394 PRACTICAL ORGANIC CHEMISTRY for i minute, a clear yellow solution being obtained. Pour into water: the yellow i-nitro-compound, m.p. 61°, solidifies. (c) Biphenyl gives 4,4'-dinitrobiphenyl, m.p. 237°. The nitration of anthracene is more difficult to perform and is not recommended as a test. 2. Sulphonation. To i ml. of benzene or toluene, add slowly i ml. of 20% fuming H 2 SO 4 . Shake well and note that a homogeneous solution is obtained. [If this is repeated using petrol, the latter does not react, but merely floats unchanged on the surface of the H 2 SO 4 (a slight darkening may take place due to traces of impurities).] Now pour the reaction mixture carefully with stirring into about 20 ml. of cold water: a clear solution of the sulphonic acid is obtained. Usually, however, a small amount of the corresponding sulphone, R 2 SO 2 , separates as fine colourless crystals. 3. Pierates. The picrates of benzene and toluene are isolated only with extreme difficulty and are not used for purposes of identification.
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.