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

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.

Novel mono- and bis-azo dyes containing the azulen-1-yl moiety: Synthesis, characterization, electronic spectra and basicity

2009 ◽  
Vol 80 (3) ◽  
pp. 337-342 ◽  
Author(s):  
A RAZUS ◽  
L BIRZAN ◽  
M CRISTEA ◽  
V TECUCEANU ◽  
L BLANARIU ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Electronic Spectra

Azo Dyes, 6. Miscellaneous Dyes and Pigments

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

Electronic spectra and structure of several azo dyes in various states of aggregation

1981 ◽  
Vol 34 (4) ◽  
pp. 434-438
Author(s):  
G. N. Rodionova ◽  
I. V. Krutovskaya ◽  
Yu. G. Tuchin ◽  
A. N. Rodionov ◽  
V. V. Karpov
Keyword(s):  
Azo Dyes ◽  
Electronic Spectra

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.

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