Org. Synth. 1931, 11, 1
DOI: 10.15227/orgsyn.011.0001
ACROLEIN ACETAL
[Acrolein, diethyl acetal]
Submitted by E. J. Witzemann, Wm. Lloyd Evans, Henry Hass, and E. F. Schroeder.
Checked by Frank C. Whitmore and Harry T. Neher.
1. Procedure
To
340 g. (6 moles) of dry, powdered potassium hydroxide (Note 1) in a
500-cc. short-necked round-bottomed flask (Note 2) is added
167 g. (1 mole) of β-chloropropionaldehyde acetal (p. 137). The mixture is shaken vigorously and attached at once to a
three-bulbed Glinsky or other suitable column, connected to a
water condenser set for distillation
(Note 3). The flask is heated in an
oil bath at 210–220° until nothing more distils
(Note 4). The distillate is transferred to a
separatory funnel and the lower aqueous layer is removed. The
acrolein acetal is dried over
10 g. of potassium carbonate, filtered, and distilled from a
modified Claisen flask (Fig. 2). The yield is
98 g. (
75 per cent of the theoretical amount) of a product which boils at
122–126°.
Fig. 2
2. Notes
1.
The powdered
potassium hydroxide should pass a
60-mesh sieve (24 per cm.). The dryness of the powder is of the utmost importance. Water must be avoided as much as possible. Therefore, the
potassium hydroxide should be fused at 350° for two hours and then pulverized as rapidly as possible. A
24-cm. (10-in.) disk pulverizer having a capacity of about 200 g. per minute is recommended. If the
potassium hydroxide is not fused before pulverizing, the yield of acetal drops to about
60 per cent.
2.
The concentrated
potassium hydroxide left at the completion of the reaction attacks the glass rapidly. For this reason
iron retorts made from 10-cm. (4-in.) pipe should be used when many runs are to be made.
3.
The reaction between the acetal and the alkali is very vigorous.
4.
A large low-boiling fraction indicates too much moisture in the
potassium hydroxide used. See
(Note 1).
3. Discussion
Acrolein acetal has been prepared by treatment of
β-chloropropionaldehyde acetal with dry, powdered
potassium hydroxide,
1 and from
acrolein,
ethyl orthoformate, and
ammonium nitrate in boiling
alcohol.
2
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
alcohol (64-17-5)
potassium carbonate (584-08-7)
Acrolein (107-02-8)
potassium hydroxide (1310-58-3)
ammonium nitrate
Ethyl orthoformate
Acrolein acetal
Acrolein, diethyl acetal
β-chloropropionaldehyde acetal (35573-93-4)
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