Aminobenzenesulfonic acids
| Aminobenzenesulfonic acids | ||||||
| Surname | 2-aminobenzenesulfonic acid | 3-aminobenzenesulfonic acid | 4-aminobenzenesulfonic acid | |||
| other names |
o -aminobenzenesulfonic acid, orthanilic acid |
m- aminobenzenesulfonic acid metanilic acid |
p -aminobenzenesulfonic acid sulfanilic acid |
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| Structural formula |
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| CAS number | 88-21-1 | 121-47-1 | 121-57-3 | |||
| ECHA InfoCard | 100.001.646 | 100.004.067 | 100.004.075 | |||
| PubChem | 6926 | 8474 | 8479 | |||
| Molecular formula | C 6 H 7 NO 3 S | |||||
| Molar mass | 173.19 g mol −1 | |||||
| Physical state | firmly | |||||
| Brief description | white crystalline powder | |||||
| Melting point | > 300 ° C | 288 ° C (dec.) | 288 ° C (dec.) | |||
| boiling point | ||||||
| pK s value | ||||||
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Solubility in water |
easily soluble | 10 g l −1 (20 ° C) | ||||
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GHS labeling |
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| H and P phrases | ||||||
| 314 | 332-312-302 | 319-315-317 | ||||
| 280-305 + 351 + 338-310 | 280 | 280-302 + 352-305 + 351 + 338 | ||||
| Tox data | 12300 mg kg −1 ( LD 50 , rat , oral ) | |||||
The aminobenzenesulfonic acids form a group of substances that are derived from both benzenesulfonic acid and aniline . The structure consists of a benzene ring with attached sulfonic acid (–SO 3 H) and amino groups (–NH 2 ) as substituents . Their different arrangement results in three constitutional isomers with the empirical formula C 6 H 7 NO 3 S. They are starting materials for the synthesis of organic, water-soluble azo dyes .
properties
The aminobenzenesulfonic acid group includes:
- Orthanilic acid = 2-aminobenzenesulfonic acid
- Metanilic acid = 3-aminobenzenesulfonic acid
- Sulfanilic acid = 4-aminobenzenesulfonic acid
The relatively high melting temperature of all isomers is explained by the possibility of the formation of zwitterions ( protolysis of the SO 3 H proton on the NH 2 group).
Individual evidence
- ↑ a b data sheet aminobenzenesulfonic acids from Acros, accessed on April 11, 2009.
- ↑ a b Entry on 3-aminobenzenesulfonic acid (metanilic acid) in the GESTIS substance database of the IFA , accessed on February 5, 2013(JavaScript required) .
- ↑ a b c d Entry on 4-aminobenzenesulfonic acid (sulfanilic acid) in the GESTIS substance database of the IFA , accessed on April 11, 2009(JavaScript required) .
- ↑ CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
- ↑ Data sheet aminobenzenesulfonic acids from Sigma-Aldrich , accessed on March 8, 2011 ( PDF ).