May, 19-w. ]
V. S.
RITREAU OF
CHEMISTRY NOTES.
669
vapors coming off were conducted through a series of chambers,
maintained at different temperatures.
The least volatile chloro-
derivatives separated o’ut in the hotter chambers, whereas the more
volatile benzoic acid collected in the colder chambers.
SOME ASPECTS OF THE BEHAVIOR OF CHARCOAL WITH
RESPECT TO CHLORINE.
By G. S. Bohart and E. Q. Adams.
[ABSTRACT.]
THIS
investigation was undertaken to determine the cause
of discrepancies between results obtained by different laboratories
for the chlorine capacity of the same charcoals. To study the
effect of temperature and humidity of the air stream with which
the chlorine was diluted (usually I
:
IOOO), mixtures of known
air, chl’orine, and moisture content were passed through the char-
coal which was held in a glass chamber in a constant temperature
bath. The chlorine and hydrochloric acid in the outgoing gas
were determined from time to time.
In the particular series of charcoals studied, the variation
in chlorine-absorbing power between different charcoals was
greater than would result from any a,ttainable variation in humid-
ity, and the order of the charcoals with respect to absorptive
power is not the same as that with respect to apparent density.
The duration of complete chlorine absorption (I ) increases
more rapidly than the thickness of the layer of charcoal, (2)
passes through a minimum at a temperature between 0” and
I2.5O, and (3) at a humidity in the neighborhood of 50 per cent.,
and (4) is diminished by increasing the flow of air, the rate of
supply of chlorine remaining constant. Reductions in pressure
up to two feet of water (barometric pressured down to 71 cm.
mercury) has little or no e#fect.
For the charcoals studied
:
Below 12.5 o chlorine appeared
beyond the charcoal before hydr’ogen chlorid; above 12.5~ hydro-
gen chlorid before chlorine, and the chlorine capacity of the
charcoal was increased by one exposure to chlorine followed by
heating in vacua to dull redness.
“Published in J. Anz. Chena. SOL., 42, 523-44 (1920).