Pt/SiO/sub 2/. V. The effect of pretreatment on apparent structure sensitivity for methylcyclopropane hydrogenation activity and selectivity

Journal Article · Sat Jul 01 04:00:00 EDT 1978 · J. Catal.; (United States)

OSTI ID:6549000

Otero-Schipper, P H; Wachter, W A; Butt, J B; Burwell, Jr, R L; Cohen, J B

The hydrogenation activity and selectivity of a set of Pt/SiO/sub 2/ catalysts, ranging in percentage of metal exposed from 6.3 to 81%, has been investigated for methylcyclopropane as a function of the pretreatment conditions. All catalysts had been originally reduced in hydrogen and stored in air. These catalysts were then subjected to an initial oxygen pretreatment at 300/sup 0/C for 0.5 hr, followed by a purge of helium at 25/sup 0/C for 0.25 hr. Samples were then successively reduced in hydrogen for 1 hr at temperatures ranging from 25 to 480/sup 0/C. The turnover frequencies on each catalyst vary considerably as hydrogen pretreatment conditions are changed. This variation consists of high activity for room temperature pretreatment, passing through a minimum in the region of 200/sup 0/C, and again increasing for temperatures greater than 250/sup 0/C. The results show that any of three types of apparent structure sensitivity (i.e., none, increasing activity with percentage exposed-Type 1, decreasing activity with percentage exposed-Type 2) can be obtained with these catalysts depending on pretreatment conditions.

• Research Organization: Northwestern Univ., Evanston, IL
• OSTI ID: 6549000
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 53:3; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKANES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CYCLOALKANES
ELEMENTS
HYDROCARBONS
HYDROGENATION
METALS
MINERALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
TEMPERATURE EFFECTS
TRANSITION ELEMENTS