PHYSICOCHEMICAL PROPERTIES OF DIMETHYL SELENIDE AND DIMETHYL DISELENIDE

Volatilization of selenium (Se) is a dissipation mechanism by which ga seous Se is redistributed in the environment. The vapor pressures of d imethyl selenide (DMSe) and dimethyl diselenide (DMDSe) were determine d using the isoteniscope method, and the solubility of DMSe in H2O was determined in a closed system by headspace analysis. The vapor pressu res at 25-degrees-C were 32.03 and 0.38 kPa for DMSe and DMDSe, respec tively. The enthalpies of vaporization were calculated as 31.90 and 74 .92 kJ mol-1, respectively. The solubility of DMSe was 0.0244 g/g of H 2O. The Henry's law constant for DMSe was calculated as 143 kPa kg mol -1 (0.144 kPa m3 mol-1).