Abstract: A process is described for producing aqueous latexes essentially consisting of composite polymeric particles which comprises: (a) a first radicalic polymerization step in aqueous emulsion of monomers selected from vinylaromatics and mixtures of vinylaromatics/conjugated dienes, thus obtaining the first latex; (b) a second radicalic polymerization step in aqueous emulsion which consists in polymerizing, on the latex obtained in step (a), chloroprene or mixtures of chloroprene and monomers copolymerizable with chloroprene, the latter in a quantity not higher than 10% by weight with respect to the chloroprene, thus obtaining the latex object of the present invention.

Abstract: An organometallic composition which can be used as activating component in a metallocene catalyst for the (co)polymerization of &agr;-olefins, comprises: (A) a fluorinated di-unsaturated cyclic compound, having a relatively acid hydrogen atom, (B) an organometallic compound sufficiently basic to react with the acid hydrogen of the above compound (A), and (C) a polar aprotic organic compound, not containing metallic atoms, having a dielectric constant, in the pure state, equal to or greater than 2, and a weak coordinating capacity. Said composition allows a metallocene catalytic system of the ionic type to be obtained, with a high activity in the (co)polymerization of olefins and a reduced content of metallic residue in the polymeric product thus obtained.

Abstract: Organometallic complex having the formula (IAP)M(X)n which can be used for die formation of catalytic systems wherein: M is a metal selected from transition metals and lanthanides, in oxidation state “s” positive and different from zero; each X is independently a group of an anionic nature bound to the metal as an anion in an ionic couple or with a convalent bond of the “&sgr;” type; “n” expresses the number of X groups sufficient for neutralizing the formal “+s” charge of the metal M, and (IAP) represents a neutral bond consisting of a mono-imine of 2,6-diacylpyridine. Said complex is prepared with relatively simple methods and can be used, combined with a suitable co-catalyst, such as for example, an aluminoxane, as a catalyst in normal (co)polymerization processes of &agr;-olefins, and especially ethylene.

Abstract: Titanium complex having general formula (1) (RCOO)nTiXp wherein R is a monofunctional hydrocarbyl radical having from 1 to 20 carbon atoms and a number of halogen atoms, selected from fluorine, chlorine and bromine, preferably chlorine, ranging from 1 to 6; X is chlorine, bromine or a beta-dicarbonyl group such as acetylacetone (AcAc), formylacetone, benzoylacetone, dibenzoylmethane; p+n=2, 3, 4, preferably p+n=3; n is greater than or equal to 1. The preparation of the above complex and its use in the co- and ter-polymerization of &agr;-olefins, are also described.

Abstract: A process is described for the hydrogenation of olefin double bonds present in polymers and copolymers of conjugated dienes, which comprises putting the above polymer or copolymer of conjugated dienes in contact with hydrogen in an inert solvent, in the presence of a catalytic system, characterized in that the above catalytic system essentially consists of one or more titanium compounds selected from those having general formula (I) 1

Abstract: Catalytic composition for the (co)polymerization of ethylene and other &agr;-olefins, including a metallocene complex of a metal M of group 4 of the periodic table or the product obtainable from the same combined with a suitable activator, wherein said metallocene complex includes at least one cyclopentadienyl group and at least one unsaturated hydrocarbyl organic group bonded to the metal M, having the following formula (I):

Abstract: A process for the polymerization of chloroprene or of a mixture of chloroprene and of up to 20% by weight of a copolymerizable monomer, in aqueous emulsion in the presence of radical initiators, at a temperature of between 5° C. and 70° C., characterized in that the polymerization is carried out in the presence of one or more copolymerizable surfactants in agreement with the formula described below (I) R3—Z—CO—C(R1)═C(R2)—COOM  (I) where: R3 is a saturated or unsaturated, linear or branched and aliphatic or aromatic Cn hydrocarbonaceous chain with n from 10 to 20; R1 and R2, which are identical or different, are chosen from H or a C1-C3 alkyl radical; Z is chosen from —O— and —NH—; M is chosen from alkali metals or NH4.

Abstract: A metallocene compound of a metal M of group 4 in the table of elements, comprising a cyclopentadienyl group and at least one oligomeric group R′ bonded to M, having the following formula (II):

Abstract: A description follows of ligands having general formula (I) wherein R1, R2, R3, R4, R5, and R6, the same or different, are selected form hydrogen, halogen, C1-C10 alkyl, C6-C15 aryl optionally halogenated, or adjacent pairs of Ri groups (with i ranging from 1 to 6) are bound to each other to give cyclic hydrocarbon structures condensed with the thiophene or pyridine ring: R7 is selected from H, C1-C10 alkyl, C6-C15 aryl: R8 is selected from C1-C10 alkyl and C6-C15 aryl. The complexes of the above ligands with transition metals are also described.

