Azo dyes and pigments

2007 ◽  
pp. 45-68 ◽  
Keyword(s):  
Azo Dyes ◽  
Dyes And Pigments

scholarly journals METHOD FOR THE PREPARATION OF 2,4,6-TRIHYDROXYTOLUENE FROM 2,4,6-TRINITROTOLUENE

2021 ◽  
pp. 143-147
Author(s):  
И.А. Щурова ◽  
Н.А. Алексеева ◽  
С.В. Сысолятин ◽  
В.В. Малыхин
Keyword(s):  
Sulfuric Acid ◽  
Azo Dyes ◽  
Catalyst Activity ◽  
Amino Derivative ◽  
Synthetic Method ◽  
Pd Catalyst ◽  
Concentrated Sulfuric Acid ◽  
Hydrolysis Of ◽  
Chemical Reactant ◽  
Dyes And Pigments

Статья посвящена усовершенствованию способа получения 2,4,6-тригидрокситолуола, востребованного химического реагента в синтезе азокрасителей и пигментов, а также химико-фармацевтических препаратов и различных полимеров. Основным сырьем для его получения является 2,4,6-тринитротолуол, который подвергают каталитическому гидрированию с последующим гидролизом образовавшегося 2,4,6-триаминотолуола. В данной работе предложены условия многоциклового использования палладиевого катализатора гидрирования 2,4,6-тринитротолуола, позволяющие сохранять активность катализатора и повысить выход 2,4,6-триаминотолуола выше 98 %. Аминопроизводное выделяется в виде дисульфата действием концентрированной серной кислоты. Кроме того, изучено влияние соотношения вода/дисульфат 2,4,6-триаминотолуола на выход 2,4,6-тригидрокситолуола; найдены условия, в которых выход на стадии гидролиза увеличен до 83-84 %. Проведен сравнительный анализ различных способов выделения 2,4,6-тригидрокситолуола из реакционной массы. The paper is concerned with upgrading the synthetic method for 2,4,6-trihydroxytoluene, an in-demand chemical reactant in the synthesis of azo-dyes and pigments, as well as chemical pharmaceuticals and various polymers. The basic feedstock for the synthesis thereof is 2,4,6-trinitrotoluene, which is subjected to catalytic hydrogenation followed by hydrolysis of the resulting 2,4,6-triaminotoluene. Here we suggest conditions for the multicycle use of Pd catalyst employed for the hydrogenation of 2,4,6-trinitrotoluene, which allow the catalyst activity to be retained and the yield of 2,4,6-triaminotoluene to be enhanced above 98%. The amino derivative is liberated as the disulfate by concentrated sulfuric acid. Moreover, we examined how the ratio of water / 2,4,6-triaminotoluene disulfate influences the yield of 2,4,6-trihydroxytoluene. Conditions were found in which the yield from hydrolysis is 83-84 %. Different methods for the isolation of 2,4,6-trihydroxytoluene from the reaction mixture were comparatively analyzed.

scholarly journals Bacterial decolourization of azo dyes

2017 ◽  
Vol 16 (4) ◽  
pp. 1-12
Author(s):  
Amrita Nair ◽  
Nandini Rajendhiran ◽  
R Varsha ◽  
Biljo V Joseph ◽  
V L Vasantha
Keyword(s):  
Azo Dyes ◽  
Organic Contaminants ◽  
Control Strategies ◽  
Textile Effluent ◽  
Health Concern ◽  
Synthetic Dyes ◽  
Chemical Methods ◽  
Physico Chemical ◽  
Pure Cultures ◽  
Dyes And Pigments

Release of textile effluent into the environment is a matter of health concern. Dyes and pigments that are part of textile effluent generate hazardous wastes which are generally inorganic or organic contaminants. Among the present pollution control strategies, biodegradation of synthetic dyes by microbes is evolving as a promising approach, even more than physico-chemical methods. While both mixed cultures and pure cultures have been used to achieve efficient biodegradation, no conclusive result has been determined. This paper aims at checking the efficiency of mixed culture of sewage and pure isolates in degradation of azo dyes, both simple dyes like methyl red and methyl orange and a more complex dye like Janus green.

