Full resolution (JPEG) - On this page / på denna sida - I. General and Physico-chemical - III. Catalysis
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
CATALYSIS. 35
The progress of the reaction can be determined by measuring the nitrogen
set free. The following figures explain the results:
Gere
: Cone. of the Cora the K K
Acid. Acid in Mol. H ions by Velocity —
per Liter. Electric Coefficient. Cy
Conductivity.
INETIIONACIOS. pa watkimeev“als. : 0.001820 0.001820 0.0703 38.7
0.000909 0.000909 0.0346 38.0
ATOMIC AGI <& eriyeie cS atidlabes.c 0.000909 0.000909 0.0356 39.2
0.000364 0.000364 0.0140 38.3
m-Nitrobenzoic acid........ 0.009900 0.001680 0.0632 olee
PUEMATIOCACION Ot ciclo O58), 0.003640 0.001460 0.0571 39.1
PS ITOGUNINGY LBIC erie ace: whol 6. 4:74 aoa oh okie 0.009090 0.000724 0.0285 38.5
Reetraracid 8... 5 eee, 0.018200 0.000563 0.0218 38.7
a
As
Cu
the velocity coefficient is here also proportional to the concentration of the H ions.
for the different acids and different quantities of acid is the same, then
As the catalytic action of acids is caused by the H ions, so are the
catalytic properties of bases due to the OH ions. The first determined
ease of this kind was the transformation of hyoscyamine into the stable
atropine.!
KoELICHEN 2 has studied a specially pretty case of the catalytic action of
OH ions in the decomposition of diacetonalcohol into acetone:
CH;.CO.CH:.C(CHs)2.0H =2CH;.CO.CH:.
The reaction is reversible, and from the following table it is seen that the
velocity constant for various concentrations of the same catalyst remains the same
as well as by using different bases.
Catalyst. Cone. of the Velocity
Catalyst. Constant.
Paperidine sigh). W3a els 0.1090 0.038
PViGtaylamie reo. ec tows 5 « 0.4900 0.036
ENTIDINIO DIL ede eten se ee ere ah 0.5500 0.038
Tetraethylammonium 0.0760 0.037
hydroxides i) pas occ. s «sl: 0076 . tee
: : .0725 .036
Sodium hydroxide........ 0.0072 0.035
By this a rule which van’ Horr and Ostwaup? proved by thermo-
dynamic means, is substantiated, namely, that the equilibrium at con-
stant temperature does not change with the quantity and kind of catalyst
when the catalyst is not changed by the reaction.
Among other kinds of ions which act as catalysts we must mention (1) iodine
ions, which decompose H:.O, in proportion to their concentration,‘ and (2) cyan-
1 Ber. d. d. chem. Gesellsch., 21, 2777 (1888).
2 Zeitschr. f. physik. Chem., 33, 129 (1900).
3 Van’t Hoff, Vorlesungen, 1, 211.
4 Walton, Zeitschr. f. physik. Chem., 47, 185, 1904.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
