Abstract: A catalyst for the polymerization of vinylaromatic monomers, and particularly styrene, with a high yield and a high syndiotacticity index, comprises the product consisting of the following two components in contact with each other: A) an &eegr;5-cyclopentadienyl complex of titanium; B) an organo-oxygenated compound of aluminum; and contains a sufficient amount of at least one carboxylated product having the following general formula: R—COO—G  (I) wherein R—COO is a carboxylic group comprising the organic radical R having from 1 to 30 carbon atoms, and G represents a hydrogen atom, an aliphatic or aromatic hydrocarbon group having from 1 to 20 carbon atoms or a metal atom, possibly substituted, linked to said carboxylic group.

Abstract: Effective catalyst in the selective hydrogenation of olefinic double bonds, comprising the reaction product between: (A) at least one cyclopentadienyl complex of a transition metal having the following general formula (I): (R)M(R1)(R2)(R3)  (I)  wherein: M is selected from titanium, zirconium and hafnium, preferably titanium; R is an anion containing an &eegr;5-cyclopentadienyl ring co-ordinated to M; and each R1, R2 or R3, independently, represents an organic or inorganic group of an anionic nature bound to M, and may, particularly, be hydride, halide, a C1-C8 alkyl group, a C3-C12 alkylsilyl group, a C5-C8 cycloalkyl group, a C6-C10 aryl group, a C1-C8 alkoxyl group, a C1-C8 carboxyl group, a C2-C10 dialkylamide group and a C4-C20 alkylsilylamide group;  the above compound (I) being solid, supported or dispersed in an inert liquid medium; and (B) at least one organometallic compound of magnesium having the following formula (II): Mg(R4)n(R5)(2−n)  (II)  whe

Abstract: Bridged cyclopentadienyl derivatives having general formula (I)A--X--B (I)wherein:1) A is a monofunctional hydrocarbyl radical having general formula (II) ##STR1## 2) --X-- is the bridge between A and B and consists of a bifunctional radical selected from an alkylene group, a silanylene group, an alkyl substituted silaalkylene group, a siloxasilanylene group;3) B is a monofunctional hydrocarbyl radical selected from:e) any of the A radicals defined above,f) a cyclopentadienyl radical.

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: 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: 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: Metallocene complexes of a metal M selected from titanium, zirconium and hafnium, comprising at least one anionic group A containing an .eta..sup.5 -cyclopentadienyl ring co-ordinated with the metal M, wherein the anionic group is substituted in at least one position of the cyclopentadienyl ring with a radical having the formula:Ph*--(CR.sup.6 R.sup.7).sub.nwherein: R.sup.6 and R.sup.7 are independently hydrogen, halogen or a C.sub.1 -C.sub.4 alkyl group, preferably hydrogen, "n" is 0 or 1, preferably 1, Ph* is a C.sub.6 -C.sub.14 group comprising an aromatic ring linked to --CR.sup.6 R.sup.7 -- or to A and substituted with at least one and up to a maximum of three electron-attractor groups, on the condition that, when A is an .eta..sup.5 -indenyl group and "n" is 0, at least one Ph group is linked to A in position 1 or 3 of indenyl.These complexes can be used in (co)polymerization processes of .alpha.

Abstract: A description follows of catalysts of the metallocene type which can be used in the (co)polymerization of alpha-olefins, particularly in the preparation of elastomeric copolymers of ethylene.

Abstract: Cyclopentadienyl derivatives are described having general formula (I) ##STR1## where R, R.sub.1, R.sub.2, R.sub.4, equivalent to or different from one another, are selected from: --H, alkyl radicals having a number of carbon atoms from 1 to 5, cycloalkyl radicals having a number of carbon atoms from 5 to 8, aryl and alkylaryl radicals having a number of carbon atoms from 6 to 8, aralkyl radicals having a number of carbon atoms from 7 to 9; n is an integer from 2 to 18; with the proviso that the number of R different from H does not exceed 2; with the exclusion of the compound having n=3, R.dbd.R.sub.1 .dbd.R.sub.2 .dbd.R.sub.4 .dbd.H. The invention a-so describes the process for the preparation of the above-mentioned cyclopentadienyl derivatives.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a high degree of syndiotacticity which comprises polymerizing vinylaromatic monomers in the presence of a catalytic system essentially consisting of:a) a complex of titanium selected from those having the general formula:(CpR.sub.1 R.sub.2 R.sub.3 R.sub.4 R.sub.5)TiX.sub.3 (I)wherein the groups R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 represent a hydrogen atom or C.sub.1 -C.sub.10 alkyl groups;X represents a hydrogen atom, a halogen such as chlorine, a C.sub.1 -C.sub.10 alkyl or oxyalkyl radical or a C.sub.6 -C.sub.12 oxyaryl radical;b) an alkylaluminoxane; andc) an organic derivative of tin;characterized in that the alkylaluminoxane is methylaluminoxane (MAO) treated at 20.degree.-80.degree. C. under vacuum for 1-100 hours and the organic derivative of tin is tin tetraphenyl.

