| 摘要 |
1. A catalyst containing by weight : a) 1 to 70 % of a bridged clay pertaining to the group of smectites, having leaves spacing maintained by inserts consisting of oxides of at least one of the following elements : boron, magnesium, aluminium, phosphorus, silicium, titanium, chrominum, zirconium, molybdenum, tungsten. b) 1 to 70 % of a stabilized acid zeolite of Y type - having a molar ratio SiO2 /Al2 O3 of 8 to 70, - whose sodium content, as determined on the zeolite roasted at 1100 degrees C, is lower than 0.15 % by weight, - whose parameter ao elementary mesh ranges from 24.55x10**-10 m to 24.24x10**-10 m, - whose capacity CNa of retaking sodium ions, expressed in grams of sodium per 100 grams of modified, neutralized and roasted zeolite, is higher than about 0.85, - whose specific surface is higher than 400 m**2xg**1, - whose steam adsorption capacity at 25 degrees C is higher than 6 % by weight (at a P/Po ratio equal to 0.10) - whose pore distribution comprises from 1 to 20 % of pore volume contained in pores of a diameter ranging from 20x10**-10 m to 80x10**-10 m, the remainder of the pore volume being essentially contained in pores of a diameter lower than 20x10**-10 m. c) 5 to 97 % of an amorphous matrix consisting of free alumina of gamma, eta, delta or theta type or mixtures thereof or of alumina associated with at least one of the oxides of the following elements : boron, magnesium, silicium, phosphorus, calcium, titanium, vanadium, chromium, manganese, iron, gallium, yttrium, zirconium, tin, lanthanum, cerium, praseodymium, neodymium. d) at least one metal or compound of metal selected from the group consisting of noble of non noble metals from group VIII of the periodic classification of elements, the concentration of the one or more noble metals from group VIII, expressed in weight of this or these metals, ranging from 0.01 to 5 %, the concentration of the one or more non noble metals from group VIII, expressed by weight of this or these metals, ranging from 0.01 to 15 %.
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