The kinetics of the three-phase methanol synthesis over a commercial Cu-Zn-Al2O3 catalyst were studied in an apolar solvent, squalane and a polar solvent, tetraethylene glycol dimethylether (TEGDME). Experimental conditions were varied as follows: P = 3.0-5.3 MPa, T = 488-533 K and Phi(vG)/w =7.5 x 10(-3)-8 x 10(-3) Nm(3) s(-1) kg(cat)(-1). The nature of the slurry-liquid influences the activation energy and the kinetic rate constant by interaction between adsorbed species and solvent and by competitive adsorption of the solvent on the catalyst surface. The rate of reaction to methanol observed in TEGDME appeared to be about 10 times lower than in squalane. TEGDME reduces the reaction rate, which is a disadvantage for its use as a solvent.