Propane oxidation cobalt oxide

Keywords nickel molybdate, cobalt molybdate, nickel cobalt molybdate, propane oxidative dehydrogenation, propylene production... 

Solsona, B., Garcia, T., Hutchings, G., et al (2009). TAP Reactor Study of the Deep Oxidation of Propane Using Cobalt Oxide and Gold-containing Cobalt Oxide Catalysts, Appl Catal. A Gen., 365, pp. 222-230. 

Some studies of potential commercial significance have been made. For instance, deposition of catalyst some distance away from the pore mouth extends the catalyst s hfe when pore mouth deactivation occui s. Oxidation of CO in automobile exhausts is sensitive to the catalyst profile. For oxidation of propane the activity is eggshell > uniform > egg white. Nonuniform distributions have been found superior for hydrodemetaUation of petroleum and hydrodesulfuriza-tion with molybdenum and cobalt sulfides. Whether any commercial processes with programmed pore distribution of catalysts are actually in use is not mentioned in the recent extensive review of GavriUidis et al. (in Becker and Pereira, eds., Computer-Aided Design of Catalysts, Dekker, 1993, pp. 137-198), with the exception of monohthic automobile exhaust cleanup where the catalyst may be deposited some distance from the mouth of the pore and where perhaps a 25-percent longer life thereby may be attained. 

Ethylene-Based (C-2> Routes. MMA and MAA can be produced from ethylene as a feedstock via propanol, propionic acid, or melhyl propionate as intermediates. Propanal may be prepared by hydrofonnylalion of ethylene over cobalt or rhodium catalysts. The propanal then reads in the liquid phase with formaldehyde in the presence of a secondary amine and. optionally, a carboxylic acid. The reaction presumably proceeds via a Mannich base intermediate which is cracked to yield methacrolcin. Alternatively, a gas-phase, crossed akin I reaelion with formaldehyde cataly zed by molecular sieves [Pg.988]

The liquid-phase oxidation (LPO) of light saturated hydrocarbons yields acetic acid and a spectrum of coproduct acids, ketones, and esters. Although propane and pentanes have been used, n-butane is the most common feedstock because it can ideally yield two moles of acetic acid. The catalytic LPO process consumes more than 500 million lb of n-butane to produce about 500 million lb of acetic acid, 70 million lb of methyl ethyl ketone, and smaller amounts of vinyl acetate and formic acid. The process employs a liquid-phase, high-pressure (850 psi), 160-180°C oxidation, using acetic acid as a diluent and a cobalt or manganese acetate catalyst. 

Also, Marsh and co-workers [145] showed that gold on cobalt oxide particles, supported on a mechanical mixture of zirconia-stabilised ceria, zirconia and titania remains active in a gas stream containing 15 ppm SO2. Haruta and co-workers [207] found that although the low-temperature CO oxidation activity of Ti02-supported Au can be inhibited by exposure to SO2, the effect on the activity for the oxidation of H2 or propane is quite small. Venezia and co-workers [208] reported that bimetallic Pd-Au catalysts supported on silica/alumina are resistant to sulphur poisoning (up to 113 ppm S in the form of dibenzothiophene) in the simultaneous hydrogenation of toluene and naphthalene at 523 K. 

This work is devoted to the synthesis of Zr02 by various methods, the synthesis of zirconium-containing pentasils and Zr02 - -zeolite based binary carriers. These materials were used as carriers of transition metal oxides (chromium, cobalt) and their catalytic properties were characterized in the selective reduction of NO by methane and propane-butane mixture, the acidic properties of the samples were investigated by thermoprogrammed desorption and IR-spectroscopy methods. 

The most studied systems for oxidative propane upgrading are vanadium [2], vanadium-antimony [3], vanadium-molybdenum [4], and vanadium-phosphorus [5] based catalysts. Another family of light paraffin oxidation catalysts are molybdenum based systems, e.g. nickel-molybdates [6], cobalt-molybdates [7] and various metal-molybdates [8-9]. Recently, we investigated binary molybdates of the formula AM0O4 where A = Ni, Co, Mg, Mn, and/or Zn and some ternary Ni-Co-molybdates promoted with P, Bi, Fe, Cr, V, Ce, K or Cs [10-11]. A good representative of these systems is the composition Nio.5Coo.5Mo04 which was recently selected for an in depth kinetic study [12] and whose mechanistic aspects are now further illuminated here. 

As in all conversions of this type, which are autocatalytic, the induction period is relatively long. Catalysts are used to shorten it. These catalysts are soluble salts of cobalt, chromium, vanadium or manganese, usually acetates. The oxidation rate rises with the number of carbon atoms in the hydrocarbon and with the extent to which the chain is linear. Thus, if it is l for ethane, it is as high as 100 for propane, 500 for n-butane and 1000 for n-pentane. 

A synergistic effect leading to the increased catalyst activity and selectivity in selective catalytic reduction (SCR) of NO with methane or propane-butane mixtures was found when cobalt, calcium and lanthanum cations were introduced into the protic MFl-type zeolite. This non-additive increase of the zeolite activity is attributed to increased concentration of the Bronsted acid sites and their defined location as result of interaction between those and cations (Co, Ca, La). Activation of the hydrocarbon reductant occurs at these centers. Doping the H-forms of zeolites (pentasils and mordenites) with alkaline earth metal and Mg cations considerably increased the activity of these catalysts and their stability to sulfur oxides. 

Zhang and Chan [420] recently reported synthesis of Pt and Pt-Co nanoparticles. The common components in the microemulsions were Triton X-100 as the surfactant, cyclohexane as the oil phase and propan-2-ol as the cosurfactant. The volume percentages in each microemulsion were surfactant 10, oil phase 35, co-surfactant 40 an aqueous phase 15. For pure platinum, the aqueous phase was a solution of H2PtCl6 (microemulsion 1) or hydrazine (microemulsion 2). The two were mixed under stirring to obtain the particles. In case of the composite particles, microemulsion 1 also contained C0CI2 in the aqueous phase. The Pt Co ratio was around 1 2.2. The particles were spherical, 3-4 nm in diameter and had a narrow size distribution. Formation of a small amount of cobalt oxide from unalloyed cobalt cannot be ruled out. 

As a filler we used a carbon nanofiber (CNF) prepared in cobalt catalyst (washed and not washed from the metal) demetallization conducted by washing the fibers with concentrated sulfuric acid, and the metal content in the sample was reduced to 38-40% up to 0.2-2% masses, and the specific adsorption surface (Ssp) increased by 2-2.5 times. The concentration of fibers in the rubber is 2% by weight of the rubber. The raw material was used to produce fibers on cobalt catalyst-propane-butane fraction. The main component of synthesis is cobalt oxide. Volumetric flow rate of gas in the synthesis is 1 vol./Hr at a temperature of 7000°C. 

---