The invention relates to a process for the preparation of a catalyst composition comprising the steps of: A) preparing a salt of boric acid or phosphoric acid and a bivalent or trivalent metal and B) mixing the salt obtained by step A) with a crystalline aluminosilicate zeolite of the faujasite structure with SiO2/Al2O3 mole ratio in the range of about 2 to about 8 and including potassium, rubidium or cesium cations or combinations thereof, wherein step A) comprises the sub-steps of A1) mixing a borate or a phosphate of an alkali metal and a water soluble salt of the bivalent or trivalent metal to obtain a suspension, A2) adding an alkaline solution to the suspension obtained by sub-step A1) to obtain a solution having a pH of 7.0-11.5 and A3) mixing the solution obtained by sub-step A2) to obtain the salt.