Video Experimental Relacionado
Updated: Jun 27, 2026
07:30
A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones
Published on: January 21, 2020
Síntesis catalizada por oro de compuestos azo aromáticos de anilinas y nitroaromáticos
Abdessamad Grirrane1, Avelino Corma, Hermenegildo García
1Instituto de Tecnología Química, Consejo Superior de Investigaciones (CSIC), Universidad Politécnica de Valencia, 46022-Valencia, Spain.
Science (New York, N.Y.)
|December 17, 2008
Resumen
Las nanopartículas de oro catalizan la síntesis eficiente de compuestos azo aromáticos de anilinas y nitroaromáticos. Este enfoque de química verde evita reactivos agresivos, ofreciendo altos rendimientos bajo condiciones suaves.
Área de la Ciencia:
- La catálisis de la catálisis.
- Química verde es la química verde.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- La síntesis tradicional de compuestos azo aromáticos a menudo se basa en reactivos estequiométricos, perjudiciales para el medio ambiente, como los metales de transición o los nitritos.
- El desarrollo de métodos catalíticos sostenibles y eficientes para la síntesis de compuestos azoicos es crucial para las aplicaciones industriales.
Objetivo del estudio:
- Desarrollar un nuevo sistema catalítico para la formación selectiva de compuestos azo aromáticos.
- Explorar el uso de nanopartículas de oro en soportes de óxido metálico para la oxidación aeróbica y las reacciones de acoplamiento reductor.
Principales métodos:
- Utilizando nanopartículas de oro apoyadas en dióxido de titanio (TiO2) y dióxido de cerio nanoparticulado (CeO2).
- Investigando la oxidación aeróbica de las anilinas aromáticas a compuestos azoicos.
- Examinando un acoplamiento reductor de dos pasos y una olla de nitroaromáticos a compuestos azoicos utilizando oro sobre TiO2.
Principales resultados:
- Se obtienen rendimientos superiores al 98% para los compuestos azo aromáticos a través de la oxidación aeróbica de las anilinas.
- Se ha demostrado una alta eficiencia catalítica en condiciones de reacción suaves.
- Sintetizó con éxito compuestos azo aromáticos simétricos y asimétricos, mostrando la versatilidad del método.
Conclusiones:
- Las nanopartículas de oro en TiO2 y CeO2 ofrecen una ruta catalítica altamente eficiente y respetuosa con el medio ambiente para la síntesis de compuestos azo aromáticos.
- El sistema catalítico desarrollado proporciona una alternativa sostenible a los métodos tradicionales, con potencial para la ampliación industrial.
- Este enfoque permite la síntesis directa de compuestos azoicos a partir de precursores fácilmente disponibles como las anilinas y los nitroaromáticos.
Videos de Conceptos Relacionados
01:22Preparation of 1° Amines: Azide Synthesis
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
01:29Preparation of Amines: Reduction of Oximes and Nitro Compounds
Oximes can be reduced to primary amines using catalytic hydrogenation, hydride reduction, or sodium metal reduction. The reduction of aliphatic and aromatic nitro compounds to primary amines takes place by either catalytic hydrogenation or by using active metals like Fe, Zn, and Sn in the presence of an acid.
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
01:28Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
01:14Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
01:20Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.