Org. Synth. 1948, 28, 73
DOI: 10.15227/orgsyn.028.0073
dl-ISOPROPYLIDENEGLYCEROL
[Glycerol, isopropylidene-; also 1,3-dioxolane-4-methanol, 2,2-dimethyl-]
Submitted by Mary Renoll and Melvin S. Newman.
Checked by R. L. Shriner and Arne Langsjoen.
1. Procedure
In a
1-l. three-necked flask, fitted with a
sealed mechanical stirrer and a
fractionating column (about 2 by 45 cm., packed with glass helices) attached to a
total reflux phase-separating head (Fig. 15) (Note 1), are placed
237 g. (300 ml., 4.09 moles) of acetone (Note 2),
100 g. (1.09 moles) of glycerol (Note 3),
300 ml. of low-boiling petroleum ether (Note 4), and
3.0 g. of p-toluenesulfonic acid monohydrate. The third neck is closed with a
cork or a ground-glass stopper, and the mixture is heated
(Note 5) with stirring so that the
petroleum ether refluxes as rapidly as the column permits. The stirring and refluxing are continued until no more water collects in the trap of the separating head; the time required varies between 21 and 36 hours
(Note 6).
The mixture is cooled to room temperature, and 3.0 g. of powdered, freshly fused sodium acetate is added. Stirring is continued for 30 minutes; the mixture is then filtered, and the petroleum ether and excess acetone are removed by distillation under reduced pressure (water pump). The residual liquid is distilled from a modified Claisen flask. The fraction boiling at 80–81°/11 mm. is collected. The yield of colorless isopropylideneglycerol (n25D 1.4339, d254 1.062) is 125–129 g. (87–90%).
Fig. 15.
2. Notes
1.
During operation, the apparatus shown in
Fig. 15 requires no attention beyond occasional draining of the
water trap. It is suitable for a number of preparations in which water is removed by distillation with an immiscible solvent; it functions only when the condensate separates into two phases, of which water is the more dense.
2.
The
acetone was the 99.5% grade obtained from the Carbide and Carbon Chemicals Company.
3.
The
glycerol should be of
U.S.P. grade; if it has absorbed moisture, it may be dehydrated by heating at 170° in an
open dish under a hood for 3 hours.
14.
Skellysolve F, b.p.
35–55°, obtainable from the Skelly Oil Company, is suitable.
5.
The mixture may be heated by means of a
steam or water bath, but in view of the long reflux period it is better to use a
hemispherical electric heating mantle controlled by a variable transformer.
6.
The period of refluxing need not be continuous. A longer reflux time, up to 70 hours, does not increase the yield. The volume of the aqueous phase collected in the separating head varies from 32 to 42 ml., depending on the quality of the
glycerol.
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3. Discussion
Isopropylideneglycerol has been prepared from
acetone and
glycerol in the presence of the following acidic catalyst:
hydrogen chloride,
2,3 hydrogen chloride and anhydrous
sodium sulfate,
4 phosphorus pentoxide,
5 and anhydrous
copper sulfate.
6 It has also been prepared from
acetone and
glycerol in the presence of
calcium carbide and a neutral surface-active agent.
7 The two optically active isomers of
isopropylideneglycerol have been prepared from
1,2,5,6-diacetone-D-mannitol and
1,2,5,6-diacetone-L-mannitol.
8 The procedure given is based on the method of Newman and Renoll.
9
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
petroleum ether
calcium carbide
1,2,5,6-diacetone-D-mannitol
1,2,5,6-diacetone-L-mannitol
hydrogen chloride (7647-01-0)
sodium acetate (127-09-3)
glycerol (56-81-5)
sodium sulfate (7757-82-6)
copper sulfate (7758-98-7)
acetone (67-64-1)
isopropylideneglycerol,
dl-ISOPROPYLIDENEGLYCEROL,
Glycerol, isopropylidene-
1,3-dioxolane-4-methanol, 2,2-dimethyl- (100-79-8)
phosphorus pentoxide (1314-56-3)
p-toluenesulfonic acid monohydrate (6192-52-5)
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