Abstract:
PURPOSE: An MFI-type zeolite based catalyst and its preparation method are provided, which catalyst is useful for the transformation of oximes into amides. CONSTITUTION: The MFI-type zeolite based catalyst is prepared by: preparing silicate oligomer by hydrolyzing silicon alkoxide; mixing the oligomer with an aqueous or aqueous alcoholic dispersion solution of sub micro particles of MFI-type zeolite which is acidified to pH below 5; emulsifying the aqueous or aqueous alcoholic ligand/zeolite mixture in an organic solvent; contacting the emulsion with a basic solution to bind the dispersed micro drops; and washing calcining the obtained micro sphere. Preferably the MFI-type zeolite is selected from the zeolite whose mole ratio of Si/Al (or Si/B, Si/Ga, Si/In, or Si/Ti) is more than 1,000, and silicalite-1. The MFI-type zeolite based catalyst is such that the silicate ligand represented by SiO2 is more than 30 wt%, the outer surface area is 60-80 square meter per gram, the specific volumes of micro pore and mesopore are 0.2-0.3 ml/g and 0.1-0.4 ml/g, respectively, the bulk density is 0.7-0.85 g/ml, and the Davison index is less than 6.
Abstract:
A process is described for regenerating exhausted zeolitic catalysts containing titanium and deriving from oxidation processes of organic substrates with hydrogen peroxide. Said process consists in carrying out a treatment in an aqueous medium with hydrogen peroxide in the presence of inorganic fluorinated compounds, subsequent to thermal treatment of the exhausted catalyst.
Abstract:
PURPOSE: To regenerate an exhausted zeolitic catalyst resulting from the oxidation process of an organic substrate using hydrogen peroxide and containing titanium. CONSTITUTION: The process for the regeneration of exhausted catalysts consisting of microporous crystalline materials with an MFI-type structure containing titanium and originally having a composition corresponding to the following chemical formula: xTiO 2·(1-x)SiO2, wherein x ranges from 0.0001 to 0.04 and preferably from 0.01 to 0.03, which consists in subjecting the catalyst, previously calcined, to a treatment in an aqueous medium with hydrogen peroxide, in the presence of fluorinated inorganic compounds.