Dinitrochlorobenzene

     During the early chemical industry days of World War I there was a lot of spare chlorine floating about and there was a big demand for benzene which made it cheap and available. Put em together and you get chlorobenzene and dichlorobenzene,of which p-dichlorobenzene is a type of mothball still used today. The nitration of chlorobenzene was started around 1862 by A. Riche. Dinitrodichlorobenzene was first manufactured as an explosive called parazol. It was mixed with with TNT in shells but did not detonate completely. Instead, the unexploded portion was atomized in the air and was a vigorous itch-producer and lachrymator (causes tears like mace), it also yielded some phosgene gas which was a dreadful chemical weapon used back then. Dinitrochlorobenzene finds more use as an ingredient in the manufacture of other explosives than as an actual explosive itself, although it has been mixed with picric acid for use in shells. Avoid contact with the solid and vapors of this chemical, it causes severe itching, as well as weakness, low blood count, digestive organ damage, and heart failure. The proper name of this compound is 1-chloro-2,4-dinitrobenzene for the most abundant isomer, and 2-chloro-1,3-dinitrobenzene for the other isomer. Other names include 2,4-dinitro-1-chlorobenzene; 2,4-dinitrochlorobenzene; 1,3-dinitro-4-chlorobenzene; chlorodinitrobenzene; DNCB; and 4-chloro-1,3-dinitrobenzene.

CHEMICALS	APPARATUS
chlorobenzene	1000-mL beaker
nitric acid	graduated cylinder
sulfuric acid	pipet/buret
water	stirrer/stirring rod
	thermometer

     90 mL of chlorobenzene is added dropwise with a dropper pipet or buret to a previously prepared, and cooled to room temperature, mixture of 110 mL of 99% nitric acid and 185 mL of 99% sulfuric acid, in a 1000-mL beaker, while the mixture is stirred mechanically with a magnetic stirrer. A stirrer is essential for the length of time required, you may try this by hand with a stirring rod at your own risk. The temperature will rise because of the heat of the reaction, but should not be allowed to go above 50-55 °C. After all the chlorobenzene has been added, the temperature is slowly raised to 95 °C and is kept there for 2 hours longer while the stirring is continued. An upper layer of light yellow liquid solidifies when cold. The layer is removed, broken up under water, and rinsed. The spent acid, on dilution with water, will precipitate an additional quantity of dinitrochlorobenzene. All the product is brought together, washed with cold water, then several times with hot water while it is melted, and once more with cold water under which it is crushed. Finally, it is drained and allowed to dry at room temperature. The product, melting at about 50 °C, consists largely of 2,4-dinitrochlorobenzene, along with a small quantity of the 2,6-dinitro compound, m.p. 87-88 °C. The two substances are equally suitable for manufacture of other explosives or alone as an explosive. You will need a graduated cylinder for measuring liquids, and a thermometer to monitor the temperature.

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