A hot solution of
sodium ethoxide is prepared, in a
3-l. round-bottomed flask, from
46 g. (2 gram atoms) of sodium and
1.6 l. of absolute ethanol. With shaking, a solution of
139 g. (2 moles) of hydroxylamine hydrochloride in 100 ml. of hot water is added. The resulting suspension is cooled quickly by placing the flask in an ice-water mixture and is then filtered with suction through a
Büchner funnel. The residue of
sodium chloride is washed with small portions
(total 200 ml.) of absolute ethanol. The filtrate is returned to the
3-l. flask, and to it is added
148 g. (1 mole) of cinnamic acid, whereupon a voluminous precipitate forms. The mixture is refluxed on a
steam bath for 9 hours (Note
1). The amino acid begins to separate after 5–6 hours; the suspended solid causes the mixture to bump (Note
2). The suspension is allowed to remain overnight at room temperature, and the crystals are then collected on a Büchner funnel (Note
3). The product is washed with
300 ml. of absolute ethanol, then with some ice-cold water to remove all the
sodium chloride, and finally with
300 ml. of absolute ethanol, always in small portions. The colorless crystals of amino acid are dried in a
vacuum desiccator over flake
sodium hydroxide. The yield is
56 g. (
34%).
If a purer product is desired, the amino acid is dissolved in 16 times its weight of boiling water, and to the solution is added
absolute ethanol (46 ml. per g. of acid). The solution is stirred mechanically while it is cooled in an ice-water mixture. After 3 hours, the snow-white crystals are collected on a Büchner funnel and are washed with
300 ml. of 95% ethanol, in small portions, and dried as before. The recovery of amino acid, melting at
221° with decomposition (Note
4), is 81%.