CN110803998B - Method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis - Google Patents
Method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis Download PDFInfo
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- C07C245/02—Azo compounds, i.e. compounds having the free valencies of —N=N— groups attached to different atoms, e.g. diazohydroxides
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- C07C245/08—Azo compounds, i.e. compounds having the free valencies of —N=N— groups attached to different atoms, e.g. diazohydroxides with nitrogen atoms of azo groups bound to carbon atoms of six-membered aromatic rings with the two nitrogen atoms of azo groups bound to carbon atoms of six-membered aromatic rings, e.g. azobenzene
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Abstract
The invention relates to a method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis, which comprises the steps of reacting an aromatic nitro compound with an aromatic amino compound by a photocatalyst under the conditions of illumination and inert gas to obtain an asymmetric azobenzene compound shown as a formula I and an asymmetric azoxybenzene compound shown as a formula II,
can be used for replacing the existing mature organic synthesis process, has mild condition, high selectivity and universality, and is suitable for industrial production.
Description
Technical Field
The invention belongs to the technical field of photocatalytic asymmetric synthesis, and particularly relates to a method for preparing asymmetric azobenzene and azoxybenzene compounds through photocatalysis.
Background
The photocatalysis technology is one of ideal ways for obtaining clean energy by utilizing solar energy. In recent years, the photocatalytic organic synthesis technology has the advantages of mild reaction conditions, no need of using an additional redox agent, controllable selectivity and the like, and provides a green and economic technical route for synthesizing various high-value-added chemicals.
Azobenzene and azoxybenzene are industrially important raw materials, and as organic synthesis intermediates, azobenzene and azoxybenzene are widely applied to the industries of dye synthesis, biomedicine, electronic liquid crystal materials and the like. The traditional synthesis method is not very unstable for diazonium salt compounds generated in the diazotization process of azobenzene and azoxybenzene, and the reaction process is very dangerous and easy to explode. Chinese patent (application No. 201410499441.0) discloses a preparation method of asymmetric aromatic azo. The method takes aromatic hydrazine and halogenated aromatic hydrocarbon as raw materials to obtain the asymmetric aromatic azo compound. Although the method avoids diazotization steps and reduces the reaction danger, the aromatic hydrazine compounds are easily decomposed by heating and release toxic nitrogen oxide smoke, and the method has the defects of low atom utilization rate, incapability of selectively regulating and controlling the synthesis of azobenzene and azoxybenzene and the like.
Therefore, the research on the new synthesis method of the asymmetric azobenzene and azoxybenzene compounds and the derivatives thereof with high efficiency, green and high atom economy has very important value. And nitrobenzene and aniline are used as reaction raw materials, wherein the nitrobenzene participates in reduction reaction in photocatalysis, and the aniline participates in oxidation reaction in photocatalysis, so that high atom utilization rate is realized. And the photocatalytic synthesis has the advantages of no toxicity, safety, high stability, recoverability and the like. Therefore, the development of photocatalytic synthesis of asymmetric azobenzene and azoxybenzene has very important significance and application prospect.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis.
In order to achieve the purpose, the invention adopts the technical scheme that: a method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis comprises reacting aromatic nitro compounds with aromatic amino compounds under the conditions of illumination and inert gas by photocatalyst to obtain asymmetric azobenzene compounds shown in formula I and asymmetric azoxybenzene compounds shown in formula II,
in the formulae I and II, R1And R2Independently of one another, are 1, 2, 3, 4 or 5 substituents bonded to the phenyl ring, each of saidThe substituents are independently of one another hydrogen, halogen, C1-C10Alkyl radical, C2-C10Alkenyl radical, C2-C10Alkynyl, C6-C20Aryl, -OR', -OCF3Any one of-NHR ', -C (═ O) OR ', -NHC (═ O) R ', and-C (═ O) R ', wherein R ' is H, C1-C6Alkyl radical, C2-C6Alkenyl radical, C2-C6Any one of alkynyl, phenyl and benzyl.
Optimally, the structural general formula of the aromatic nitro compound is shown as a formula III:
further, the structural general formula of the aromatic amino compound is shown as a formula IV:
specifically, it comprises the following steps:
(a) mixing the aromatic nitro compound, the aromatic amino compound and a base in a molar ratio of 1: (0.1-10): (1-10) mixing, adding a solvent and a photocatalyst, and performing ultrasonic dispersion to obtain a mixed solution;
(b) the mixed solution is put under the protection of inert atmosphere at 0.001-50W/cm2Stirring and reacting under illumination, and controlling the reaction temperature to be 0-100 ℃;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain asymmetric azobenzene and azoxybenzene compounds.
