Abstract: A process for transforming a gas oil cut into a dearomatized fuel with a high cetane number comprises at least one first, deep desulphurization and deep denitrogenation step in which the gas oil cut and hydrogen are passed over a catalyst comprising a mineral support, at least one group VIB metal or metal compound, at least one group VIII metal or metal compound, and phosphorous or at least one phosphorous compound, and at least one subsequent second step, dearomatization, in which the desulphurized and denitrogenated product from the first step is passed with hydrogen over a catalyst comprising a mineral support and at least one group VIII noble metal or noble metal compound.

Abstract: The invention concerns a process for improving the pour point of a feed comprising paraffins containing more than 10 carbon atoms, in which process the feed to be treated is brought into contact with a catalyst comprising an NU-87 zeolite comprising silicon and at least one clement T selected from the group formed by Al, Fe, Ga and B, from which at least a portion of clement T has been removed, and having a global Si/T ratio of over 20, the catalyst also containing at least one hydro-dehydrogenating element. The process is carried out at a temperature which is in the range 170.degree. C. to 500.degree. C., a pressure in the range 1 to 250 bar and at an hourly space velocity in the range 0.05 to 100 h.sup.-1, in the presence of hydrogen in a proportion of 50 to 2000 l/l of feed. The oils obtained have good pour points and high viscosity indices (VI). The process is also applicable to gas oils and other feeds requiring a reduction of pour point. The catalyst is also claimed.

Abstract: The invention concerns a hydrotreated catalyst comprising a support, at least one group VI metal, silicon, boron, optionally at least one metal from group VIII of the periodic table, optionally phosphorus, and optionally a halogen, also a particular preparation of this catalyst. The invention also concerns the use of the catalyst for hydrotreating hydrocarbon feeds.

Abstract: The invention concerns a process for the selective hydroisomerisation of compounds containing at least one n-alkane chain containing more than 10 carbon atoms, in which the compound to be treated is brought into contact with a catalyst comprising at least one hydro-dehydrogenating element and at least one molecular sieve with a mono- or bidimensional pore network in which the openings of the accessible pores are delimited by 10 oxygen atoms, and the distance termed the bridge width between the pores is less than 0.70 nm, and in which the catalyst, when subjected to a standard n-heptadecane isomerization test, has a selectivity of at least 70% towards isomerized products for a conversion of 95%.The sieve is preferably a NU-10, NU-23, NU-87, EU-13 or Theta-1 zeolite.

Abstract: The invention relates to a process for improving the pour point of a feedstock that comprises paraffins of more than 10 carbon atoms, in which the feedstock that is to be treated is brought into contact with a catalyst that comprises the IM-5 zeolite and at least one hydro-dehydrogenating element, at a temperature of between 170 and 500.degree. C., a pressure of between 1 and 250 bar, and an hourly volume velocity of between 0.05 and 100 h.sup.-1, in the presence of hydrogen at a ratio of 50 to 2000 l/l of feedstock. The oils that are obtained have good pour points and high viscosity indices (VI). The process can also be applied to gas-oils and other feedstocks whose pour points need to be lowered.

Abstract: A mild hydroconversion process for petroleum cuts using a catalyst comprising at least one matrix, at least one Y zeolite with a lattice parameter which is in the range 24.15 .ANG. to 24.38 .ANG. (1 nm--10 .ANG.), at least one Y zeolite with a lattice parameter of more than 24.38 .ANG. and less than or equal to 24.51 .ANG., and at least one hydro-dehydrogenating element.

Abstract: The invention concerns a process for improving the pour point of a feed comprising paraffins containing more than 10 carbon atoms, in which process the feed to be treated is brought into contact with a catalyst comprising NU-86 zeolite, preferably dealuminated, and at least one hydro-dehydrogenating element, at a temperature which is in the range 170.degree. C. to 500.degree. C., a pressure in the range 1 to 250 bar and an hourly space velocity in the range 0.05 to 100 h.sup.-1, in the presence of hydrogen in a proportion of 50 to 2000 l/l of feed. The product from heavy feeds is fractionated to produce at least one cut including at least one middle distillate with a reduced pour point, and a residue including oil bases with a reduced pour point and a high viscosity index.

Abstract: The invention concerns a composition comprising at least one matrix, at least one faujasite type zeolite and at least one TON type zeolite. The TON type zeolite can be Nu-10, THETA-1, KZ-2, or ISI-1. The catalyst also contains at least one hydrogenating element from groups VIII and VI.The catalyst is particularly for use for hydrocracking to maximize the yield of middle distillates (kerosine and gas oil).