2-Hydroxy-1- naphthalene-3,6-disulfonic

The Chemicaly3.bstractIndexis 2,7-naphthalene-disulfonic acid, 4-amino-5-hydroxy-3-[[4 -[(4-hydroxyphenyl)azo] [l,l -biphenyl]-4-yl]azo]-6-(phenylazo)-, disodium salt. 

A method frequently used to determine aromatic amines in water-soluble dyes involves their extraction with chloroform, followed by diazotization of amines and coupling of diazonium salts with a reagent R-salt (disodium-3-hydroxy-naphthalene-2,7-disulfonate) or pyrazolone T (4,5-dihydro-5-oxo-l-(4-sulfophenyl-)l/7-pyrazole-3-carboxylic acid). The separated products are detected by UV-VIS spectrophotometry or fluorescence (210-212). 

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). 

SYNS A.F. RED No. 1 CERVEN KUMIDINOVA C.1.16155 C.I. FOOD RED 6 C.I. FOOD RED 6, DISODIUxM SALT DISODIUM-3-HYDROXY-4-((2,4,5-TRIMETHYLPHENYL)AZO)-2,7-NAPHTHALENE-DISULFONATE DISODIUM-3-HYDROXY-4-((2,4,5-TRIMETHYLPHENYL)AZO)-2,7-NAPHTHALENE-DISULFONIC ACID DISODIUM-3-HYDROXY-4-((2,4,5-TRIMETHYLPHENYL)AZO)-2,7-NAPHTHALENE-DISULPHONATE DISODIUM-3-HYDROXY-4-((2,4,5-TRIMETHYLPHENYL)AZO)-2,7-NAPHTHALENE-DISULPHONIC ACID DOLKWAL PONCEAU 3R EXT. D C RED No. 15 3-HYDROXY-4-((2,4,5-TRIMETHYLPHENYL)AZO)-2,7-NAPHTHALENE-DISULFONIC ACID, DISODIUM SALT 3-HYDROXY-4-((2,4,5-TRIMETHYLPHENYL)AZO)-2.7-NAPHTHAL-ENEDISULPHONIC ACID, DISODIUM SALT MAPLE PONCEAU 3R PONCEAU 3R SODIUM CUMENE-AZO-P-NAPHTHOLDISULPHONATE USACERTRED No. 1... 

Acid red 18 [7-hydroxy-8-(4-sulfo-l-naphthyl) azo-1,3-naphthalene disulfonic acid trisodium salt, SX purple, coccine. Cl 16255] [2611-82-7]... 

Acid blue 92 [4-((4-anilino-5-sulfo-l-naphthyl)azo-5-hydroxy-2,7-naphthalene-disulfonic acid trisodium salt, trisodium 4 -anilino-8-hydroxy-1,1 -azonaphthalene-3,6,5-trisulfonate, benzyl blue R, Cl 13390] [3861-73-2]... 

Amanil blue 2BX[3,3 -((4,4 -biphenylylene) bis(azo)bis(5-amino-4-hydroxy-2,7-naphthalene disulfonic acid tetrasodium salt, sodium diphenyl-4,4 bis-azo-2, 8 -amino-l -naphthol-3, 6 -disulfonate, benzanil blue 2B, paramine blue 2B, Cl 22610] [2602-46-2] Amanil sky blue [3,3 -((3,3 -dimethoxy-4,4 -biphenylene)bis(azo))bis(5-amino-4-hydroxy)-2,7-naphthalenedisulfonic acid tetrasodium salt benzanil sky blue direct blue 5 Cl 24400] [2429-74-5]... 

Avoidance of Wastewater and Residues in the Production of H Acid (l-Amino-8-hydroxy-naphthalene-3 6-disulfonic acid)... 