Optimally, the photocatalyst is a semiconductor material with the bandwidth range of 1-4 eV. More specifically, the photocatalyst is composed of one or more selected from the group consisting of a metal oxide semiconductor, a metal nitrogen compound semiconductor, a metal sulfide semiconductor, a metal selenide semiconductor, a perovskite semiconductor, a delafossite semiconductor, a carbon-based polymer semiconductor and a nitrogen-based polymer semiconductorAnd (3) mixing. The inert gas is He, Ar, N2、CO2CO or H2. In the step (a), the concentration of the aromatic nitro compound in the mixed solution is 1-100 mmol/L, and the concentration of the photocatalyst is 1-100 mg/mL. In the step (a), the alkali is sodium hydroxide, potassium tert-butoxide, sodium carbonate or sodium bicarbonate
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: the method for preparing the asymmetric azobenzene and azoxybenzene compounds by photocatalysis realizes the reaction of the aromatic nitro compounds and the aromatic amino compounds by the action of the photocatalyst to obtain the asymmetric azobenzene and azoxybenzene compounds, can be used for replacing the existing mature organic synthesis process, has mild conditions, high selectivity and universality, and is suitable for industrial production.
Drawings
FIG. 1 is a mass spectrum of 4-chlorophenylazobenzene in example 1.
Detailed Description
The invention relates to a method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis, which comprises the steps of reacting an aromatic nitro compound with an aromatic amino compound by a photocatalyst under the conditions of illumination and inert gas to obtain an asymmetric azobenzene compound shown as a formula I and an asymmetric azoxybenzene compound shown as a formula II,
in the formulae I and II, R1And R2Independently of one another, 1, 2, 3, 4 or 5 substituents attached to the phenyl ring, each of said substituents independently of one another being hydrogen, halogen, C1-C10Alkyl radical, C2-C10Alkenyl radical, C2-C10Alkynyl, C6-C20Aryl, -OR', -OCF3Any one of-NHR ', -C (═ O) OR ', -NHC (═ O) R ', and-C (═ O) R ', wherein R ' is H, C1-C6Alkyl radical, C2-C6Alkenyl radical, C2-C6Any one of alkynyl, phenyl and benzyl. The reaction of the aromatic nitro compound and the aromatic amino compound is realized through the action of the photocatalyst to obtain asymmetric azobenzene and azoxybenzene compounds, the asymmetric azobenzene and azoxybenzene compounds can be used for replacing the existing mature organic synthesis process, and the photocatalyst has the advantages of mild conditions, high selectivity, universality and suitability for industrial production. The structural general formula of the aromatic nitro compound is shown as a formula III:
the structural general formula of the aromatic amino compound is shown as a formula IV:
the method for preparing the asymmetric azobenzene and azoxybenzene compounds by photocatalysis specifically comprises the following steps: (a) mixing the aromatic nitro compound, the aromatic amino compound and a base in a molar ratio of 1: (0.1-10): (1-10), adding a solvent (or not using the solvent according to the requirement) and a photocatalyst, and performing ultrasonic dispersion to obtain a mixed solution; (b) under the protection of inert atmosphere, the mixed solution is put at 0.001-50W/cm2Stirring and reacting under illumination, and controlling the reaction temperature to be 0-100 ℃; (c) drying and concentrating the organic phase obtained in the step (b) to obtain asymmetric azobenzene and azoxybenzene compounds.
The photocatalyst is required to be a semiconductor material with the bandwidth range of 1-4 eV so as to ensure the selectivity of asymmetric synthesis. May be a mixture of one or more selected from the group consisting of a metal oxide semiconductor, a metal nitride compound semiconductor, a metal sulfide semiconductor, a metal selenide semiconductor, a perovskite semiconductor, a delafossite semiconductor, a carbon-based polymer semiconductor and a nitrogen-based polymer semiconductor. That is, the photocatalyst is a metal oxide semiconductor, a metal sulfide (selenide) semiconductor, a metal nitrogen (oxygen) compound semiconductor, a perovskite semiconductor (ABO)3) Delafossite, ABO2) A carbon (nitrogen) -based polymeric semiconductor material or any of the aboveCompounding the two materials; a metal oxide semiconductor including an oxide of Ti, Zn, Zr, W, V, Cu, Fe, Ce, Ta, In or Nb; metal sulfide (selenide) semiconductors, sulfur-containing, selenium compounds including Cd, Zn, Cu, W, or Bi; a metal-nitrogen (oxy) compound semiconductor comprising a nitrogen-oxygen containing compound of C, Ti, Ga, Ge or Ta. The photocatalyst is also typically loaded with a cocatalyst which is one or more of Pt, Au, Ag, Pd, Ir, Ru, Ni and NiO.
