Synthesis of 2,4-diaminobenzenesulfonic acid

Preparation of 2,4-diaminobenzenesulfonic acid

101 g 2,4-dinitrochlorobenzene are dissolved in 250 ml of methanol. To obtained solution 40 g of sulfur dioxide are added, in the form of a concentrated solution of sodium sulfite, about 160 g sodium hydrosulfite, containing 25% sulfur dioxide are mixed with 50 g 40% sodium hydroxide until alkaline to phenolphthalein. The sodium sulphite may separate out, even when the mixture is hot, but this is of no conseuence. The mixture is heated on the water bath to boiling for 5 hours with good stirring. The product is then cooled, and the sodium salt of the 2,4-dinitrobenzene sulfonic acid separates in glistening, yellow leaflets. 150 ml water are placed in the reduction pot and heated up to 95 °, and sodium salt of the 2,4-dinitrobenzene sulfonic acid is then added. 10 ml of conc. hydrochloric acid and about 120 g of fine iron powder are added gradually, care being taken that the contents do not froth over. Then a solution of sodium carbonate is then added until an alkaline reaction is obtained. It is boiled and filtered from the iron residue. The iron residue is again boiled with water and filtered. The combined filtrates are evaporated down to about 20ml and 50 g common salt added. It is then just acidified with hydrogen chloride (Congo paper should be turned only faint violet), and the free 2,4-diaminobenzenesulfonic acid crystallises out. It is filtered and washed with very little water. Yield 65% theoretical (61 g).

Systematic organic chemistry, by W. M. Cumming, 321-322, 1937.


2,4-diaminobenzenesulfonic acid



InChI Key


Canonical SMILES


MeSH Synonyms

1,3-phenylenediamine-4-sulfo acid, 2,4-diaminobenzenesulfonic acid, 2,4-diaminobenzenesulfonic acid, calcium salt, 2,4-diaminobenzenesulfonic acid, monosodium salt, 2,4-diaminobenzenesulfonic acid, sulfate

Depositor-Supplied Synonyms

2,4-Diaminobenzenesulfonic acid, 88-63-1, o-Aminosulfanilic acid, 1,3-Diaminobenzene-4-sulfonic acid, 1,3-Phenylenediamine-4-sulfonic acid, m-Phenylenediaminesulfonic acid, 1,3-Diaminobenzenesulfonic acid, 2,4-Diaminobenzenesulphonic acid, m-Phenylenediamine-4-sulfonic acid, 1,3-Diaminobenzene-6-sulfonic acid, Benzenesulfonic acid, 2,4-diamino-, Kyselina 2,4-diaminobenzensulfonova, NSC 7835, EINECS 201-846-5, BRN 2694057, Kyselina 1,3-fenylendiamin-4-sulfonova, Kyselina 2,4-diaminobenzensulfonova [Czech], Kyselina 1,3-fenylendiamin-4-sulfonova [Czech], WLN: ZR BSWQ EZ, DSSTox_CID_24465, DSSTox_RID_80249, DSSTox_GSID_44465, 32778_ALDRICH, SCHEMBL343300, 4-sulfo-1,3-phenylenediamine, AC1L25S8, CHEMBL3184102, UNII-863X637R5Q, 32778_FLUKA, CTK3J4279, NSC7835, 2,4-diaminobenzene sulphonic acid, 93920-38-8 (sulfate), JVMSQRAXNZPDHF-UHFFFAOYSA-N, MolPort-001-768-557, 51247-58-6 (calcium-salt), NSC-7835, ZINC1688384, 2,4-diaminobenzene-1-sulfonic acid, Tox21_302078, 1,3-diaminobenzene-4-sulphonic acid, ANW-39086, STK366992, AKOS003237071, 863X637R5Q, MCULE-7296339714, NE10911, RTR-032607, CAS-88-63-1, 3177-22-8 (mono-hydrochloride salt), NCGC00255816-01, AJ-29940, AK117229, AN-24781, KB-17264, LS-31840, OR174886, OR174887, P335, SC-74896, T281, 2,4-DIAMINO BENZENE SULFONIC ACID, DB-057091, ST2415741, TR-032607, FT-0606741, P0893, ST50411668, 2-14-00-00443 (Beilstein Handbook Reference), T7106632, W-100397

Removed Synonyms

Benzenesulfonic acid,4-diamino-, CID66623, 2,4-DIAMINOBENZENE SULFONIC ACID

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