Activation enthalphy

This leads to the conclusion that the formation of either epimeric stmcture can be controled by the conditions under which the reaction is carried out, and for most reactions it turns out that the endo-endo epimer is the thermodynamically controled product (see Chart 18). For p-nitrophenyl substituented bispidones, the free activation enthalphy for the isomerization, deduced from NMR experiments, was calculated to be 105kJmoP For phenyl- or m-nitrophenyl-substituted bispidinones, the endo-endo isomer is 8.4kJmoP ... 

For all other oxide, fluoride, chalcogenide, metallic, polymer and molecular glasses, for which viscosity data is available in wide temperature ranges, log(77) vs 1/T plots have a negative curvature and thus the apparent values of decrease with temperature. The activation enthalphy for flow can vary by almost an order of magnitude between the melting point and the glass transition, as shown in Table 2 [1]. 

The activity coefficients of the components of a regular solution assume a simple form which results from the general expression of excess enthalphy and the characteristic relationships of these solutions as follows ... 

UDPgalactose-independent MGDG synthesis is an enzymatic activity of the chloroplast envelope and that galactolipidrgalactolipid galactosyltransferase (GGGT) is involved in the synthesis. Thus, GGGT catalyzes the reversible reaction of Eq.(l), permitted by an expected, low reaction enthalphy ... 

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