摘要:
Process for the alkylation of phenols comprising reacting a phenol with a vinyl-aromatic hydrocarbon in the presence of an acidic catalyst and of a solvent.
摘要:
Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p.-methylbenzyltrimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a ketone of the formula:Ch.sub.3 --CO--CH.sub.2 --R (I)wherein R is hydrogen, a halogen, or an alkyl-carboxylic group.
摘要:
A process for the preparation of (2,2)-paracyclophane by conversion of p.methylbenzyltrimethylammonium halide to the corresponding hydroxide and by Hofmann elimination from p.methylbenzyltrimethylammonium hydroxide, wherein both reactions are carried out in the same aqueous solution of an alkaline hydroxide and in the presence of a copper or iron compound.
摘要:
A method is described for improving the catalytic performances of titanium silicalite having formula (I) by the activation of the catalyst (I) in an aqueous medium with hydrogen peroxide, in the presence of precursors of fluoride ions or anionic species containing fluorine. The activated catalyst (I) is particularly useful in oxidation processes with hydrogen peroxide of organic substrates and, in particular, in hydroxylation reactions of aromatic compounds, amoximation reactions of carbonyl compounds, epoxidation reactions of olefinic compounds and oxidation reactions of nitrogenated compounds.
摘要:
The present invention relates to silica/zeolite composite materials in spherical form and the process for their preparation which occurs by the dispersion of submicronic particles of titanium silicalite, beta zeolite, or mixtures of beta zeolite with titanium silicalite, in a silica sol synthesized by acid hydrolysis of silicon alkoxides; the hybrid sol thus obtained, subjected to emulsification and gelation techniques in organic mediums, produces these materials in a spherical form with an average diameter of between 20 and 150 .mu.m and containing up to 70% by weight of titanium silicalite, beta zeolite or mixtures of titanium silicalite/beta zeolite.The materials of the invention, having a high mechanical resistance and characterized by a surface area of between 300 and 800 m.sup.2 /g, are applied as catalysts; in particular, those consisting of titanium silicalite or mixtures of titanium silicalite/beta zeolite are advantageously used in oxidation reactions of organic compounds with hydrogen peroxide.
摘要:
A process for producing a silane or siloxane compound containing at least one cycloalkyl ring by hydrogenation of a corresponding derivative containing at least one aromatic ring in the presence of a Raney nickel catalyst modified with chromium.
摘要:
An improved process is described for the synthesis of hydroxylated aromatic compounds by means of the oxidation of an aromatic substrate with hydrogen, peroxide in an organic solvent, in the presence of synthetic zeolites, wherein the improvement consists in the fact that the organic solvent is selected from compounds having general formula (I) ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4, the same or different, represent a hydrogen atom or an alkyl group with from 1 to 4 carbon atoms or from compounds having general formula (II) ##STR2## wherein R and R', the same or different, represent an alkyl radical with from 1 to 4 carbon atoms.
摘要:
Process for preparing porous spherical silica particles substantially consisting in emulsifying an acidic silica sol in a dispersing media, gelifying the microdrops of the sol in the emulsified state and submitting the resulting gel to thermal treatment in the presence of the emulsifier liquid and of sol gelation base.
摘要:
A process for the preparation of mixed silica-zirconia sols and mixed oxides in spherical form, comprising mixing a silicon alkoxide with a solution of an inorganic zirconium salt in a low molecular weight polyol and subjecting the intermediate thus formed to acid hydrolysis in a water medium.
摘要:
A process of producing a silanic or siloxanic compound containing at least one cycloalkyl ring by the hydrogenation of a corresponding compound containing at least one aromatic ring, in the presence of a Raney nickel catalyst having a granulometry comprised essentially between 10 and 150 micrometers and a surface area of at least 80 m.sup.2 /g.