Equilibrium transfer

In photoexcited n-type semiconductor electrodes, photoexcited electron-hole pairs recombine in the electrodes in addition to the transfer of holes or electrons across the electrode interface. The recombination of photoexcited holes with electrons in the space charge layer requires a cathodic electron flow from the electrode interior towards the electrode interface. The current associated with the recombination of cathodic holes, im, in n-type electrodes, at which the interfadal reaction is in equilibrium, has already been given by Eqn. 8-70. Assuming that Eqn. 8-70 applies not only to equilibrium but also to non-equilibrium transfer reactions involving interfadal holes, we obtain Eqn. 10-43 ... 

One especially interesting experiment that the authors have encountered involved the equilibrium transfer of an amine, which was immobilised on a resin as the enamine species (Scheme 6.35) (I.R. Baxendale, and S.V. Ley, unpublished results). This resin was added in stoichiometric excess to a wet THF solution of a ketone and an immobilised cyanoborohydride resin, followed by a relatively short microwave heating sequence. This resulted in an essentially pure solution of the required amine product, which was both cleaner and was also obtained in a higher yield than any other method attempted. It is worth pointing out that this particular case represented a very specific set of examples and no additional effort was made to determine its generic applicability. 

Brocchini, S. J. Eberle, M. Lawton, R. G. Molecular yardsticks. Synthesis of extended equilibrium transfer alkylating cross-link reagents and their use in the formation of macrocydes./. Am. Chem. Soc. 1988, 110, 5211-5212. 

We note that relation (9) can also be derived if we consider the equilibrium transfer of an electron directly from the red particle to the ox particle within the solution. 

We assume that the solutions are dilute enough for Eq. (13-175) to apply. To achieve equilibrium, transfer of salts through the membrane... 

Determination of ALT ALT (formerly glutamate pyruvate transaminase) catalyzes the equilibrium transfer reaction of the amino group from L-alanine to 2-oxoglutarate to form L-glutamate and pyruvate ALT requires pyridoxal phosphate as coenzyme, which acts as an amino carrier. It is found in the main organs, such as the liver, kidney, and heart. The ALT activity in serum is elevated in diseases of the liver. 

When the reaction flask containing the toluene solution of polyol has reached 40 °C, pipette into this flask 50 cm of normal phenyl isocyanate stock solution (at 25 °C), allowing a 15 s pipette draining time. No reaction occurs between polyol and phenyl isocyanate in the absence of Dabco catalyst. Leave the mixture for 15 minutes to reach thermal equilibrium. Transfer, by pipette, 50 cm of stock 0.56% wiv Dabco solution from the storage vessel (thermostatted at 25 °C) into a dry 50 cm volumetric flask. Remove the B34/B24 sampling adaptor from the reaction flask assembly and insert the neck of the 50 cm volumetric flask into the B34 socket to introduce the Dabco catalyst into the reaction mixture. Allow a 15 s draining time for the Dabco flask and replace the B34/B24 sampling adaptor. Start the stopwatch at the same moment that the Dabco solution is first tipped into the reaction flask, (i.e., at the exact moment that the Dabco catalysed reaction between polyol and phenyl isocyanate commences). 

For an equilibrium / transfer of dm of mass from phase 1 to phase 2,... 

Key ++ methylation occurs and may be strongly exothermic + methylation occurs - little reaction (+) equilibrium transfer reaction - reaction is complex. 

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