The inert gas is He, Ar, N2、CO2CO or H2. In the step (a), the concentration of the aromatic nitro compound in the mixed solution is 1-100 mmol/L, and the concentration of the photocatalyst is 1-100 mg/mL. In the step (a), the alkali is sodium hydroxide, potassium tert-butoxide, sodium carbonate or sodium bicarbonate. The solvent is water, methyl sulfoxide, acetonitrile, N-dimethylformamide or 1, 4-dioxane, or a mixed solvent of the following volume ratios: methyl sulfoxide (2): water (v/v) ═ 1: (0-100), acetonitrile: water (v/v) ═ 1: (0-100), N-dimethylformamide: water (v/v) ═ 1: (0-100), 1, 4-dioxane: water (v/v) ═ 1: (0-100), or a combination of any two of the above 4 solvents (in a ratio of solvent 1: solvent 2(v/v) ═ 1 (1-100)), or a combination of any two of the above 4 solvents and water (in a ratio of solvent 1: solvent 2: water (v/v) ═ 1 (1-100): (1-100)), or a combination of any 3 of the above 4 solvents (in a ratio of solvent 1: solvent 2: solvent 3 (v/v): 1 (1-100)).
The present invention will be further described with reference to examples.
Example 1
The embodiment provides a method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis, which comprises the following steps:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst (the synthesis of the copper/graphene photocatalyst is as follows: 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2mL of ethanol and 50mL of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and placing in an oven at 60 ℃ for drying for 24 h), 80 mu mol of nitrobenzene, 800 mu mol of parachloroaniline, 100 mu mol of potassium hydroxide and 10mL of dimethyl sulfoxide: uniformly mixing a mixed solvent with water (v/v) ═ 7:3, and dispersing for 10min by ultrasonic waves (with electric power of 80W) to obtain a suspension;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-chlorobenzene azoxybenzene
Through the test and analysis of a gas chromatograph, the conversion rate of nitrobenzene is 90 percent, and the selectivity of 4-chlorobenzene azoxybenzene is 94 percent; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
Results were analyzed by gas chromatograph test: the nitrobenzene conversion was 95% and the 4-chlorophenylazobenzene selectivity 98%.
Example 2
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the used base is potassium tert-butoxide; the final result of the step (c) is that the nitrobenzene conversion rate is 89% and the 4-chlorobenzene azoxybenzene selectivity is 82% through the test and analysis of a gas chromatograph; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 78% and the 4-chlorophenylazobenzene selectivity was 85%.
Example 3
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in step (a), the base used is sodium bicarbonate; the final result of the step (c) is that the nitrobenzene conversion rate is 79 percent and the selectivity of the 4-chlorobenzene azoxybenzene is 81 percent through the test and analysis of a gas chromatograph; chamberStirring the mixture at a low temperature for 12 hours to react to obtain 4-chlorobenzene azobenzene
The nitrobenzene conversion was 85% and the 4-chlorophenylazobenzene selectivity 65%.
Example 4
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the alkali used is 800 mu mol of potassium hydroxide; finally, the result of the step (c) is tested and analyzed by a gas chromatograph, the nitrobenzene conversion rate is 80 percent, and the selectivity of the 4-chlorobenzene azoxybenzene is 32 percent; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 84% and the 4-chlorophenylazobenzene selectivity was 55%.
Example 5
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the alkali used is 80 mu mol of potassium hydroxide; finally, the result of the step (c) is tested and analyzed by a gas chromatograph, the nitrobenzene conversion rate is 77 percent, and the selectivity of the 4-chlorobenzene azoxybenzene is 91 percent; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 85% and the 4-chlorophenylazobenzene selectivity was 76%.
Example 6
This example provides a photocatalytic process for the preparation of asymmetric azobenzene and azoxybenzene compounds, which is essentially the same as that described in example 1, except that: in the step (a), 8 mu mol of p-chloroaniline is used as the base; finally, the result of the step (c) is tested and analyzed by a gas chromatograph, the nitrobenzene conversion rate is 79 percent, and the selectivity of the 4-chlorobenzene azoxybenzene is 88 percent; stirring at room temperature for 12h to obtain4-Chlorobenzeneazobenzene
The nitrobenzene conversion was 84% and the 4-chlorophenylazobenzene selectivity was 79%.
