Pt/Al/sub 2/O/sub 3/. II. Activity and selectivity patterns for methylcyclopropane hydrogenolysis and cyclopentane exchange with deuterium: comparison with Pt/SiO/sub 2/

Journal Article · Tue Jul 01 04:00:00 EDT 1980 · J. Catal.; (United States)

OSTI ID:6604750

Wong, S S; Otero-Schipper, P H; Wachter, W A; Inoue, Y; Kobayashi, M; Butt, J B; Burwell, Jr, R L; Cohen, J B

The activity and selectivity of a series of Pt/Al/sub 2/O/sub 3/ catalysts for the hydrogenolysis of methylcyclopropane and exchange between deuterium and cyclopentane have been determined. The series investigated included the range from 4.1 to 106 percentage exposed of platinum (D/sub h/). Turnover frequencies, N/sub t/, for methylcyclopropane hydrogenolysis at 0/sup 0/C determined after high-temperature pretreatment (H/sub 2/, T/sub p/ > 350/sup 0/, 1) were independent of D/sub h/ as were the activation energies for i-butane and n-butane formation, 36.4 +- 2 and 42.3 +- 4 kJ mol/sup -1/, respectively. For cyclopentane-deuterium exchange at 81/sup 0/C the isotopic distribution patterns were clearly dependent upon D/sub h/, particularly noted as a decrease in d/sub 10//(d/sub 2/-d/sub 10/), with increasing D/sub h/. Activation energy for overall exchange was about 75 kJ mol/sup -1/ with some dependence on D/sub h/ for the individual distributions. Catalyst pretreatment conditions affect activity for both reactions. For methylcyclopropane a minimum is observed for T/sub p/ about 200/sup 0/C, with an inversion in ordering of N/sub t/ vs D/sub h/ at higher temperatures, as previously observed for Pt/SiO/sub 2/. For cyclopentane, N/sub t/ decreases with increasing D/sub h/ at T/sub p/ = 450/sup 0/C. The method of catalyst preparation also showed some effect on N/sub t/ for methylcyclopropane, but not for cyclopentane. A summary discussion of the factors responsible for various pretreatment effects on Pt/SiO//sub 2/ and Pt/Al/sub 2/O/sub 3/ is given for both reactions.

• Research Organization: Northwestern Univ., Evanston, IL
• OSTI ID: 6604750
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 64:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
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ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CYCLOALKANES
DEUTERIUM
ELEMENTS
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
HYDROGENATION
ISOTOPES
ISOTOPIC EXCHANGE
LIGHT NUCLEI
METALS
MINERALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
STABLE ISOTOPES
TRANSITION ELEMENTS