Dyestuffs manufacture

Preparation of Dispersion. The reduction process is a two-phase reaction between soluble reducing agent and insoluble dye particles, and therefore the rate of reduction is influenced by the particle size distribution of the dye dispersion. The smaller the particle size the greater the surface area and hence the more rapid the reduction process. However, if the particles are too small, migration will occur in continuous dyeing. It is therefore extremely important to control the size and range of particle size and this is a closely guarded piece of dyestuff manufacturers know-how. 

In 1980, approximately 111,000 t of synthetic organic dyestuffs were produced in the United States alone. In addition, another 13,000 t were imported. The largest consumer of these dyes is the textile industry accounting for two-thirds of the market (246). Recent estimates indicate 12% of the synthetic textile dyes used yearly are lost to waste streams during dyestuff manufacturing and textile processing operations. Approximately 20% of these losses enter the environment through effluents from wastewater treatment plants (3). 

Until recently, few papers appeared on the fate of dyes in the environment. But because of the importance of this subject, work is being done primarily by the U.S. Environmental Protection Agency (USEPA) and the Ecological and Toxicological Association of the Dyestuff Manufacturing Industry (ETAD). 

T. M. Keinath, Technology Evaluation for Priority Pollutant Removalfrom Dyestuff Manufacture Wastewaters, USEPA report 600/S2-84-055, Washington, D.C., Apr. 1984. 

Rai HS, Bhattacharyya MS, Singh J et al (2005) Removal of dyes from the effluent of textile and dyestuff manufacturing industry a review of emerging techniques with reference to biological treatment. Crit Rev Env Sci Technol 35 219-238... 

Let me explain that, amongst other things, I possessed three houses my estate at Wola which E together with my brothers and sisters, inherited from our father, also a house in Warsaw and an estate at Orwick which I had turned over to my sick son. When the Germans crossed the border, I fled first to my brother s house at Orwick and later to my own house in Warsaw. In the cellar of my house in Warsaw, I had stored part of the dyestuffs manufactured in Wola. It was then in September 1939 that Schwab and Schoener visited me in this house. After introducing themselves as I.G. commissioners, they stated that all my dyestuffs were confiscated, and all my houses. They prohibited my use of any article in any of these houses. They confiscated my cars. The dyestuffs were then put under seal. 

As a basis for evaluating individual schemes, the Ecological and Toxicological Association of the Dyestuffs Manufacturing Industry (ETAD) concluded that a satisfactory scheme should meet the following criteria ... 

The above reactions can be used to prepare a variety of multi-purpose intermediates that are of great value in dyestuffs manufacture. Many of these intermediates were prepared and found to be of value in dye manufacture before the orientation of their substituents was established. This early lack of basic knowledge resulted in these intermediates being given trivial names that have persisted in the dyestuffs industry. 

Because the chemical has no agricultural or food chemical application, it is very imlikely that 3,3 -dichloro-benzidine occurs in food in general. [ C]-3,3 -Dichlorobenzidine was foimd to rapidly accumulate in bluegill sunfish as a result of their exposiue to water in which either 5 or 100 g/L of the chemical was intentionally added. Residues were distributed in both the edible and nonedible portions (Appleton and Sikka 1980). However, 3,3 -dichlorobenzidine was not detected in fish samples obtained from rivers near nine textile dyestuff manufacturers known to use 3,3 -dichlorobenzidine-based pigments (Diachenko 1979). 

Baron, H. Renfry, F. G. P. Thorpe, J. F. J. Chem. Soc. 1904, 85, 1726. Jocelyn F. Thorpe spent two years in Germany where he worked in the laboratory of a dyestuff manufacturer before taking a post as a lecturer at Manchester. Thorpe later became FRS (Fellow of the Royal Society) and professor of organic chemistry at Imperial College. 

Kelshaw, P. The future for West Emopean dyestuff manufacturers. Journal of Society of Dyers and Colourists, 1998 114,35-37. 

Ecological and toxicological association of the dyestuff manufacturing industry (ETAD). E 3022 Environmental hazard and risk assessment in the context of EC directive 79/831/ from 31 May 1991. 

Toxicology of Certain Azo Dyes. It has been known for over 100 years that certain amines used to manufacture synthetic dyes caused bladder cancer, especially 2-naphthylamine, benzidine and 4-aminodiphenyl. All the major dyestuff manufacturers abandoned the use of these amines in the production of dyes in the early 1970s. 

It should be noted that none of the major dyestuff manufacturers now make any of the dyestnffs which have these amines as diazo components. The new laws have also had a marked inflnence on dye makers in such countries as India and China, because they cannot now nse these dyestuffs in consumer goods to be imported into the EU. 

Cupric Sulfate, CUSO4 5H 0, blue triclinic crystals, moderately soluble in cold HjO, quite soluble in hot H-O. very slightly soluble in alcohol. Used in copper plating, dyestuff manufacture, water treatment, germicides, and coppering of steels. 

Recent estimates indicate 29t of the synthetic textile dyes used yearly are lost to waste streams during dyestuff manufacturing and textile processing operations. Approximately 20% of these losses enter the environment through effluents from wastewater treatment plants. 

This has led lo concern about possible carcinogenicity from these dyestuffs, and therefore benzidine-based dyes and pigments are no longer produced by the large dyestuff manufacturers. 

The fact that only one proton is lost from an o.o -diaminodiarylazo compound on metal complex formation is not only of theoretical interest but has important practical implications in the synthesis of unsymmetrical 2 1 chromium(III) and cobalt(III) complex dyestuffs for wool. The most important complexes of these types are those which are doubly negatively charged (Section 58.1) and are obtained from one molecule of a sulfonated tridentate azo compound and one molecule of an unsulfonated tridentate azo compound. In general the latter are insoluble in water and it is necessary to use organic solvents in the manufacture of complexes such as (10). This is very undesirable from the point of view of the dyestuffs manufacturer and any means of avoiding the use of solvents is attractive to him. The use of sulfonated o,u -diaminodiarylazo compounds in combination with, for example, sulfonated o,o -dihydroxydiarylazo compounds opened up one such possibility, e.g. (77), although this has not yet been exploited commercially. 

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