Tritium isotope fractionation between hydrogen sulphide and methanol

Abstract

Tritium isotope fractionation in the exchange reaction between methanol and hydrogen sulphide has been studied in the gaseous phase over the temperature range 283–373 K. It was found that the heavier isotope accumulates in methanol and that the tritium–protium isotope effect characterizing the exchange reaction studied reaches large values: from 2.70 at 373 K to 3.72 at 283 K. The temperature dependence can be described by the simple relation: In α = −0.1221 + 431.5/T. Using observed vibrational frequencies, theoretical fractionation factors could be calculated and good agreement with the experimentally determined values was observed. The results presently obtained were also compared with those obtained for the CH3SH–H2S system.