Organic Syntheses, Coll. Vol. 5, p.660 (1973); Vol. 43, p.62 (1963).
Caution! Reactions and subsequent operations involving peracids and peroxy compounds should be run behind a safety shield. For relatively fast reactions, the rate of addition of the peroxy compound should be slow enough so that it reacts rapidly and no significant unreacted excess is allowed to build up. The reaction mixture should be stirred efficiently while the peroxy compound is being added, and cooling should generally be provided since many reactions of peroxy compounds are exothermic. New or unfamiliar reactions, particularly those run at elevated temperatures, should be run first on a small scale. Reaction products should never be recovered from the final reaction mixture by distillation until all residual active oxygen compounds (including unreacted peroxy compounds) have been destroyed. Decomposition of active oxygen compounds may be accomplished by the procedure described in Korach, M.; Nielsen, D. R.; Rideout, W. H. Org. Synth. 1962, 42, 50 (Org. Synth. 1973, Coll. Vol. 5, 414). [Note added January 2011].
Caution! Avoid inhaling the vapor of peracetic acid
or allowing the liquid to come into contact with the skin. The reaction is best carried out in a hood (Note 1)
The apparatus consists of a 200-ml. beaker
equipped with a magnetic stirrer
or any other type suitable for stirring a small volume of liquid. The flask is charged with 20.4 g. (0.10 mole) of iodobenzene2
and is immersed in a water bath
maintained at 30° (Note 2)
. Thirty-six grams (31 ml., 0.24 mole) of commercial 40% peracetic acid (Note 3)
is added dropwise to the well-stirred iodobenzene
over a period of 30–40 minutes. Stirring is continued for another 20 minutes at a bath temperature of 30°, during which time a homogeneous yellow solution is formed. Crystallization of iodosobenzene diacetate
may begin during this period.
The beaker is chilled in an ice bath
for 1 hour. The crystalline diacetate that separates is collected on a Büchner funnel
and washed with three 20-ml. portions of cold water. After drying for 30 minutes on the funnel with suction, the diacetate is dried overnight in a vacuum desiccator containing calcium chloride (Note 4)
. The dried diacetate weighs 26.7–29.3 g.
) and melts at 158–159°
with decomposition. The purity of the diacetate, determined by the titration method of Lucas, Kennedy, and Formo,3
, which is good enough for most purposes. The purity can be increased to 99–100%
by a recrystallization from 5M acetic acid
Rubber gloves should be worn when handling vessels containing peracetic acid
, for traces of the liquid can cause severe irritation. Skin that has come into contact with peracetic acid
should be washed immediately and treated with sodium bicarbonate
. Details for the safe handling of peracetic acid
are found in Bulletin 4 supplied by Buffalo Electrochemical Corp.
Appreciable amounts of iodoxybenzene
are formed if the temperature of the bath is allowed to go above 30° or if the addition of peracetic acid
is faster than indicated.
The surface of the diacetate may become yellow during the drying, but this does not affect its usefulness for most purposes.
4. Merits of the Preparation
is best prepared by the action of peracetic acid
and acetic acid
. The present procedure is superior to earlier ones5,6,7,8
because it uses inexpensive, commercially available peracetic acid
, is faster, and gives higher yields. The procedure seems general for aryl iodides with electron-releasing substituents, for the submitters have obtained good yields of diacetates from o-, m- and p-iodotoluene
, 2- and 4-iodo-m-xylene
, and 4-iodobiphenyl
is used as a reagent for the preparation of glycol diacetates from olefins,9
for the oxidation of aromatic amines to corresponding azo compounds,10
for the ring acetylation of N-arylacetamides,11
for oxidation of some phenols to phenyl ethers,12
and as a coupling agent in the preparation of iodonium salts.13
Its hydrolysis to iodosobenzene
constitutes the best synthesis of that compound.14
This preparation is referenced from:
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