Example 7
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the used alkali is 100 mu mol of parachloroaniline; the final result of the step (c) is that the nitrobenzene conversion rate is 88 percent and the selectivity of the 4-chlorobenzene azoxybenzene is 84 percent through the test and analysis of a gas chromatograph; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 90% and the 4-chlorophenylazobenzene selectivity was 89%.
Example 8
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the used solvents are methyl sulfoxide, acetonitrile and N, N-dimethylformamide according to the volume ratio of 1: 1: 1; the final result of the step (c) is that the nitrobenzene conversion rate is 88 percent and the selectivity of the 4-chlorobenzene azoxybenzene is 56 percent through the test and analysis of a gas chromatograph; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 90% and the 4-chlorophenylazobenzene selectivity was 76%.
Example 9
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the solvent used is 1, 4-dioxane; the final result of step (c) was that the nitrobenzene conversion was 89% and the 4-chlorobenzene azoxybenzene selectivity was 89% as determined by gas chromatograph test analysis(ii) a Stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 95% and the 4-chlorophenylazobenzene selectivity was 86%.
Example 10
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the used photocatalyst is Pt/GaN (400mg of gallium nitride, 97.3mg of chloroplatinic acid hexahydrate, 2ml of ethanol and 50ml of water are uniformly mixed, stirred at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuged, and placed in an oven at 60 ℃ to be dried for 24 h); the final result of the step (c) is that the nitrobenzene conversion rate is 80 percent and the selectivity of the 4-chlorobenzene azoxybenzene is 81 percent through the test and analysis of a gas chromatograph; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 85% and the 4-chlorophenylazobenzene selectivity was 78%.
Example 11
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: in the step (a), the photocatalyst is Au/ZnS (400mg of zinc sulfide, 40.0mg of tetrachloroauric acid trihydrate, 2ml of ethanol and 50ml of water are uniformly mixed, stirred at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuged, and placed in an oven at 60 ℃ to be dried for 24 h); the final result of the step (c) is that the nitrobenzene conversion rate is 50 percent and the selectivity of the 4-chlorobenzene azoxybenzene is 77 percent through the test and analysis of a gas chromatograph; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene
The nitrobenzene conversion was 64% and the 4-chlorophenylazobenzene selectivity was 78%.
Example 12
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: the raw materials used are 80 mu mol of p-chloronitrobenzene and 800 mu mol of p-methoxyaniline, and the 4-methoxybenzene azoxy 4-chlorobenzene can be obtained by stirring and reacting for 7 hours at room temperature
Wherein the conversion rate of p-chloronitrobenzene is 89 percent, and the selectivity of 4-methoxybenzene azoxy-4-chlorobenzene is 91 percent; stirring at room temperature for 18h to obtain 4-methoxybenzeneazo-4-chlorobenzene
Wherein the conversion rate of p-chloronitrobenzene is 93 percent, and the selectivity of 4-methoxybenzeneazo-4-chlorobenzene is 94 percent.
Example 13
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: the raw materials used are 80 mu mol of 2-methylnitrobenzene and 800 mu mol of 4-trifluoromethylaniline, and the 4-trifluoromethylbenzene oxidized azo 2-methylbenzene can be obtained by stirring and reacting for 5 hours at room temperature, wherein the conversion rate of the 2-methylnitrobenzene is 91 percent
The selectivity of 4-trifluoromethyl benzene azoxy 2-methylbenzene is 92 percent; stirring at room temperature for 18h to obtain 4-trifluoromethylphenylazo 2-methylbenzene
Wherein the conversion rate of the 2-methylnitrobenzene is 93 percent, and the selectivity of the 4-trifluoromethylbenzene azo 2-methylbenzene is 95 percent.
Example 14
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: the raw materials used were 80. mu. mol of 3-bromonitrobenzene and 800. mu.mThe final reaction of 4-methylaniline with 4-methyl aniline at room temperature for 6 hr to obtain 4-methyl azoxy 3-bromobenzene
Wherein the conversion rate of the 3-bromonitrobenzene is 90 percent, and the selectivity of the 4-methyl-benzene azoxy 3-bromobenzene is 93 percent; stirring the mixture at room temperature for reaction for 16 hours to obtain 4-methyl-phenylazo 3-bromobenzene
Wherein the conversion rate of the 3-bromonitrobenzene is 95 percent, and the selectivity of the 4-methylbenzeneazo 3-bromobenzene is 96 percent.
