Abstract: An active catalyst in the polymerization of alpha-olefins is obtained by:(i) bringing a dialkyl magnesium, or an alkyl magnesium halide into contact with a silicon or tin halide, in solution in an inert organic solvent, until a granular solid precipitates off;(ii) suspending said solid precipitate in an inert organic solvent and bringing it into contact with a compound which can be defined by the formula: ##STR1## wherein M represents a metal from Group IVB of the Periodic Table of Elements, and each R and C.sub.p has the meaning as reported in the disclosure, in order to form a granular solid catalyst; and(iii) recovering said solid catalyst from the resulting suspension.

Abstract: Process for preparing elastomeric copolymers of ethylene-propylene (EPM) type and elastomeric terpolymers of ethylene-propylene-diene (EPDM) type with a propylene content comprised within the range of from 15 to 75%, carried out in the presence of metallocenes of formula (I) ##STR1##

Abstract: Complexes of lanthanides are described, which are effective in the polymerization of conjugated dienes, obtained by reacting LnX.sub.3 with at least one Lithium compound selected from:(i) Li(A), the molar ratio Li(A)/LnX.sub.3 being from 1.5 to 2.5;(ii) LiLn(A).sub.4, the molar ratio between LiLn(A).sub.4 and LnX.sub.3 being from 0.5 to 1.5;wherein Ln is selected from any of the Lanthanides; X is selected from halides, carboxylates, alcoholates, --N(R.sub.x) (R.sub.y) wherein R.sub.x and R.sub.y, the same or different, are C.sub.1 -C.sub.5 alkyl radicals;A is an allyl radical having the general formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5, the same or different, are selected from hydrogen and C.sub.1 -C.sub.10 alkyl radicals.

Abstract: Process for the preparation of vinylaromatic copolymers reinforced with rubber which comprises:a) dissolving a dienic rubber (i) and/or a linear block elastomer, vinylaromatic monomer-1,3 conjugated diene (ii), in a mixture comprising at least one vinylaromatic monomer and a pair of solvents consisting of a polar solvent and a nonpolar solvent;b) polymerizing the solution thus obtained, possibly in the presence of an initiator.

Abstract: Process for the production of epoxides by the reaction of at least one olefin and hydrogen peroxide, or a compound capable of producing hydrogen peroxide under the reaction conditions, in the presence of a catalyst consisting of titanium silicalite subjected to ion exchange treatment with metal cations (M.sup.n+) present on the catalyst in a quantity ranging from 0.01 to 1% by weight with respect to the total weight.

Abstract: 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.

Abstract: The present invention relates to a continuous process for the selective cross-linking of the dispersed phase of polymers based on acrylonitrile/ethylene-propylene-diene monomer (EPDM) rubber/styrene (AES), which comprises: a) addition to the polymer, which leaves the end of the synthesis plant still in the molten state, of cross-linking substances and coreagents; b) passing the compound through suitable mixing equipment.

Abstract: The invention relates to a process for the hydroxylation of aromatic hydrocarbons by direct oxidation with hydrogen peroxide. The process is carried out in the presence of a catalyst comprising:iron, administered as an inorganic salt;a carboxylic acid of an aromatic compound containing nitrogen, in particular a pyrazin-2-carboxylic acid or derivative;acidifying agent, especially trifluoracetic acid, and a solvent system comprising an organic phase consisting of a substrate and acetonitrile and an aqueous phase containing the catalyst and hydrogen peroxide.

Abstract: Process for the preparation of manufactured products based on vinylaromatic polymers with a predominantly syndiotactic structure which comprises:a) compressing the polymer in powder form in a mould at a pressure ranging from 0.1 to 500 MPa;b) sintering, under pressure, the compact powder at a temperature ranging from the glass transition temperature (Tg) of the polymer to the melting temperature (Tm);c) cooling the manufactured product to room temperature.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing the vinylaromatic monomers, alone or mixed with at least another copolymerizable ethylenically unsaturated monomer, in the presence of a catalytic system essentially consisting of:a) an adduct between a derivative of titanium having the formula R.sub.1 R.sub.2 R.sub.3 R.sub.4 Ti and a calix-[n]-arene, or an oxa-calix-[n]-arene;b) a co-catalyst selected from an alkylalumoxane and a compound of boron having the formula (II):BX.sub.1 X.sub.2 X.sub.3or its salt.

