Simulation of hydroxycinnamic acids (caffeic, p-coumaric, ferulic, synapic) in pure and modified by polar cosolvents (methanol, acetone) supercritical carbon dioxide has been carried out using classical molecular dynamics. Dependences of solvation free energies of the acids on the pressure and cosolvent mole fraction have been calculated using Bennett's acceptance ratio method. When a polar cosolvent is added, the solvation free energy decreases sharply, and with a subsequent increase in its concentration, it changes slightly. The cosolvent-induced effect decreases with increasing pressure. The structural parameters characterizing the selective solvation of the acids have been calculated. A correlation between the cosolvent-induced solubility enhancement and the average number of solute - cosolvent hydrogen bonds has been found. (C) 2019 Published by Elsevier B.V.