Metanilic acid

Structural formula
General
Surname	Metanilic acid
other names	3-aminobenzenesulfonic acid; 3-aminobesilate; Aniline-3-sulfonic acid; m -aminobenzenesulfonic acid; m -anilinesulfonic acid;
Molecular formula	C 6 H 7 NO 3 S
Brief description	white, crystalline solid
External identifiers / databases
EC number	204-473-6
ECHA InfoCard	100.004.067
PubChem	8474
ChemSpider	8161
Wikidata	Q1422618
properties
Molar mass	173.19 g mol −1
Physical state	firmly
density	1.69 g cm −3 (25 ° C)
Melting point	288 ° C (decomposition)
solubility	little in water (12.8 g l −1 at 7 ° C)
safety instructions
GHS hazard labeling from Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution
H and P phrases	H: 302-312-332
	P: 280
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Metanilic acid is the common name for 3-aminobenzenesulfonic acid . Aminobenzenesulfonic acids are important industrial intermediates for the synthesis of organic , water-soluble dyes . Due to the high acidity of the sulfonic acid function, in contrast to aminocarboxylic acids , their isoelectric point (IEP) is acidic.

synthesis

Industrial production starts from nitrobenzene , which is first selectively sulfonated to 3-nitrobenzenesulfonic acid . This is followed by a Béchamp reduction .

Alternatively, benzenesulfonic acid can also be nitrated , whereby an isomer mixture of nitrobenzenesulfonic acids is formed, which has to be separated. The meta-isomer is then reduced to metanilic acid as above. This process is used when orthanilic acid is to be obtained at the same time .

application

Metanilic acid is used as a reagent in the detection of nitrites .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Entry on 3-aminobenzenesulphonic acid in the GESTIS substance database of the IFA , accessed on February 14, 2017(JavaScript required) .
↑ Entry on 3-aminobenzenesulphonic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f Entry on 3-aminobenzenesulphonic acid in the GESTIS substance database of the IFA , accessed on February 14, 2017(JavaScript required) .

[CLP_100.004.067-2] Entry on 3-aminobenzenesulphonic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .