Highly reduced MoO3/Al2O3 catalysts II. Hydrogenolyses of cyclopropane, methylcyclopropane, and propane
1989; Elsevier BV; Volume: 116; Issue: 2 Linguagem: Inglês
10.1016/0021-9517(89)90118-8
ISSN1090-2694
Autores Tópico(s)Catalysts for Methane Reforming
ResumoThe preparation of Mo(0)Al2O3 by Mo(CO)6DA;H2,300 – 500 °;H2, 650 – 950 ° (Mo(CO)6 deposited on highly dehydroxylated alumina, heated in flowing He to 300 – 500 °C and then in H2 to 650 – 950 °C) and by MoO3Al2O3;H2, 950 ° give essentially equivalent results with respect to activity and selectivity in the hydrogenolyses of cyclopropane (CP) and methylcyclopropane (MCP) at 100 °C and of propane at 250 °C. Thus, one can prepare metallic Mo on alumina by the easier and more flexible preparation from MoO3Al2O3. MCP undergoes single hydrogenolysis to isobutane and butane and double hydrogenolysis to (a) CH4 + C3H8 and to (b) 2C2H6. The product ratio, butane/isobutane, is greater than unity which is uncommon on metals. After one to several pulses in a pulse reactor, catalyst samples were heated to 950 °C in flowing H2. The amount of liberated methane gave the amount of carbonaceous deposit. With one to seven pulses of CP or MCP in H2, (C atoms in deposit)/(C atoms in product) was 0.03 – 0.04 but only 0.007 with propane. Activities usually declined with pulse number, but selectivities changed little. The Mo(0)Al2O3 catalyst is initially metallic molybdenum and metallic molybdenum is catalytically active.
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