Propane propene oxide

Propane-propene oxidation Catalysts were characterized by activity measurements for hydrocarbon oxidation. Hydrocarbon oxidation was performed in a flow reactor system equipped with a flame ionization detector. The reactant mixture was composed of 0.2 % propene and 0.2 % propane ... 

Figure 5. Propane-propene oxidation under lean conditions (5 % excess oxygen) on aged alumina supported catalysts propene on Pt/Al203 A propene on Pt-Rh/AbOa propane on Pt/Al203 X propane on Pt- Al203.

In order to evaluate the interaction between platinum and rhodium deposited on the alumina-lanthanum oxide, the different catalysts were characterized by temperature programmed reduction and measure of the activity for the reaction of propane-propene oxidation. 

In the following scheme, an oxidation pathway for propane and propene is proposed. This mechanism, that could be generalized to different hansition metal oxide catalysts, implies that propene oxidation can follow the allylic oxidation way, or alternatively, the oxidation way at C2, through acetone. The latter easily gives rise to combustion, because it can give rise to enolization and C-C bond oxidative breaking. This is believed to be the main combustion way for propene over some catalysts, while for other catalysts acrolein overoxidation could... 

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... 

Table 8.6. Kinetic parameters of CO, propane and propene oxidation over M/A1203 and M/Ce02—A1203 catalysts (M = Pt, Pd or Rh)...

In a similar study, Zhang and Wang (1997) studied the reaction of zero-valent iron powder and palladium-coated iron particles with trichloroethylene and PCBs. In the batch scale experiments, 50 mL of 20 mg/L trichloroethylene solution and 1.0 g of iron or palladium-coated iron were placed into a 50 mL vial. The vial was placed on a rotary shaker (30 rpm) at room temperature. Trichloroethylene was completely degraded by palladium/commercial iron powders (<2 h), by nanoscale iron powder (<1.7 h), and nanoscale palladium/iron bimetallic powders (<30 min). Degradation products included ethane, ethylene, propane, propene, butane, butene, and pentane. The investigators concluded that nanoscale iron powder was more reactive than commercial iron powders due to the high specific surface area and less surface area of the iron oxide layer. In addition, air-dried nanoscale iron powder was not effective in the dechlorination process because of the formation of iron oxide. 

Alcoholysis of ester and epoxide with various basic catalysts including alkaline earth metal oxides and hydroxides was reported recently by Hattori et alF61 Various alcohols were transesterified with ethyl acetate at 273 K. The results show that in the presence of strongly basic catalysts such as CaO, SrO and BaO, propan-2-ol reacted much faster than methanol, whereas in the presence of more weakly basic catalysts such as MgO, Sr(0H)2-8H20 and Ba(0H)28H20, methanol reacted faster than propan-2-ol. When the alcoholysis was performed with propene oxide, alkaline earth metal oxides were found to be more reactive than hydroxides the reactivity of the alcohols was in the order methanol > ethanol > propan-2-ol > 2-methylpropan-2-ol, regardless of the type of catalyst. 

Mo is the essential element of effective catalysts for propene oxidation to acrolein and acrolein oxidation to acrylic acid, while V is an essential element for effective catalysis of acrolein oxidation to acrylic acid. Mo-V-Nb oxide catalysts are capable of activating propane even at 573 K, but yields products of acetic acid, acetaldehyde, and carbon oxides. The addition of Te or Sb to Mo-V-Nb oxides induces certain structural changes leading to the formation of acrylic acid. ... 

Table 7 Catalytic activity and selectivity for propane oxidation and propene oxidation over Mo-V-Te-(Nb) oxide catalysts...

Propane Selective Oxidation to Propene and Oxygenates on Metal Oxides. In Metal Oxides, Chemistry and Applications (ed. J.LG. Eierro), CRC Press, Boca Raton, p. 414. 

The oxidative dehydrogenation (ODH) of lower alkanes is an attractive process for the formation of alkenes. The ODH of propane to produce propene has been particularly studied, given its high demand for the production of polypropene, acrylonitrile and propene oxide. There is a combined influence of the redox and acid-base properties of the surface of the oxides used for propane ODH. Intermediate reducibility, weak Lewis acid centers and oxygen mobility represent the essential requirements for selective ODH, as they are consistent with the trends in ODH rates observed in VO, MoO and WO based catalysts. 

The inclusion of reactions to represent the low-temperature chemistry in a detailed model for n-butane oxidation at high pressures, that is appropriate to temperatures down to about 600 K began in 1986 [225]. At the present time, models which include around 500 species and more than 2000 reversible reactions to represent alkane isomers up to heptane, are in use [219] and still larger schemes are under development [220]. Progress in the validation and application of these models, and kinetic representations for propane and propene oxidation, are discussed in the next subsection. Modelling of the low-temperature combustion of ethene has also been undertaken more recently [20]. 

The highest propene oxide yields were obtained with both the Ti-SBA-15- and the Ti-silica-supported catalysts, although a higher reaction temperature was needed in comparison to the titania-supported catalyst. The deactivation for these catalysts was also considerably less. At lower temperatures (up to 423 K), all catalysts had an inhibition period for both propene oxide and water formation, which is explained by product adsorption on the support. The side products produced by all catalysts were similar. Primarily, carbon dioxide and acetaldehyde were produced as side products and, in smaller quantities, also propanal, acrolein, acetic acid, and formaldehyde. Propanol (both 1- and 2- as well as propanediol), acetone, carbon monoxide, and methanol were only observed in trace amounts. 

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