Org. Synth. 1930, 10, 1
DOI: 10.15227/orgsyn.010.0001
ACETOL
[2-Propanone, 1-hydroxy-]
Submitted by P. A. Levene and A. Walti.
Checked by Frank C. Whitmore and J. Pauline Hollingshead.
1. Procedure
In a 3-l. round-bottomed flask fitted with a 75-cm. Liebig condenser is placed 210 g. of potassium hydroxide (purified with alcohol) dissolved in 1.5 l. of anhydrous methyl alcohol. The solution is cooled to below 50° (Note 1), 300 g. of purified ethyl formate is added, and the mixture is refluxed for two hours (Note 2) and (Note 3).
Then
410 g. (251 cc., 3 moles) of bromoacetone (p. 88) is added, and the mixture is refluxed for sixteen hours on a
water bath at 95–97°. At the end of the operation the solution is cooled to 0° in an
ice-salt bath. The
potassium bromide which settles is filtered on a cooled
suction filter, and the filtrate is fractionated.
The fraction boiling at 23–35°/12 mm. is discarded, as it contains very little acetol. The main fraction distils at 35–47°/12 mm. and weighs 160 g. This material is refractionated, and the portion boiling at 40–43°/12 mm. is collected. The yield is 120–130 g. (54–58 per cent of the theoretical amount) (Note 4).
2. Notes
1.
It is necessary to cool the mixture below 50° to prevent loss of the volatile
ethyl formate.
2.
Technical
ethyl formate was purified by washing with
3 per cent sodium carbonate solution, then with cold water, drying over anhydrous
sodium sulfate, filtering, and fractionating. Compare
p. 180. It is very important that all the materials used in the synthesis of
acetol be anhydrous, as otherwise condensation products are formed.
3.
If commercial
potassium formate is used it should be dried under reduced pressure at 80°. One and one-half to two moles should be used per mole of the bromo compound.
4.
Acetol polymerizes very readily on standing but remains unchanged when dissolved in an equal volume of
methyl alcohol.
3. Discussion
Acetol has usually been prepared by the reaction between
bromoacetone and
sodium or potassium formate or acetate, followed by hydrolysis of the ester with
methyl alcohol.
1,
2 Treatment of
glycerol3 or
propylene glycol4 at 200–300° with a dehydrogenating catalyst leads to the formation of
acetol, while the direct oxidation of
acetone with
Baeyer and Villiger's acetone-peroxide reagent furnishes
acetol together with
pyruvic acid.
5
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
sodium or potassium formate
Baeyer and Villiger's acetone-peroxide reagent
alcohol (64-17-5)
Acetol (64-19-7)
methyl alcohol (67-56-1)
glycerol (56-81-5)
sodium carbonate (497-19-8)
sodium sulfate (7757-82-6)
acetone (67-64-1)
potassium hydroxide (1310-58-3)
potassium bromide (7758-02-3)
ethyl formate (109-94-4)
Pyruvic acid (127-17-3)
2-Propanone, 1-hydroxy- (116-09-6)
Bromoacetone (598-31-2)
potassium formate
propylene glycol (57-55-6)
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