Patent ID: 7270738

Claim:
A catalyst comprising: at least one hydro-dehydrogenating element which is an element of group VIB or of group VIII of the periodic table, a non-zeolitic silica-alumina-based substrate containing an amount of more than 10% by weight and less than or equal to 80% by weight of silica (SiO 2 ), a mean pore diameter, measured by mercury porosimetry, between 20 and 140 Å, a total pore volume, measured by mercury porosimetry, between 0.1 ml/g and 0.6 ml/g, a total pore volume, measured by nitrogen porosimetry, between 0.1 ml/g and 0.6 ml/g, a BET specific surface area between 150 and 500 m 2 /g, a pore volume, measured by mercury porosimetry, in the pores with diameters of more than 140 Å, of less than 0.1 ml/g, a pore volume, measured by mercury porosimetry, in the pores with diameters of more than 160 Å, of less than 0.1 ml/g, a pore volume, measured by mercury porosimetry, in the pores with diameters of more than 200 Å, of less than 0.1 ml/g, a pore volume, measured by mercury porosimetry, in the pores with diameters of more than 500 Å, of less than 0.01 ml/g, a pore distribution such that the ratio between volume V2, measured by mercury porosimetry, between D mean −30 Å and D mean +30 Å to the total mercury volume is more than 0.6−volume V3, measured by mercury porosimetry, in the pores with diameters of more than D mean +30 Å is less than 0.1 ml/g−volume V6, measured by mercury porosimetry, in the pores with diameters of more than D mean +15 Å is less than 0.2 ml/g, an X ray diffraction diagram that contains at least the main lines that are characteristic of at least one of a transition alumina, which is an alpha, rho, chi, eta, gamma, kappa, theta or delta alumina.