Production of bio-based acetate is commonly hindered by the high costs of the downstream processing. In this paper, a model is developed to describe a new method that recovers acetate salts using anion exchange resins, and subsequently desorbs and upgrades them using CO2-expanded alcohol. The model consists of equilibrium parameters for both the adsorption and desorption step. The calculated parameters are: for the adsorption K-Cl-(Ac-) = 0.125, K-Cl-(HCO3-) = 0.206 and K-OV,K-HAC = 0.674mol/kg(resin)/mol/kg(solution), and for the desorption pK(MeCO3-)(Ac-) = 3.71. The maximum experimental concentration of acetic acid obtained in CO2-expanded methanol is 0.427 mol/kg (20 g/L-MeOH) at an operating pressure of 31 bar. The model represents the expected trends for all species, and can be used to design a multicolumn system for the recovery and upgrading of carboxylates.