Abstract: A process for the preparation of a catalyst from a catalytic precursor comprising a support based on alumina and/or silica-alumina and/or zeolite and comprising at least one element of group VIB and optionally at least one element of group VIII, by impregnation of said precursor with a solution of a C1-C4 dialkyl succinate. An impregnation step for impregnation of said precursor which is dried, calcined or regenerated, with at least one solution containing at least one carboxylic acid other than acetic acid, then maturing and drying at a temperature less than or equal to 200° C., optionally a heat treatment at a temperature lower than 350° C., followed by an impregnation step with a solution containing at least one C1-C4 dialkyl succinate followed by maturing and drying at a temperature less than 200° C. without subsequent calcination step. The catalyst is used in hydrotreatment and/or hydroconversion.

Abstract: A catalyst usable in hydrotreatment processes: an alumina-based amorphous support, phosphorus, a C1-C4 dialkyl succinate, acetic acid and a hydro-dehydrogenizing function of at least one group VIII element and at least one group VIB element, preferably made up of cobalt and molybdenum, a catalyst whose Raman spectrum comprises the most intense bands characteristic of the Keggin heteropolyanions (974 and/or 990 cm?1), C1-C4 dialkyl succinate and acetic acid (896 cm?1). Preferably, the dialkyl succinate concerned is dimethyl succinate and its main band is at 853 cm?1.

Abstract: The invention relates to a catalyst usable in hydrotreatment processes, which comprises an alumina-based amorphous support, phosphorus, a C1-C4 dialkyl succinate, acetic acid and a hydro-dehydrogenizing function comprising at least one group VIII element and at least one group VIB element, preferably made up of cobalt and molybdenum, a catalyst whose Raman spectrum comprises the most intense bands characteristic of the Keggin heteropolyanions (974 and/or 990 cm?1), C1-C4 dialkyl succinate and acetic acid (896 cm?1). Preferably, the dialkyl succinate concerned is dimethyl succinate and its main band is at 853 cm?1. The invention also relates to the method of preparing said catalyst, wherein a catalytic precursor comprising the group VIB and group VIII elements, in particular the molybdenum-cobalt pair, and phosphorus, introduced by impregnation, then dried at a temperature below 180° C.

Abstract: The invention relates to a process for sulfurization of catalysts for hydrotreatment, in particular the catalysts for hydrotreating refractory oxides by sulfurization, in which said catalysts are subjected to a sulfurization stage under a gas atmosphere that contains hydrogen sulfide (H2S), hydrogen (H2), and optionally a cover gas for dilution and in which the H2S/H2 molar ratio is more than 4 and the H2S partial pressure is at least equal to 1 kPa. Said sulfurization stage can be carried out in the hydrotreatment unit (sulfurization in situ) or, prior to the charging of the catalyst, in the hydrotreatment unit (sulfurization ex situ) and is generally carried out at a temperature of less than 600° C., preferably less than 500° C. The invention also relates to the catalysts that are sulfurized by said sulfurization process and their use for hydrorefining and/or hydroconversion/hydrocracking of hydrocarbon feedstocks.

Abstract: The invention relates to a process for sulfurization of catalysts for hydrotreatment, in particular the catalysts for hydrotreating refractory oxides by sulfurization, in which said catalysts are subjected to a sulfurization stage under a gas atmosphere that contains hydrogen sulfide (H2S), hydrogen (H2), and optionally a cover gas for dilution and in which the H2S/H2 molar ratio is more than 4 and the H2S partial pressure is at least equal to 1 kPa. Said sulfurization stage can be carried out in the hydrotreatment unit (sulfurization in situ) or, prior to the charging of the catalyst, in the hydrotreatment unit (sulfurization ex situ) and is generally carried out at a temperature of less than 600° C., preferably less than 500° C. The invention also relates to the catalysts that are sulfurized by said sulfurization process and their use for hydrorefining and/or hydroconversion/hydrocracking of hydrocarbon feedstocks.