Dinitrobenzoic acids

The dinitrobenzoic acids form a group of aromatic compounds that are derived from benzoic acid as well as from nitrobenzene or dinitrobenzene . The structure consists of a benzene ring with an attached carboxy group  (-COOH) and two nitro groups  (-NO ₂ ) as substituents . Their different arrangement results in six constitutional isomers with the empirical formula C ₇ H ₄ N ₂ O ₆ . The 3,5-dinitrobenzoic acid is mainly used in the analysis of organic substances by derivatization .

presentation

2,4-Dinitrotoluene is oxidized to 2,4-Dinitrobenzoic acid with sodium dichromate in sulfuric acid. From 4-nitrobenzoic acid is produced by nitrating a mixture of 2,4- and 3,4-dinitro benzoic acid. 2,6-Dinitrotoluene is metabolized to 2,6-Dinitrobenzoic acid. Oxidation of 3,4-dinitrotoluene with an ozone-oxygen mixture in the presence of cobalt (II) acetate leads to 3,4-dinitrobenzoic acid.

properties

The dinitrobenzoic acids are yellowish crystalline solids with melting points between 166 and 206 ° C. The solubilities in water vary between 18.5 g / l and poor solubility. Due to the −M effect of the two nitro groups, the dinitrobenzoic acids have a higher acidity than the benzoic acid and the nitrobenzoic acids . The pK _s values are therefore correspondingly lower (benzoic acid: 4.20).

Dinitrobenzoic acids
Surname	2,3-dinitrobenzoic acid	2,4-dinitrobenzoic acid	2,5-dinitrobenzoic acid	2,6-dinitrobenzoic acid	3,4-dinitrobenzoic acid	3,5-dinitrobenzoic acid
Structural formula
CAS number	15147-64-5	610-30-0	610-28-6	603-12-3	528-45-0	99-34-3
PubChem	283327	11880	11879	119206	10709	7433
Molecular formula	C 7 H 4 N 2 O 6
Molar mass	212.12 g mol −1
Physical state	firmly
Brief description	yellowish crystalline solids
Melting point	201 ° C	179-183 ° C	178-182 ° C	202 ° C (dec.)	166 ° C	204-206 ° C
pK s value (25 ° C)	1.85	1.42	1.62	1.14	2.82	2.82
solubility		18.5 g / l			6.73 g / l (25 ° C)
GHS labeling	no classification available	Caution	no GHS pictograms	no classification available	Caution	Caution
H and P phrases	see above	315-319-335	see above	no H-phrases	315-319-335	302-315-319-335-413
	see above	no EUH phrases	see above	no EUH phrases	no EUH phrases	no EUH phrases
	see above	261-302 + 352 305 + 351 + 338-321-405-501	see above	no P-phrases	261-305 + 351 + 338	261-305 + 351 + 338

Individual evidence

1. ^ ^{A b} Streitwieser / Heathcock: Organische Chemie , 1st edition, Verlag Chemie, Weinheim 1980, ISBN 3-527-25810-8 , p. 1042.
2. ↑ M. Mori, T. Kawajiri, M. Sayama, Y. Taniuchi, T. Miyahara, H. Kozuka: "Metabolism of 2,6-dinitrotoluene in male Wistar rat", in: Xenobiotica , 1989 , 19  (7), Pp. 731-741 ( PMID 2773509 ).
3. ↑ P. Yu. Andreev, EV Potapenko, IP Pogorelova, SN Krasil'nikov, AN Volume: “A New Procedure for Preparing 3,4-Dinitrobenzoic Acid”, in: Zhurnal Prikladnoi Khimii , 2008 , 81  (3), pp. 518-520 (translated in: Russian Journal of Applied Chemistry , 81  (3), pp. 503-505, doi : 10.1134 / S1070427208030348 ).
4. ↑ ^{a b c d e f g} CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
5. ^ ^{A b} International Critical Tables of Numerical Data, Physics, Chemistry and Technology , Volume 1, Callie Hull, National Academies, 1926, p. 206 ( limited preview in Google Book Search).
6. ↑ ^{a b} Entry on 2,4-dinitrobenzoic acid in the GESTIS substance database of the IFA , accessed on October 21, 2012(JavaScript required) .
7. ↑ ^{a b} Data sheet 2,5-Dinitrobenzoic acid from Sigma-Aldrich , accessed on April 29, 2011 ( PDF ).
8. ↑ ^{a b} Entry on 3,4-dinitrobenzoic acid in the GESTIS substance database of the IFA , accessed on October 21, 2012(JavaScript required) .
9. ↑ ^{a b} Data sheet 3,5-Dinitrobenzoic acid from Sigma-Aldrich , accessed on December 16, 2013 ( PDF ).

See also

• Nitrobenzoic acids
• 2,4,6-trinitrobenzoic acid

Web links

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