Organic Syntheses, Coll. Vol. 2, p.254 (1943); Vol. 10, p.40 (1930).
.—A solution of 13.4 g. (0.1 mole) (Note 1) and (Note 2) of durene (p. 248)
in 100 cc. of chloroform
is added to 75 cc. of concentrated sulfuric acid
in an 800-cc. beaker
provided with a thermometer
and an efficient mechanical stirrer
. The mixture is cooled to 10°, and 16 g. (10.7 cc.) of fuming nitric acid
(sp. gr. 1.5) (Note 3)
is added drop by drop, with stirring, from a 125-cc. separatory funnel
, the mixture being cooled in an ice-salt bath
and the nitric acid
added at such a rate that the temperature does not rise above 50° (about fifteen minutes is required for the addition). As soon as all the acid has been added the mixture is poured into a separatory funnel, the sulfuric acid
layer is removed, and the upper chloroform
layer is immediately (Note 4)
run into 500 cc. of 10 per cent sodium carbonate
solution. The sulfuric acid
layer is discarded because it contains very little dinitrodurene
. Four portions are nitrated, and the combined chloroform
solutions are washed twice with 2.5 per cent sodium carbonate
solution, dried overnight with 30 g. of anhydrous calcium chloride
, filtered, and the chloroform
distilled until crystals of dinitrodurene
begin to appear. At this point four times the volume of hot 95 per cent ethyl alcohol is added (about 500 cc.)
, and the resulting mixture is cooled to 10°. The solid is filtered and washed twice with 50 cc. of cold (10°) 95 per cent ethyl alcohol
. The yield from four nitrations is 82.5–84 g.
per cent of the theoretical amount) of a product melting at 207–208° (Note 5)
) Reduction of Dinitrodurene
.—A solution of 90 g. of dinitrodurene
in 1 l. of glacial acetic acid
is boiled in a 12-l. flask (Note 6)
; 700 g. of stannous chloride
is dissolved in 800 cc. of concentrated hydrochloric acid
and heated to boiling. The heat is removed from the acetic acid
solution of the nitro compound, and the stannous chloride
solution is poured very carefully (during about ten minutes) into the dinitrodurene
solution. The reaction is complete in fifteen minutes, and, as the solution cools, the stannic chloride
compound of the diamine begins to crystallize. The reaction mixture is cooled to 10° in an ice-water bath
, and the solid is filtered by suction, washed twice with 50 cc. of 95 per cent ethyl alcohol
and twice with 50 cc. of ether
, and dried. The filtrates from the tin compound contain very little of the reduction product and may be discarded. The composition of this compound is [C6(CH3)4(NH2·HCl)2]2·SnCl4
, and it crystallizes from the reaction mixture in fine, glistening plates which are almost colorless. The yield is 145 g.
per cent of the theoretical amount).
.—A suspension of 100 g. of the tin compound
in a solution of 300 g. of ferric chloride
crystals in a mixture of 150 cc. of water and 20 cc. of concentrated hydrochloric acid
is allowed to stand overnight at about 30°, and is then filtered. The product is dissolved in 150 cc. of hot 95 per cent ethyl alcohol
. The solution is filtered and allowed to stand overnight at 30°. The yield is 40 g.
per cent of the theoretical amount) melting at 109–110°
It is better to nitrate the durene
in small batches, for a high yield and pure product are obtained only with a minimal contact of the reaction mixture and the nitric acid
is absolutely essential for good results. Durene
should be recrystallized from methyl alcohol
until the melting point is 79–80°.
A large excess of nitric acid
is undesirable, since it lowers the yield. The concentration of the nitric acid
is also of importance, and, to obtain the best results, it should have a specific gravity of 1.5 or more.
It is important that the chloroform
layer be run into the carbonate solution as quickly as possible, for continued standing in contact with even small amounts of acid leads to the formation of considerable amounts of red, tarry material. This renders the subsequent purification of the nitro compound much more difficult.
is ever obtained in this process. Either the dinitro compound results, or else unchanged material and oxidation products.
A large flask
is necessary because the reduction is vigorous and the reaction mixture will boil up and practically fill the flask of the size recommended.
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