Org. Synth. 1952, 32, 20
DOI: 10.15227/orgsyn.032.0020
tert-BUTYL HYPOCHLORITE
Submitted by H. M. Teeter and E. W. Bell
1.
Checked by Charles C. Price and T. C. Schwann.
1. Procedure
Caution! See the discussion in Org. Synth. 1973, Coll. Vol. 5, 183 with regard to potential hazards associated with the title compound.
Caution! This preparation should be carried out in a good hood. The product should be protected from strong light, over-heating, or exposure to rubber to avoid vigorous decomposition.
A solution of 80 g. (2 moles) (Note 1) of sodium hydroxide in about 500 ml. of water is prepared in a 2-l. three-necked round-bottomed flask equipped (Note 2) with a gas inlet tube reaching nearly to the bottom of the flask, a gas outlet tube, and a mechanical stirrer. The flask is placed in a water bath at 15–20° (Note 3), and, after the contents have cooled to this temperature, 74 g. (96 ml., 1 mole) of tert-butyl alcohol (Note 4) is added together with enough water (about 500 ml.) to form a homogeneous solution. With constant stirring, chlorine is passed into the mixture for 30 minutes at a rate of approximately 1 l. per minute (Note 5) and then for an additional 30 minutes at a rate of 0.5–0.6 l. per minute.
The upper oily layer is then separated with the aid of a separatory funnel (Note 6). It is washed with 50-ml. portions of 10% sodium carbonate solution until the washings are no longer acidic to Congo red. It is finally washed 4 times with an equal volume of water and dried over calcium chloride. The yield is 78–107 g. (72–99%) (Note 7); d2020 0.910; n20D 1.403. The product is best stored under an inert atmosphere (Note 8) in sealed bottles kept in the dark in a refrigerator (Note 9).
2. Notes
1.
The submitters have successfully carried out this preparation in quantities up to
7 moles (519 g.) of tert-butyl alcohol using 2.25 hours for the addition of
chlorine at each rate.
2.
tert-Butyl hypochlorite reacts violently with rubber. The apparatus should therefore be assembled by means of ground-glass joints. Synthetic plastic tubing (Tygon) may be used instead of rubber tubing.
3.
For 7-mole runs, a satisfactory bath consists of a
10-gal. earthenware jar fitted with a water inlet and an overflow device. The desired temperature is obtained by adjusting the rate of flow of tap water through the jar. The reaction can also be carried out successfully using an
ice-water bath.
4.
The
tert-butyl alcohol was a commercial product obtained from the Shell Chemical Corporation, New York, New York.
5.
Rates of flow are conveniently measured with the usual U-tube and capillary using one of the liquid Arochlors as the indicating fluid. The checkers did not use a flow meter but passed in
chlorine rapidly at first and then slowly for 30 minutes after the initial rapid absorption.
6.
In 7-mole runs carried out by the submitters, the bulk of the aqueous layer was removed conveniently by siphoning through the gas inlet tube.
7.
This product, which is sufficiently pure for most purposes, contains about
2% free chlorine. It may be purified by distillation in an all-glass apparatus heated by a
steam bath. The yield of pure product is
75–104 g. (
69–96%); b.p.
77–78°/760 mm. Active
chlorine assay indicates 97–98% purity for the crude product, 98–100% purity for the distilled material.
8.
The inert atmosphere helps to minimize any tendency of vapors to ignite during sealing of the bottle. Filled bottles should be cooled in solid
carbon dioxide before sealing.
9.
When exposed to light,
tert-butyl hypochlorite decomposes with formation of
acetone and methyl chloride. When induced by radiation from an ultraviolet lamp, this decomposition proceeds rapidly enough to raise the temperature of the hypochlorite to the boiling point. The decomposition does not continue after irradiation is stopped. Customary room illumination does not induce the decomposition to a noticeable extent during ordinary handling of this material. However, a sealed glass bottle of hypochlorite should not be allowed to stand in light for a prolonged time as pressure sufficient to burst the bottle may be built up gradually.
3. Discussion
tert-Butyl hypochlorite has been prepared by the action of
chlorine upon alkaline solutions of
tert-butyl alcohol.
2,3,4,5 Solutions of
tert-butyl hypochlorite have been prepared by shaking a solution of the alcohol in
carbon tetrachloride,
6 fluorotrichloromethane (Freon 11), and other solvents
7 with aqueous
hypochlorous acid. The procedure described is that of Teeter et al.
4
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
calcium chloride (10043-52-4)
sodium hydroxide (1310-73-2)
sodium carbonate (497-19-8)
carbon tetrachloride (56-23-5)
carbon dioxide (124-38-9)
methyl chloride (74-87-3)
acetone (67-64-1)
chlorine (7782-50-5)
hypochlorous acid (7790-92-3)
fluorotrichloromethane (75-69-4)
tert-butyl alcohol (75-65-0)
tert-Butyl hypochlorite (507-40-4)
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