Abstract: The method of using a bi-functional catalyst for the one-step preparation of para-aminophenol. The catalyst includes a mixture of a hydrogenation noble metal and a zirconium sulfate. Also, an improved single-step process for the preparation of para-aminophenol from nitrobenzene, in an aqueous medium, using the bi-functional catalyst.

Abstract: The method of using a bi-functional catalyst for the one-step preparation of para-aminophenol. The catalyst includes a mixture of a hydrogenation noble metal and a zirconium sulfate. Also, an improved single-step process for the preparation of para-aminophenol from nitrobenzene, in an aqueous medium, using the bi-functional catalyst.

Abstract: The invention concerns solids comprising a single tungsten oxide layer on a zirconia support and/or titanium dioxide support, characterized in that the tungsten exhibits tetrahedral co-ordination, before and after calcining. The invention also concerns the method for preparing the solids, and their uses as acid catalysis reactions catalyst.

Abstract: The invention concerns the use of a solid basic catalyst comprising a hydrotalcite structure wherein part at least of the compensating anions are fluoride anions F? for producing Knoevenagel of Michael condensation reactions. The invention also concerns novel solid basic catalysts comprising a hydrotalcite structure characterized by a Mg/Al molar ratio ranging between 2.5 and 3.8 wherein at least part of the compensating anions are fluoride anions F?, and methods for preparing said novel catalysts.

Abstract: The invention concerns solids comprising a single tungsten oxide layer on a zirconia support and/or titanium dioxide support, characterized in that the tungsten exhibits tetrahedral co-ordination, before and after calcining. The invention also concerns the method for preparing the solids, and their uses as acid catalysis reactions catalyst.

Abstract: The invention concerns the use of a solid basic catalyst comprising a hydrotalcite structure wherein part at least of the compensating anions are fluoride anions F? for producing Knoevenagel of Michael condensation reactions. The invention also concerns novel solid basic catalysts comprising a hydrotalcite structure characterised by a Mg/Al molar ratio ranging between 2.5 and 3.8 wherein at least part of the compensating anions are fluoride anions F?, and methods for preparing said novel catalysts.

Abstract: The invention concerns the use of a solid basic catalyst comprising a hydrotalcite structure wherein part at least of the compensating anions are fluoride anions F for producing Knoevenagel or Michael condensation reactions. The invention also concerns novel solid basic catalysts comprising a hydrotalcite structure characterised by a Mg/Al molar ratio ranging between 2.5 and 3.8 wherein at least part of the compensating anions are fluoride anions F, and methods for preparing said novel catalysts.

Abstract: This invention relates to a new zeolite from the class of mazzite, containing a fraction of non-exchangeable potassium cations, and also to a process for its synthesis. The crystallinity and the adsorption capacity of the protonated form of this zeolite are maintained after a prolonged hydrothermal treatment.

Abstract: This invention relates to a new zeolite from the class of mazzite, containing a fraction of non-exchangeable potassium cations, and also to a process for its synthesis. The crystallinity and the adsorption capacity of the protonated form of this zeolite are maintained after a prolonged hydrothermal treatment.

Abstract: The invention relates to a process for isomerizing normal paraffins, particularly C.sub.5 -C.sub.6, in the presence of at least one catalyst based on an omega zeolite having a molar ratio SiO.sub.2 /Al.sub.2 O.sub.3 ranging from 6.5 to 80, a content by weight of sodium lower than 0.2%, crystalline parameters "a" and "c" respectively smaller than or equal to 1.814 nm and 0.760 nm, a capacity of adsorption of nitrogen, measured at 77K under a partial pressure of 0.19, higher than about 8% by weight, the catalyst also comprising at least one metal from group VIII of the periodic table of elements, preferably platinum or/and palladium.

Abstract: The present invention concerns binary zeolitic systems comprising two zeolites A and B having different crystalline structures while having common structural units. The crystals of the zeolite A form a central core surrounded by a crown of crystals of zeolite B, the zeolites A and B being disposed concentrically and following the same longitudinal axis. These systems are formed by the introduction of a nucleation gel containing germs of the zeolite A in a growth gel where the crystallization parameters are favorable to the crystallization of the zeolite B. The binary zeolitic systems are useful as catalysts for transforming hydrocarbons and more especially as cracking catalysts.

Abstract: This invention concerns an omega type zeolite of high thermal stability, present in the form of hexagonal prismatic monocrystals having scored or plane faces of 0.1 .mu.m in edge and 0.5 to 5 .mu.m in length, this zeolite being obtained through crystallization from a mother solution containing a silica source, alumina, metallic oxide, an organic cation and water, in which the alumina source is a crystalline aluminosilicate of which at least one part is in suspension in the mother solution. In its acid form this zeolite can be used as catalyst for hydration of olefins and isomeric change of xylenes.

Abstract: The present invention concerns binary zeolitic systems comprising two zeolites A and B having different crystalline structures while having common structural units. The crystals of the zeolite A form a central core surrounded by a crown of crystals of zeolite B, the zeolites A and B being disposed concentrically and following the same longitudinal axis. These systems are formed by the introduction of a nucleation gel containing seeds of the zeolite A in a growth gel where the crystallization parameters are favorable to the crystallization of the zeolite B. The binary zeolitic systems are useful as catalysts for transforming hydrocarbons and more especially as cracking catalysts.

Abstract: A crystalline alumino-silicate having a powder X-ray diffraction diagram, a specific area, and a porous volume to nitrogen corresponding to offretite, and containing at least one metal selected from the groups I, II, VI, VII, VII, rare earth group, and/or at least an ammonium or quaternary ammonium group, presenting an aspect of the crystals as observed by electron microscopy in the form of hexagonal prisms with well defined edges of a length of 0.5 to 2.5 micrometers and a width of 0.1 to 1 micrometer.

Abstract: There are provided clays of laminated structure bridged by metallic oxides selected from oxides of aluminum and zirconium and containing from 10 to 50% and preferably from 20 to 40% of an oxide of the metal of the group of the lanthanides, preferably of cerium. The presence of cerium improves the thermal resistance during a dry calcination or even under humid air. The clays can be used as catalysts during the conversion of hydrocarbons.

Abstract: A process for the preparation of aliphatic alcohols by hydration of olefins in the presence of a catalyst comprising a zeolitic crystalline silicoaluminate of the offretite type. The offretite used can be natural or sythetic. Particularly convenient among the olefins are olefins of low molecular weight having up to 5 carbon atoms. The alcohols obtained are used as solvents, as bases for lubricants and as adjuvants of essences.