This advice is too late, but why did you use Sn instead of Fe? Better yield / purer product / easier workup? IIRC when using Fe the amount of HCl
could be decreased as it is there only as a catalyst.
Oh I found the answer, in small lab scale the Sn method is better. For Fe you need very fine Fe dust:
https://www.prepchem.com/synthesis-of-aniline/
Quote: | The reduction of nitrobenzene, as well as other aromatic nitro derivatives, is carried out on the large-scale by the use of iron borings. This cannot
be satisfactorily imitated in the laboratory; consequently it is usual to reduce nitrobenzene on the small-scale by means of tin and hydrochloric
acid. If, however, very finely divided iron or “iron powder ” is used, the reduction proceeds very smoothly, and a good yield is easily obtained.
120 g of iron, powder together with 160 ml water are placed in a large flask of 2-3 liters capacity with stirring. The flask is warmed slightly, and a
few drops of nitrobenzene added. Then 10 g of hydrochloric acid is poured into the flask, and the 100 g of the nitrobenzene in small portions at a
time. During addition the flask is well stirred and cooled with cold water. The addition of nitrobenzene and amount of cooling are so arranged that
the temperature keeps at about 80-90° C. When the reaction is finished (shown by no further rise in temperature), the contents of the flask
are distilled with steam (it is not necessary to make the mixture alkaline) till the distillate is no longer milky. The volume of the
distillate is about 400-500 ml. The distillate is transferred to a separating funnel, allowed to settle (if necessary), and the aniline, which forms
the lower layer, drawn off. The water (which contains about 3 % of aniline in solution) is saturated with sodium chloride and allowed to stand for
some time. The aniline, which rises to the top, is separated with a separating funnel, added to the first portion of crude aniline. The aniline is
purified by distillation, were a little water passes over at first and is separately collected; the aniline then passes over at 182° C yielding
50-70 g of aniline. Aniline is colorless oil with a peculiar smell, boils at 184° C. |
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