Reforming reactions of heptane on platinum crystals at atmospheric pressures
In dehydrocyclization of n-heptane to toluene studied at 300/sup 0/-340/sup 0/C, 0.66-4 kPa heptane, and 0-100 kPa hydrogen over a flat Pt(111) surface (A) and stepped Pt(s)-(6(111) x (100)) (B) and Pt(s)-(2(111) x (610)) (C) surfaces, the initial activities of the A and B surfaces were almost equal and twice as large as that of the C surface. The stepped surfaces retained full activity for three hours, but the A surface rapidly deactivated. On each surface, deactivation correlated with carbon deposition, but the amounts of carbon deposited on different surfaces after three hours were similar, suggesting a strong effect of the structure and distribution of surface carbon. Both the initial aromatization rate and the carbon deposition and deactivation increased with increasing temperature and heptane pressure and with decreasing hydrogen pressure. Apparently, the narrow terraces of the C surface are inactive, and aromatization occurs at its step sites. On the B surface, both the steps and the wider terraces are active, with the presence of steps stabilizing the activity of the terraces.
- Research Organization:
- Univ. of California, Berkeley
- OSTI ID:
- 6187589
- Report Number(s):
- CONF-791108-
- Journal Information:
- 72nd AIChE Annu. Meet. Prepr.; (United States), Journal Name: 72nd AIChE Annu. Meet. Prepr.; (United States) Vol. 23D
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKANES
ALKYLATED AROMATICS
AROMATICS
CARBON
CATALYSTS
CATALYTIC EFFECTS
CATALYTIC REFORMING
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DATA
DEACTIVATION
DEHYDROCYCLIZATION
DEPOSITION
ELEMENTS
EXPERIMENTAL DATA
HEPTANE
HIGH TEMPERATURE
HYDROCARBONS
INFORMATION
KINETICS
METALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
PLATINUM
PLATINUM METALS
PRESSURE DEPENDENCE
REACTION KINETICS
REFORMER PROCESSES
TEMPERATURE DEPENDENCE
TOLUENE
TRANSITION ELEMENTS