Synthesis of sulfanilic acid (4-aminobenzenesulfonic acid)

Preparation of sulfanilic acid

Preparation of sulfanilic acid (4-aminobenzenesulfonic acid)

Preparation of sulfanilic acid (4-aminobenzenesulfonic acid)

100 g of aniline are slowly added into 61 ml (110 g) of concentrated sulfuric acid contained in a shallow porcelain basin, and the aniline sulfate thus obtained is heated till the temperature reaches 205° C. This must take four hours. To complete the reaction, the reaction mixture is heated for additional six hours. Then the crude sulfanilic acid is broken up and dissolved in hot water with the addition of 40 g of sodium hydroxide to obtain the alkaline solution. Further, this solution of sodium sulfanilate is boiled for a few minutes with a little amount of  activated charcoal and filtered hot. On acidifying with hydrochloric acid, the sulfanilic acid crystallizes out and after standing overnight it is filtered and dried at 100° C. The yield of sulfanilic acid is 150-160 g.

The Synthetic Dyestuffs and the Intermediate Products from which They are Derived, by J. C. Cain, 204, 1905


4-aminobenzenesulfonic acid



InChI Key


Canonical SMILES


MeSH Synonyms

4-aminobenzenesulfonic acid, 4-aminobenzenethiol, 4-sulfanilic acid, 4-sulfanilic acid, sodium salt, 4-sulfanilic acid, zinc (2:1) salt, para-aminobenzenesulfonic acid

Depositor-Supplied Synonyms

SULFANILIC ACID, 4-Aminobenzenesulfonic acid, 121-57-3, Sulphanilic acid, p-Aminobenzenesulfonic acid, Aniline-4-sulfonic acid, Sulfanilsaeure, Aniline-p-sulfonic acid, Aniline-p-sulphonic acid, Benzenesulfonic acid, 4-amino-, p-Aminophenylsulfonic acid, sulfanilicacid, 4-Sulfanilic acid, 4-Amino-benzenesulfonic acid, Kyselina sulfanilova, p-Anilinesulfonic acid, CHEBI:27500, Sulfanilsaeure [German], NSC 7170, P-SULFANILIC ACID, Kyselina sulfanilova [Czech], CCRIS 4576, CHEMBL1566888, HSDB 5590, HVBSAKJJOYLTQU-UHFFFAOYSA-N, UNII-434Z8C2635, EINECS 204-482-5, AI3-15414, 4-Sulfoaniline, p-sulphanilic acid, 4-aminobesylic acid, SUFANILIC ACID, SULFANILLIC ACID, PubChem20323, ACMC-1BOZB, NITRATE REAGENT B, AC1Q6WPM, aniline-4-sulphonic acid, SULFANILIC ACID TS, bmse000726, Epitope ID:122241, p-aminobenzenesulphonic acid, 4-azanylbenzenesulfonic acid, C6H7NO3S, 4-aminobenzene-sulfonic acid, SULFANILIC ACID, ACS, SCHEMBL24407, 4-Amino benzenesulphonic acid, KSC175E5L, 4-ANILINESULFONIC ACID, S5263_SIGMA, ANILINE P-SULFONIC ACID, P-ANILINE SULFONIC ACID, 4-aminobenzene-1-sulfonic acid, AC1L1R31, AC1Q51Y7, S5263_SIAL, 86090_FLUKA, CTK0H5255, TIMTEC-BB SBB028140, NSC7170, MolPort-001-783-839, 86090_SIAL, BB_SC-7049, LABOTEST-BB LTBB002174, 515-74-2 (hydrochloride salt), Sulfanilate Zinc (sulfanilic acid), 251917_SIAL, 4-AMINOBENZENESULPHONIC ACID, NSC-7170, UKRORGSYN-BB BBR-006490, ANW-17754, AR-1L5745, BBL011603, LS-650, SBB028140, STK661383, AKOS000118732, AM91128, AS01575, MCULE-9573132621, RP23551, RTR-034638, NCGC00090886-01, NCGC00090886-02, AC-12565, AJ-26659, AK-53425, AN-22849, BC204845, BR-53425, H459, KB-36490, SC-26832, 22484-64-6 (zinc[2:1] salt), AB1003505, ST2411105, ST4084010, TR-034638, 434Z8C2635, FT-0651611, S0120, S0135, C06335, M-6005, 28029-EP2311809A1, 28029-EP2314588A1, 3B4-0132, I05-0157, 4-Aminobenzenesulfonic acid; Aniline-4-sulfonic acid, A3126/0132260, Benzenesulfonicacid,4-amino-,diazotized,coupledwithm-phenylenediamine, Benzenesulfonicacid,4-amino-,diazotized,coupledwith5,5′-oxybis[1,3-benzenediol],sodiumsalt, Benzenesulfonicacid,4-amino-,diazotized,coupledwithDyer’smulberryextract,sodiumsalts, InChI=1/C6H7NO3S/c7-5-1-3-6(4-2-5)11(8,9)10/h1-4H,7H2,(H,8,9,10, 85049-60-1, 85203-66-3, 856062-06-1, 90218-16-9, 90218-18-1, 94552-15-5, 97675-28-0, Benzenesulfonicacid,4-amino-,diazotized,coupledwith4-methyl-1,3-benzenediamineandm-phenylenediamine,sodiumsalt, Benzenesulfonicacid,4-amino-,diazotized,coupledwithdiazotized4-[ azo]benzenesulfonicacidandresorcinol, Benzenesulfonicacid,4-amino-,diazotized,coupledwithformaldehyde-resorcinolcondensate,reactionproductswithnitrousacid

Removed Synonyms

4-Aminobenzenesulfonate, CID8479, 5271-39-6

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