| abstract |
The invention relates to an improved process for the production of very high quality base oils with simultaneous production of high quality middle distillates starting from feedstocks that are obtained from the distillation of crude or that are obtained from units for transformation and refining of the latter. The process according to the invention comprises a converting pretreatment stage of the feedstock and a catalytic dewaxing stage. The converting pretreatment stage takes place in the presence of a catalyst that contains at least one noble metal that is deposited on an acid substrate that is a particular silica-alumina. The catalytic dewaxing takes place in the presence of a catalyst with a zeolite base that is preferably selected from the group that is formed by zeolites of the TON-structural type (theta-1, ISI-1, ZSM-22, KZ-2, NU-10), and the zeolites ZSM-48, ZBM-30, EU-2, EU-11, ferrierite, EU-1 and EU-13, whereby the catalyst also contains at least one hydro-dehydrogenating element. |