Example 15
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: the raw materials used are 80 mu mol of 4-fluoronitrobenzene and 800 mu mol of 4-methylaniline, and the 4-methylbenzeneazoxy 4-fluorobenzene can be obtained by stirring and reacting for 6h at room temperature
Wherein the conversion rate of the 4-fluoronitrobenzene is 90 percent, and the selectivity of the 4-methylbenzene azoxy 4-fluorobenzene is 93 percent; stirring the mixture at room temperature for reaction for 16 hours to obtain 4-methylbenzeneazo 4-fluorobenzene
Wherein the conversion rate of the 4-fluoronitrobenzene is 95 percent, and the selectivity of the 4-methylbenzeneazo-4-fluorobenzene is 96 percent.
Example 16
This example provides a photocatalytic process for the preparation of asymmetric azobenzenes and azoxybenzenes, which is essentially the same as in example 1, except that: the raw materials used are 80 mu mol of nitrobenzene and 800 mu mol of 4- (N, N-dimethyl) aniline, and the 4- (N, N-dimethyl) benzene azoxybenzene can be obtained by stirring and reacting for 5 hours at room temperature
Wherein the conversion rate of nitrobenzene is 90 percent, and 4- (N, N-dimethyl) benzene is oxidizedThe selectivity of azobenzene is 89%; stirring the mixture at room temperature for 20 hours to react to obtain 4- (N, N-dimethyl) phenylazobenzene
Wherein the conversion rate of nitrobenzene is 96 percent, and the selectivity of 4- (N, N-dimethyl) phenylazobenzene is 98 percent.
Comparative example 1
This example is substantially the same as in example 1, except that: the photocatalyst used is ZrO2(bandwidth 5eV), and finally, step (c) results in failure to obtain the asymmetric azobenzene and azoxybenzene-based compounds.
Comparative example 2
This example is substantially the same as in example 1, except that: asymmetric azobenzene and azoxybenzene compounds cannot be obtained without using a photocatalyst.
The above examples are only for illustrating the technical idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (3)
1. A method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis is characterized by comprising the following steps:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of nitrobenzene, 800 mu mol of parachloroaniline and alkali with 10mL of mixed solvent, and performing ultrasonic dispersion for 10min by using electric power of 80W to obtain suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the mixed solvent is formed by mixing dimethyl sulfoxide and water according to the volume ratio of 7: 3;
the alkali is potassium tert-butoxide or sodium bicarbonate, and the usage amount is 100 mu mol; or the like, or, alternatively,
the alkali is potassium hydroxide, and the usage amount of the alkali is 80 mu mol, 100 mu mol or 800 mu mol;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-chlorobenzene azoxybenzene; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene;
or, comprising the steps of:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of nitrobenzene, 800 mu mol of parachloroaniline, 100 mu mol of potassium hydroxide and 10mL of mixed solvent, and performing ultrasonic dispersion for 10min by using electric power of 80W to obtain suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the mixed solvent is methyl sulfoxide, acetonitrile and N, N-dimethylformamide according to the volume ratio of 1: 1: 1;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-chlorobenzene azoxybenzene; stirring at room temperature for 12h to obtain 4-chlorophenylazobenzene;
or, comprising the steps of:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of nitrobenzene, 800 mu mol of parachloroaniline, 100 mu mol of potassium hydroxide and 10mL of solvent, and performing ultrasonic dispersion for 10min by using electric power of 80W to obtain a suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the solvent is 1, 4-dioxane;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-chlorobenzene azoxybenzene; stirring the mixture at room temperature for 12 hours to react to obtain the 4-chlorophenylazobenzene.
2. A method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis is characterized by comprising the following steps:
(a) uniformly mixing 50mg of 1wt% photocatalyst, 80 mu mol of nitrobenzene, 800 mu mol of parachloroaniline, 100 mu mol of potassium hydroxide and 10mL of mixed solvent, and performing ultrasonic dispersion for 10min by using electric power of 80W to obtain suspension; the mixed solvent is formed by mixing dimethyl sulfoxide and water according to the volume ratio of 7: 3; the photocatalyst is Pt/GaN or Au/ZnS, and the synthesis of the Pt/GaN is as follows: uniformly mixing 400mg of gallium nitride, 97.3mg of chloroplatinic acid hexahydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the synthesis of Au/ZnS is as follows: uniformly mixing 400mg of zinc sulfide, 40.0mg of tetrachloroauric acid trihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-chlorobenzene azoxybenzene; stirring the mixture at room temperature for 12 hours to react to obtain the 4-chlorophenylazobenzene.
