Flows and heat transfers in micro-nano conducts are subject to significant interphase phenomena linked to molecular interaction in the vicinity of the wall. In the literature, both experiments and simulations revealed evidence of an enhancement of flow-rate, originated from slip velocity at the solid boundary, due to collisions between gas atoms and the solid wall. Accommodation coefficient and condensation/evaporation coefficients are used to express these velocity boundary conditions. In this work, we have developed a kinetic boundary condition model by a statistical learning study from the incident and reflected velocities of the gas molecules (methane) on the solid wall (quartz), collected from molecular dynamics simulations, using a Lennard Jones potential for methane molecules and a Buckingham potential for quartz. We first obtained the density profiles of the methane gas/liquid at the quartz surface as well as the residence time and the penetration depth of CH 4 in the quartz substrate. The value of the saturated vapor density obtained is in excellent agreement with those of the literature. Finally, we have determined the accommodation and condensation/evaporation coefficients.