Wool Silk Yellow

Yellow, red, and navy blue for leather can be obtained with monoazo dyes. Generally speaking, azo dyes with naphthalene moieties give deeper shades than those with phenyl residues. These classical acid dyes were developed for wool, silk, and polyamide fibers, and suitable ranges are applied to leather. The molecular weight for penetration dyes is below 500. Typical leather penetration dyes are C.I. Acid Yellow 11 18820 [6359-82-6] (7) and C.I. Acid Red 7, 14895 [5 5 -61-7] (8 Orange II), which are still used today. 

Perspiration tests similarly indicated the presence of two dyestuffs. In the alkali solution, the yellow color seemed to be removed almost completely, leaving a pink-colored fabric. In the acidic solution, the yellow dye migrated to the wool, silk, and nylon sections of the multifiber test strips, staining these fibers a bright yellow shade. The pink color seemed to bleed minimally a small amount of color was transferred in the alkali solution tests, but generally this pink color remained comparatively very fast. 

Yellow Dyestuff. The yellow-producing dyestuff is suspected to be an acid dye, primarily because its behavior responses to the A.A.T.C.C. tests parallel those typical of this class of dyes, as outlined by Corbman (17). The poor washfastness, tendency to bleed easily, and fair perspiration fastness exhibited by this yellow component are distinctly like those of the acid dyes. The historic textile, moreover, demonstrates the acid dye s typically excellent resistance to crocking. This yellow color was transferred to wool, silk, and nylon—all of which have an affinity for acid dyes. 

Benzaurin dyes wool and silk yellow from an acid bath. It yields dioxytriphenylmethane on reduction. This compound crystallises from alcohol in yellowish needles. 

Hazardous Decomp. Prods. Heated to decomp., emits toxic vapors of NOx and SOx Uses Colorant in foods, cosmetics, hair dyes, pharmaceuticals dye for paper, wool, silk, nylon pigment for printing inks Regulatory D C Yellow No. 10 FDA 21CFR 74.2710, 74.3710, 82.1710 FDA approved for dentals, implants, orals, rectals, sublinguals, topicals... 

Storage Store in cool, dry place keep container tightly closed when not in use Uses Dye for wool, silk, polyamide, inks Manuf/Distrib. Acres Org. http //www.acros.be, Al drich http //www.sigma-aldrich. com Acid yellow 65... 

The yellow dye curcumin, [458-37-7] (Cl Natural Ye//oii> 3 Cl 75300) (41), also known as tumeric, occurs in the roots of the plant Curcuma tinctoria found growing wild in Asia. The dye was well known to the ancient Romans and Greeks who used it to dye wool, cotton, and silk. The dye is an oil-soluble bright yellow material, and is the only natural yellow dye that requires no mordant. It finds use as a colorant for baked goods such as cakes. 

Barberry root is a yellow-red dye that has been used since prehistoric times it is extracted with hot water from the stems, bark, and roots of Berberis vulgaris, a bush that grows indigenously in Europe as well as in North America. The coloring matter in the dye is the organic compound berberine. Silk and wool can be dyed directly with barberry root, yielding a yellow color however, for dyeing cotton, a mordant is required to attach the dye to the substrate fibers. 

Rhodamine 6G does not fluoresce in the solid state but shows a green-yellow fluorescence in aqueous solution. It dyes silk, wool and cotton a yellow-red but the dyed silk shows a strong yellow fluorescence, the dyed wool practically no fluorescence and the dyed cotton no fluorescence. Consequently we deduce that rhodamine 6G is distinctly ionized on silk, only very slightly on wool and not at all on cotton. 

Experiments with rhodamine B gave results that were similar in type but we are not able at present to accoimt for the colors of the fluorescence in the several cases. Rhodamine B does not fluoresce in the solid state but shows a brownish-yellow fluorescence in aqueous solution. On silk the color is blue-red with a strong red fluoresecnce, on wool a blue-red with a very slight fluorescence and on cotton a blue-pink with no fluorescence. The stannic oxide lake is purple and does not fluoresce. The zinc oxide and the alumina lakes are pink and show a slight yellow fluorescence. The silica lake is pink and shows a distinct yellow fluorescence. 

Silk dyed with rhodamine 6G is yellow-red with a strong yellow fluorescence on wool and cotton the color is yellow-red with little or no fluorescence. 

Picric acid is a strong acid, very toxic, soluble in hot water, alcohol, ether, benzene and acetone, and is a fast yellow dye for silk and wool. It attacks common metals, except for aluminium and tin, and produces salts which are very explosive. The explosive power of picric acid is somewhat superior to that of TNT, both with regard to the strength and... 

Hydroxyl Derivatives. The building block of most hydroxyl-substituted xanthenes, or fluorones, is fluorescein (2). The sodium or potassium salt of fluorescein, commonly called uranine (Cl 45350). is used for dyeing wool and silk brilliant yellow shades. However, the principal use of fluorescein is as an intermediate for more highly substituted hydroxyxanthenes. 

Brass yellow prismatic needlos soluble in hot water to a bluish-green solution dyes silk, wool, jute and leather, a bluish-green directly, and cotton which has been previously mordanted with tannin and tartar emetic. 

In this connection it must be borne in mind that in some of these extraction tests on naturally coloured and raw cotton, flax, wool, hair, etc, an appreciable quantity of yellowish-brown colouring matter is removed, and that raw silks of a natural yellow or green colour exhibit special behaviour if subjected to some of these tests, eg, to treatment with concentrated acids ... 

These dyes are now of only minor commercial importance, but are of interest for their small molecular structures. The early nitro dyes were acid dyes used for dyeing natural animal fibers such as wool and silk. They are nitro derivatives of phenols, e.g., picric acid (4) or naphthols, e.g., C.I. Acid Yellow 1, 10316 [846-70-8] (5). 

The ammonium salt of hexyl known as Aurantia had been used for a long time as a yellow dye for silk and wool. 

There were experiments prior to this working in the same area. In 1771 Woulfe treated indigo with nitric acid and discovered a yellow substance that dyed wool and silk. In 1779 Welter nitrated silk in another version of the same experiment. Both chemists had made picric acid, but without knowing it. In 1776 Scheele treated uric acid with nitric acid and evaporated the contents of the reaction. The reddish residue that appeared could dye skin. Scheele named it purpuric acid. In 1818 Proust prepared mureside from this. These experiments were not fully understood, but they were an unconscious groping towards the synthesizing of colour. 

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