2-Naphthol

November 2022 changed 477214746 Beta-Naphthol.svg 180px Skeletal formula skin-invert 2-Naphthol-3D-balls.png 180px bg-transparent Β-Naphthol.jpg 220px Naphthalen-2-ol 2-Hydroxynaphthalene; 2-Naphthalenol; beta-Naphthol; Naphth-2-ol correct CAS 135-19-3 742134 correct EBI 10432 correct EBI 14126 correct chemspider 8341 205-182-7 27395 correct kegg C11713 8663 QL2975000 3077 correct FDA P2Z71CIK5H Oc2ccc1c(cccc1)c2 1/C10H8O/c11-10-6-5-8-3-1-2-4-9(8)7-10/h1-7,11H JWAZRIHNYRIHIV-UHFFFAOYAV correct chemspider 1S/C10H8O/c11-10-6-5-8-3-1-2-4-9(8)7-10/h1-7,11H correct chemspider JWAZRIHNYRIHIV-UHFFFAOYSA-N c1ccc2cc(ccc2c1)O 10 8 1 Colorless crystalline solid 1.280 g/cm3 121 to 123 285 0.74 g/L 9.51 −98.25·10−6 cm3/mol Harmful when inhaled or swallowed; dangerous to environment, esp. aquatic organisms.MSDS safety data for 2-naphthol https://msds.chem.ox.ac.uk/NA/2-naphthol.html dead https://web.archive.org/web/20110303133020/https://msds.chem.ox.ac.uk/NA/2-naphthol.html dmy-all 2011-03-03 161 2 1 0 07 09 Warning 302 332 400 261 264 270 271 273 301+312 304+312 304+340 312 330 391 501 1-Naphthol 2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple alcohols, ethers, and chloroform. 2-Naphthol is a widely used intermediate for the production of dyes and other compounds. Production Traditionally, 2-naphthol is produced by a two-step process that begins with the sulfonation of naphthalene in sulfuric acid:Gerald Booth Naphthalene Derivatives 2005 10.1002/14356007.a17_009. full-text PDF C10H8 + H2SO4 → C10H7SO3H + H2O The sulfonic acid group is then cleaved in molten sodium hydroxide: C10H7(SO3H) + 3 NaOH → C10H7ONa + Na2SO3 + 2 H2O Neutralization of the product with acid gives 2-naphthol. 2-Naphthol can also be produced by a method analogous to the cumene process. 2-Naphthol-derived dyes The Sudan dyes are popular dyes noted for being soluble in organic solvents. Several of the Sudan dyes are derived from 2-naphthol by coupling with diazonium salts.Booth Gerald Heinrich Zollinger Keith McLaren William G. Sharples Alan Westwell 2000 Wiley-VCH 10.1002/14356007.a09_073 Ullmann's Encyclopedia of Industrial Chemistry 9783527306732 Dyes, General Survey Sudan dyes I–IV and Sudan Red G consist of arylazo-substituted naphthols. Reactions Some reactions of 2-naphthol are explicable with reference to its tautomerism, which produces a small amount of the keto tautomer. thumb|Tautomeric equilibrium for beta-naphthol|left|384px One consequence of this tautomerism is the Bucherer reaction, the ammonolysis of 2-naphthol to give 2-aminonaphthalene. 2-Naphthol can be oxidatively coupled to form BINOL, a C2-symmetric ligand popularized for use in asymmetric catalysis. 400px|left|Coupling of beta-naphthol using CuCl2 2-Naphthol converts to 2-naphthalenethiol by reaction with dimethylthiocarbamoyl chloride via the Newman–Kwart rearrangement.Thiophenols from Phenols: 2-Naphthalenethiol Melvin S. Newman Frederick W. Hetzel https://www.orgsyn.org/demo.aspx?prep=CV6P0824 Organic Syntheses 1971 51 139 10.15227/orgsyn.051.0139 free subscription The OH→Br conversion has been described.10.15227/orgsyn.049.0006 free 2-Bromonaphthalene Organic Syntheses 1969 49 6 J. P. Schaefer Jerry Higgins P. K. Shenoy 2-Bromonaphthalene is prepared by treatment of naphthol with phosphorus bromide: 10.15227/orgsyn.049.0006 free 2-Bromonaphthalene Organic Syntheses 1969 49 6 J. P. Schaefer Jerry Higgins P. K. Shenoy C10H7(OH) + (C6H5)3PBr2 → C10H7Br + (C6H5)3PO + HBr Electrophilic attack occurs characteristically at the 1-position as indicated by nitrosylation to give 1-nitroso-2-naphthol.10.15227/orgsyn.002.0061 free Organic Syntheses 1922 2 61 Nitroso-β-Naphthol C. S. Marvel P. K. Porter Bromination10.15227/orgsyn.020.0018 free 6-Bromo-2-Naphthol Organic Syntheses 1940 20 18 C. Frederick Koelsch and alkylations proceed with similar regiochemistry.10.15227/orgsyn.022.0063 free 2-Hydroxy-1-Naphthaldehyde Organic Syntheses 1942 22 63 Alfred Russell Luther B. Lockhart Ring-opening reactions have been documented.10.15227/orgsyn.034.0008 free Organic Syntheses 1954 34 8 β-(o-Carboxyphenyl)propionic Acid G. A. Page, D. S. Tarbell Carbonation of 2-naphthol gives 2-hydroxy-1-naphthoic acid. Safety 2-Naphthol has been described as "moderately toxic". References External links NIST Chemistry WebBook 2-Naphthalenol Naphthols 19 168–169 1 Category:2-Naphthyl compounds