3. A method for preparing asymmetric azobenzene and azoxybenzene compounds by photocatalysis is characterized by comprising the following steps:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of p-chloronitrobenzene, 800 mu mol of p-anisidine, 100 mu mol of potassium hydroxide and 10mL of mixed solvent, and performing ultrasonic dispersion for 10min by using electric power of 80W to obtain suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the mixed solvent is formed by mixing dimethyl sulfoxide and water according to the volume ratio of 7: 3;
(b) stirring the dispersed suspension at room temperature for reaction for 7 hours under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-methoxybenzene azoxy 4-chlorobenzene; stirring at room temperature for 18h to obtain 4-methoxybenzeneazo-4-chlorobenzene;
or, comprising the steps of:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of 3-bromonitrobenzene, 800 mu mol of 4-methylaniline, 100 mu mol of potassium hydroxide and 10mL of mixed solvent, and ultrasonically dispersing for 10min by using 80W electric power to obtain a suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the mixed solvent is formed by mixing dimethyl sulfoxide and water according to the volume ratio of 7: 3;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-methylbenzene azoxy 3-bromobenzene; stirring at room temperature for 16h to obtain 4-methylbenzene azo 3-bromobenzene;
or, comprising the steps of:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of 4-fluoronitrobenzene, 800 mu mol of 4-methylaniline, 100 mu mol of potassium hydroxide and 10mL of mixed solvent, and ultrasonically dispersing for 10min by using 80W of electric power to obtain a suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the mixed solvent is formed by mixing dimethyl sulfoxide and water according to the volume ratio of 7: 3;
(b) stirring and reacting the dispersed suspension for 6 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4-methylbenzene azoxy 4-fluorobenzene; stirring at room temperature for 16h to obtain 4-methylbenzeneazo 4-fluorobenzene;
or, comprising the steps of:
(a) uniformly mixing 50mg of 1wt% copper/graphene photocatalyst, 80 mu mol of nitrobenzene, 800 mu mol of 4- (N, N-dimethyl) aniline, 100 mu mol of potassium hydroxide and 10mL of mixed solvent, and performing ultrasonic dispersion for 10min by using electric power of 80W to obtain suspension; the copper/graphene photocatalyst is synthesized as follows: uniformly mixing 400mg of carbon nitride graphene, 53.6mg of copper chloride dihydrate, 2ml of ethanol and 50ml of water, stirring at room temperature for 2-3h under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen, centrifuging, and drying in an oven at 60 ℃ for 24 h; the mixed solvent is formed by mixing dimethyl sulfoxide and water according to the volume ratio of 7: 3;
(b) stirring and reacting the dispersed suspension for 5 hours at room temperature under the irradiation of an LED lamp simulating sunlight and the protection of nitrogen;
(c) drying and concentrating the organic phase obtained in the step (b) to obtain 4- (N, N-dimethyl) benzene azoxybenzene; stirring the mixture at room temperature for 20 hours to react to obtain 4- (N, N-dimethyl) phenylazobenzene.
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| CN115337919B (en) * | 2021-05-14 | 2023-11-28 | 兰州大学 | Application of zirconium hydroxide as catalyst in catalyzing aniline or derivative thereof to prepare diphenyldiazene or derivative thereof |
| CN115959997A (en) * | 2021-10-13 | 2023-04-14 | 中国科学院大连化学物理研究所 | Method for reducing nitro-substituted aromatic compound |
| CN114315653B (en) * | 2022-01-05 | 2023-07-04 | 重庆第二师范学院 | Method for synthesizing azoxybenzene by photocatalysis |
| CN114436902B (en) * | 2022-02-28 | 2023-04-14 | 苏州大学张家港工业技术研究院 | Heterogeneous photocatalysis method for mobile phase system |
| CN114805142B (en) * | 2022-04-18 | 2024-06-25 | 杭州师范大学 | Method for preparing 1-diphenyl diazene oxide and derivatives thereof by photocatalysis continuous reduction coupling |
| CN116393127B (en) * | 2023-03-03 | 2024-05-24 | 安徽大学 | Defect copper-based catalyst for synthesizing azobenzene compound and preparation method thereof |
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