Process for preparing a catalyst composition containing a modified crystalline aluminosilicate and a binder, wherein the catalyst composition comprises from 5 to 95 % by weight of crystalline aluminosilicate as based on the total weight of the catalyst composition, the process being characterized in that it comprises the following steps: a) providing a crystalline aluminosilicate having a Si/AI framework molar ratio greater than 10; b) optionally calcining said crystalline aluminosilicate; c) steaming said crystalline aluminosilicate: - at a temperature ranging from 100 °C to 380 °C; and - under a gas phase atmosphere, without liquid, containing from 5 wt % to 100 wt % of steam, the rest being one or more gas selected from N 2, CO 2, Ar, He, CH 4, air, or any mixture of thereof; with preference air is selected from air and depleted air containing below 10 wt% of oxygen as based on the total weight of the depleted air, preferably below 5 wt%, more preferably below 1 wt%; and - at a pressure ranging from 2 to 200 bars; - at a partial pressure of H 2 O ranging from 2 to 200 bars; and - said steaming being performed during at least 30 min and up to 144 h; and in that the process comprises a step of shaping, or of extruding, the crystalline aluminosilicate with a binder, wherein the binder is selected to comprise: - at least 85 wt % of silica as based on the total weight of the binder, and - less than 1000 ppm by weight as based on the total weight of the binder of aluminium, gallium, boron, iron and/or chromium. a) providing a crystalline aluminosilicate having a Si/AI framework molar ratio greater than 10; b) optionally calcining said crystalline aluminosilicate; c) steaming said crystalline aluminosilicate: - at a temperature ranging from 100 °C to 380 °C; and - under a gas phase atmosphere, without liquid, containing from 5 wt % to 100 wt % of steam, the rest being one or more gas selected from N 2, CO 2, Ar, He, CH 4, air, or any mixture of thereof; with preference air is selected from air and depleted air containing below 10 wt% of oxygen as based on the total weight of the depleted air, preferably below 5 wt%, more preferably below 1 wt%; and - at a pressure ranging from 2 to 200 bars; - at a partial pressure of H 2 O ranging from 2 to 200 bars; and - said steaming being performed during at least 30 min and up to 144 h; and in that the process comprises a step of shaping, or of extruding, the crystalline aluminosilicate with a binder, wherein the binder is selected to comprise: - at least 85 wt % of silica as based on the total weight of the binder, and - less than 1000 ppm by weight as based on the total weight of the binder of aluminium, gallium, boron, iron and/or chromium. - at a temperature ranging from 100 °C to 380 °C; and - under a gas phase atmosphere, without liquid, containing from 5 wt % to 100 wt % of steam, the rest being one or more gas selected from N 2, CO 2, Ar, He, CH 4, air, or any mixture of thereof; with preference air is selected from air and depleted air containing below 10 wt% of oxygen as based on the total weight of the depleted air, preferably below 5 wt%, more preferably below 1 wt%; and - at a pressure ranging from 2 to 200 bars; - at a partial pressure of H 2 O ranging from 2 to 200 bars; and - said steaming being performed during at least 30 min and up to 144 h; - at least 85 wt % of silica as based on the total weight of the binder, and - less than 1000 ppm by weight as based on the total weight of the binder of aluminium, gallium, boron, iron and/or chromium.