Propane catalytic oxidation

Fig. 2. Left catalytic oxidation of C3 organic compounds over MgCr204. Conversion of propane A acetone X acrolein propene. Right catalytic oxidation of 2-propanol over MgCr204. conversion of 2-propanol selectivities to acetone A propene X COx-...

Catalytic oxidative dehydrogenation of propane by N20 (ODHP) over Fe-zeolite catalysts represents a potential process for simultaneous functionalization of propane and utilization of N20 waste as an environmentally harmful gas. The assumed structure of highly active Fe-species is presented by iron ions balanced by negative framework charge, mostly populated at low Fe loadings. These isolated Fe sites are able to stabilize the atomic oxygen and prevent its recombination to a molecular form, and facilitate its transfer to a paraffin molecule [1], A major drawback of iron zeolites in ODHP with N20 is their deactivation by accumulated coke, leading to a rapid decrease of the propylene yield. 

Costs for catalytic oxidation systems are often included as a part of the entire remedial activity. Typical operating costs for a catalytic oxidation system alone, operating at 100 to 200 standard cubic feet per minute (scfm), will range from 8 to 15 per day (for natural gas or propane-fired systems) to 20 to 40 per day (for electrically heated systems). Capital costs of equipment operating at throughputs of 100 to 200 scfm are estimated to be in a range from 50,000 to 100,000 (D16641Q, p. 7). 

The base price of the MMC-5 unit is 56,200 (1992 dollars). For the thermal oxidizer portion of the MMC-5 unit, maximum daily fuel cost for natural gas would be 60 (1992 dollars), and maximum daily fuel cost for propane would be 95 (1992 dollars). For the catalytic oxidizer portion of the MMC-5 unit, the maximum daily electrical cost would be 22 (1992 dollars), assuming an electric preheater rated for 36 kW at 480 V is used at 240 V. The daily cost to operate the vacuum/compression unit for the MMC-5 is 6 (1992 dollars), assuming a 3-hp electric motor drawing 2.3 kW is used. 

On the contrary, for propane combustion on Pd/AljOj modified by ceria addition, Shyu and co-workers observed that ceria allows to maintain Pd in a more stable oxidised state less prompt to react with propane [78], Catalytic oxidation which occurred from 200°C to 350°C is now delayed to higher temperature by 50°C to 100°C from 250°C to 450°C. More dramatically is the decrease of the conversion at 350°C from 100% to 20% as the partial pressure of oxygen increases beyond the stoichiometric ratio up to 8 times. They concluded from their studies that ceria and palladium are in close interaction, may be in a Pd-O-O-Ce-0 model via a O2 species. 

Contrary to the case of olefins, homogeneous catalytic oxidations of light alkanes occur at temperatures similar to those of the catalytic reaction. This certainly led to misinterpretation of supposedly catalytic data in certain cases. Two examples will illustrate the role of homogeneous reaction the oxidative dehydration of propane and the reactions of pentane with oxygen. 

Also in the case of the C3-diol catalytic oxidation there is a lack of literature concerning the selective oxidation of the hydroxyl groups. According to a recent patent the selective oxidation of propane-1,2-diol has been claimed for either the primary or the secondary hydroxyl group, but no examples were reported for primary ones [6b]. Palladium on carbon has been reported to oxidize propane-1,2-diol in a non selective maimer [12] whereas a patent claims 86% selectivity in propane-1,3-diol oxidation to 3-hydroxy-propanoic acid using a commercial Pd/C catalyst [6a]. 

As an extension of the ethane-l,2-diol oxidation, we investigated the catalytic oxidation of propane-1,2-diol. In this case the problem of chemoselectivity, arising from the presence of a primary and a secondary alcoholic function, is of great interest as both hydroxyacetone and lactic acid are products of synthetic importance (Fig. 1)... 

Another important difference between oxidation of Ci-C2 and C3+ hydrocarbons is the appearance in the latter case of degeneration of the primary alkyl radicals. Already in the case of propane, the existence of two isomeric forms of propyl species (not always taken into account) can lead to substantial kinetic consequences because of the distinct difference in their thermochemistry and reactivity. Even certain reaction channels may vary depending on the isomeric form of propyl radicals. This factor may cause a substantial uncertainty especially in the case of modeling of catalytic oxidation due to a poor knowledge about thermochemistry and reactivity of surface active sites and chemisorbed species. 

