Oxidative dehydrogenation of ethane over a lithium-promoted magnesium oxide catalyst

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90315-1· OSTI ID:7261156

Morales, E; Lunsford, J H ^[1]

---

1. Texas A and M Univ., College Station (USA)

Lithium-promoted magnesium oxide is an effective catalyst for the conversion of ethane to ethylene. A selectivity of 75% for ethylene was obtained at 40% ethane conversion over 6.5 g of 3 wt% Li{sup +}/MgO catalyst at 600 C. These results were obtained with initial pressures of 95 Torr C{sub 2}H{sub 6} and 47 Torr O{sub 2} at a space velocity of 260 h{sup {minus}1}. An apparent activation energy of 37.3 kcal mol{sup {minus}1} was observed for this process. The carbon oxides are formed both by the direct oxidation of ethane and the secondary oxidation of ethylene. In the reactor employed in this study homogeneous reactions became dominant at temperatures greater than 675 C. The catalytic system is believed to involve the generation of C{sub 2}H{sub 5} {center dot} radicals on the surface, followed by the emanation of these radicals into the gas phase where they react with O{sub 2} to form C{sub 2}H{sub 4}. The ability of this catalyst to generate alkyl radicals from CH{sub 4} or C{sub 2}H{sub 6} appears to be a general phenomenon. The subsequent reactions of these alkyl radicals (e.g., coupling or reaction with O{sub 2}) determines to a large extent the final product distribution. Ethylene also may be formed via surface ethoxide ions.

• OSTI ID: 7261156
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 118:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ACTIVATION ENERGY
ALKALI METALS
ALKALINE EARTH METAL COMPOUNDS
ALKANES
ALKENES
ALKYL RADICALS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
DEHYDROGENATION
ELEMENTS
ENERGY
ETHANE
ETHYL RADICALS
ETHYLENE
HYDROCARBONS
LITHIUM
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
METALS
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PROMOTERS
RADICALS
REACTION INTERMEDIATES
SYNTHESIS