Other Aqueous Transmethylations Chemical Rate Studies

OTHER AQUEOUS TRANSMETHYLATIONS CHEMICAL RATE STUDIES 

Various groups have reported on methyl exchange among metals other than methylcobalamin in aqueous solution. This area has been discussed in some detail by Jewett et al. 51) and by Pratt and Craig (59). Table III lists representative examples of such systems, along with the reported 

Methyl Exchange hf.i ween Metals in Aqueous Media0 

All systems of this type for which kinetic studies have been reported show a second-order rate dependence, first order in each reactant. The methyl transfer for such systems may follow this pattern (68)  

Changes in the electrophilicity of the acceptor enormously affects the rate of exchange (69), This trend is illustrated by Fig. 4, which shows the rates of transmethylation of some methylmetals toward chloromercury species in certain cases there is a 107-fold dimunition of rate constant as salinity increases. This strongly suggests that the frequent salinity gradients found in natural waters will markedly influence the rates of naturally occurring transmethylations (vide infra). 

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III. Other Aqueous Transmethylations Chemical Rate Studies 322... 

OTHER AQUEOUS TRANSMETHYLATIONS CHEMICAL RATE STUDIES... 

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