Abstract: The invention concerns a process for synthesising aluminas with a controlled porosity in which the pore diameter is in the range 0.6 nm to 80 nm. This process is carried out in a plurality of steps including at least one step a) in which an alumina precursor is prepared by hydrolysis of at least one anionic inorganic source of aluminium in the presence of at least one surfactant. Step a) of the process is carried out in an essentially aqueous medium the pH of which is generally higher than the isoelectric point of the alumina. The process of the invention also comprises at least one step b) in which the precipitate obtained is dried in air at a temperature of about 40° C. to 110° C. for a period of about 2 to 30 hours, and at least one step c) in which the dried precipitate is calcined at a temperature which is sufficient to eliminate the molecules of surfactant present in the precursor.

Abstract: Hydrated aluminium compounds of the present invention are represented by the general formula nS, mM, Al2O3, xH2O where S is a surfactant or a group of surfactants, n is the number of moles of S, M is an alkaline cation, preferably selected from the group formed by Na+, K+, NH4+, m is the number of moles of M and x is the number of moles of water. The hydrated compounds are obtained from inorganic aluminium sources which are in the form of cation-monomers and/or cation-oligomers. The surfactants are anionic and/or non-ionic surfactants. When the group of surfactants comprises at least one anionic surfactant, at least one cationic surfactant can optionally be added.

Abstract: Novel calcined zeolites of MFI type, based on silica and germanium oxide, are well adapted for the catalysis, e.g., of hydrogenolysis, hydrogenation and reforming reactions, and have the general formula:(Si.sub.96-x Ge.sub.x)O.sub.192wherein x ranges from 0.1 to about 36.

Abstract: A process for preparing a metallosilicate catalyst includes the steps of: forming a mixture of at least one non-alkali metal, a templating agent, and an organic base; adding a silicon additive to the mixture so as to form a metallosilicate hydrogel; aging the hydrogel to obtain a crystalline metallosilicate composition; washing and drying the crystalline composition; and calcining the crystalline composition so as to provide a metallosilicate catalyst. Two or more non-alkali metals may be selected so as to provide a multifunctional catalyst.