Some of the diazo compound was boiled with dilute nitric acid as described by Nevile and Winther, and a yellowish precipitate of needles obtained, which on recrystallization from denatured alcohol gave light yellow needles of dinitro ortho cresol, (3-hydroxy 3,5-dinitro toluene), melting at 83.5-84° uncorr. (Nevile and Winther gave 85° for the pure substance.) This dinitro compound was obtained in nearly quantitative yield indicating that the diazo compound was presumably pure.
PHYSICAL PROPERTIES OF THE DIAZO COMPOUND
It is almost insoluble in water, and is insoluble in denatured alcohol and ether.
It is a white solid which can be dried and kept without apparent decomposition; it gradually turns pink when exposed to the light for several days, so is kept in a brown bottle if not required for immediate use. It does not explode when struck with a hammer, but deflagrates violently if a flame is brought near or if heated on porcelain.
DECOMPOSITION OF THE DIAZO COMPOUND
(1) With n-Butyl alcohol in the presence of sodium carbonate.
A portion of the dry diazo compound was placed in a flask connected with a reflux condenser, and solid sodium carbonate and n-butyl alcohol added. No reaction took place at ordinary temperature so heat was applied. Decomposition started at 65° and evolution of hydrogen proceeded evenly and smoothly until all the diazo compound had disappeared. The alcohol, at first colorless, became an orange and finally a brown color. The solution was then refluxed an hour to ensure complete decomposition of the diazo compound. The smell of an aldehyde was evident indicating that the hydrogen reaction was taking place; the solution was tested with Schiff’s reagent and with ammoniacal silver nitrate with distinct positive results in both cases, showing aldehyde was present. The alcoholic solution was filtered from the sodium carbonate remaining, and the alcohol distilled off on an oil bath. A yellowish-orange porous solid was left in such a small amount that no derivatives could be made and studied. It was free from the diazo compound, shown by its giving no color with an alkaline solution of H acid.
(2) With n-Butyl Alcohol alone.
The previous experiment showed that n-butyl alcohol would decompose the diazo compound in the presence of sodium carbonate and replace the amino group by hydrogen, so this time a decomposition with the alcohol alone was tried. Decomposition took place evenly and smoothly as before at the same temperature, and the solution became a clear brownish-orange. Aldehyde was given off and tested for as before with positive results. The alcohol was removed by distillation and a thick brownish syrupy liquid was left. This was easily soluble in water, so was dissolved, filtered, and the solution used in the following experiments. At this point it is similar in every way to the solution obtained by Griffin (loc. cit.) from the diazo compound of para toluidine meta sulphonic acid.
Subsequent preparations of this syrup were made in the above way with similar results in every case. The only precaution to be observed is that no part of the flask containing the reaction mixture be allowed to become too hot as the diazo compound is then decomposed violently leaving a grayish ash.