In a
5-l. three-necked flask fitted with a stopper, a reflux condenser, and a 250-ml. dropping funnel are placed
1.5 kg. (22.9 g. atoms) of amalgamated zinc (Note
1) and
800 ml. of concentrated hydrochloric acid. The flask is heated to cause gentle refluxing to occur. A solution of
152 g. (1.0 mole) of vanillin in
450 ml. of 95% ethanol and
1.5 l. of concentrated hydrochloric acid (Note
2) is added dropwise through the dropping funnel over an 8-hour period (Note
3). After the addition of the
vanillin is complete the mixture is refluxed for 30 minutes more. The liquid, consisting of two layers, is decanted from the
zinc (Note
4) into a
4-l. separatory funnel. The aqueous layer is removed and washed three times with
200-ml. portions of benzene, and the
benzene extracts are
combined with the crude
creosol separated initially. The residual amalgamated
zinc is washed twice with
100-ml. portions of benzene, and this
benzene solution is added to the combined extracts. The extracts are washed twice with
200-ml. portions of 5% sodium bicarbonate solution, and the resultant precipitate of metallic salts is removed by filtration. The solution is washed once with 200 ml. of water.
The
benzene is removed under reduced pressure by distillation on a
steam bath. The residue is distilled under reduced pressure, the fraction boiling at
78–79°/4 mm., at
104–105°/15 mm., or at
219–222.5°/760 mm. being collected. A yield of
83–92.5 g. (
60–67%) of colorless or pale yellow
creosol is obtained,
d254, 1.092;
n20D 1.5354 (Note
5) and (Note
6).