Abstract: A solid component of catalyst for the (co)polymerization of ethylene and &agr;-olefins contains magnesium-carboxylate bonds and transition metal-carboxylate and can be represented by the formula: M1Mg(0.3-20)X(2-60)Al(0-6)(R—COO)(0.1-3)  (I) wherein: M is at least one metal selected from titanium, vanadium, zirconium and hafnium, X is a halogen excluding iodine, and R is an aliphatic, cycloaliphatic or aromatic hydrocarbon radical, containing at least 4 carbon atoms. A description follows of the preparation of a solid component of catalyst (I) and its use in procedures for the (co)polymerization of ethylene and &agr;-olefins.

Abstract: Allyl polyalkylcyclopentadienyl complex of a metal of group 4 of the periodic table, and its use in the preparation of a catalytic composition for the (co) polymerization of &agr;-olefins. said complex is advantageously stable in solution and rapidly forms catalytic compositions with a high activity without the necessity of effecting alkylating pretreatment.

Abstract: Process for the selective oligomerization of ethylene to give &agr;-olefins essentially consisting of C4 to C8, character in that it is carried out in the presence of a catalytic system comprising the complex having general formula (II): (L)M(Y)n wherein L represents the ligand having general formula (I) M represents a transition metal; Y is selected from groups of an anionic nature bound to the metal as anion in ionic couple or with a covalent bond of the “&sgr;” type.

Abstract: Process for the production of statistic elastomeric conjugated diene-vinyl arene copolymers having a branched structure which comprises: (1) anionic copolymerization in solution of the conjugated diene and vinyl arene monomers, in the presence of randomizing agents and an initiator selected from the group of Lithium alkyls, the copolymerization being carried out until the almost total disappearance of the monomers; (2) addition to the solution of step (1) of a quantity of Lithium alkyl from 1 to 4 times the molar quantity of the Lithium alkyl of step (1); (3) addition to the polymeric solution of step (2) of a compound having the general formula R—Br, the molar ratio between R—Br and the total Lithium alkyl ranging from 0.6/1 to 1/1, preferably from 0.7/1 to 0.9/1, thus obtaining an elastomeric branched copolymer.

Abstract: An organometallic composition of a reaction product of a fluorinated organic compound of formula (I): wherein R1 to R8 are as described in the specification, m is 0 or 1; and an organometallic compound of formula (II): M′RnX(p−n)  (II) wherein M′, R, X, n and p are as described in the specification; a polymerization catalyst composition using the above organometallic composition and a metallocene complex a method of making the catalyst composition and using the catalyst composition to polymerize &agr;-olefins.

Abstract: The disclosure is made of a process for the polymerization of chloroprene or of a mixture of chloroprene and of up to 20% by weight of a copolymerizable monomer, in aqueous emulsion in the presence of radical initiators, at a temperature of between 5° C. and 70° C.

Abstract: Vanadium complex having general formula (I) (RCOO)nVXpLm  (I) wherein R is a monofunctional hydrocarbon radical having from 1 to 20 carbon atoms and from 1 to 6 halogen atoms, selected from chlorine and bromine, preferably chlorine; X is chlorine or bromine, preferably chlorine; L is an electron donor; p+n=3, 4 or 5, preferably=3; n is greater than or equal to 1; m is between 0 and 3. The preparation of the above complex is also described together with its use in the (co)polymerization of &agr;-olefins.

Abstract: Process for the preparation of 1-hexane consisting in effecting the oligomerization of ethylene in the presence of a catalyst comprising a vanaduim complex having the formula: (arene)2 VX wherein the term arene represents benzene or mono-, di-, or tri-alkylsubstituted benzene, V is a vanaduim ion with a low wxidation state, and X is an anion selected from non-coordinated anions such as B(Ar)4—, AlCl4—, carboxylates and sulfonates.

Abstract: A “bridged” bis-cyclopentadienyl complex which can be advantageously used for the formation of a catalytic system active in the (co)polymerization of ethylene and other &agr;-olefins is represented by means of the following formula (II): wherein: M represents a metal selected from titanium, zirconium or hafnium; A′ and A″ each independently represent an anion containing an &eegr;5-cyclopentadienyl ring coordinated to M; R′ or R″ each independently represents a group of an anionic nature &sgr;-bound to the metal M; B represents an unsaturated bivalent organic residue having from 1 to 30 carbon atoms, bound, respectively, to the ring of group A′ and to the —CH2-methylene group by means of carbon atoms.

Abstract: A “bridged” bis-cyclopentadienyl complex which can be advantageously used for the formation of a catalytic system active in the (co)polymerization of ethylene and other a-olefins is represented by means of the following formula (II): 1

Abstract: A catalytic composition effective in the selective hydrogenation of olefinic double bonds, comprising the reaction product between: (A) at least one complex of a transition metal having the following general formula (I): M(R1)(R2)(R3)(R4)  (I)  wherein: M is selected from titanium and zirconium, preferably titanium; each of the radicals R1, R2, R3 or R4, independently, represents an organic or inorganic group of an anionic nature &sgr;-bound to M, on the condition that at least one, and preferablyat at least two, of these radicals is an organic group; and (B) at least one organometallic compound of magnesium having the following formula (II): Mg(R5)n(R6)(2−n)  (II)  wherein: R5 or R6 each independently represent an aliphatic or aromatic hydrocarbon group having from 1 to 20 carbon atoms, and “n” is a decimal number between 0 and 2.0.