A solution of
294 g. (3 moles) of cyclohexanone,
343 g. (3.3 moles) of acetone dimethyl acetal,
418 g. (7.2 moles) of allyl alcohol,
1 l. of benzene, and
0.2 g. of p-toluenesulfonic acid monohydrate (Note
1) is distilled using a good
fractionating column until the
acetone and the
benzene-methanol azeotrope are completely removed (Note
2). The solution is cooled below the boiling point, and a solution of
0.5 g. of sodium methoxide in
20 ml. of methanol is added all at once with stirring (Note
3). Distillation is resumed, and unreacted
allyl alcohol and
benzene are removed at atmospheric pressure and then at reduced pressure (Note
4). Distillation is continued at a pressure in the range 5–20 mm. to remove forerun (on the order of 100 ml.) (Note
5). The
cyclohexanone diallyl acetal, b.p.
84°/5 mm.,
98°/10 mm.,
114°/20 mm.,
nD25 1.4600, is then collected. The yield is
382–435 g. (
65–74%). A small amount of higher-boiling residue remains.