Vapor pressures, vaporization enthalpies and acentric factors for new compounds, diethoxy(methyl)(o-tolyl)silane, diethoxy(methyl)(m-tolyl)silane and diethoxy(methyl)(p-tolyl)silane were reported. The saturated temperature was measured using the inclined ebulliometer in the pressure range from 2000 to 61,000 Pa and the normal boiling point was measured according to the Siwoloboff method. The standard vaporization enthalpy was derived from the temperature dependence of vapor pressure data. The critical parameters were estimated by an improved group contribution method and the acentric factors have been estimated from the Antoine equation and the experimental normal boiling points. (C) 2012 Elsevier B.V. All rights reserved.