Hydrocarbons reactions

C2.7.6.7 SHAPE-SELECTIVE HYDROCARBON REACTIONS CATALYSED BY ZEOLITES... 

Fig. 5. Methanol-to-hydrocarbons reaction path at 371°C, where (A ) is methanol ( ), dimethyl ether (), water (D), paraffins (and Cg...

Hydrocarbon Reactions. Some interesting features of reactions involving olefins and saturated hydrocarbons are shown by investigating the effects of translational energy. The reactions ... 

Predictive equations for the rates of decomposition of four families of free radical initiators are established in this research. The four initiator families, each treated separately, are irons-symmetric bisalkyl diazenes (reaction 1), trans-phenyl, alkyl diazenes (reaction 2), tert-butyl peresters (reaction 3) and hydrocarbons (reaction 4). The probable rate determining steps of these reactions are given below. For the decomposition of peresters, R is chosen so that the concerted mechanism of decomposition operates for all the members of the family (see below)... 

The quality of fit to the linear equation 7 is excellent for the radical forming decompositions of Irons-symmetric bisalkyl diazenes (reaction 1 - Table II) and Irons-phenyl, alkyl diazenes (reaction 2 - Table II). The quality of fit to equation 7 is not as high for the radical forming decompositions of lerl-butyl peresters (reaction 3 - Table II) and hydrocarbons (reaction 4 - Table II). This suggests that transition state arguments may be used to rationalize the rates of reactivity very well for reactions 1 and 2, and fairly well for reactions 3 and 4. 

Catalysis zeolites possess acid sites that are catalytically active in many hydrocarbon reactions, as we shall discuss in Chapter 9. The pore system only allo vs molecules that are small enough to enter, hence it affects the selectivity of reactions by excluding both the participation and formation of molecules that are too large for the pores. 

Data accunnilated in the last years on the Ft/Cu alloys, in particular on the 1) surface composition, 2) electronic structure, 3) adsorption properties, 4) catalytic behaviour and 5) various side effects, make a detailed discussion possible of the catalytic selectivity and mechanism of hydrocarbon reactions. 

Grosjean D, EL Williams, E Grosjean, JM Andino, JH Seinfeld (1993c) Atmospheric oxidation of biogenic hydrocarbons reaction of ozone with 3-pinene, D-limonene, and rra -caryophyllene. Environ Sci Technol 27 2754-2758. 

First there are the physical chemists, chemical engineers, and surface scientists, who study mainly nonpolar hydrocarbon reactions on clean and relatively clean metals and metal oxides. These have been the traditional studies formerly driven by the petroleum industry and now driven by environmental concerns. These workers typically treat the surface as a real entity composed of active sites (usually not identified, but believed in). These investigators typically, although not always, interpret mechanisms in terms of radical reactions on metals and in terms of acid-base reactions on metal oxides. 

Radical hydrocarbon-stable hydrocarbon reactions also play a role in synthesis the reaction,... 

Atomic metal ion-hydrocarbon reactions bond dissociation energies for fragments, 15,16t endothermic reactions, 13,15,17f Atomic transition metal ion reactions development of approach for real-time measurements of dissociation kinetics, 39 ion beam apparatus, 12,14f studies of... 

Other catalytic hydrocarbon reactions indude decomposition of olefins over a powdered nickel catalyst [84], hydrogenation of alkenes, hydrocracking of cycloalk-enes, and water-gas shift reactions [64]. 

Figure 5.11 Hydrocarbon reactions leading to PAH synthesis. (Adapted with permission from Fraser, 2002)...

Industrial hydrocarbon reactions are a complex between a variety of... 

Swaminathan, N. and R. W. Bilger (1997). Direct numerical simulation of turbulent nonpremixed hydrocarbon reaction zones using a two-step reduced mechanism. Combustion Science and Technology 127, 167-196. 

Numerous studies suggest that alkyl-aluminumsilyl oxonium ions should be the real intermediates in hydrocarbon reactions over zeolite, whereas carbocations should be just transition states (J). Equilibrium between the alkyl-aluminumsilyl oxonium ion and the carbocation, although suggested in some cases, has never been experimentally or theoretically proven, but recent calculations indicated that the tert-butyl carbenium ion is an intermediate on some specific zeolite structures 6,7). 

The flame speed for a combustible hydrocarbon-air mixture is known to be 30cm/s. The activation energy of such hydrocarbon reactions is generally assumed to be 160kJ/mol. The true adiabatic flame temperature for this mixture is known to be 1600 K. An inert diluent is added to the mixture to lower the flame temperature to 1450 K. Since the reaction is of second-order, the addition of the inert can be considered to have no other effect on any property of the system. Estimate the flame speed after the diluent is added. 

Basic rate information permits one to examine these phenomena in detail. Leighton [2], in his excellent book Photochemistry of Air Pollution, gives numerous tables of rates and products of photochemical nitrogen oxide-hydrocarbon reactions in air this early work is followed here to give fundamental insight into the photochemical smog problem. The data in these tables show low rates of photochemical consumption of the saturated hydrocarbons, as compared to the unsaturates, and the absence of aldehydes in the products of the saturated hydrocarbon reactions. These data conform to the relatively low rate of reaction of the saturated hydrocarbons with oxygen atoms and their inertness with respect to ozone. 

The term prompt NO derives from the fact that the nitrogen in air can form small quantities of CN compounds in the flame zone. In contrast, thermal NO forms in the high-temperature post-flame zone. These CN compounds subsequently react to form NO. The stable compound HCN has been found in the flame zone and is a product in very fuel-rich flames. Chemical models of hydrocarbon reaction processes reveal that, early in the reaction, O atom concentrations can reach superequilibrium proportions and, indeed, if temperatures are high enough, these high concentrations could lead to early formation of NO by the same mechanisms that describe thermal NO formation. 

C complexes, 32 185-186 CFjHCFjH, 39 340 chemisorption complexes, 32 170-172 CjH, enthalpies, 37 141, 143 "C-labeling studies, 25 166-172 commercial, 6 197 complex molecules, 30 58-72 medium-sized rings, 30 68-72 polymethylcycloalkanes, 30 59-65 substituted aromatics, 30 65-68 cyclic-acyclic product ratio, 30 8-9 cycloalkanes, 30 68-69 function, hydrogen pressure, 30 12, 15-16 hydrocarbon reaction models, 32 202-205 hydrogenolysis and, 23 93, 103 interconversion, 30 81-82 isopentane, 30 17 label scrambling, 30 7, 12-13 mechanism, 30 5-16 bifunctional, 30 4 catalyst particle size and, 30 72-85 concerted, 30 20... 

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