When the dianil is boiled with glacial acetic acid for some time, the
color of the solution changes to a much lighter shade of yellow, or
becomes colorless. On evaporating the solution to small volume, and
allowing it to cool, a colorless substance separates. This is infusible
anilid. It could not be obtained in crystals from any solvent, but
always separated in flakes. It does not melt or undergo change at 340°.
Like the fusible anilid it dissolves in dilute alkali, but on
acidifying the solution it does not immediately reappear. After
standing for some time, however, it gradually separates in perfectly
pure form. In this particular my observation differs from that of
Gray,[27] who states that this anilid is decomposed by solution in
alkali.
[27] Inaug. Diss. J. H. Unis. 1895.
A specimen that had been repeatedly precipitated gave the following
results on analysis.