Oxidative dehydrogenation of isobutane over magnesium molybdate catalysts

Evaluation of calcined hydrocalumite-type materials as supports of CoMo and NiMo for thiophene hydrodesulfuration reaction

“…An intermediate temperature signal between 450 and 700°C could include further reduction of the above species plus the partial reduction of additional unpromoted octahedral supported phases, and of tetrahedral Mo species from CaMoO 4 . It is worth mentioning that TPR peaks of alkali and alkali-earth metal molybdates appear at higher temperatures (usually above 700°C), and that they have been found to be incompletely reduced under the dynamic conditions of TPR at temperatures well in excess of 1000°C [18][19][20][21] . However, the presence of Ni and Co helps in attaining higher rates (TPR peaks at lower temperatures) and extents of reduction (more intense peaks) of these phases 22,23 .…”

“…As the active phases of both promoted and unpromoted Mo catalysts consist of sulfides of the metals, mainly Mo, it can be assumed that the interaction with HC and the other phases observed (e.g., scheelite), render the Mo-containing phases very difficult to be sulfided, as was confirmed in TPR profiles. In particular, alkali and alkaline-earth metal molybdates have been shown to be much less reducible (and thus, probably less sulfidable) than MoO 3 and/or mixed Co-and Ni-molybdates [18][19][20][21] . However, for CoMo catalyst supported on non calcined HC the conversion was very high at the start of reaction and kept higher at the end than that on the calcined support.…”

Research on Isobutane Dehydrogenation over Mo/MgAl2O4Catalysts and Pilot-Scale Evaluation in a Circulating Fluidized-Bed Unit

“…Mo-based catalysts, which are safe and relatively inexpensive, have been comprehensively studied in the oxidative dehydrogenation (ODH) of light alkanes such as ethane, propane, − and isobutane . Highly exothermic ODH eliminates the equilibrium conversion restriction of dehydrogenation and decreases energy consumption. − However, compared with catalytic dehydrogenation (CDH), ODH exhibits lower selectivity to olefins because deep oxidative reactions of alkanes to CO x are difficult to control. − The safety of cofeeding paraffins and oxygen is also a cause of concern, as appropriate paraffin-to-oxygen ratios must be maintained .…”

An FT-IR study of the adsorption of isopropanol on calcined layered double hydroxides containing isopolymolybdate

“…Catalytic oxidative dehydrogenation (ODH) of light alkanes has been extensively studied over vanadium [1][2][3][4] or molybdenum [5][6][7][8][9][10][11] based oxides (magnesium decavanadate, pyrovanadates and different molybdates of Mg, Zn, Co, Mn, etc.). It has been reported that the catalytic activities depend on many factors, such as the precise nature of the metal cation, the composition or the structure; in this way, Ueda and co-workers [5] reported that the activity of magnesium molybdate in ODH of propane to propene depends on the presence of surface MoO x clusters which account for their acid properties.…”