Submitted by W. W. Moyer and C. S. Marvel.
Checked by Frank C. Whitmore and D. J. Loder.
1. Procedure
In a
3-l. three-necked flask, fitted with a
mechanical stirrer, a
500-cc. separatory funnel, and an
efficient reflux condenser to which a
calcium chloride tube is attached, are placed
107 g. (4.4 gram atoms) of magnesium turnings and
800 cc. of anhydrous ether. The reaction is started by adding
5 cc. (7 g., 0.06 mole) of ethyl bromide (Note
1) without stirring. The stirrer is started, and a solution of
480 g. (4.4 moles) of ethyl bromide in 1 l. of anhydrous ether is added as rapidly as the refluxing of the
ether allows. The addition requires about two hours (Note
2). The reaction is practically complete when all the halide has been added, but stirring should be continued for fifteen minutes longer.
A solution of
156 g. (1.32 moles) of ethyl carbonate (Note 3) in 200 cc. of ether is added to the
Grignard reagent, with rapid stirring, over a period of approximately three hours. The reaction is vigorous, and the
ether refluxes continually. After all the
diethyl carbonate has been added, the flask is heated on a
water bath and stirring is continued for another hour.
The reaction mixture is hydrolyzed by pouring it, with frequent shaking, into a
5-l. round-bottomed flask containing 1.5 kg. of cracked ice and a solution of
300 g. of ammonium chloride in 600 cc. of water. The
ether layer is separated in a
large separatory funnel, and the aqueous residue is extracted with two
500-cc. portions of ether (Note
4).
The
ether is distilled from the combined extracts, and the crude
triethyl carbinol is dried with
10 g. of anhydrous potassium carbonate. The alcohol is then distilled at atmospheric pressure, and the portion (
80–90 g.) boiling at
139–142° is collected. The low-boiling distillate is treated with
5 g. of anhydrous potassium carbonate, filtered, and redistilled, whereby another portion (about
25 g.) of
triethyl carbinol boiling at
139–142° is obtained. The process is repeated once, or twice if necessary, and an additional
20 g. is collected (Note
5). The total yield is
125–135 g. (
82–88 per cent of the theoretical amount) (Note
6).
Triethyl carbinol is a viscous liquid with a penetrating, camphor-like odor.
2. Notes
2. The time of addition may be decreased by cooling the flask externally. A towel is folded in a narrow strip and wrapped about the flask above the
ether line, and cracked ice is packed on top of the flask. This arrangement allows the
ether vapor to be condensed without appreciable cooling of the reaction mixture.
3. The commercial "99 per cent" ester was used. It was purified according to the description given in
Note 2 on p. 283 above.
5. In checking this preparation the first drying was allowed to continue for fifteen hours. The first fractionation of the carbinol yielded
122 g., the second
10 g., and the third yielded none.
3. Discussion
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