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REACTIONS BETWEEN HYDROCARBONS AND DEUTERIUM ON CHROMIUM OXIDE GEL. II. ISOTOPIC EXCHANGE OF ALKANES

Journal Article · · Journal of the American Chemical Society (U.S.)
DOI:https://doi.org/10.1021/ja01509a020· OSTI ID:4118562
Chromium oxide gel develops significant catalytic activity for isotopic exchange between alkanes and deuterium only after it has been heated above 3O0 deg C. A treatment temperature of about 470 deg C results in maximum activity. Higher temperatures lead to declining activity. Exchange is readily measurable on an optimally activated catalyst at 2O0 deg C. Two isotopic exchange processes occur simultaneously. The predominant one leads to the exchange of one hydrogen atom per period of adsorption; the minor one leads to extensively exchanged alkane. With hexane, the fraction of total exchange represented by the minor process increases throughout the temperature interval 200 to 35O deg C. The general characteristics of isotopic exchange including activation energy are independent of the degree of activation of the catalyst. A primary hydrogen atom in propane exchanges at least six times as rapidly as a secondary one and primary hydrogen atoms in hexane exchange more readily than secondary ones. Correspondingly, neopentane exchanges somewhat faster than propane. The activation energies for exchange of propane and neopentane. 15 kcal, are essentially the same as that for hexane, 16 kcal. (auth)
Research Organization:
Northwestern Univ., Evanston, Ill.
Sponsoring Organization:
USDOE
NSA Number:
NSA-15-007256
OSTI ID:
4118562
Journal Information:
Journal of the American Chemical Society (U.S.), Journal Name: Journal of the American Chemical Society (U.S.) Vol. Vol: 82; ISSN JACSA
Country of Publication:
Country unknown/Code not available
Language:
English