A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 155
mediate compound formed by the catalyst, or the catalyst may favour the decomposition
of the intermediate compound formed by the promotor.
A. Orlowsky 13 found that the affinity of sulphur for platinum is quite small.
C. Ridolfi observed that no sulphide is formed by the direct action of sulphur.
E. Davy observed that some platinum sulphide is formed when the metal is heated
with sulphur ; and G. Preuner observed that the action is not particularly strong
even between 950° and 1240°. A. Wigand found that the metal acquires a dark
brown film in boiling sulphur. W. C. Heraeus and W. Geibel, and W. R. Hodgkinson
and F. K. S. Lowndes, observed that sulphur vapour had no perceptible action on
an electrically heated platinum wire. A. Jedele observed that sulphur has a
limited solubility in platinum, and that the effect of sulphur on the yield point
and fracture, in kgrms. per sq. mm., and the percentage elongation at room
temp., and at 850°, are indicated in Table II. J. Milbauer found that platinum
S
per cent.
015
006
0-02
0-006
TABLE II.—THE EITBCT OF STTI/PHTJIC ON TITE TENACITY OF PLATINUM.
Yield
12-7
11-2
9-9
9-4
Room temperature I
Fracture
19-9
16-6
16-3
15-3
Elongation
14-7
1O-1
26-2
24-7
Yield
6-4
61
5-3
4-3
850°
Fracture
8-7
6-9
7-4
5-3
Elongation
black accelerates catalytically the formation of hydrogen sulphide by passing
hydrogen over molten sulphur at 278° ; and Y. Venkataramaiah observed that
hydrogen which has diffused through platinum will attack sulphur. According
to R. Bottger, if gun-cotton be impregnated with platinum black, it detonates
immediately when exposed to hydrogen sulphide. E. B. Maxted noted that the
presence of hydrogen sulphide retards the adsorption of hydrogen by platinum.
The gas is strongly adsorbed by platinum, and on degassing the metal at 100°,
an equal vol. of hydrogen is evolved, the sulphur remaining on the platinum.
Both before, and to a smaller extent after this treatment, the rate of adsorption
of hydrogen by platinum is markedly retarded, but there is no decrease in the
ultimate proportion of gas adsorbed. W. Skey noted that the surface of platinum
is altered by exposure to hydrogen sulphide, or ammonium sulphide, so that the
metal no longer amalgamates with mercury. M. Domanicky said that the attack
by sulphur monochloride is very slow if at all. According to W. R. Hodgkinson
and F. K. S. Lowndes, sulphur dioxide has no action on an electrically heated
platinum wire. J. TJhI observed that sulphur dioxide acts on platinum,
producing platinum sulphide and sulphur trioxide. E. Mulder noted the action of
sulphur dioxide in a gas-name on platinum crucibles. A. Sieverts and E. Jurisch
noted that sulphur dioxide is insoluble in compact platinum ; but G. Magnus
said that at 0° platinum absorbs about one-third of its vol. of sulphur dioxide.
J. P. Cooke and T. W. Richards, D. O. Shiels, and D. Tommasi also noted that
some sulphur dioxide is absorbed by platinum. P. Chappuis measured the
heat developed when platinum black absorbs sulphur dioxide ; and G. B. Taylor
and co-workers gave approximately 25,CXX) cals. for the heat of adsorption.
The subject was studied by B. Neumann and E. Goebel. The oxidation of sulphur
dioxide by air or oxygen in the presence of spongy platinum or platinum black
was discussed by I. E. AdadurofE and co-workers, T. von Artner, Badische
Anilin- und Sodafabrik, E. Baur, M. Bodenstein and co-workers, G. Bodlander
and K. von Koppen, M. O. Charmandarian and G. D. Dachniuk, Chemische Fabrik
vorm. Goldenberg und Geromont, C. L. Clark and co-workers, P. D. DankofF and
co-workers, J. W.Dobereiner, Li.Duparc and co-workers, O.Efrem, Farbwerke vorm.
5-8
5-5
14-O
14-5