| Name | 2-Amino-1,5-naphthalenedisulfonic acid |
| Synonyms | SULFO TOBIAS ACID SULPHOTOBIAS ACID Sulfonic Tobias Acid 2-amino-1,5-naphthalenedisulfonic 2-amino-5-naphthalenedisulfonicacid 2-Amino-1,5-naphthalenedisulfonic acid 2-Amino-1,5-naphthalene disulfonic acid 1,5-Naphthalenedisulfonic acid, 2-amino- 2-NAPHTHYLAMINE-1 5-DISULFONIC ACID SODI 2-NAPHTHYLAMINE-1,5-DISULFONIC ACID, F. PROT. SEQ. ANALYSIS |
| CAS | 117-62-4 |
| EINECS | 204-201-6 |
| InChI | InChI=1/C10H9NO6S2/c11-8-5-4-6-7(10(8)19(15,16)17)2-1-3-9(6)18(12,13)14/h1-5H,11H2,(H,12,13,14)(H,15,16,17)/p-2 |
| Molecular Formula | C10H9NO6S2 |
| Molar Mass | 303.31 |
| Density | 1.6329 (rough estimate) |
| Boling Point | 205.8°C (rough estimate) |
| Water Solubility | soluble |
| pKa | -0.51±0.40(Predicted) |
| Storage Condition | 2-8°C |
| Refractive Index | 1.7330 (estimate) |
| Risk Codes | R36 - Irritating to the eyes R34 - Causes burns |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S28A - |
| UN IDs | 1759 |
| WGK Germany | 2 |
| RTECS | QJ6135000 |
| FLUKA BRAND F CODES | 8-10 |
| Hazard Class | 8 |
| Packing Group | III |
| Toxicity | LD50 oral in rat: 5430mg/kg |
| LogP | -1.85 |
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| overview | 2-naphthylamine-1, 5-disulfonic acid is an important intermediate product for the manufacture of dyes, especially reactive dyes. The preparation method is to sulfonate 2-naphthylamine-1-sulfonic acid (Tobias acid), for example, in fuming sulfuric acid ("Olem")(SO3 content 15-30% (weight)) at room temperature. 2-naphthylamine -1, 5-disulfonic acid can be precipitated from the resulting reaction mixture by dilution. The disadvantage of this free acid precipitation method is that 2-naphthylamine -1, 5-disulfonic acid separated in the form of free acid is contaminated by decomposition products such as 2-naphthylamine and 2-naphthylamine -5-sulfonic acid and precipitated in a crystalline shape, which contains a considerable amount (15-20% (weight)) of sulfuric acid. This sulfuric acid content in the separated 2-naphthylamine -1, 5-disulfonic acid can be reduced by washing with water or highly diluted sulfuric acid washing, but due to the high solubility of 2-naphthylamine -1, 5-disulfonic acid in water and dilute sulfuric acid, it is only at the expense of a large yield loss. It has been found that difficulties arising from the precipitation of 2-naphthylamine -1, 5-disulfonic acid in the form of free acids can be avoided by diluting the reaction mixture under clearly defined conditions. |
| Use | Used as dye intermediate |
| category | toxic substances |
| toxicity classification | low toxicity |
| acute toxicity | oral-rat LD50: 5430 mg/kg |
| stimulation data | skin-rabbit 500 mg/24 hours mild; Eye-rabbit 20 mg/24 hours moderate |
| flammability hazard characteristics | combustible; combustion produces toxic nitrogen oxides and sulfur oxide smoke |
| storage and transportation characteristics | warehouse ventilation and low temperature drying |
| fire extinguishing agent | dry powder, foam, sand, carbon dioxide, mist water |