Abstract: A catalyst active in the (co)polymerization of .alpha.-olefins is obtained by putting the following components in contact with each other:(i) a "bridged" bis-metallocene derivative of a metal M selected from titanium, zirconium or hafnium, wherein the divalent "bridge" has a rigid structure linked to two .eta..sup.5 -cyclopentadienyl ring with two methylene groups having a distance from each other of less than 3.5 .ANG.;(ii) a co-catalyst consisting of an organic derivative of a metal M' selected from boron, aluminium, gallium and tin.Such a catalyst allows high polymerization rates to be reached and is particularly suitable for high temperature polymerization process and co-polymerization of ethylene with other .alpha.-olefins.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing vinylaromatic monomers, alone or mixed with at least one other monomer, in the presence of a catalytic system essentially consisting of:a) a complex of titanium or zirconium selected from those having general formula:MR.sub.1 R.sub.2 R.sub.3 R.sub.4, A.sub.1 MR.sub.1 R.sub.2 R.sub.3, A.sub.1 A.sub.2 MR.sub.1 R.sub.2 (I)b) a co-catalyst selected from an alkylalumoxane and a compound of boron having formula (II):BX.sub.1 X.sub.2 X.sub.3 (II)or one of its salts;c) a derivative of tin having general formula:SnR.sub.5 R.sub.6 R.sub.7 R.sub.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a predominant syndiotactic structure which involves polymerizing vinylaromatic monomers in the presence of a catalytic system comprising: a titanium complex having general formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4, the same or different, represent a hydrogen atom or a C.sub.1 -C.sub.20 alkyl radical or a C.sub.6 -C.sub.20 arylalkyl or aryl radical, on the condition that at least one of these is different from hydrogen.

Abstract: Process for the preparation of (co) polymers of .alpha.-olefins which comprises polymerizing at least one .alpha.-olefin in the presence of a catalytic system consisting essentially of:a) a complex of a metal of groups VIB or VB having general formula (I):M(OCONRR').sub.n (I)wherein M represents a transition metal selected from the group consisting of Ti, Zr, H& and V; R and R', the same or different, represent a C.sub.1 -C.sub.12 aliphatic or C.sub.18 aromatic radical whereas n represents the oxidation state of the metal; andb) a cocatalyst consisting of aluminoxane.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing the vinylaromatic monomers in the presence of a catalytic system consisting essentially of:a) a complex of titanium having the formula (I):Ti(OCONRR').sub.n (I)wherein R and R', the same or different, represent a C.sub.1 -C.sub.12 aliphatic radical or C.sub.6 -C.sub.12 aromatic radical whereas n is an integer equal to 3 or 4;b) a cocatalyst selected from aluminoxane and a compound of boron having formula (II):BX.sub.1 X.sub.2 X.sub.3 (II)wherein X.sub.1, X.sub.2 and X.sub.3, the same or different, represent a C.sub.1 -C.sub.20 perfluorinated hydrocarbon radical.

Abstract: A cobalt based catalyst, and the method for preparing it, are disclosed. The catalyst is obtained from the reaction between NaCo(CO).sub.4 and s-trichloro triazine and is advantageously used in the processes of carbonylation of naphthalene mono- and disulfonates in order to yield naphthalene esters and acids.

Abstract: Process of synthetizing ethylene-tetracarboxylic esters by duplication of lonic compounds of the formula: ##STR1## wherein X=COOR, Y=COOR' and R and R' represent an organic group, characterized in that the duplication is an oxidative duplication conducted in the presence of a catalyst consisting of the salt of a transition metal.

Abstract: The invention concerns a process for the preparation of the esters of an alkyltartronic acid by direct oxidation, with O.sub.2 or the like, at 30.degree.-200.degree. C., of the corresponding alkyl-malonic esters, in the presence of a catalytic system, comprising a salt of a transition metal, selected from Mn, Fe, Co and Cu, and an alkali-metal salt of an aliphatic carboxylic acid, optionally in the presence of a polar solvent.

Abstract: There is described a process for preparing carbonyl compounds of formula: ##STR1## by oxidation of compounds of formula: ##STR2## wherein X=--CN, --COOR, Y=--COOR.sub.1, --CN, and R, R.sub.1, like or unlike each other, are inert radicals, by employing oxygen or air as oxidants, at least a catalyst selected from the salts of organic or inorganic acids of Mn, Co, Cu and Fe, from 0 to 60 moles of an alkaline salt of an aliphatic carboxylic acid per gram-atom of catalyst metal, in a polar solvent, at temperatures ranging from 30.degree. C. to 200.degree. C. and maintaining the reaction medium anhydrous.The present invention relates to a process for preparing carbonyl compounds by catalytic oxidation of compounds containing an activated methylene group.

Abstract: There is disclosed an improved process for selectively preparing 2-(6'-methoxy-2'-naphthyl)-propionic acid in the active antipode (+) form by reacting 2-acetyl-6-methoxynaphthalene, in an organic solvent, with a system consisting of(a) a haloform selected from CHCl.sub.3 and CHBr.sub.3 ;(b) an aqueous solution of an inorganic base selected from NaOH and KOH; and(c) a crown-ether or hydrocarbyl salt of quaternary ammonium, or of phosphonium;and hydrogenating the 2-(6'-methoxy-2'-naphthyl)-acrylic acid thus formed to obtain 2-(6'-methoxy-2'-naphthyl)-propionic acid.