Azo Dyes, 6. Miscellaneous Dyes and Pigments

2011 ◽  
Author(s):  
Klaus Hunger ◽  
Peter Mischke ◽  
Wolfgang Rieper
Keyword(s):  
Azo Dyes ◽  
Dyes And Pigments

scholarly journals Synthesis of azo pyridone dyes

2011 ◽  
Vol 65 (5) ◽  
pp. 517-532 ◽  
Author(s):  
Dusan Mijin ◽  
Gordana Uscumlic ◽  
Natasa Valentic ◽  
Aleksandar Marinkovic
Keyword(s):  
Azo Dyes ◽  
Diazo Compound ◽  
Coupling Reaction ◽  
Disperse Dyes ◽  
Transfer Printing ◽  
Substituted Anilines ◽  
Light Fastness ◽  
Synthetic Fibers ◽  
Heterocyclic Derivatives ◽  
Dyes And Pigments

Over 50% of all colorants which are used nowdays are azo dyes and pigments, and among them arylazo pyridone dyes (and pigments) have became of interest in last several decades due to the high molar extinction coefficient, and the medium to high light and wet fastness properties. They find application generally as disperse dyes. The importance of disperse dyes increased in the 1970s and 1980s due to the use of polyester and nylon as the main synthetic fibers. Also, disperse dyes were used rapidly since 1970 in inks for the heat-transfer printing of polyester. The main synthetic route for the preparation of azo dyes is coupling reaction between an aromatic diazo compound and a coupling component. Of all dyes manufactured, about 60% are produced by this reaction. Arylazo pyridone dyes can be prepared from pyridone moiety as a coupling component, where substituent can be on nitrogen, and diazonim salts which can be derived from different substituted anilines or other heterocyclic derivatives. In addition, arylazo dyes containing pyridone ring can be prepared from arylazo diketones or arylazo ketoesters (obtained by coupling ?-diketones or ?-ketoesters with diazonim salts) by condensation with cyanoacetamide. Disazo dyes can be prepared by tetrazotizing a dianiline and coupling it with a pyridone or by diazotizing aniline and coupling it with a dipyridone. Trisazo dyes can be also prepared by diazotizing of aniline and coupling it with a tripyridone or by hexazotizing a trianiline and coupling it with a pyridone. The main goal of this paper is to give a brief review on the synthesis of arylazo pyridone dyes due to the lack of such reviews. In addition, some properties of arylazo pyridone dyes as light fastness and azo-hydrazon tautomerism are disccused.

Toxicology of Dyes

2020 ◽  
pp. 50-69
Author(s):  
Aarti Singh ◽  
Anupama Mittal ◽  
Nirmala Kumari Jangid
Keyword(s):  
Human Health ◽  
Azo Dyes ◽  
Dominant Role ◽  
Human Life ◽  
Toxic Effects ◽  
Toxic Level ◽  
Carcinogenic Effect ◽  
Manufacturing Procedure ◽  
Dyes And Pigments

Colours play a prominent and dominant role in human life. The dominating feature of any product has been found with its colours elevating the market of colouration in different sectors. Studies have shown that around 10,000 dyes are being circulated in market. Chemistry has been found to lead this industry of colours. Vast production of fabric colours include azo dyes, whereas anthroquinone is also one of the prevailing complexes for cotton and fabric dyeing. The toxic level of the dyes and pigments are not confined till manufacturing but also have after usage effect of the products. It has been found that the chemicals have a carcinogenic effect on human health. During the manufacturing procedure, around 50% of dye stuff gets along with the effluents of the industry leading to release of colourful water. Modification in choice of chemicals is being considered to lessen the toxic effects of existing complexes. This chapter is mainly focused on the toxicology of dyes.

Erratum to “Novel mono- and bis-azo dyes containing the azulen-1-yl moiety: Synthesis, characterization, electronic spectra and basicity” [Dyes and Pigments 2009, 80, 337-42]

2009 ◽  
Vol 83 (1) ◽  
pp. 134
Author(s):  
Alexandru C. Razus ◽  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Victorita Tecuceanu ◽  
Liliana Blanariu ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Electronic Spectra ◽  
Dyes And Pigments

Synthesis and Characterization of Some New Esters Containing Heterocyclic and Derived From Azo Dyes

2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Zena G. Alrecabi ◽  
Zainab Amer ◽  
Naeemah Al-Lami
Keyword(s):  
Schiff Base ◽  
13C Nmr ◽  
Azo Dyes ◽  
Spectral Methods ◽  
Anthranilic Acid ◽  
Heterocyclic Compounds ◽  
Synthesis And Characterization ◽  
Cooh Group ◽  
Molecular Weights

This study including prepared new colored esters containing heterocyclic with high molecular weights. In the first part of work we synthesized azo dyes [1,2] from the reaction p-toluidine with β-naphthol and o-nitro phenol, thin we synthesized Schiff bases [3,4] by the reaction anthranilic acid with benzaldehyde and dimethyl benzaldehyde. The reaction azo dyes (contain OH group) with Schiff base (contain COOH group) these led to produce the new colored esters [A1-A4]. The second part of work was modification the (C=N-) group in esters to heterocyclic compounds by reacting with phenyl iso cyanide to produce new β-lactam [B1-B4] and with anthranilic acid to get new hydroquinazoline [C1-C4]. All these compounds were characterized by physical properties and spectral methods FTIR, 1H-NMR and 13C-NMR.

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