(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.
A STUDY OF THE SOLUTION OBTAINED BY THE DECOMPOSITION OF THE DIAZO
COMPOUND
The syrup which remained after distilling off the n-butyl alcohol was
a thick brown viscous fluid in all cases. It has an acid reaction and
is completely soluble in water. On testing it showed the presence of
sulphur in quantity and the absence of nitrogen. Some was dissolved in
water, filtered, and evaporated on the water bath. After its volume had
been considerably reduced it turned a very dark brown, then blackish,
and smelled very tarry. It did not crystallize at all, finally becoming
very black. To a drop on a watch glass, a drop and then an excess of
concentrated hydrochloric acid was added but with no apparent result.
Another portion of the syrup was dissolved in water, boiled with
purified animal charcoal, and filtered. The filtrate was colorless.
It was then evaporated on the water bath and solidified completely.
Some of this solid was ignited and a white ash was left; had it been a
sulphonic acid there would have been no residue. A qualitative analysis
of the ash was made and much phosphate and calcium found present;
therefore this solid was presumed to be a mixture of calcium phosphate
from the animal charcoal and perhaps the calcium salt of the sulphonic
acid. This showed that animal charcoal could not be used for purposes
of purification.
“Activated charcoal” has been advocated for decolorizing solutions as
well as for absorbing toxic gases; the author had become acquainted
with this material while in the Chemical Warfare Service, and had
obtained small samples of “Dorsite” and “Carbonite”. Some of this was
powdered and the brown solution boiled with it until most of the color
was removed. The solution was then filtered and evaporated on the
water bath; a white crystalline solid was again left. Investigation of
the activated charcoal showed that concentrated acids extracted some
substance which was thrown down in a flocculent white precipitate on
making alkaline with ammonia. Therefore another sample of the activated
charcoal was boiled with concentrated nitric acid, filtered, and the
charcoal washed free from acid; this sample did not decolorize well.
A sample of a specially prepared charcoal for decolorizing purposes
manufactured by the Barneby-Cheney Co. was obtained and tried, but was
unsuccessful; the color was not removed.
Infusorial earth, kiesel guhr, and “Sil-o-cel” were also tried
unsuccessfully; Fullers Earth made a very clear solution but no color
was removed.
Some of the brown viscous solution was dissolved in water, the solution
filtered and evaporated to a constant volume (estimated when no more
vapor could be seen to condense) under diminished pressure (water
pump) until it became more brown. It was then allowed to cool, and
dry hydrochloric acid gas passed in, first to expel all air or other
vapor present, and then under pressure. The solution became slightly
warm. A few fine crystals formed on the interior surface of the flask
where some of the solution had spattered during distillation, which
however were quite indistinct and seemed to be in the center of a drop
of water or solution. On allowing the flask to stand over night the
whole of the solution seemed to be filled with crystals. They were too
indistinct to enable their crystalline form to be determined so an
attempt was made to remove some for examination. As soon as they came
into contact with the air they disappeared and left a very viscous
solution, indicating that they are very hygroscopic. A small amount was
removed and placed in a dish in a vacuum desiccator which was evacuated
and left for a month, with periodical examinations. No solid appeared
at any time.
This is as far as the investigation has been carried at the present
time, April twenty-fifth, but its study is being continued.