Physiology and biochemistry of reduction of azo compounds.
Aryl azo compounds (). Aryl azo compounds are usually stable, crystalline species. Azobenzene is the prototypical aromatic azo compound. It exists mainly as the trans isomer, but upon illumination, converts to the cis isomer. Aromatic azo compounds can be synthesized by azo coupling, which entails an electrophilic substitution reaction where an aryl diazonium cation is attacked by another.
Para Red BS. Para Red YS. Lake Red 2R. Para Nitraniline Red. Kromon Para Red BS. Kromon Para Red YS. Para Red Toner RPT-52. Monolite Fast Red B. Recolite Para Red B. Recolite Para Red G. Conc. Para Red YS. 1-((4-Nitrophenyl)diazenyl)naphthalen-2-ol. Carnelio Para Red YS. Monolite Fast Red BA. Tertropigment Red PAB. Sanyo Signal Red Pure.
One reaction that includes an azo compound in a role other than that as an initiator is shown in eq 17, where the imine 11 is produced by reaction of a carbohydrate radical with an azo compound. 52,53 The dimer 12 is a suggested intermediate in the proposed mechanism for this reaction, which is pictured in Scheme 7. 52,53 After radical reaction is complete, the imine 11 can be hydrolyzed to.
The color of the azo compound is the result of the conjugated system, which facilitates electron delocalization, with the energy absorption in the visible region of the spectrum. If the double bond of the azo compounds is reduced, the azo compounds are decolorized. Therefore, the rate of azoreduction was quantified using the change in optical density value measured at a specific wavelength.
Azo pigments are colorless particles (typically earths or clays), which have been colored using an azo compound. Azo pigments are important in a variety of paints including artist's paints. They have excellent coloring properties, again mainly in the yellow to red range, as well as lightfastness. The lightfastness depends not only on the properties of the organic azo compound, but also on the.
Azo pigments are synthetic compounds that contain in their molecular structure one or more azo groups (N N), being the oldest and most used pigments in food. The base for the development of azo pigments was the discovery of diazo reaction in the laboratory of Peter Griess in 1858, when the first azo compound was produced, and very rapidly after these, organic chemists have discovered new azo.
With an alkaline solution of napthalein-2-ol, a red azo compound is formed: Coupling with amines. A yellow dye is often formed when a diazonium salt is reacted with arylamines: Many different azo compounds can be formed by coupling different diazonium salts with a range of coupling agents. The azo compounds are stable and so their colours do not fade. Useful books for revision Revise A2.