Thermodynamics/thermodynamic driving force/gain

A mainstay of the classical partition model is the experimental observation that the major thermodynamic driving force for sorption is the hydrophobic effect. The hydrophobic effect results from gain in free energy when non- or weakly-polar molecular surface is transferred out of the polar medium of water 2-4), The hydrophobic effect is manifested by a linear free energy relationship (LFER) between the NOM-normalized partition coefficient (A om) and the w-octanol-water partition coefficient K ) [i.e.. In nom a n + b where a and b are regression constants], or the inverse of the compound s liquid (or theoretical subcooled liquid) saturated water solubility CJ) [i.e.. In AT om = -c In + d. ... 

The 02 -elimination reactions maybe divided into three groups. Those peroxyl radicals that have an -OH or -NH function in the a-position make up the first group. Such peroxyl radicals play a major role in nucleobase peroxyl radical chemistry [cf. reactions (12) and (13)]. Upon deprotonation at die heteroatom by OH" [reactions (10) and (12)], the peroxyl radical anion is formed (cf. the enhancement of the acidity of the functions a to the peroxyl group discussed above for the thermodynamics of the various equilibria that are involved in these reactions see Goldstein et al. 2002). As before, the driving force for the elimination reaction is the formation of a double bond [in addition to the energy gain by the formation of the stabilized 02- radical [cf. reactions (11) and (13)]. 

No activation (energy) barrier separates the donor and the acceptor from the ET products (and vice versa). The electron transfer in Scheme 18 is not a kinetic process, but is dependent on the thermodynamics, whereby electron redistribution is concurrent with complex formation. Accordingly, the rate-limiting activation barrier is simply given by the sum of the energy gain from complex formation and the driving force for electron transfer, i.e. ... 

Considerable insight into the mechanisms of both solution stability and protein stability has been gained by studying the interactions between osmolytes and proteins (Auton and Bolen 2004, 2005, 2007). This has provided new models of the protein folding landscape (Rose et al. 2006). Thermodynamic measurements carried out on proteins and osmolyte aqueous solutions have determined that an important driving force responsible for osmolyte activity is the thermodynamic interactions of the osmolyte with the peptide backbone and thus the solution density distributions, fluctuations, and correlations (Liu and Bolen 1995 Auton and Bolen 2004). 

For any spontaneous process to occur chemical thermodynamics tells us that there must be a lowering of the free energy, AG, of the system. The driving force for polymer adsorption is thus the competition between the net energy change on adsorption (enthalpy of adsorption), the loss of conformational entropy of the adsorbed polymer, and the gain in entropy of solvent molecules released from the surface and polymer upon adsorption. 

The thermodynamics involved in this process were explained previously." In brief, before the solubilized polymer intercalates the layered nanofillers, the solvent molecules that occupy the spaces in between have to be displaced hence a negative variation in the Gibbs free energy change is required. The driving force for this process is hypothesized to be due to entropy gained by desorption of solvent molecules, compensating the decreased entropy of the confined intercalated polymeric chain. ... 

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