<p>In this work, Keggin heteropolyacid cesium salts were evaluated as solid catalysts in reactions to obtain terpene acetals, which are attractive products to the pharmaceutical and fine chemical industries. Salts of cesium (Cs₃PW₁₂O₄₀, Cs₃PMo₁₂O₄₀, and Cs₄SiW₁₂O₄₀) were obtained through precipitation of Keggin heteropolyacids with Cs₂CO₃ and used in reactions of condensation of β-citronellal with alkyl alcohols (methyl, ethyl, propyl, butyl, and isopropyl) at room temperature. Among the salts tested, the Cs_2.5H_0.5PW₁₂O₄₀ was the most active and selective catalyst toward the β-citronellyl methyl acetal. The superior performance of cesium phosphotungstate salt was assigned to the increase in acidity strength of protons remaining in the phosphotungstate anion, whereas the observed difference in the two other cesium heteropoly salts. The effects of temperature, time, alcohol nature, and catalyst load were evaluated. The use of solid, easily synthesizable, and non-corrosive catalysts in acetalization reactions at room temperature comprises a positive aspect of this process.</p> Graphical abstract <p></p>