Org. Synth. 1932, 12, 64
DOI: 10.15227/orgsyn.012.0064
PROPIONALDEHYDE
Submitted by Charles D. Hurd and R. N. Meinert.
Checked by W. L. McEwen and W. H. Carothers.
1. Procedure
One hundred grams (125 cc., 1.7 moles) of n-propyl alcohol, b.p. 96–96.6°, is placed in a 2-l. three-necked, round-bottomed flask fitted with a mercury-sealed stirrer (Note 1), a dropping funnel, and a 60-cm. bulb condenser (Note 2) set at an angle of 45°. Water at 60° is kept circulating through this condenser. A condenser set for downward distillation is connected to the top of the first condenser. Cold water circulates through the second condenser. By means of an adapter, the lower end of the second condenser is fitted to a receiver which is cooled with ice water.
The alcohol in the flask is heated to boiling, stirred, and a mixture of 164 g. (0.56 mole) of potassium dichromate, 120 cc. of concentrated sulfuric acid (2.2 moles), and 1 l. of water is added through the dropping funnel. The addition takes about thirty minutes, and during this time the contents of the flask are kept vigorously boiling. After all the oxidizing mixture has been added, the contents of the flask are boiled for fifteen minutes to distil the last of the aldehyde. The propionaldehyde which collects in the receiver is dried with 5 g. of anhydrous sodium sulfate and fractionally distilled. The yield of propionaldehyde boiling at 48–55°, and having a refractive index of 1.364 (Note 3), is 44–47 g. (45–49 per cent of the calculated amount).
2. Notes
1.
The yield of
propionaldehyde depends largely upon the efficiency of the stirrer.
2.
The purpose of the first condenser is to condense and return to the flask any
propyl alcohol which escapes.
3.
The recorded value for the index of refraction (
N20°D) is 1.3636.
3. Discussion
Propionaldehyde has been prepared by passing
propyl alcohol over finely powdered reduced
copper;
1 by passing a mixture of
propyl alcohol and air over a hot
platinum spiral2 or a
silver catalyst containing a small amount of
samarium oxide;
3 by passing a mixture of steam and
propylene oxide over
silica gel at 300°;
4 by adding
propyl alcohol to a dichromate oxidizing mixture
5 or adding a dichromate oxidizing mixture to
propyl alcohol;
6 by heating
propylene glycol to 500°;
7 by heating a mixture of
calcium formate and calcium propionate;
8 by the action of
ethylmagnesium iodide on
amyl formate;
9 by catalytic hydrogenation of
acrolein;
10 by electrolysis of
calcium chloride or dilute sulfuric acid solutions of propyl alcohol;
11 by passing vapors of
propyl alcohol over
cadmium oxide at 325°;
12 by passing vapors of
propionic acid and
formic acid over
titanium oxide at 250–300°;
13 by oxidizing
propyl alcohol with a stream of air in the presence of
copper bronze,
nitrobenzene, and
quinoline;
14 and by treating
ethyl orthoformate with
ethylmagnesium bromide.
15
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
silica gel
copper bronze
platinum spiral
calcium chloride (10043-52-4)
sulfuric acid (7664-93-9)
Acrolein (107-02-8)
propionic acid (79-09-4)
sodium sulfate (7757-82-6)
formic acid (64-18-6)
Propionaldehyde (123-38-6)
propylene oxide (75-56-9)
copper (7440-50-8)
Nitrobenzene (98-95-3)
propyl alcohol,
n-propyl alcohol (71-23-8)
Ethyl orthoformate
Quinoline (91-22-5)
potassium dichromate (7778-50-9)
ethylmagnesium bromide (925-90-6)
propylene glycol (57-55-6)
silver (7440-22-4)
calcium formate (544-17-2)
samarium oxide (12060-58-1)
calcium propionate (4075-81-4)
ethylmagnesium iodide
amyl formate (638-49-3)
cadmium oxide
titanium oxide
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