Organic Syntheses, Coll. Vol. 4, p.702 (1963); Vol. 32, p.90 (1952).
In a 2-l. three-necked flask
equipped with a mechanical stirrer
, and dropping funnel
are placed 500 g. (570 ml., 6.4 moles) of benzene (Note 1)
and 34.6 g. (18.8 ml.) of concentrated sulfuric acid
(sp. gr. 1.84). The resultant mixture is brought to 20°. To this is added dropwise 201 g. (219 ml., 2.22 moles) of methallyl chloride (Note 2)
over a period of 12 hours, during which time vigorous stirring is maintained and the temperature is kept at 20° with the aid of a water bath
. The mixture, which becomes an amber color, is stirred for an additional 12 hours.
The reaction mixture is then transferred to a 1-l. separatory funnel
, and the sulfuric acid
layer is removed. The remaining benzene
solution is then washed with four 200-ml. portions of distilled water (Note 3)
. In this step the amber color disappears and the liquid becomes colorless. The benzene
solution is dried with anhydrous sodium sulfate
and transferred to a 1-l. distilling flask
. The benzene
is removed by distillation under a pressure of about 45 mm. The liquid residue is poured into a 500-ml. flask
and distilled through a 40-cm. Vigreux column
under reduced pressure. The yield of neophyl chloride
boiling at 97–98° /10 mm.
is 262–275 g.
) (Note 4)
and (Note 5)
The methallyl chloride
used was a redistilled commercial sample and had the following properties: b.p. 71–72° /760 mm.
To ensure good results it is necessary to remove all of the sulfuric acid
by washing the mixture thoroughly with water. The final washing should be neutral to litmus.
If the residue in the distilling flask is dissolved in ether
, treated with activated carbon
, and evaporated to dryness, the solid so obtained can be recrystallized from about 25 ml. of 95% ethanol
to give 10 g.
) of p-di(chloro-tert-butyl)benzene
; m.p. 54.5–55.0°.
In a run in which the temperature was kept at 10–15° during the addition of methallyl chloride
, the methallyl chloride
was added over a period of 1 hour. Stirring was continued for 1 hour, and the reaction mixture was worked up as described above to give a 53%
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