Process for producing ethers by reacting a catalytic cracking C.sub.4 olefinic cut which may contain such impurities as NaOH, an alkanolamine, an alkaline earth metal compound or an iron, copper or lead compound, with an alcohol, in the liquid phase, in the presence of an expanded bed of an etherification solid catalyst of the sulfonic resin type in acid form, in a circuit of two or more successive reaction zones wherethrough the order of passage of the reactants is periodically modified by disconnecting the first zone from the circuit, feeding the reactants to the second zone, replacing the catalyst of the first zone with fresh catalyst and thereafter connecting said first zone at the end of the circuit.