Date of Award
Master of Science in Chemical Engineering - (M.S.)
With the publication of a method for the preparation of anhydrous stannous chloride (1), T. E. de Kiewiet and H. Stephen were prompted to investigate its use in the reduction of aromatic nitro compounds under anhydrous conditions. In a paper entitled "A New Method of Reducing Aromatic nitro Compounds" (2), reporting the results of this investigation, they claimed simultaneous reduction, acetylation, and also chlorination in the position para to that of the original nitro group.
In experiments using para substituted nitro compounds, they found that no chlorination took place except in the case of para-chloronitro-benzene, which, if hydrochloric acid were present during the reaction, gave 2, 4-dichloroacetanilide. In the absence of hydrochloric acid, para-chloroacetanilide was formed.
Careful following of their directions for the reaction with nitrobenzene (simplest of the aromatic nitro compounds) failed to confirm their claim of almost theoretical yields, although the experiment did prove their claim that the only isolated product of the reaction was para-chloroacetanilide in almost pure form (melting point 173-174°C). Repeated experiments following their directions resulted in a yield of approximately ten percent of the theoretical yield.
As a result of the inability to reproduce the results which these authors reported, it was decided to investigate this reaction with a view to determining: the conditions under which the best yield could be obtained; the effect of blocking the position para to the nitro group; the effect of other groups on the benzene ring, in other than the position para to the nitro group; and the effect of two nitro groups on the ring.
Unnasch, Raymond Albert, "The reduction of aromatic nitro compounds with anhydrous stannous chloride" (1954). Theses. 2276.