Azoxystilbene

They obtained the following results p-Dinitrostilbene, reduced in alkaline solution, gives p-azoxystilbene in hydrochloric-acid solution with addition of stannous chloride (method of C. F. Boehringer Sohne), p-diaminostilbene. 

Tetrazostilbene (obtained by reduction of azoxystilbene and diazotisation of the resulting diamidostilbenej and its sulphonic acids yield numerous dyestuffs, some of which are capable of industrial application. Hessian Yellow, for example, is obtained by combining tetrazostilbenedisulphonic acid with salicylic acid. 

Another dyestuff closely related to the azo-compounds is a derivative of the so-called azoxystilbene. Its sulphonic acids dye cotton directly from an acid bath. 

This yellow dyestuff is obtained by heating paranitrotoluene-orthosulphonic acid with alkalies. It yields diamidostilbenesul-phonic acid on reduction, but whether it is azoxystilbene or whether a ring-formation between the methane-group and the azo-chain has taken place is doubtful [78, 79]. 

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