2,5-dihydroxyterephthalic acid, pyrimidine-4,6-dicarboxylic acid, and terephthalic acid. The structure directing agent in S2 is composed of hexadecyltrimethylammonium bromide and nonionic fluorocarbon surfactant in a mass ratio of 2:1-4; In alcohol R-(OH)n, R is a saturated hydrocarbon group, which can be alkyl or cycloalkyl; n is the number of hydroxyl groups in alcohol R-(OH)n, and n≥1.

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

3. The method for synthesizing ultraviolet absorbers by alcohol reduction reaction according to claim 1, characterized in that, The reaction temperature in S3 is 100-150℃, and the time is 6-12h; the calcination temperature is 300-400℃, and the time is 1-5h.

4. 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 catalyst used is 0.5-1.5% of the mass of azo compound (Ⅰ) or intermediate nitrous oxide (Ⅱ).

5. 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 step is 42-120℃ and the time is 2-4h; the temperature of the second step is 120-230℃ and the time is 1-3h.

Images