Preparation of Triarylmethyl Radicals or the Corresponding Ethanes

In addition to Gomberg s original method using the reaction of the triarylmethyl halide with copper, zinc, or silver amalgam in an inert solvent, a number of other methods have been used. Table II shows some of them. Some of the methods amount to oxidation of a 

But the trinitro-substituted compound seems to give free radicals directly  

Although the reaction with thiosulfate and with iodide ions may be a mere reduction of the halide, the reaction with sodium benzoate would appear to be a radical dissociation induced by the attack of a negative ion. The fate of the benzoate ion is unknown. Tris-( -nitrophenyl)-methyl benzoate is a stable substance which does not dissociate into radicals.23 

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