2440-22-4Relevant academic research and scientific papers
Reductive cyclization of o-nitrophenylazobenzenes to 2-aryl-2H- benzotriazoles by SmI2
Kim, Byeong Hyo,Kim, Sun Kyong,Lee, Yoon Seok,Jun, Young Moo,Baik, Woonphil,Lee, Byung Min
, p. 8303 - 8306 (1997)
In a mild reaction with SmI2, ortho-nitro substituted phenylazobenzenes have been converted into 2-aryl-2H-benzotriazoles.
Preparation method of benzotriazole ultraviolet light absorber
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Paragraph 0092; 0096-0098; 0102-0104; 0108-0110; 0114-0116, (2021/04/14)
The invention relates to a preparation method of a benzotriazole ultraviolet absorbent. The method comprises the following steps: under the action of a magnesium oxide supported metal catalyst, carrying out transfer hydrogenation reaction on an azo intermediate shown in a formula I and a hydrogen donor to obtain a target product shown in a formula III. The method provided by the invention is small in catalyst dosage, the raw material conversion rate can reach 100%, and the target product selectivity is 90% or above.
Hydrogenation of Substituted Benzenes Containing Nitro and Azo Groups over Skeletal Nickel in Aqueous Solutions of 2-Propanol
An’, Khoang,Belova, A. V.,Lefedova, O. V.,Nemtseva, M. P.
, p. 720 - 724 (2020/04/24)
Abstract: An analysis is made of the kinetic characteristics of the hydrogenation of 4-nitro- and 2-nitro-2'-hydroxy-5'-methylazobenzenes, 4-nitroaniline and 4-aminoazobenzene over skeletal nickel in neutral azeotropic 2-propanol–water mixture and in the same solvent in the presence of acetic acid or sodium hydroxide. It is found that the selectivity of the hydrogenation of these isomers to the intermediate products depends on the composition and nature of the solvent, and is determined by the rate of reactive group conversion. Compared to the process in the presence of sodium hydroxide, which suppresses the route leading to the predominant hydrogenation of the nitro group, the contribution from the transformation of azo group is considerably greater in the hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene in the presence of acetic acid. Adding a base to the solvent during the hydrogenation of 2-nitro-2'-hydroxy-5'-methylazobenzene accelerates the rate of nitro group conversion and the intramolecular cyclization of the intermediate compound, increasing the selectivity towards the products containing the benzotriazole cycle (particularly 2-(2-hydroxy-5-methylphenyl)benzotriazole-N-oxide). The almost linear correlation between the selectivity of the catalytic hydrogenation of isomers of nitro-2'-hydroxy-5'-methylazobenzene and the kinetic characteristics of the hydrogenation of nitro and azo groups in compounds containing a single reactive substituent at different values of medium’s pH is estimated.
The Continuous Synthesis of 2-(2'-Hydroxy-5'-Methylphenyl)Benzotriazole over Cu/γ-Al2O3
Yan,Si,Tao,Liu,Wang,Li
, p. 635 - 641 (2019/10/19)
Abstract: The samples of 20% Cu/γ-Al2O3, 20% Co/γ-Al2O3 and 20% Ni/γ-Al2O3 were prepared as hydrogenation catalysts for continuous synthesis of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole. The best yield (86.62%) was afforded by the 20% Cu/γ-Al2O3 catalyst. The characterizations results obtained for the 20% Cu/γ-Al2O3 sample confirmed that Cu particles are evenly distributed over the surface of γ-Al2O3. A reduction of acid sites in the catalyst favored the selectivity to 2-(2'-hydroxy-5'-methylphenyl)benzotriazole. Furthermore, the effect of Cu content, reaction temperature, hydrogen pressure and liquid hourly space velocity was studied. Finally, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole in 86.62% yield was attained under the optimized conditions.
