Org. Synth. 1928, 8, 112
Submitted by C. S. Marvel and H. O. Calvery.
Checked by H. T. Clarke and M. R. Brethen.
A 100-cc. round-bottomed, wide-mouthed flask
(or a large test tube 18 cm. long and 4.5 cm. wide
) is fitted with a rubber stopper
carrying a separatory funnel
, a thermometer
, an inlet tube
reaching almost to the bottom of the flask, and an outlet tube
leading to a condenser set
for downward distillation. A receiver consisting of a suction flask
is attached tightly to the end of the condenser, and the side arm of the receiver is attached to a reflux condenser
. A tube is led from the top of the condenser to the hood
in order to take care of excess hydrogen chloride
during the distillation, or a gas-absorption trap (Fig. 7, p. 97)
can be used for this purpose. About 25–30 cc. of trimethylene glycol
) is placed in the flask and heated by means of an oil or metal bath
to 150–170°. A very
rapid stream of dry hydrogen chloride (Note 1)
is now led into the hot glycol through the inlet tube. A reddish distillate consisting of water, trimethylene chlorohydrin
, hydrogen chloride
, and some unchanged glycol begins to distil. As rapidly as the glycol is used up in the reaction flask, more is added from the separatory funnel. It is always advisable to keep the amount of material in the reaction flask as small as possible. The rate at which the hydrogen chloride
is passed through the flask controls the reaction and also has a marked effect on the yield (Note 2)
. The best results are obtained by passing in the gas rapidly enough to use up 2–3 cc. of trimethylene glycol
in one minute. The process is continuous and can be run indefinitely without changing the apparatus. The weight of crude distillate from 1800 g. of trimethylene glycol
is usually 2300–2500 g.
To obtain the trimethylene chlorohydrin
, the distillate from this operation is heated for about one hour on a steam bath
in order to drive out most of the excess hydrogen chloride
. The distillate is then fractionated under reduced pressure (Note 3)
in a modified Claisen flask (p. 130)
. The fractionating side arm should be 25 cm. in length
. The fractions collected under 10 mm. are: to 55°, 55–57°, 57–65°, 65–85°, 85–105°, residue.
Before a further fractionation is carried out, the residue is discarded; the portion boiling at 85–105°, consisting chiefly of unchanged trimethylene glycol, is set aside for use in a later preparation; the low-boiling portion up to 55°, consisting mainly of water and hydrogen chloride with some trimethylene chloride (Note 4) and trimethylene chlorohydrin, is neutralized carefully with powdered sodium carbonate. Two layers form, and the upper containing the chlorohydrin is separated, dried over anhydrous potassium carbonate, and again replaced as the portion boiling up to 55°. Another complete fractional distillation, carried out in the usual way, is now made except that the highest fraction boils at 65–85°/10 mm.
The material boiling above 65°/10 mm. is chiefly trimethylene glycol and is used in a succeeding experiment. The final yield of trimethylene chlorohydrin (Note 5) boiling at 60–64°/10 mm. is 835–1000 g. from 1800 g. of trimethylene glycol (50–60 per cent of the theoretical amount), and 400–450 g. of trimethylene glycol is recovered.
.—The hydrogen chloride
may be generated by any method desired. Since a large quantity of gas is required, the first procedure described on p. 293
is rather expensive. A more satisfactory arrangement is to half fill a 12-l. flask
with a paste of salt and concentrated hydrochloric acid
and run into this commercial sulfuric acid
. The gas is dried by a single wash bottle
of sulfuric acid
If sulfuric and hydrochloric acids are used, then, for the conversion of 1800 g. of trimethylene glycol, a 20-l. bottle half-filled with concentrated sulfuric acid is treated with concentrated hydrochloric acid introduced through a tube reaching to the bottom. The hydrochloric acid is added at the rate of 30–40 drops per minute. Two charges of sulfuric acid are needed and a total of about 24 kg. of hydrochloric acid.
The yield of chlorohydrin is largely determined by the rate at which the reaction is carried out. A very rapid stream of hydrogen chloride
is absolutely essential for obtaining the yields mentioned. Moreover, it is very important to keep as small an amount of glycol as possible in the reaction flask. If larger amounts of glycol are present at any one time, the yield of product is lowered and considerable tar is produced.
cannot be distilled under atmospheric pressure without some decomposition. The fractionation can be carried out at ordinary pressures when the fractions collected are up to 125°, 125–158°, 158–164°, 164–190°, 190–210° and residue. This procedure is less desirable as some hydrogen chloride
is evolved and the product turns dark on standing.
The portion boiling up to 55°/10 mm., obtained after the second fractionation, was washed with concentrated sulfuric acid
, then water, and finally dried and distilled. A certain amount of trimethylene chloride
was sometimes obtained, boiling at 115–120°
and amounting to about 30 per cent of the total fraction.
The chlorohydrin contains a very small amount (less than 0.5 per cent) of water-insoluble material, which is probably trimethylene chloride
and di-γ-chloropropyl ether
can be prepared from trimethylene glycol
by the action of dry hydrogen chloride
under various conditions;1
by the action of aqueous hydrochloric acid
and by the action of sulfur chloride
It can also be prepared from γ-chloropropyl acetate
and methyl alcoholic hydrochloric acid
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
sulfuric and hydrochloric acids
methyl alcoholic hydrochloric acid
potassium carbonate (584-08-7)
sulfuric acid (7664-93-9)
hydrochloric acid (7647-01-0)
sodium carbonate (497-19-8)
trimethylene glycol (504-63-2)
1-Propanol, 3-chloro- (627-30-5)
trimethylene chloride (142-28-9)
di-γ-chloropropyl ether (629-36-7)
γ-Chloropropyl acetate (628-09-1)
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved