This study addresses the diffusion coefficient CO2 into light-hydrocarbons. Experiments were done under nonisothermal and nonisobaric conditions, using dynamic pendant drop volume analysis to measure the change in hydrocarbon drop volume due to CO2 diffusion, for 25-45 degrees C and 25-65 bar. A new numerical model was developed, where a spherical drop was used rather than the actual pendant shaped drop, which enabled sensitivity studies. The approach showed 3-6% difference in the surface area of the spherical drop compared to experimental drop. This is translated to less than 6% difference when compared to the published data. Interfacial tension investigations showed a change from a negative (decreasing) to positive (increasing) trend with temperature for pressures 30-60 bar. A suggested explanation was based on the density difference between the drop (CO2+hydrocarbon) and the surrounding CO2. Further, the observed higher diffusion coefficient of n-hexane compared to n-decane may be attributed to viscosity.