DEUTERIUM-EXCHANGE REACTION ON TRIMETHYLAMINE-BORANE WITH SULFONATE CATION-EXCHANGER IN THE DEUTERIO FORM

The kinetics of H-D exchange on trimethylamino-borane in bi- and triph ase systems involving sulfonate cation exchangers in the D+ form show that the rate of the isotope exchange is lower in triphase systems in comparison to the liquid-liquid extraction system; nevertheless the yi eld of the deuterated product in polymeric deuterating systems is esse ntially much higher than that obtained in applying liquid deuterating agents. The cation-exchange resin when applied in triphase system demo nstrates ambivalent behavior, acting as a catalyst toward deuterio-exc hange reaction and as a suppressor toward the hydrolysis of TMAB. The hydrolysis of TMAB results in the formation of trimethylamine which ac celerates the hydrolysis and inhibits the H-D exchange by saturation o f the SO3- resin sites. The immobilization of the aqueous phase (D2O) in swollen ion exchanger creates unique conditions for isotope exchang e, completely suppressing hydrolytic side reactions, and pure deuterat ed product can be achieved in quantitative yield.