Colours INDEX

Colour Index name CAS Registry Number Selected manufacturers... 

Diphenylmethane Dyes. The diphenyhnethane dyes aie usually classed with the tiiaiyhnethane dyes. The dyes of this subclass are ketoimine derivatives, and only three such dyes are registered in the Colour Index. They ate Auramine O [2465-27-2J Cl Basic Yellow 2 (Cl 41000) (21, R = CHg), Auramine G [2151 -60-2] Cl Basic Yellow 3 (Cl 41005) (22), and Cl Basic Yellow 37 [6358-36-7] (Cl 41001) (21, R = C2H5). These dyes are still used extensively for the coloration of paper and in the preparation of pigment lakes. 

Chemically, the azo class is subdivided according to the number of azo groups present into mono-, dis-, tris-, tetrakis-, etc. Mono- and disazo dyes are essentially equal in importance, trisazo dyes are less important, and tetrakisazo dyes, except for a few, are much less important. For this reason, substances with more than three azo linkages are generally included under the heading of polyazo dyes. The Colour Index]isX.s the azo dyes as follows ... 

The Colour Index (up to June 1991) Hsts 21 direct violets with disclosed chemical constitutions. Commercially important are Cl Direct Violet 9 [6227-14-1] (79) (Cl 27885) (sulfanihc acid coupled to cresidiue followed by alkaline coupling to V-phenyl J-acid) and Cl Direct Violet 66 [6798-03-4] (80) (Cl 29120) (a copper complex of 2-arniao-l-phenol-4-sulfonarnide (2 mol) coupled to 6,6 -imiQobis-l-naphthol-3-sulfonic acid). 

Colour Index, and its Additions and Amendments, 3rd ed.. Society of Dyers and Colourists, London, and American Association of Textile Chemists and Colorists, Durham, N.C. It now consists of seven volumes. The Colourindex was originally written by and for the textile industry, but pigments are receiving increasing attention. 

The classification given in this article maintains the backbone of the Colour Index classification, but attempts to simplify and update it. This is done by showing the stmctural interrelationships of dyes that are given separate classes by the Colour Index, and the classification is chosen to highlight some of the more recent discoveries in dye chemistry (4). 

Classification by usage or appHcation is the principal system adopted by the Colour Index (5). Because the most important textile fibers are cotton (qv) and polyester, the most important dye types are those used for dyeing these two fibers, including polyester—cotton blends (see Fibers, polyester). 

Dyes ate named either by then commercial trade name or by then Colour Index (Cl) name. In the Colour Index (5) these ate cross-referenced. 

Some examples of metal ion indicators. Numerous compounds have been proposed for use as pM indicators a selected few of these will be described. Where applicable, Colour Index (C.I.) references are given.12 It has been pointed out by West,11 that apart from a few miscellaneous compounds, the important visual metallochromic indicators fall into three main groups (a) hydroxyazo compounds (b) phenolic compounds and hydroxy-substituted triphenylmethane compounds (c) compounds containing an aminomethyldicarboxymethyl group many of these are also triphenylmethane compounds. 

Solochrome black (eriochrome black T). This substance is sodium 1-(1-hydroxy-2-naphthylazo)-6-nitro-2-naphthol-4-sulphonate, and has the Colour Index reference C.I. 14645. In strongly acidic solutions the dye tends to polymerise to a red-brown product, and consequently the indicator is rarely applied in titrations of solutions more acidic than pH = 6.5. 

Anon, Colour Index, 2nd edn, Society of Dyers and Colourists, Bradford, 1956... 

The procedure utilises eriochrome blue black RC (also called pontachrome blue black R Colour Index No. 15705) at a pH of 4,8 in a buffer solution. Beryllium gives no fluorescence and does not interfere iron, chromium, copper, nickel, and cobalt mask the fluorescence fluoride must be removed if present. The method may be adapted for the determination of aluminium in steel. 

Corn i to Euro peon de Normalisation European Committee for Standardisation (Brussels, Belgium) Code of Federal Regulations (USA) Colour Index... 

Pigments are classified by an internationally recognised convention, published in the International Colour Index by the Society of Dyers and Colourists in Bradford, in association with the American Association of Textile Chemists and Colorists. The Index issues a generic name to chemically identical products (e.g., titanium dioxide is classified as C.I. Pigment White 6). Where structures are known, pigments are also given a constitution number (e.g., titanium dioxide has the constitution number Cl 77891).This number is reserved for the essential colorant, other ingredients, such as the carriers used in a masterbatch, do not affect this classification. 

The interstellar extinction has a great effect on distance determination for stars. The B/V index derived in Chapter 2 will be distorted by the presence of interstellar dust, with an amount of radiation in the blue part of the spectrum removed. The difference between the observed colour index and the colour index on which it should have based its temperature is called the colour excess. We defined m to be the measured apparent magnitude, which must now be corrected by an amount Av and added to the distance modulus equation ... 

A major objective of this chapter is to outline the principal system by which colorants are classified, namely the widely accepted Colour Index classification. After tracing the developments from which this system has evolved [12,13], the distribution of existing dyes and pigments among the various classes listed therein will be introduced. Each of these classes will be discussed in turn, illustrated by structural formulae. 

The number of chemical entries rose from about 280 to nearly 1500 over these years. The later editions of this work pioneered many of the features eventually adopted in the Colour Index. 

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