Of particular interest are the block honeycomb-structure SHS catalysts. In these catalytic systems, the gas-dynamic resistance is much lower than in conventional ones, the catalytic layer is immobilized, and the active surface is used more efficiently. The data on the oxidation of carbon monoxide and propane in the block oxynitride SHS catalyst (1.5% CO, 1.5% CsHg, 10% O2 W=7010 h ) are presented in Fig. 4. Note, that at high flow rates, the conversion degree for carbon monoxide and propane attains 100% at 450-500 C. The temperature of complete oxidation can be lowered upon immobilization of the "id transition metals (Co, Ni, Cr, and Fe) oxides on the catalyst surface. Efficiency of the catalysts with immobilized Co and Ni oxides (0.2%) for the oxidation of carbon monoxide and propane is shown in Fig. 5. In this case, carbon monoxide is oxidized at 400-450"C while propane is oxidized at 125-175°C. 

Oxidation or Propane, Butane, Isouutane Catalytic Oxidation... 

S. J. Gentry and A. Jones, "Poisoning and Inhibition of Catalytic Oxidations. I. The Effect of Silicone Vapour on the Gas-Phase Oxidations of Methane, Propane, Carbon Monoxide and Hydrogen over Platinum and Palladium Catalysts", J. Appl. Chem. Biotech.. 1978,727... 

The dynamic phenomena associated with the rhodium-catalyzed oxidation of carbon monoxide, methane and propane have been studied by in-situ infrared thermography. High-resolution temperature maps of the reacting catalyst revealed the mobility of the reaction front during ignition and extinction of the CO oxidation, and the development of thermokinetic oscillations. The catalytic oxidation of methane and propane produced weaker dynamics. Chemisorption and kinetic experiments suggest that the competitive adsorption of the reactants and the occurrence of self-inhibition, represent key factors in the development of the observed transient effects. 

CATALYTIC OXIDATION OF PROPANE OVER PALLADIUM SUPPORTED ON ALUMINA AEROGEL. EFFECTS OF THE PRETREATMENT ON THE ACTIVITY AND INVESTIGATION OF THE STATE OF PALLADIUM BY GRAZING-INCIDENCE-X-RAY DIFFRACTION... 

The present work is concerned with the influence of the pretreatment of an alumina-aerogel supported Pd catalyst on its activity in propane oxidation. The state of Pd and the crystalline state of alumina aerogel were investigated by grazing-incidence X-ray diffraction (GIXD). To our knowledge, this method is applied for the first time to supported metal catalysts. In addition, a comparison of the structural and catalytic oxidation properties of Pd, Pt and Pt-Rh supported on alumina carriers was made. 

FTIR spectroscopy, interaction with oxygen, NO, N2O, catalytic oxidation of NO to NO2, and reduction of NOx with propane have been used to characterise Fe cations in FER and BEA zeolites. Three cationic positions for Fe ions in dehydrated samples of Fe-FER, and one in Fe-BEA have been identified. A complex nature of the reversible interaction of the Fe(II) cations in FER and BEA with O2, NO, N2O has been described. The experimental study is complemented with a simple theorical investigation of Fe(II) and Fe(IlI) coordination over the most populated P site. 

The Cg alkylaromatics fraction is formed by ethylbenzene and the three xylene isomers. Ethylbenzene is used as a raw material to produce styrene by dehydrogenation, or oxidative dehydrogenation. Para-xylene and ortho-xylene are catalytically oxidized to give terephthalic and phthalic acid. The meta-xylene isomer can also be oxidized to give isophthalic acid. The major industrial source of these products is the catalytic reforming of naphthas. The Cyclar process, can also produce xylenes from propane and butane. However, using this process, xylenes are formed less selectively than toluene or benzene in the BTX. 

Recently, the catalytic oxidation of the lignin model 1-(3, 4-dimethoxyphenyl)-2-(2-methoxyphenoxy)propane-l, 3-diol (4) has been reported [21]. Reactions were run in 80 % acetic acid at 170 C and ca. 35 atm total pressure with 4 % 0 in N. In the presence of the... 

Matis G, Juillet F, Teichner SJ (1976) Catalytic oxidation of paraffins on nickel oxide-based catalysts. I. Selectivity in the partial oxidation of isobutane and propane. Bull Soc Chim Fr 1633-1636 Pajonk GM (1991) Aerogel catalysts. Appl Catal 72 217-276... 

Ueda W, Vitry D, Katou T (2004) Stmctural organization of catalytic functions in Mo-based oxides for propane selective oxidation. Catal Today 96 (4) 235-240 Farges F, Brown GE, Rehr JJ (1997) Ti K-edge XANES studies of Ti coordination and disorder in oxide compounds Comparison between theory and experiment Phys Rev B 56 (4) 1809-1819... 

B. (2013) The different catalytic behaviour in the propane total oxidation of cobalt and manganese oxides prepared by a wet combustion procedure. Chem. Eng. J., 229, 547-558. 

---