Abstract: This dialkylmagnesium is represented by the formula R--(CH.sub.2 --CH.sub.2).sub.n --Mg--(CH.sub.2 --CH.sub.2).sub.n' --R', (E--O--E').sub.x, where R and R' each independently represent a C.sub.1 -C.sub.20 hydrocarbon residue, branched or not, substituted or not, of the alkyl, cycloalkyl or aralkyl type; n and n', identical or substantially identical, represent an average number of --CH.sub.2 --CH.sub.2 -- linkages such that the average number of carbon atoms in each of the two chains borne by Mg is greater than 20; E and E', identical or different, each represent an alkyl radical, linear or cyclical, branched or not; and 0.ltoreq.x.ltoreq.2, x being the average value of the number of moles of E--O--E' ether complexed to the dialkylmagnesium. In order to prepare a dialkylmagnesium of this type, ethylene is polymerized in an anhydrous, de-oxygenated hydrocarbonaceous solution by means of a catalyst Cp*.sub.2 MCl.sub.2 Li(OEt.sub.2).sub.

Abstract: Process for the production of epoxides by reaction between at least one olefin and hydrogen peroxide, or a compound capable of producing hydrogen peroxide under the reaction conditions, in the presence of a catalyst consisting of titanium silicalite subjected to treatment with organic molecules comprising an amide group substituted on the nitrogen atom.

Abstract: A catalytic composition is described for the alkylation and/or transalkylation of aromatic hydrocarbons consisting of beta zeolite, as such or modified by the isomorphous substitution of aluminum with boron, iron or gallium or by the introduction of alkaline and/or earth alkaline metals following an ion-exchange process, and an inorganic ligand, wherein the extrazeolite porosity, i.e. the porosity obtained by adding the mesoporosity and macroporosity fractions present in the catalytic composition itself, is such that a fraction of at least 25% is composed of pores with a radius higher than 100 .ANG., said composition being characterized by a total volume of extrazeolitic pores greater than or equal to 0.80 ml/g.

Abstract: A process is described for preparing monoalkylated aromatic compounds which comprises subjecting an aromatic hydrocarbon to alkylation with an olefin containing from 2 to 4 carbon atoms, or to transalkylation with a polyalkylaromatic hydrocarbon, in the presence of ERS-10 zeolite.

Abstract: 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.

Abstract: Integrated process for the production of butene-1 which comprises feeding a C.sub.4 hydrocarbon stream to a separation unit of butene-1 and recycling the remaining stream to the same unit after treatment in a bond isomerization section to convert the remaining butenes-2 into butene-1, a molecular sieve separation unit is inserted in the cycle operating with the hydrocarbons in a vapour phase, for the purge of the paraffins.

Abstract: Catalytic component for the copolymerization of ethylene with alpha-olefins having general formula (I): ##STR1## wherein: A is a cyclopentadienyl derivative having general formula (II) ##STR2## B is selected from: 1) any of the cyclopentadienyl derivatives A defined above2) a monofunctional cyclopentadienyl radical (F) selected from cyclopentadienyl, indenyl, fluorenyl and the relative alkyl, aryl, trialkylsilyl substituted derivatives;Q, a bridge between A and B, is a bifunctional radical.

Abstract: The preparation of objects, in particular optical components and/or devices, is described using, as precursors of optical materials, amorphous monolithic aerogels for high-precision mechanical machining.

Abstract: Catalytic composition effective in the selective hydrogenation of olefinic double bonds prepared by the reaction between:(A) at least one bis(cyclopentadienyl)Titanium derivative having the general formula (I) (C.sub.5 H.sub.5).sub.2 Ti(R) (R.sub.1) wherein R and R.sub.1, the same or different, are halogens; the above compound (I) being solid or dispersed in one or more non-solvent diluents;(B) at least one organo derivative having general formula (II) M(R.sub.2) (R.sub.3) wherein M is selected from Zinc and Magnesium, and R.sub.2 and R.sub.3, the same or different, are selected from C.sub.1 -C.sub.16 alkyls;(C) at least one modifier.

Abstract: Process for manufacturing vinyl-aromatic polymers reinforced with rubber and with bimodal morphology of the rubber phase, which process comprises:blending a first stream of a first vinyl-aromatic prepolymer, containing a fine-particle rubber phase prepared in a reactor of PFR type, with a second stream consisting of a larger-particle prepolymer, prepared in a CFSTR (Continuous Flow Stirred Tank Reactor);completing the polymerization until a rubber-reinforced vinyl-aromatic polymer with bimodal morphology is obtained, which is characterized by a considerable improvement in mechanical synergism associated with excellent aesthetic properties.