Platinum branched molecules

Other Cg hydrocarbons. The dehydrogenation of normal hexane and 2,3-di methyl butane also proceeds but not as voraciously on small platinum clusters. Figure 8 is a plot of the hydrogen content in the first adduct as a function of the size of the platinum metal cluster. The metal atom reacts via dihydrogen elimination to produce PtC6Hi2 products. The platinum trimer is now the smallest cluster that will produce a C H near one. The similarity of size dependent dehydrogenation of the normal hexane and the branched molecule suggest that these systems may not readily aromatize these alkanes. Further structural studies are needed to identify the reaction products. 

The isomerization of the butanes and of neopentane has been studied over various types of evaporated platinum films by Anderson and Baker (68) and Anderson and Avery (108,24). Table II gives some typical results. It is clear that the proportion of parent hydrocarbon reacting to isomeric rather than to hydrogenolytic product is considerably smaller for a hydrocarbon with an unbranched as opposed to a branched chain containing an isostructural unit indeed, neopentane was studied as the archetypal molecule of the latter class. 

A catalyst used in industry is very rarely a pure element or compound. Most catalysts contain a complex mixture of chemical additives or modifiers that are essential ingredients for high activity and selectivity. Promoters are beneficial additives that increase activity, selectivity, or useful catalyst lifetime (stability). Structural promoters inhibit sintering of the active catalyst phase or present compound formation between the active component and the support. The most frequently used chemical promoters are electron donors such as the alkali metals or electron acceptors such as oxygen and chlorine. For example, in the petroleum industry, chlorine and oxygen are often added to commercial platinum catalysts used for reforming reactions by which aliphatic straight-chain hydrocarbons are converted to aromatic molecules (dehydrocyclization) and branched isomers (isomerization). 

The Bohmian quantum-classical and QMF approaches have been tested with a model application designed to simulate the interaction of an oxygen molecule with a platinum surface [13,21,22,91]. With trajectory branching the Bohmian quantum-classical method recovers the correct asymptotic behavior of the scattering probability of the quantum subsystem. The QMF approach shows improvement in both the short and long time scattering probabilities. The improvement is achieved due to the proper treatment of ZPE. 

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