In our laboratory, this method was appUed to the purification of food mono-azo dyes. Amaranth, New Coccine, and Sunset Yellow FCF were purified at 99.7%, 99.5%, and 99.3%, respectively, from 1-23 g of commercial dyes. Continued research has led to the purification of impurities present in commercial Sunset Yellow FCF that include RS-SA (trisodium salt of 3-hydroxy-4-[sulfophenyl] azo-2,7-naphthalene disulfonic acid), GS-S A (1 -[4-sulfophenyl]azo)-2-naphthol-6,8-disulfonic acid), DONS (disodium salt of 6,6 -oxybis-2-naphthalene sulfonic acid), and 2N-SA (sodium salt of 4-[(2-hydroxy-l-naphthalenyl)azo]benzenesulfonic add). The method successfully isolated GS-SA from Sunset Yellow FCF. " ... 

Method used for rate measurements A, Temp, jump B, fluorescence quenching, stopped flow. l-Napthol-4[4-(4 -azobenzeneazo)]-phenylarsonate. l-Hydroxy-4-(2,4-dinitrophenylazo)-2.5-naphthalene disulfonate. 

The orange-red solution of the azo dyestuff thoron (l-(o-arsenobenzene-azo)-2-hydroxy-naphthalene-3,6-disulfonic acid) (I) forms a yellow chelate with lithium ions. Interfering ions can be removed with a suspension of magnesium carbonate. ... 

I [3,3 -Dimethyl(l, 1 -biphenyl-4,4 -diyl[6ij-(azo)l6 j(4-amino-5-hydroxy-l, 3-naphthalene-disulfonic acid), tetrasodium salt (Evans Blue)... 

Hydroxy-5-[[4-[ 4-methylpheny[)amino-5-sulfo-l-naphthaleny[ azo]-2J-naphthalene]disulfonic acid, 9CI. C.L 13405... 

Naphthalene-3,7-disulfonic acid, 1,2-diamino-iron complexes filter dyes, 6,104 Naphthoic acid, hydroxy-metal complexes, 2, 480, 482... 

Amaranth (E 123, Cl Food Red 9) is a mono azo dye, with the chemical name trisodium 3-hydroxy-4(4-sulfonato-l-naphtylazo)-2,7-naphthalenedisulfonate) (or trisodium 2-hydroxy-l-(4-sulfonato-l-napthylazo) naphthalene-3,6-disulfonate). The calcium and potassium salts are also permitted. Amaranth is a reddish-brown powder or granules, soluble in water, sparingly soluble in ethanol, with a maximum absorption in water at 520 nm (Ei " = 440). It has been banned in the US since 1976. " Amaranth can be used also as a dye for cosmetics, synthetic fibers, leather, papers, and some plastics. 

Brilliant black BN, black PN E 151 28440 A Tetrasodium-4-acetamido-5-hydroxy-6-[7-sulfo-4-(4-sulfo-phenylazo)-1 -naphthylazo]naphthalene-1,7-disulfonate 28 i7N2Na50 4S4 867.69 ... 

In a similar manner, the corresponding (l,3,5-triazin-2-yloxy)naphthalene derivatives 3 rearrange with oxygen to nitrogen migration of the 1,3,5-triazinyl group to the peri /V-atom. Subsequent hydrolysis leads to the l-hydroxy-8-(l,3,5-triazin-2-ylamino)naphthalene-3,6-disulfonic acid derivative 5. These conversions are conducted at room temperature at pH 10.5— 11.0 for 6— 16 h, finally the pH is lowered to 5-6.7... 

In the presenee of coneentrated sulfuric acid, chromotropic acid (1,8-dihydroxy-naphthalene-3,6-disulfonic acid) reacts with formaldehyde to give a red-violet hydroxy-diphenylmethane derivative, as shown in Eq. (2) (Eegriwe, 1937), which is soluble in acid. In the second step of the reaction, a violet quinoid oxidation product is formed with atmospheric oxygen. The concentrated sulfuric acid behaves as a catalyst for dehydration and oxidation. The absorption maximum at 580 nm is used for colorimetric detection. 

Hydroxy-8-(phenylazo)naphthalene-l,3-disulfonic acid (Orange G)... 

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