The thermal decomposition of propylene was investigated for temperatures ranging from 680°C up to 870°C and with percentages of decomposition from 0.01 percent up to about 2 percent. The reaction was shown to be a homogenous gas reaction of the first order, the first‐order constant being given by an expression 1.1·1013 exp—(72,000/RT). Two mechanisms are discussed, both of which account for the observed kinetics and products of decomposition. It is demonstrated that the first step in the thermal decomposition of propylene is the splitting of the C–H bond leading to the formation of H atoms and allyl radicals. The problem of the value of D(C–H) in propylene is discussed in the light of the two suggested mechanisms. An attempt is made to account for the variety of the reactions between H atoms and propylene molecules as observed by various investigators.

1.
F. E.
Frey
and
D. F.
Smith
,
Ind. Eng. Chem.
20
,
948
(
1928
).
2.
C. D.
Hurd
and
R. N.
Meinert
,
J. Am. Chem. Soc.
52
,
4978
(
1930
).
3.
H.
Tropsch
,
C. I.
Parrish
, and
G.
Egloff
,
Ind. Eng. Chem.
28
,
581
(
1936
).
4.
M.
Szwarc
,
J. Chem. Phys.
16
,
128
(
1948
).
5.
M.
Szwarc
,
Nature
160
,
403
(
1947
).
6.
M.
Szwarc
and
J. S.
Roberts
,
J. Chem. Phys.
16
,
609
(
1948
).
7.
J. S.
Roberts
and
M.
Szwarc
,
J. Chem. Phys.
16
,
981
(
1948
).
8.
R. N.
Meinert
and
C. D.
Hurd
,
J. Am. Chem. Soc.
52
,
4540
(
1930
).
9.
M.
Polanyi
and
E.
Wigner
,
Zeits. f. Physik. Chemie
A139
,
439
(
1928
).
10.
H. S.
Taylor
and
J. O.
Smith
,
J. Chem. Phys.
8
,
543
(
1940
).
11.
E. T.
Butler
and
M.
Polanyi
,
Trans. Faraday Soc.
39
,
19
(
1943
).
12.
A. Shaw and M. Szwarc, unpublished results.
13.
B. S.
Rabinovitch
,
S. G.
Davis
, and
C. A.
Winkler
,
Can. J. Research
21B
,
251
(
1943
).
14.
W. J.
Moore
and
H. S.
Taylor
,
J. Chem. Phys.
8
,
504
(
1940
).
This content is only available via PDF.
You do not currently have access to this content.