Catalytic dehydrogenation of higher

Catalytic Dehydrogenation of Higher Normal Paraffins to Linear Olefins... 

Significant progress has been made in the direct catalytic dehydrogenation of higher normal paraffins to linear olefins, and further developments in this area of technology are likely to occur in the future. 

A commercial Pt-Sn on y-Al203 catalyst showed 2-3 times higher activity in the catalytic dehydrogenation of a mixture of Ci0—CJ2 alkanes to linear monoalkenes when applied in a supercritical phase.332 The strong shift of the equilibrium under supercritical conditions is believed to be due to the high solubility of the product in supercritical fluids or the rapid desorption of alkenes from the catalyst surface. 

Butadiene (> 98%w/w) 20 ooo longtons Catalytic dehydrogenation of n-butenes feedstock of liquid mixed hydrocarbon stream containing 80.5 mol % n-butenes, 11.5 mol % n-butane, and 1 mol % of higher hydrocarbons. 

These results have profound effects for the selective catalytic dehydrogenation of cyclohexane to benzene, a prototypical hydrocarbon conversion reaction. On Pt(lll), the intermediates, cyclohexene and a species, have been identified and the rate constants for some of the sequential reaction steps measured [56]. Adsorption and reaction studies of cyclohexane [39], cyclohexene [44], 1,3-cyclo-hexadiene [48], and benzene [39] on the two Sn/Pt(lll) alloys provide a rational basis for understanding the role of Sn in promoting higher selectivity for this reaction. One example of structure sensitivity is shown in Fig. 2.7, in which a monolayer of cyclohexyl (C H ) was prepared by electron-induced dissociation (EID) of physi-orbed cyclohexane to overcome the completely reversible adsorption of cyclohexane... 

Higher alkenes can be obtained from thermal cracking of wax, and although a thermodynamic mixture of internal alkenes might have been expected, the wax-cracker product contains a high proportion of 1-aIkenes, the kinetically controlled product. For the cobalt-catalyzed hydroformylation the nature of the alkene mixture is not relevant, but for other derivatizations the isomer composition is pivotal to the quality of the product. Another process involves the catalytic dehydrogenation of alkanes over a platinum catalyst. 

Catalytic dehydrogenation of methyl vinyl carbinol at temperatures above 250 C in presence of a brass spelter catalyst is claimed to give a 33 per cent yield of methyl vinyl ketone, CHs-CO CH=CH2. Catalytic vapo>phase oxidation of the unsaturated alcohols to form unsaturated carbonyl compounds has been found to give considerably higher yields. Temperatures in the range of 360-550 C and use of a metallic silver catalyst are described. 

Catalytic Dehydrogenation of Diethanolamine Monsanto has developed a new method for production of the herbicide that eliminates most manufacturing hazards and all use of cyanide, ammonia, and formaldehyde in the synthesis of the key intermediate, DSIDA. Monsanto s novel catalytic synthesis of DSIDA uses a copper catalyst, and is safer because it is endothermic, produces higher overall yield, and has fewer process steps. 

One of the most studied applications of Catalytic Membrane Reactors (CMRs) is the dehydrogenation of alkanes. For this reaction, in conventional reactors and under classical conditions, the conversion is controlled by thermodynamics and high temperatures are required leading to a rapid catalyst deactivation and expensive operative costs In a CMR, the selective removal of hydrogen from the reaction zone through a permselective membrane will favour the conversion and then allow higher olefin yields when compared to conventional (nonmembrane) reactors [1-3]... 

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