A solution of
α-naphthylmagnesium bromide is prepared from
24.3 g. (1 gram atom) of magnesium and
207 g. (1 mole) of α-bromonaphthalene by the procedure given on
p. 425 (Note
1), but using a
large separatory funnel and a
3-l. three-necked flask. The Grignard reagent is transferred to the separatory funnel, and
177 g. (1.5 moles) of ethyl carbonate (Note
2) and
100 cc. of absolute ether are placed in the flask. Stirring is begun, and the
α-naphthylmagnesium bromide is added as rapidly as the refluxing of the solution permits. Stirring is continued for a half hour after the addition is finished, and the reaction mixture is then left to stand overnight.
Hydrolysis is effected by pouring the reaction mixture, with shaking, into a
5-l. flask containing 1.2–1.5 kg. of cracked ice. The basic magnesium bromide is dissolved by adding gradually
145 cc. of cold 30 per cent sulfuric acid (30 cc. of concentrated acid and 120 cc. of water). The organic layer is separated and the aqueous layer extracted with
100 cc. of ether. The combined
ether solutions are concentrated by distilling the solvent from a
steam bath until the volume of the residue is about 400 cc. The residue is washed with two
40-cc. portions of 5 per cent sodium carbonate solution (Note
3) and dried with
20 g. of anhydrous calcium chloride. The
calcium chloride is removed by filtration and the
ether is distilled from a steam bath. The residue is then transferred to a
500-cc. distilling flask and distilled; the fraction boiling from
287° to 307° is collected as crude
ethyl α-naphthoate. The crude product is redistilled from a
250-cc. modified Claisen flask. The yield of pure ester, boiling at
143–144.5°/3 mm., is
136–147 g. (
68–73 per cent of the theoretical amount) (Note
4).