Nopinone was successfully separated from a methanol-water mixed solvent using a DOW BW30 RO membrane via a dead end batch separation process. Overall, good membrane separation performance was observed with a high solute rejection (nearing 𝑅 = 1). Data analysis via the solution-diffusion model revealed the presence of convective transport, while the Spiegler-Kedem model obtained a reasonable system description when using a single coefficient for mass transfer description. Solute/solute permeability coefficients were obtained of order 10 -7 and 10 -8 , respectively, with a membrane selectivity of ~30 bar -1 .