1,4-Dihydroxynaphthalene

1,4-Dihydroxynaphthalene is an organic compound with the formula C₁₀H₆(OH)₂. It is one of several isomers of dihydroxynaphthalene. The compound attracted some interest because in its molten state, it exists mainly as the diketo tautomer.^[2]

Quick facts Names, Identifiers ...

1,4-Dihydroxynaphthalene

Names
Other names 1,4-Naphthoquinol 1,4-naphthalenediol
Identifiers
CAS Number	571-60-8
3D model (JSmol)	Interactive image
ChEBI	CHEBI:34063
ChEMBL	ChEMBL206816
ChemSpider	10830
ECHA InfoCard	100.008.489
EC Number	209-336-4
KEGG	C14785
PubChem CID	11305
UNII	AML1P6T42C
CompTox Dashboard (EPA)	DTXSID5060350
InChI InChI=1S/C10H8O2/c11-9-5-6-10(12)8-4-2-1-3-7(8)9/h1-6,11-12H Key: PCILLCXFKWDRMK-UHFFFAOYSA-N
SMILES C1=CC=C2C(=C1)C(=CC=C2O)O
Properties
Chemical formula	C10H8O2
Molar mass	160.172 g·mol−1
Appearance	white solid
Melting point	190 Â°C (374 Â°F; 463 K) tautomerizes
Acidity (pKa)	pKa1 = 9.37 (26.5 Â°C) pKa2 = 10.93 (26.5 Â°C)
Hazards
GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H302, H315, H318, H335, H412
Precautionary statements	P261, P264, P264+P265, P270, P271, P273, P280, P301+P317, P302+P352, P304+P340, P305+P354+P338, P317, P319, P321, P330, P332+P317, P362+P364, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa). Infobox references

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It can be prepared by reduction of 1,4-naphthoquinone with dithionite as well as by acid-hydrolysis of 1-hydroxy-4-aminonaphthalene. Both routes are reversible: oxidation of the diol give the naphthoquinone and addition of ammonia gives back the hydroxyaminonaphthalene.^[3]