Org. Synth. 1945, 25, 1
DOI: 10.15227/orgsyn.025.0001
β-ETHOXYPROPIONALDEHYDE ACETAL
[Propionaldehyde, β-ethoxy-, diethyl acetal]
Submitted by C. G. Alberti and R. Sollazzo.
Checked by Miriam Sharp, V. L. Stromberg, and E. C. Horning.
1. Procedure
In a 1-l. three-necked round-bottomed flask fitted with a reflux condenser, a mechanical stirrer, and a thermometer dipping below the surface of the mixture are placed 158 g. (2.8 moles) of acrolein (Note 1), 500 ml. of absolute ethanol, and 10 g. of ammonium chloride (Note 2). The material is stirred for 1 hour without external heating; the temperature of the mixture should rise to about 30°. Over a 3-hour period the temperature is raised to 80°, and the mixture is maintained at this temperature for an additional hour. The flask is then cooled, and anhydrous sodium or magnesium sulfate is added as a drying agent.
After 24 hours the mixture is filtered and distilled under reduced pressure through a good column
(Note 3). The following fractions are collected
(Note 4):
|
Below 23°/20 mm.
|
Acrolein and alcohol
|
|
38–42°/16 mm.
|
β-Ethoxypropionaldehyde
|
|
75–78°/16 mm.
|
β-Ethoxypropionaldehyde acetal
|
|
The yield of β-ethoxypropionaldehyde is 22–24 g. (7–8%) and of β-ethoxypropionaldehyde acetal is 166–193 g. (31–39%), nD20 1.4067, d415 0.898.
2. Notes
1.
Commercial
acrolein may be employed. It should be dried over anhydrous
sodium sulfate.
2.
Reagent grade
ammonium chloride is used. It should be washed several times with absolute
ethanol.
3.
A
1-m. Fenske column packed with 3/32-in. glass helices was employed by the submitters.
4.
Ammonium chloride separates during the distillation. It is advisable to decant the liquid into a clean flask for distillation of the last two fractions.
3. Discussion
β-Ethoxypropionaldehyde acetal is best prepared from
acrolein by reaction with
ethanol.
1,
2
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
ethanol (64-17-5)
ammonium chloride (12125-02-9)
Acrolein (107-02-8)
sodium sulfate (7757-82-6)
magnesium sulfate (7487-88-9)
β-Ethoxypropionaldehyde acetal (7789-92-6)
Propionaldehyde, β-ethoxy-, diethyl acetal
β-Ethoxypropionaldehyde (2806-85-1)
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved