The effects of temperature and pressure on the equilibrium reaction of acetone and methanol to form a hemiketal (2-methoxy-2-propanol), when dissolved in either tetrahydorfuran or diethyl ether, are analyzed using the perturbed hard fluid (PHF) model. Experimental global reaction thermodynamic results (DeltaG,DeltaH,DeltaS,DeltaV,DeltaU,DeltaA) are obtained from pressure- and temperature-dependent calibrated Raman peak area measurements. The PHF theoretical analysis separates the effects of repulsive and attractive solute-solvent interactions by combining hard sphere fluid and van der Waals mean field approximations. The results offer a critical test of these approximations and elucidate the way in which the balance of repulsive and attractive interactions contribute to each reaction thermodynamic function. (C) 2003 American Institute of Physics.