example 5 is replaced by an equal volume of extrudates of the same dimension of mordenite zeolon 900h commercially sold by the norton company 3 69 l h of a gaseous mixture of n 2 ethyl acetate containing 66 7 ester by volume are passed over the catalyst at 300 u00b0 c in the reactor of example 1 during the course of the catalytic decomposition 55 of the ester is converted with the selectivity in acetic acid attaining 99 and the ethylene produced having a purity above 99 5 in the reactor of example 1 3 85 l h of a gaseous mixture of nitrogen and ethyl acetate containing 66 3 of ester by volume are passed at 300 u00b0 c over 30 ml of zeolite 13x in the form of spheres having a diameter of 1 4 mm to 2 4 mm supplied by the touzart and matignon company 13 of the ester is converted with a selectivity of 100 into ethylene and acetic acid the ethylene produced contains only trace amounts of methane and hydrocarbons containing three carbon atoms the catalyst of example 7 is subjected to washing with the help of an ammonium nitrate solution followed by a thermal treatment at 550 u00b0 c 30 ml of zeolite 13x thus partially acidified serve for the decomposition at 250 u00b0 c of the ethyl acetate contained at a concentration of 63 4 by volume in the 3 96 l h of gaseous mixture of n 2 ester passing over the catalyst in the reactor of example 1 22 of the ester is selectively converted into.