Isomeric reaction

From stochastic molecnlar dynamics calcnlations on the same system, in the viscosity regime covered by the experiment, it appears that intra- and intennolecnlar energy flow occur on comparable time scales, which leads to the conclnsion that cyclohexane isomerization in liquid CS2 is an activated process [99]. Classical molecnlar dynamics calcnlations [104] also reprodnce the observed non-monotonic viscosity dependence of ic. Furthennore, they also yield a solvent contribntion to the free energy of activation for tlie isomerization reaction which in liquid CS, increases by abont 0.4 kJ moC when the solvent density is increased from 1.3 to 1.5 g cm T Tims the molecnlar dynamics calcnlations support the conclnsion that the high-pressure limit of this unimolecular reaction is not attained in liquid solntion at ambient pressure. It has to be remembered, though, that the analysis of the measnred isomerization rates depends critically on the estimated valne of... 

Schroeder J and Troe J 1993 Soivent effects in the dynamics of dissociation, recombination and isomerization reactions Activated Barrier Crossing ed G R Fieming and P Hanggi (Singapore Worid Scientific) p 206... 

Zhu S-B, Lee J, Robinson G W and Lin S H 1988 A microscopic form of the extended Kramers equation. A simple friction model for cis-trans isomerization reactions Chem. Phys. Lett. 148 164-8... 

Acid-catalyzed isomerization reactions of alkanes as well as alkylation and condensation reactions are initiated by protolytic ionization. Available evidence indicates nonlinear but not necessarily triangular... 

Annular tautomerism does not occur in isothiazoles or benzisothiazoles. Substituent tautomers can sometimes be distinguished by chemical methods, but it is important that reaction mechanisms and the relative rates of interconversion of tautomeric starting materials or isomeric reaction products are carefully investigated. Physical methods only will be considered in this section, and references to original publications can be found in a comprehensive review (76AHC(S1)1). 

In simple chemical systems, it is often possible to make a good first guess at the dominant reaction pathway [25-28]. An example of such a reaction is the chair-to-boat isomerization in cyclohexane. In that pathway, a clever combination of two torsion angles provides an excellent reaction coordinate for the isomerization reaction [29,30]. 

The isomerization reaction, which is acid-site controlled, includes the conversion of alkylcyclopentanes into alkylcyclohexanes, which, in turn, are quickly converted to aromatics by dehydrogenation. In addition, isomerization also includes the conversion of feed n-paraffms into higher octane I-paraffins. 

Considerthereactionofamoleculethattakesplaceonasolidcatalystsurface.Thisreaction simply involves converting one form of the molecule into another in other words, it is an isomerization reaction. However, the reaction in question takes place only on the catalyst surfaceandnotwithoutthecatalyst. 

Similar isomerization reactions were observed in CDCI3 solutions of N-( -aminomethyl)-l,2,4-triazoles and -tetrazoles (90T633). As for the analogous benzotriazoles, these reactions are-intermolecular and slow at 20°C in the NMR time scale. 

The irradiation of 2- and 3-cyanothiophene gave interesting results in agreement with the scheme described above (Scheme 19). The photoisomerization reaction involved only the excited singlet state and Dewar thiophenes were isolated when the reactions were carried out at -68°C and shown to be intermediates in the isomerization reactions [79JCS(CC)881 79JCS(CC)966]. 

The Wolff-Kishner reduction is an important alternative method to the Clem-mensen reduction, and is especially useful for the reduction of acid-labile or high-molecular substrates. Yields are often below 70%, due to various side-reactions such as elimination or isomerization reactions. ... 

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