urbaf2

AROMATIC NITRO COMPOUNDS 193

A number of reactions on the mobility of the NO 2 group have been carried

out by Qvist and his co-workers [3,4,5]:

(3)

In presence of an excess of hydrazine, denitration occurs, probably because

of the reducing action of this reagent. Pentachloronitrobenzene (a well known

fungicide “Terraclor”) hydrolyses to form pentachlorophenol or its ethers:

“Terraclor” Pentachlorophenetole

The yield of the reaction amounts to 50% and it can be utilized for quantitative

analysis of pentachloronitrobenzene by determining the quantity of KNO 2 split

off (Ackermann et al. [6]).

On mobility of nitro groups, see also Loudon and Robson [158].

Nitro groups can be replaced by chlorine and bromine on drastic action of phos-

phorous pentachloride (Ganguly [6a]) or chlorine [151] and bromine [152] respectively.

A nitro group adjacent to chlorine atoms in the ortho and meta position can

be replaced by fluorine on heating with potassium fluoride at 147°C:

(5)

The reaction yield is 10%. It may be increased up to 37% by heating in dimethyl-

formamide solution (Finger and Kruze [7].)

On vigorous reaction with basic reagents (sodium hydroxide or sodium alcohol-

ate), a nitro group located symmetrically, in the meta position to other nitro groups