Energetics carbon atoms

X. Reaction Mechanisms of Energetic Carbon Atoms in Hydrocarbons... 

XI. Reactions of Energetic Carbon Atoms in Some Other Systems... 

A. Production of Energetic Carbon Atoms Many of the same difficulties involving work with recoiling tritium atoms also beset work with recoiling carbon atoms. Information... 

Fio. 6. Effect of oxygen on reactions of energetic carbon atoms with methane. 

Work in this field is continuing and the future may bring basic contributions to our understanding of the reactions of energetic carbon atoms. 

In summary, the present status of the reaction of energetic carbon atoms is as follows. 

The syn-anti conformational problem of a- and /3-pyrazofurins (756 one of the rare naturally occurring pyrazole compounds, see Section 4.04.4.4.3), which involves a rotation around a pyrazolic sp carbon atom and a sugar sp carbon atom, has been studied theoretically using the PCILO method (81MI40403). In agreement with the experimental observations, the /3 anomer is energetically more favourable than the a anomer, the preferred conformations being anti and syn, respectively. 

For intermediate temperatures from 400-1000°C (Fig. 11), the volatilization of carbon atoms by energetic plasma ions becomes important. As seen in the upper curve of Fig. 11, helium does not have a chemical erosion component of its sputter yield. In currently operating machines the two major contributors to chemical erosion are the ions of hydrogen and oxygen. The typical chemical species which evolve from the surface, as measured by residual gas analysis [37] and optical emission [38], are hydrocarbons, carbon monoxide, and carbon dioxide. 

Apnular tautomerism has been defined as the class of tautomeric rearrangements in which only annular nitrogen or carbon atoms are involved [76AHC(S1), p. 266], In azoles, the latter case is frequently energetically un-... 

The shape of the ethylene molecule has been learned by a variety of types of experiments. Ethylene is a planar molecule—the four hydrogen and the two carbon atoms all lie in one plane. The implication of this experimental fact is that there is a rigidity of the double bond which prevents a twisting movement of one of the CHj groups relative to the other. Rotation of one CHt group relative to the other—with the C—C bond as an axis—must be energetically restricted or the molecule would not retain this flat form. 

Energetically, the lively debated soccerball-form of C0q compares rather favorably with a graphite-like sheet of carbon atoms. This, or course, does not prove that BF really is (fully or partly) responsible for the observed. 

Figure 4. Side and top views of the energetically most favorable complexes formed between protonated cinchonidine and methyl pyruvate which would yield (R)-methyl lactate (left) and (S)-methyl lactate (right), respectively, upon hydrogenation. The complexes have been accomodated on a space filling model of platinum (111) surface in order to illustrate the space requirements of the adsorbed complexes. For the sake of clarity, in the side views the carbon atoms of the reactant are marked with a white square and the oxygen atoms with an o. Data taken from ref. [41].

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