The methyl and ethyl ethers of B-naphthol are both used extensively for perfuming cheaper grades of soap. In commerce these ethers are known as nerolin. The methyl ether is sometimes differentiated as nerolin "old" or "jara-jara", the ethyl ether as nerolin "new" or "bromelia". Neither of these ethers have been found in nature thus for. They are prepared artificially by digesting for several hours ,i-naphtholpotassium with the molecular amounts of the respective alkyl halides in methyl or ethyl alcoholic solution.1) According to another method,2) one part of i-naphthol, three parts of methyl or ethyl alcohol and one part of hydrochloric acid are heated in an autoclave to 150°. Simpler, however, is the method of Henriques, originally used for the preparation of a-naphthol ethers, but which, according to Gatter-mann,3) is likewise well suited to the preparation of B-naphthol ethers. It consists in heating B-naphthol with the respective alcohol and sulphuric acid to 125 to 140° using a reflux condenser. The methyl ether results better when a slight pressure is employed.
1) Berl. Berichte 30 (1897), 2152. 2) Ibidem 32 (1899), 2262.
Both ethers consist of colorless crystalline laminae, which are rather difficultly soluble in methyl and ethyl alcohol, but readily soluble in other organic solvents. The odor of both ethers is strong and persistent, however, that of the ethyl ether is more delicate than that of the methyl ether. In great dilution their odor resembles that of orange blossom oil, for which they are a cheap, though not perfect, substitute. The odor of the ethyl ether is also compared with that of pine apple, though the comparison does not seem fully justified. It is possibly due to this analogy that the name Bromelia may be traced.
The following constants for B-naphthol methyl ether are recorded in chemical literature:
M. p. 72°;4) m. p. 70°, b. p. 2740;5) and for B-naphthol ethyl ether:
M. p. 37°;6) b. p. 274 to 275°;7) 282° (corr.); d40o1,0547, d50o1,501.8)
1) Schaeffer, Liebig's Annalen 152 (1869), 286.
2) Liebermann and Hagen, Berl. Berichte 15 (1882), 1428.
3) Liebig's Annalen 244 (1888), 72.
4) Stadel, Liebig's Annalen 217 (1883), 43.
5) Marchetti, Gazz. chim. ital. 9 (1879), 544; Jahresber. d. Chem. 1879, 543.
6) Orndorff and Kortright, Americ. chem. Journ. 13 (1891), 162.
7) Liebermann and Hagen, Berl. Berichte 15 (1882), 1428.
8) Perkin, Journ. chem. Soc. 69 (1896), 1190.