Chromotropic acid is a chemical compound with the formula (HO)2C10H4(SO3H)2.

Chromotropic acid
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
4,5-Dihydroxynaphthalene-2,7-disulfonic acid[1]
Identifiers
3D model (JSmol)
1827764
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.005.194 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C10H8O8S2/c11-8-3-6(19(13,14)15)1-5-2-7(20(16,17)18)4-9(12)10(5)8/h1-4,11-12H,(H,13,14,15)(H,16,17,18) checkY
    Key: HLVXFWDLRHCZEI-UHFFFAOYSA-N checkY
  • InChI=1/C10H8O8S2/c11-8-3-6(19(13,14)15)1-5-2-7(20(16,17)18)4-9(12)10(5)8/h1-4,11-12H,(H,13,14,15)(H,16,17,18)
    Key: HLVXFWDLRHCZEI-UHFFFAOYAH
  • O=S(=O)(O)c1cc(O)c2c(c1)cc(cc2O)S(=O)(=O)O
Properties
C10H8O8S2
Molar mass 320.29 g·mol−1
Acidity (pKa) 5.36, 15.6[2]
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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It can be used for as a reagent in the quantitative determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D).[3]

Chromotropic acid is also used for testing for the presence of formaldehyde.[4][5] The usefulness of this reagent in quantitative determination is the formation of a red coloration (peaking at 580 nm wavelength) when chromotropic acid in 50% sulfuric acid reacts with formaldehyde. The coloration is specific to this aldehyde and is not produced from other organic species such as other aldehydes, ketones and carboxylic acids. The NIOSH Formaldehyde method #3500 is the reference analytical standard that uses chromotropic acid.

References

edit
  1. ^ "Safety (MSDS) data". Archived from the original on 2007-07-13. Retrieved 2008-02-01.
  2. ^ Dawson, R.M.C.; et al. (1959). Data for Biochemical Research. Oxford: Clarendon Press.
  3. ^ Duane Letourneau and Norman Krog (1952). "The Use of Chromotropic Acid for the Quantitative Determination of 2,4-Dichlorophenoxy-acetic Acid". Plant Physiology. 27 (4): 822–7. doi:10.1104/pp.27.4.822. PMC 547994. PMID 16654508.
  4. ^ Jingping Zhang, David Thickett, and Lorna Green (1994). "Two Tests for the Detection of Volatile Organic Acids and Formaldehyde". Journal of the American Institute for Conservation. 33 (1): 47–53. doi:10.2307/3179669. JSTOR 3179669.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ Sanath Rao, Shruthakirthi D Shenoy, Suraj Davis, Sudharkar Nayak (2004). "Detection of Formaldehyde in Textiles by Chromotropic Acid Method". Indian Journal of Dermatology, Venereology and Leprology. 70 (6): 342–344. PMID 17642659.{{cite journal}}: CS1 maint: multiple names: authors list (link)