Hydroxynaphthol blue

Hydroxynaphthol blue
Names
Other names
Hydroxynaphthol blue
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.058.343 Edit this at Wikidata
UNII
  • InChI=1S/C20H14N2O11S3.3Na/c23-15-9-16(35(28,29)30)13-3-1-2-4-14(13)18(15)21-22-19-12-6-5-11(34(25,26)27)7-10(12)8-17(20(19)24)36(31,32)33;;;/h1-9,23-24H,(H,25,26,27)(H,28,29,30)(H,31,32,33);;;/q;3*+1/p-3/b22-21+;;; ☒N
    Key: AUIINJJXRXMPGT-ZRUFZDNISA-K ☒N
  • InChI=1/C20H14N2O11S3.3Na/c23-15-9-16(35(28,29)30)13-3-1-2-4-14(13)18(15)21-22-19-12-6-5-11(34(25,26)27)7-10(12)8-17(20(19)24)36(31,32)33;;;/h1-9,23-24H,(H,25,26,27)(H,28,29,30)(H,31,32,33);;;/q;3*+1/p-3/b22-21+;;;
    Key: AUIINJJXRXMPGT-QWKJSYRZBJ
  • O=S(C(C=C4)=CC1=C4C(/N=N/C2=C3C(C=CC=C3)=C(S(=O)(O[Na])=O)C=C2O)=C(O)C(S(=O)(O[Na])=O)=C1)(O[Na])=O
Properties
C20H11N2Na3O11S3
Molar mass 620.46301 g/mol
Appearance Black-violet Powder
Soluble
Acidity (pKa) 6.44, 12.93[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Hydroxynaphthol blue is an azo dye. It is used for determining the endpoint in complexometric titrations/Metal Titration.

  1. ^ Atuko Itoh; Keihei Ueno (1970). "Evaluation of 2-hydroxy-1-(20hydroxy-4-sulpho-1-naphthylazo)-3-naphthoic acid and hydroxynaphtol blue as metallochromic indicators in the EDTA titration of calcium". Analyst. 95 (1131): 583–589. Bibcode:1970Ana....95..583I. doi:10.1039/an9709500583. ISSN 1364-5528.