Abstract: The present invention relates to a process for activating catalysts for isomerizing aromatic compounds containing 8 carbon atoms, the catalysts containing at least one group VIII metal, comprising at least one sulfurization and at least one passivation using ammonia.

Abstract: Process for isomerization of a feedstock that contains aromatic compounds with eight carbon atoms characterized in that it comprises at least one isomerization stage a) that is carried out in the presence of a catalyst that contains at least one metal of group VIII and that is activated according to an activation process that comprises at least one sulfurization stage and at least one stage for passivation with ammonia, and at least one dehydrogenation stage b).

Abstract: This invention relates to a process for synthesis of an EUO-structural-type zeolite that comprises at least one element X that is selected from among silicon and germanium and at least one element T that is selected from among aluminum, iron, gallium, boron, titanium, vanadium, zirconium, molybdenum, arsenic, antimony, chromium and manganese, whereby said process is carried out in the presence of an organic structuring agent that is derived from dibenzyldimethylammonium (DEDMA) or its precursors and in the presence of nuclei of at least one zeolitic material of the same structure as the zeolite that is to be synthesized. The zeolite that is thus obtained has an X/T ratio of between 5 and 50. It is used in particular as a catalyst, for example in a process for isomerization of aromatic compounds with 8 carbon atoms per molecule.

Abstract: The present invention relates to a process for isomerizing aromatic compounds containing 8 carbon atoms, the catalysts containing at least one group VIII metal, comprising at least one sulfurization step and at least one passivation step using ammonia.

Abstract: A novel catalyst comprises at least one support and at least one metal from group VIII or the periodic table e.g. palladium and is characterized in that the metal particles deposited on the support are not isolated from each other, e.g. at least 50% of the particles have a point of contact with one other particle.

Abstract: The present invention relates to a process for isomerizing aromatic C8 cuts in the presence of a catalyst containing a mordenite which is slightly or not dealuminated and a binder. This mordenite is generally present at least in part in its acid form and its Si/Al atomic ratio is less than 20, preferably in the range 5 to 15, and more preferably in the range 5 to 10. The catalyst also contains at least one metal from group VIII of the periodic table, preferably selected from the group formed by palladium and platinum. Finally, the catalyst further contains at least one metal from group III of the periodic table, namely gallium, indium or thallium, preferably indium, and optionally at least one metal from group IV of the periodic table, namely germanium, tin or lead, preferably tin. The present invention also relates to the catalyst used in the isomerization process and to a process for its preparation.

Abstract: A C.sub.8 aromatic feedstock is isomerized by an isomerization stage conducted at 320-380.degree. C. with a catalyst containing at least one EUO-structure-type zeolite and at least one metal of group VIII, to obtain an effluent containing isomerized alkyl aromatics and about 10-30% by weight of naphthenes. The effluent is then subjected to a dehydrogenation stage so as to convert the naphthenes to additional alkyl aromatics.

Abstract: The invention concerns a catalyst comprising at least one zeolite with structure type EUO for example EU-1, at least partialy in its acid form, at least one matrix, and at least one metal from group VIII of the periodic table. the zeolite comprising silicon and at least one element T selected from the group formed by aluminium, iron, gallium and boron (preferably aluminium and boron), with a global Si/T atomic ratio over 5, the catalyst being characterized in that the dispersion of the group VIII metal is in the range 50% to 100%, limits included, and the macroscopic distribution coefficient of the group VIII metal is in the range 0.7 to 1.3, limits included, the catalyst having a mechanical strength such that the bed crush strength is more than 0.7 MPa. The invention also relates to the preparation of the catalyst and to the use of the catalyst in a process for isomerizing aromatic compounds containing 8 carbon atoms per molecule.

Abstract: A catalyst for transforming aromatic hydrocarbons, preferably for dismutation of toluene to produce benzene and xylenes and transalkylation of toluene and aromatic compounds containing at least 9 carbon atoms per molecule, preferably trimethylbenzenes, to produce xylenes, contains a mordenite in its acid form in a proportion of 40% to 90% by weight and a binder, which is preferably alumina, and which is generally present in a proportion of 10% to 60% by weight. The mordenite contains less than 0.1% by weight of sodium and has a SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of over 40-60.