2-Aminonaphthalene-1,5-disulfonate

C. I. Direct Yellow 50, 29025 [3214-47-9] (26) is obtained, for example, by phosgene treatment of two equivalents of the aminoazo dye prepared from diazo-tized 2-aminonaphthalene-4,8-disulfonic acid coupled to w-toluidine. 

Table 2.3 Dependence of l-aminonaphthalene-3,6-disulfonic acid (ANDS) conversion on the electrooxidation temperature of the platinum anode, c = 10-3 mol dm-3, volume of...

Similar results were also obtained by Socha et al. (2005) for the electrochemical treatment of l-Aminonaphthalene-3,6-disulfonic acid (ANDS), a component of the wastewater produced during the synthesis of many synthetic dyes. An increase in the temperature caused a slight increase in the efficiency of the substrate oxidation (Table 2.3), but even at 80°C the removal of TOC and COD was only 18 and 36%, although the decolorization of the solution, i.e., decrease of absorbance, was achieved. 

The l-aminonaphthalene-4,8-disulfonic acid is precipitated as the neutral sodium salt by the addition of enough salt to make a 20 per cent salt solution (30° B6). The sulfonate is then filtered off. The l-aminonaphthalene-3,8-disulfonic acid is precipitated with hydrochloric acid as the acid sodium salt. If the whole mixture was limed, then the mother liquor is neutralized and evaporated to the point where salt separates. The supernatant liquid is poured off and allowed to crystallize at 20°C. The neutral sodium salt of 2-aminonaphthalene-4,8-disulfonic acid separates. This neutral salt is dissolved in water (24° Be solution) and precipitated by making the solution acid to Congo red with concentrated hydrochloric acid. The mixture is then allowed to cool, and the product is filtered off. 

Certain sulfonic acids may be cleaved by Na(Hg) thus l-aminonaphthalene-3,8-disulfonic acid can be reductively cleaved to l-aminonapththalene-3-sulfonic acid. The sulfonic group in the 8-position is more easily removed reductively than sulfonic groups in the 2-, 4-, or 6-positions [79]. 

Also useful in dye manufacture are the aminonaphthalenedisulfonic acids 2-amino-naphthalene-5,7-disulfonic acid (6-aminonaphthalene-l,3-disulfonic acid, 6-amino-l,3-naphthalenedisulfonic acid), or amino I acid (49a), and 2-aminonaphthalene-6,8-disulfonic acid (7-aminonaphthalene-l,3-disulfonic acid), or amino G acid (49b). 

Beilstein Handbook Reference) 2-Amino-6,8-disulfonaphthalene 2-Aminonaphthalene-6,8-disulfonic acid 7-Amino-1,3-naphthalenedisulfonic acid 7-Aminonaphthalene-1,3-disulphonic acid AI3-28530 Amido-G-acid Amino-G-Acid BRN 2669649 EINECS 201-689-2 1,3-Naphthalenedisulfonic acid, 7-amino- p-Naphthylamine-6,8-disulfonic acid 2-Naphthylamine-6,8-disuflbnic xid NSC 4013. Used as an intermediate in manufacture of chemicals, particularly dyestuffs, mp = 274" soluble in H2O (92 g/l), EtOH, less soluble in non-polar organic solvents. Zen Brasal Pvt. Ltd. 

Amido-R-acid 2-Amino-3,6xJisulfbnaphthalene 2-Am-inonaphthalene-3,6-disulfonic acid 3-Amino-2,7-naph-thalenedisulfonic acid 3-Aminonaphthalene-2,7-disulph-onic acid Amino-R-acid EINECS 202-143-6 2-Naph-thylamine-3,6-disulfonic acid 2,7-Naphthalenedisulfbnic acid, 3-amino- NSC 5525. Used in manufacture of dyes. Crystals soluble in H2O. 

In addition to its importance in the mechanism of formation of naph-thalene-2-sulfonates, the desulfonation reaction has preparative utility in producing the dye intermediate 6-aminonaphthalene-l,3-disulfonic acid from the 1,3,5-trisulfonate. This is accomplished by refluxing at 125°C for 4 hr in dilute sulfuric acid. 

Precolumn fluorescent derivatization 5-Aminonaphthalene-1-sulfonic acid (ANSA) 7- Aminonaphthalene-1,3-disulfonic acid (ANDSA) 8- Aminonaphthalene-1,3,6-trisulfonic acid (ANTS) Fluorescein isothiocyanate (FITC) 9- fluroenylmethyl chloroformate All the analytes ANSA enhances the enantio-separation... 

Five impurities of 8-amino-l-naphthol-3,6-disulfonic acid (e.g., l-naphthol-4-sulfonic acid, 8-aminonaphthalene-l,3,6-trisulfonic acid, chromotropic acid) were resolved on a C,g column (A = 235 nm) using an aqueous 0.3 M sodium sulfate mobile phase [1561]. All compounds eluted in <8 min. Detection limits of... 

Table 9.4 The chiral resolution of phenoxy acid herbicides (underivatized and deriva-tized with 7-aminonaphthalene-l,3-disulfonic acid) using various cyclodextrins as chiral selectors [37]...

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