Classifications, properties, recent synthesis and applications of azo dyes

Abstract

In this work, we have presented a very detailed review of the different classification of azo dyes as a function of the number of azo groups and the appropriate functional groups. Then we pointed out some chemical properties of these dyes such as reactivity, isomerization and tautomerism and listed. In the following, we have summarized some recent syntheses of azo dyes and the mechanism of azo dye/polymer conjugation. Finally, we indicate the principle of Gewald's reaction and its application to the synthesis of new azo dyes.

Microbial degradation of dyes: An overview

“…Several other methods are also available for synthesis of azo dyes such as oxidation of primary amines by lead tetraacetate or permanganate potassium, reduction of nitroso compounds by AlLiH 4 , condonation of quinone and hydrazine, etc. (Benkhaya et al, 2020). These dyes are recorded for industrial applications and only azo dye forms 60% ratio as compared to all other types of dyes (Shah, 2014;Iark et al, 2019).…”

“…Dyes are an important source in various industries such as textile, leather, paint, food, cosmetic and paper industries. There are approximately twenty-five types of dye groups available based on their chemical structure of chromophore (Sudha et al, 2014;Benkhaya et al, 2020). More than thousand dyes have been classified as textile dyes which are used to color variety of fabrics (Sponza, 2006;Abe et al, 2019).…”

Bacilli-Mediated Degradation of Xenobiotic Compounds and Heavy Metals

“…Azo dyes are a large group of synthetic aromatic compounds which contain one or more azo groups (-N=N-) between organic residues. Based on the number of azo linkages, azo dyes are classified as monoazo, disazo, trisazo, and polyazo (Benkhaya et al, 2020 ). Few examples of azo dyes are Metanil Yellow, Navy Blue 2GL, Dye Orange T4LL, Reactive Red 2, Direct Red-22, Turquoise Blue dye, and Acid Black 24.…”

Influence of Solvents' Polarity on the Physicochemical Properties and Photocatalytic Activity of Titania Synthesized Using Deinbollia pinnata Leaves

“…The dye effluents are usually non-biodegradable, highly oxidizing, and stable to heat and light (Khataee and Mirzajani, 2010; which attributed to their toxicity, undesirable aesthetic, and carcinogenicity (Khalik et al, 2017). This is due to their diversity and complex structure (Benkhaya et al, 2017), which need to be degraded. One example is methyl orange (MO), which is a commonly used dye.…”