Action of Cuprous Chloride on Nitro-diazonium Compounds

Reaction LII. (b) Action of Cuprous Chloride on Nitro-diazonium Compounds. (B., 34, 3802 38, 725.)—Ordinarily when cuprous chloride acts on a diazonium salt in acid solution, a chloro-compound is the chief product (Sandmeyer s reaction, p. 345), and only a small quantity of the corresponding diphenyl compound is formed. But if a nitro-diazonium 

2C8H4(N02)N2C1 + Cu2Cl2 = (N02)C8H4.C8H4(N02) + 2CuC12 + 2N2. Preparation 92.—p-p -Dinitrodiphenyl. 

By-product p-Chloronitrobenzene. (1 -GMoro-4-nitrobenzene) C8H4(C1)(N02)[1 4], C8H402NC1. 157-5. 

In an exactly analogous manner there is obtained from 30 gms. of m-nitroamlinc, 23 gms. (87%) of 3 3 -dinitrodiphenyl (yellow needles insoluble in cold glacial acetic acid M.P. 200°) and 6 gms. (20%) of m-chloronitrobenzene (colourless crystals insoluble in cold benzene M.P. 45° if rapidly cooled after fusion, melts at 24°, but in a short time reverts to the stable modification). (O. S., IX., 92.) 

Similarly 30 gms. of o-nitroaniline yield 17-6 gms. (64%) of 2 2 -di-nitrodiphenyl (crystalline solid, insoluble in cold benzene M.P. 127°) and 9 gms. (30%) of o-nitrochlorobenzene (colourless crystals, insoluble in cold benzene M.P. 32-5°). 

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