A benzo triazole ultraviolet absorbing agent preparation method (by machine translation)
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Paragraph 0044-0057, (2018/06/15)
The invention discloses a benzo triazole ultraviolet absorbing agent preparation method, including the raw material compound and alkali is dissolved in the solvent, is configured to raw material is added to the reaction device; then the Fe3 O4 /Catalyst is added to the raw material liquid in the graphene, access hydrogen, keeping the pressure 0.1 - 5 mpa, temperature 40 - 120 °C; in the reaction process using high performance liquid chromatography to real-time monitoring of the reaction solution, after the reaction, cooling, the restoration of normal pressure and recovering the catalyst after treatment, be benzo triazole ultraviolet absorbent. The method of this invention simple process, environmental protection, low cost, mild reaction conditions, product yield and quality is high, is suitable for industrial production, Fe used therein3 O4 /Graphene catalyst economic and environmental protection, stable properties, is recycled. (by machine translation)
A benzotriazole compound synthesis method (by machine translation)
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Paragraph 0032; 0033; 0034; 0035, (2018/03/26)
The invention discloses a synthetic method of a benzotriazoles compound. The synthetic method comprises the following steps: loading a bifunctional catalyst of hydrogenation-solid alkali into a fixed bed reactor; continuously leading a solution of a compound represented by the formula (I) into the fixed bed reactor, leading hydrogen, and performing heating; enabling the reaction liquid to continuously flow out from a lower end of the fixed bed reactor; cooling the effluent reaction liquid to the room temperature; performing gas-liquid separation, liquid filtration, and filtrate condensation to remove the solvent; and performing purification to obtain the benzotriazoles compound represented by the formula (II). The bifunctional catalyst of hydrogenation-solid alkali is adopted for catalytic hydrogenation to synthesize the benzotriazoles compound. The bifunctional catalyst has catalytic performance of solid alkali during catalytic hydrogenation, so that insufficient addition of alkali liquor is effectively avoided in the prior art. The bifunctional catalyst is high in catalytic activity and is convenient to recycle and reuse. Post-treatment of synthesizing the benzotriazoles compound is simplified, and the problem of environmental pollution resulting from post-treatment of the alkali liquor is effectively avoided. The synthetic method is efficient, and is low in cost and easy and simple to operate.
Preparation method of ultraviolet absorbent
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Paragraph 0033; 0036; 0037; 0038; 0040; 0042; 0044, (2018/11/03)
The invention belongs to the field of macromolecules, and particularly relates to a preparation method of an ultraviolet absorbent. The preparation method of the ultraviolet absorbent adopts rutheniumphosphide as a catalyst, the formula I has catalytic hydrogenation reaction with the ruthenium phosphide to prepare the ultraviolet absorbent, and the structural formula of the ultraviolet absorbentis formula II, wherein (shown in the description), R is H or Cl; R1 is (CH3)3 or H, R2 is CH3, (CH3)3 or t-C8H17. The preparation method of the ultraviolet absorbent solves the technical problems in the prior art that the environment is polluted, the operation is complicated, the atom utilization rate is low, and the cost is higher.
Catalytic hydrogenation of 2-nitro-2′-hydroxy-5′-methylazobenzene over solid base-hydrogenation bifunctional catalysts: Effect of alkali metals on Pd/γ-Al2O3
Si, Leilei,Wang, Bowei,Chen, Shipeng,Hou, Jingru,Yan, Xilong,Li, Yang,Chen, Ligong
, p. 35 - 38 (2016/11/25)
Alkali metals doped Pd solid base-hydrogenation bifunctional catalysts were prepared, characterized, and employed in the hydrogenation of 2-nitro-2′-hydroxy-5′-methylazobenzene. The results indicated that the basicity of catalyst endowed by the alkali met
Preparation method of benzotriazole ultraviolet light absorber
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Paragraph 0021; 0022, (2017/01/19)
The invention discloses a preparation method of a benzotriazole ultraviolet light absorber. The method comprises the following steps: adding an azo dye intermediate represented by formula I to hydrazine hydrate, carrying out reduction to form an intermediate nitrogen oxide represented by formula II, and reducing the intermediate nitrogen oxide represented by formula II with hydrogen to prepare the benzotriazole ultraviolet light absorber represented by formula III, wherein the formula I, the formula II and the formula III are respectively shown in the description. The preparation method allows wastewater generated in the invention to be environmentally-friendly.
Reductive cyclization of 2-nitro-2′-hydroxy-5′-methylazobenzene to benzotriazole over K-doped Pd/γ-Al2O3
Wang, Bowei,Si, Leilei,Yuan, Yanyan,Li, Yang,Chen, Ligong,Yan, Xilong
, p. 16766 - 16771 (2016/02/20)
A series of Pd/γ-Al2O3 catalysts modified by potassium salts were prepared and evaluated in the reductive cyclization of 2-nitro-2′-hydroxy-5′-methylazobenzene without additional base. These solid base-hydrogenation bifunctional catalysts were characterized and the results demonstrated that potassium salts could have an important impact on the properties and catalytic performance of Pd/γ-Al2O3.
