Isomerization of n-heptane on an oxygen-modified molybdenum carbide catalyst

Journal Article · Fri Jul 01 00:00:00 EDT 1994 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00031a003· OSTI ID:6905635

Blekkan, E A; Pham-Huu, C; Ledoux, M J; Guille, J ^[1]

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1. Univ. Louis Pasteur, Strasbourg (France). Lab. de Chimie des Materiaux Catalytiques

The isomerization of n-heptane in the presence of hydrogen has been carried out over a molybdenum carbide catalyst modified by an oxygen treatment. Heptane was isomerized selectively to isoheptanes, a reaction which is difficult over traditional bifunctional catalysts due to extensive cracking. The C[sub 7] products were mainly monomethylhexanes, 2-methylhexane and 3-methylhexane, in close to equilibrium ratios. A typical bifunctional catalyst (Pt supported on an acidic zeolite) gave similar isomerization products, but mostly propane and isobutane as the cracked products. The selectivity over the oxidized carbide was found to be a function of pressure but independent of the conversion; increased the hydrogen pressure led to a decrease in the C[sub 7] selectivity. This was found to be different from the Pt/zeolite catalyst, over which the selectivity was a function of the conversion; a high selectivity was only obtained at low conversions. The active carbide-based catalyst was probably an oxycarbide of molybdenum. The results obtained over the oxidized carbide catalyst are discussed in terms of a bond-shift mechanism via a metallocyclobutane intermediate.

• OSTI ID: 6905635
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Vol. 33:7; ISSN 0888-5885
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
HEPTANE
ISOMERIZATION
MOLYBDENUM CARBIDES
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
PLATINUM
REACTION INTERMEDIATES
ALKANES
CARBIDES
CARBON COMPOUNDS
CHEMICAL REACTIONS
ELEMENTS
HYDROCARBONS
KINETICS
METALS
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
PLATINUM METALS
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
020500* - Petroleum- Products & By-Products