523-44-4 Usage
Chemical Properties
Crystalline
Preparation
4-Aminobenzenesulfonic acid diazo, and Naphthalen-1-ol?coupling.
Properties and Applications
orange. Soluble in water for palm light orange, slightly soluble in ethanol, acetone, insoluble in most organic solvents. The strong sulfuric acid for purple, diluted into palm orange, red with purple precipitation. Its water solution to join strong hydrochloric acid for orange brown; Add sodium hydroxide in red. Used for wool, silk fiber dyeing, etc. Also used in leather dyeing and indicator.
Purification Methods
Purify the dye by dissolving it in the minimum volume of H2O, adding, with stirring, a large excess of EtOH. The salt separates as orange needles. It is collected by centrifugation or filtration, washed with absolute EtOH (3x) and Et2O (2x) in the same way and dried in a vacuum desiccator over KOH. The free acid can be recrystallised from EtOH. [Slotta & Franke Chem Ber 64 86 1931, Beilstein 16 H 275, 16 II 117, 16 IV 410.] The purity can be checked by titration with titanium chloride [Klotz J Am Chem Soc 68 2299 1946].
Check Digit Verification of cas no
The CAS Registry Mumber 523-44-4 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 5,2 and 3 respectively; the second part has 2 digits, 4 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 523-44:
(5*5)+(4*2)+(3*3)+(2*4)+(1*4)=54
54 % 10 = 4
So 523-44-4 is a valid CAS Registry Number.
InChI:InChI=1/C16H12N2O4S.Na/c19-16-10-9-15(13-3-1-2-4-14(13)16)18-17-11-5-7-12(8-6-11)23(20,21)22;/h1-10,19H,(H,20,21,22);/q;+1/p-1/b18-17+;
523-44-4Relevant articles and documents
Can be azo dyes obtained by grinding under solvent-free conditions?
Noroozi-Pesyan, Nader,Khalafy, Jabbar,Malekpoor, Zahra
experimental part, p. 1018 - 1027 (2010/09/10)
The solid-solid reactions of some electron-donors with sulfanilic acid in the presence of solid sodium nitrite afford azo dyes by self-catalyzed diazotization of sulfanilic acid (2) under solvent-free conditions with moderate yields. Also the reactions of some electron-donors with diazotization of o-nitroaniline (5), m-nitroaniline (6) and p-nitroaniline (7) in the presence of solid sodium nitrite catalyzed by p-toluenesulfonic acid (PTSA) afford azo dyes under solvent-free conditions in good yields. This new method totally avoids the use of acids, alkalies, and toxic and/or expensive solvents in diazotization and diazo coupling reactions.