Abstract : After natural gas treatment, methanol is found as a trace contaminant. Our objective is to determine thermodynamic properties of “hydrocarbon(s) – methanol” mixtures at operating conditions related to fractionators, at high and low temperatures. In effect, industries may be penalized financially when methanol composition is higher than 50 ppm moles in final products. Therefore, our aim is to understand phase equilibrium at specific conditions of these units. There is almost no literature for such little methanol quantities. Furthermore, thermodynamic models (predictive and with parameters adjusted for the whole composition range) do not allow correct representation of “vapor – liquid” equilibrium at infinite dilution. A “static – analytic” still with phase sampling and GC analysis is used to perform these measurements. At high temperatures, we have determined methanol partition coefficients. The equipment has been adapted, along time, to increase methanol trace quantifications (molar fractions below 1 000 ppm). A unique calibration procedure taking into account methanol adsorption during the analysis stage was developed. New measurements show that for the studied composition range and within the experimental uncertainty, total pressures of the system and methanol partition coefficients are only temperature dependant. The methanol Henry's law constants as well as infinite dilution activity coefficients in the different hydrocarbon mixtures are calculated. At low temperatures, we are interested in determining the methanol limiting solubilities in “nitrogen – hydrocarbon(s)” liquid mixtures. An apparatus is under development to realize these measurements. Our new specific measurements will be used as a basis for fractionator process simulators, to estimate as precisely as possible methanol contents inside fractionator products.