Organic Syntheses, Coll. Vol. 3, p.195 (1955); Vol. 24, p.30 (1944).
Caution! Both chloromethylnaphthalene
and the by-products are lachrymators and vesicants. Although it is not necessary to work in a hood
, precautions should be taken during the handling of the substance and apparatus.
After the mixture has been cooled to 15–20° it is transferred to a 2-l. separatory funnel
and the crude product is washed first with two 1-l. portions of water cooled to 5–15°, then with 500 ml. of cold 10% potassium carbonate
solution, and finally with 500 ml. of cold water. The product is the lower layer in all the washings. After the addition of 200 ml. of ether
, the solution is given a preliminary drying by being allowed to stand over 10 g. of anhydrous potassium carbonate
, with frequent shaking, for 1 hour. The lower aqueous layer which forms is separated, and the ether
solution is again dried over 20 g. of potassium carbonate
for 8–10 hours (Note 3)
and (Note 4)
The dried solution is distilled, first at atmospheric pressure to remove most of the solvent, and then under reduced pressure (Note 5)
. A fore-run of unused naphthalene amounting to 35–40 g.
is collected at 90–110°/5 mm. (Note 6)
. This is followed by 195–204 g.
which boils at 128–133°/5 mm
. or at 148–153°/14 mm
based on naphthalene
consumed) (Note 7)
and (Note 8)
"Trioxymethylene" from the Eastman Kodak Company
The level of the water bath should be maintained at the same height as that of the stirred reaction mixture.
Both the washing and drying operations must be done very carefully, because the presence of small amounts of water or acid is liable to cause the product to resinify during the final distillation.
The checkers added 50 ml. of dry benzene
before distilling the solvent to remove traces of water by azeotropic distillation.
A clean, dry flask and a moderate rate of distillation help to overcome the tendency of the product to resinify.
Care should be taken to prevent clogging of the line by the naphthalene
The oil pump
should be protected from acid fumes by means of a trap
has been made from naphthalene
and a variety of reagents: methyl chloromethyl ether
and hydrogen chloride
with or without sulfuric acid
as a condensing agent;2,3,4,5,6,7,8
with hydrogen chloride
or hydrochloric acid
Catalysts employed have been zinc chloride
,2,12,13,14 aluminum chloride
,13 phosphoric acid
and p-toluenesulfonyl chloride
.18 Petroleum ether
and glacial acetic acid
have been used as solvents. The present method is a modification of that described by Cambron.15
The chloromethylation of aromatic hydrocarbons has been discussed by Fuson and McKeever.19
It is reported that arsenic salts are helpful in the chloromethylation process.20
This preparation is referenced from:
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