A.
Acetone carboxymethoxime. A mixture of
612 g. (4.4 moles) of bromoacetic acid (Note
1) and 500 g. of crushed ice is chilled in an
ice-salt bath and made distinctly alkaline to litmus with
sodium hydroxide (about 440 g. of a 40% solution). During the neutralization an additional 500 g. of ice is added. To the solution are then added
292 g. (4.0 moles) of acetoxime1 and
440 g. of 40% sodium hydroxide (4.4 moles), the temperature being held below 20° during the addition of the alkali. The mixture is then allowed to flow dropwise, during 3–4 hours, through the inner tube of a
steam-heated Liebig condenser (jacket 75 cm. long; inner tube 10-mm. diameter; angle of inclination about 20°) into a
5-l. round-bottomed flask cooled with running water (Note
2). The resulting solution is extracted three times with
500-ml. quantities of freshly distilled peroxide-free ether (Note
3), and the aqueous solution is then cooled and made strongly acid by the addition of 500 ml. of concentrated
hydrochloric acid (6 moles). During the acidification the temperature should not rise above 15°. The solution is saturated with
sodium chloride and immediately extracted with six successive 1.5-l. portions of peroxide-free
ether. The
ether is distilled from the combined ethereal extracts, and the residue, consisting of the crude
acetone carboxymethoxime (
333–345 g.), is used for the next step. The
acetone carboxymethoxime may be purified by distillation under reduced pressure, the fraction boiling at
95–97°/1 mm. (Note
4) being collected (Note
5). The yield is
300 g. (
57%) of a colorless product melting at
76°.