1-Hydroxynaphthalene; 1-Naphthalenol; alpha-Naphthol
|Molar mass||144.17 g/mol|
|Appearance||Colorless or white solid; commercial material is often strongly colored|
|Melting point||95 °C (203 °F; 368 K)|
|Boiling point||278 °C (532 °F; 551 K)|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
1-Naphthol, or α-naphthol, is a fluorescent organic compound with the formula C10H7OH. It is a white solid. It is an isomer of 2-naphthol differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, with the hydroxyl group being more reactive than in the phenols. Both isomers are soluble in simple alcohols, ethers, and chloroform. They are precursors to a variety of useful compounds. Naphthols (both 1 and 2 isomers) are used as biomarkers for livestock and humans exposed to polycyclic aromatic hydrocarbons.
1-Naphthol is prepared by two main routes. In one method, naphthalene is nitrated to give 1-nitronaphthalene, which is hydrogenated to the amine followed by hydrolysed:
- C10H8 + HNO3 → C10H7NO2 + H2O
- C10H7NO2 + 3 H2 → C10H7NH2 + 2 H2O
- C10H7NH2 + H2O → C10H7OH + NH3
Alternatively, naphthalene is hydrogenated to tetralin, which is oxidized to 1-tetralone, which undergoes dehydrogenation.
1-Naphthol is a precursor to a variety of insecticides including carbyl and pharmaceuticals including nadolol. It undergoes azo coupling to give various azo dyes, but these are generally less useful than those derived from 2-naphthol.
In Molisch's test, 1-naphthol dissolved in ethanol, known as Molisch's reagent, is used as reagent for detecting the presence of carbohydrates. The test known as Molisch's test would give a red- or purple-colored compound to indicate the presence of carbohydrate. The rapid furfural test, similar to Molisch's test, also uses 1-Naphthol.
- Sreekanth, R; Prasanthkumar, KP; Sunil Paul, MM; Aravind, UK; Aravindakumar, CT (7 November 2013). "Oxidation reactions of 1- and 2-naphthols: an experimental and theoretical study.". The journal of physical chemistry. A 117 (44): 11261–70. doi:10.1021/jp4081355. PMID 24093754. Retrieved 2 December 2013.
- Gerald Booth "Naphthalene Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a17_009.
- Meeker, John D.; Ryan, Louise; Barr, Dana B.; Hauser, Russ (January 2006). "Exposure to Nonpersistent Insecticides and Male Reproductive Hormones". Epidemiology 17 (1): 61–68. doi:10.1097/01.ede.0000190602.14691.70. PMID 16357596.