Brown dyes

Brown crepes Brown dyes Brownian particles Brown oxides... 

Various methods of home-dyeing cotton and wool materials using natural dyes made from hulls of butternut, hickory nut, pecan, eastern black walnut, and Knglish walnut have been described (149). As far back as during the Civil War, butternut hulls have been used to furnish the yellow dye for uniforms of the Confederate troops. More recent attempts have been made to manufacture yellow and brown dyes from filbert shells on a commercial scale. The hulls are treated with copper sulfate and concentrated nitric acid to produce a yellow color, with ferrous sulfate to produce oHve-green, or with ammonia to produce mby-red (150) (see Dyes AND DYE INTERMEDIATES Dyes, natural). 

Juglone [481-39-0] (Cl Natural Brown 7 Cl 75500) was isolated from the husks of walnuts in 1856 (50). Juglone belongs to the Juglandaceae family of which there are a number of species Jug/ans cinerea (butter nuts), J. regia (Persian walnuts), and J. nigra (black walnuts). Persian walnuts were known to the ancient Romans who brought them over from Asia Minor to Europe. As early as 1664, the American colonists knew how to extract the brown dye from the nuts of the black walnut and butternut trees, both native to eastern North America (51). 

The monochloiotiiazine reactive group is also found in a metallized brown dye [77934-00-0] (72). 

Braunelle, /. self-heal (Prunella vulgaria). braunen, v.t. brown dye brown bronze burnish. 

Braun-saLz, n, any of certain brown dyes. -schliff, m. (Paper) steamed mechanical wood pulp, brown wood pulp, braunschwarz, a, brown-black, very dark brown. 

The reddish brown dye Cl Vat Brown 45 (6.100) is a dichloro derivative of the unusual acedianthrone system. This dye is prepared by condensing two moles of 2-chloroanthrone with one mole of glyoxal followed by oxidative cyclisation, which probably takes place in a stepwise manner [31]. 

Three major approaches have been followed to provide reactive dyes in this important sector. One category is closely related to the reddish blue monoazo 1 1 copper complexes already described (section 7.5.8). To provide the higher substantivity and deeper intensity for build-up to navy blue shades, a second unmetallised azo grouping is introduced. As with the brown dyes, the A—>M—>E pattern is adopted for their synthesis. Component A is normally a sulphonated aniline, M an aminophenol or aminocresol and E a sulphonated naphthol or aminonaphthol. The reactive system (Z) is usually, but not invariably, located on the E component and the copper atom always coordinates with an o,o -dihydroxyazo grouping provided by the M and E components (7.109). 

Awad, HS Abo Galwa N. Electrochemical degradation of Acid Blue and Basic Brown dyes on Pb/Pb02 electrode in the presence of different conductive electrolyte and effect of various operating factors. Chemosphere, 2005 61, 1327-1335. 

A brown dye, soluble in alcohol. Phenacetolin is a product resulting from the action of concentrated sulphuric acid on glacial acetic acid and phenol. The indicator solution is prepared by digesting 1 gm. of phenacetolin with warm alcohol, then diluting to 100 cc., and filtering. 

A particularly important class of coupling components are the aminohydroxy-naphthalenesulfonic acids. Appropriate variation of the disazo component permits the development of shades ranging from orange to black. Orange and scarlet are achieved with I-acid (6-amino-l-hydroxy-naphthalene-3-sulfonic acid) and y-acid (7-amino-1-hydroxynaphthaIcne-3-sulfonic acid), whereas H-acid (8-amino-l-hydroxynaphthalene-3,6-disulfonic acid) and K-acid (8-amino-l-hydroxy-naphthalene-3,5-disulfonic acid) derivatives are useful for red to bluish-red hues. Extremely lightfast red shades are also accessible with disazo dyes ( brown dyes ). For chemical structures see Section 3.1.5). 

The o,o -dihydroxyaminoazo and o-hydroxy- o -aminoaxo compounds with phenols or aniline derivatives as coupling components yield largely brown shades on chroming they include an important brown dye with very good fastness properties, namely, C.I. Mordant Brown 33, 13250 [3618-62-0] (26). 

Testing of Brown Natural Dyeings. When brown dyeings produced with natural dyes become much lighter in shade upon boiling in 102 sulfuric acid, usually the presence of iron tannate is indicated. In such cases, iron can be identified in the sulfuric acid. If an excess of ammonia is added to the sulfuric acid decoction, the fiber regains its original brown shade. 

Sulfur compounds are also important examples of vat dyes—water insoluble, coloured solids which can be reduced to colourless, water soluble leuco compounds. The fabric to be dyed is dipped in the colourless leuco solution, and when subsequently exposed to the air, the leuco compound is oxidised to the coloured dye within the fabric. An example is the dibenzothioindigo (12) (Figure 2), a brown dye, which is introduced as the water soluble reduced form and subsequently oxidised in air to give the dye (12). 

Uranium salts have been used as mordants for both silk and wool,4 as well as in calico printing. Uranium salts also produce a pleasing brown dye on textiles when the fabric is first heated with solutions of uranium salts, and then the color is fixed by reduction with potassium ferrocyanide, gallic acid, or pyro-gallol,... 

Walnut peel, rind The rind of the black walnut used as a brown dye. 

Uses dyestuff used to dye furs brown and reddish-brown dye intermediate in semi-permanent and permanent hair coloring products (produces brown and red shades on the hair) in different hair-dyeing preparations. 2-NITRO-P-PHENYLENEDIAMINE A... 

Cutch, Cutechu Acacia Catechu The dye stuff known as Cutch or Cutechu is an extract usually made from the heat wood of Acacia Catechu, a small thorny tree. It yields orange-brown dyes that are rich in tannins, and was used in India calico printing before its introduction to West. It is used mainly to dye cotton and silk. 

A microdrop (0.01 ml) of the test solution and one drop of an acetic acid solution of benzidine are brought successively on filter paper. The diazotization and coupling give a yellow or brown dye. (Idn, Limit 0.7 y NaNOa). ... 

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