Organic Syntheses, CV 4, 677
Submitted by Raymond I. Longley, Jr. and William S. Emerson
1.
Checked by T. L. Cairns and W. W. Gilbert.
1. Procedure
A
1-l. three-necked flask fitted with an efficient stirrer, a thermometer, and a reflux condenser attached to a device for measuring gas evolution (Note
1) is charged with
197 g. (1.67 moles) of 3-methyl-1,5-pentanediol (
p. 660) and
10 g. of copper chromite (Note
2). The mixture is heated rapidly to 200° (Note
3) with good stirring and is held at 195–205° for 1.5–3.0 hours, during which time 3.1 cu. ft. of
hydrogen is evolved (Note
4). The product is distilled directly from the flask with stirring through a
2 by 120 cm. Vigreux column (Note
5). The yield of
β-methyl-δ-valerolactone is
172–180 g. (
90–95%), b.p.
110–111°/15 mm.,
n25D 1.4495.
2. Notes
1. A standard wet test meter may be used.
3. At this point gas evolution becomes so rapid that the temperature tends to drop slightly.
4. If gas evolution subsides more catalyst may be added.
5. The column is substituted for the reflux condenser in the same set-up. Stirring during distillation prevents serious bumping.
3. Discussion
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