Organic Syntheses, Coll. Vol. 3, p.827 (1955); Vol. 21, p.108 (1941).
One hundred and six grams (1 mole) of benzaldehyde (Note 1)
and 107 g. (1 mole) of m-toluidine
are mixed in a suitable flask; the temperature rises to about 60° (Note 2)
and (Note 3)
. The mixture is cooled below 35° in cold water, 200 ml. of ether
is added, and the solution is placed in the steel reaction vessel
of a high-pressure hydrogenation apparatus. Eight to ten grams of Raney nickel
catalyst (p. 181)
is added, the bomb is closed, and hydrogen
is admitted up to 1000 lb. pressure (Note 4)
. The bomb is shaken continuously at room temperature for 15 minutes (Note 5)
. The contents are removed, and the bomb is washed out with two 200-ml. portions of ether
. After the catalyst has been separated by filtration (Note 6)
, the ether
is removed by distillation and the product is distilled from a modified Claisen flask (Note 7)
. After a small fore-run the N-benzyl-m-toluidine
boils at 153–157° /4 mm.
; 315–317° /760 mm.
The yield is 175–185 g.
) (Note 8)
and (Note 9)
It is unnecessary to isolate the Schiff base.
used as solvent may be replaced by an equal amount of 95% ethanol
. If ethanol
is used, cooling is unnecessary.
The initial pressure of hydrogen
used is determined by the apparatus available. The drop in pressure depends upon the size of the bomb.
With a less active Raney nickel
catalyst it may be necessary to carry out the reduction at a somewhat higher temperature. If necessary, the reaction mixture may be heated slowly to 60° and the reduction carried out at this temperature. The yield is then somewhat lower (82–84%).
The catalyst is filtered through paper on a Büchner funnel
. Owing to its activity, suction should be discontinued as soon as all the liquid has passed through. If this precaution is not observed, a fire may result.
In some instances (o-tolylbenzylamine
), a part of the product may crystallize and can be filtered.
, m.p. 198–199°
, may serve for characterization.
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved