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| 2-Aminonaphthalene-1-sulfonic acid Basic information |
| 2-Aminonaphthalene-1-sulfonic acid Chemical Properties |
Melting point | 180 °C | Boiling point | 220°C (rough estimate) | density | 1.3588 (rough estimate) | refractive index | 1.5250 (estimate) | storage temp. | -20°C Freezer, Under inert atmosphere | solubility | DMSO (Slightly), Methanol (Slightly, Heated), Water (Slightly, Heated) | form | Solid | pka | pK1: 2.35 (25°C) | color | White to Off-White | Water Solubility | 4.083g/L(20 ºC) | Merck | 14,6406 | BRN | 613084 | CAS DataBase Reference | 81-16-3(CAS DataBase Reference) | NIST Chemistry Reference | | EPA Substance Registry System | |
Risk Statements | 36/37/38-40 | Safety Statements | 26-36/37/39 | RIDADR | 2585 | WGK Germany | 1 | RTECS | QK1250000 | TSCA | Yes | HS Code | 2921.45.9010 | HazardClass | 8 | PackingGroup | III | Hazardous Substances Data | |
| 2-Aminonaphthalene-1-sulfonic acid Usage And Synthesis |
Chemical Properties | Grey white to light pink powder. 2-Aminonaphthalene-1-sulfonic acid [81-16-3]. Tobias acid, C10H9NO3S, Mr 223.24, is sparingly soluble in water but the sodium salt is readily soluble. Coupling with diazo compounds takes place in the 1-position with elimination of the sulfonic acid group. | Uses | Azo dye intermediate, optical brighteners. Sulfonation with oleum gives 2-aminonaphthalene-1,5-disulfonic acid, which can be desulfonated to produce 2-aminonaphthalene-5- sulfonic acid. Tobias acid is used as a diazo component in acid dyes (e.g., C.I. Acid Yellow 19), red reactive dyes, and pigments such as the important Lithol Reds, [e.g., C.I. Pigment Red 49]. The free acid of C.I. Pigment Red 49 is also remarkably insoluble and can be used as a pigment. | Uses | 2-Amino-1-naphthalenesulfonic acid has been used in the preparation of 2-(2-naphthylamino)benzoxazole by reacting with 2-chlorobenzoxazole. | Production Methods | 2-Hydroxynaphthalene-1-sulfonic acid is heated with a mixture of ammonia and ammonium sulfite in an autoclave at 150 ℃ and 1 MPa for 30 h. The reaction mixture is added to a slurry of lime, and excess ammonia is driven off. Inorganic calcium salts are filtered off at 80℃, and the filtrate is acidified with hydrochloric acid at 40℃ to precipitate Tobias acid in 95 % yield. Care must be taken throughout the process to avoid desulfonation and formation of 2- naphthylamine. | General Description | 2-Amino-1-naphthalenesulfonic acid is a manufacturing intermediate in the monosulfo monoazo color additive D&C Red No. 34 and its lakes. | Purification Methods | Crystallise the acid under nitrogen from boiling water and dry it in a steam oven [Bryson Trans Faraday Soc 47 522, 527 1951]. [Beilstein 14 III 2240, 14 IV 2792.] |
| 2-Aminonaphthalene-1-sulfonic acid Preparation Products And Raw materials |
Raw materials | Sodium hydroxide-->Hydrochloric acid-->Sulfuric acid-->Ammonia-->Chlorosulfonic acid-->Sulfur dioxide-->2-Naphthol-->2-Ethylnitrobenzene-->1,2,3-Triazine, 4,5,6-trifluoro--->2-HYDROXY-1-NAPHTHALENESULFONIC ACID-->1-Amino-8-hydroxynaphthalene-3,6-disulphonic acid | Preparation Products | J acid-->Lithol Red-->sodium 2-[(2-hydroxynaphthyl)azo]naphthalenesulphonate-->3-Hydroxy-N-2-naphthyl-2-naphthamide-->ReactivebrilliantredKE-7B-->disodium 2-[[1-(2,5-dichloro-4-sulphonatophenyl)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-4-yl]azo]naphthalene-1-sulphonate-->REACTIVE RED 195-->2-Amino-1,5-naphthalenedisulfonic acid-->6-AMINO-1-NAPHTHOL-->1,2-DICHLORONAPHTHALENE-->2-Naphthylamine-->6-Amino-1-naphthalenesulfonic acid-->2-Aminotoluene-5-sulfonic acid-->disodium 2-[[1-(2-chloro-5-sulphonatophenyl)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-4-yl]azo]naphthalene-1-sulphonate-->ACID YELLOW 19 |
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