Abstract: Process for modifying the relative ratios of the components of a liquid starting mixture of specific diastereoisomers, containing at least two asymmetric carbon atoms comprising contacting said liquid mixture with a Lewis acid compound capable of co-ordinating said specific diastereoisomers and subjecting the resulting mixture to conditions such that a reaction product, having a molar ratio between its diastereoisomeric components different from the corresponding molar ratio in the said liquid starting mixture, becomes separated from the said liquid mixture, said process being carried out using an amount of said Lewis acid not enough to co-ordinate the total amount of the diastereoisomeric components of the liquid starting mixture. This method shows an excellent balance of efficiency and easiness of procedure that cannot be reached with the physical methods of diastereoisomers separation known in the art.

Abstract: Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.

Abstract: Supported catalysts for the polymerization of olefins comprise the following components:

Abstract: A class of metallocene compounds having two cyclopentadienyl rings bridged by an alkylidene group is disclosed. These metallocene compounds can be suitably used as catalyst components for the polymerization of olefins. In particular, by polymerising propylene in the presence of a catalyst based on these metallocene compounds, polymers having very high isotactic indexes, high molecular weights and narrow molecular weight distributions can be obtained in high yields.

Abstract: A class of metallocene compounds having two cyclopentadienyl rings bridged by an alkylidene group is disclosed. These metallocene compounds can be suitably used as catalyst components for the polymerization of olefins. In particular, by polymerising propylene in the presence of a catalyst based on these metallocene compounds, polymers having very high isotactic indexes, high molecular weights and narrow molecular weight distributions can be obtained in high yields.

Abstract: Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.

Abstract: Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.

Abstract: It is possible to prepare substantially amorphous polymers of propylene endowed with high molecular weights, operating at temperatures of industrial interest, by carrying out the polymerization reaction of propylene in the presence of metallocene catalysts comprising particular bis-indenyl or bis-4,5,6,7-tetrahydroindenyl compounds substituted in the 2-position on the indenyl or tetrahydroindenyl groups.

Abstract: Amorphous polymers of propylene modified with ethylene units are prepared in high yields, by carrying out the polymerization reaction in the presence of a catalyst based on a metallocene compound that has two bridged fluorenyl ligands. These copolymers have glass transition temperatures (T.sub.g) well below 0.degree. C., making it possible for the products manufactured from them to be used at low temperatures.

Abstract: Fractionable, reactor blend polypropylenes, directly obtainable from the polymerization reaction of propylene, having:(a) content of isotactic pentads (mmmm) comprised between 25 and 85%;(b) ratio M.sub.w /M.sub.n <5;containing from 10 to 70% by weight of a fraction soluble in boiling diethyl ether, said fraction having a content of isotactic pentads (mmmm) comprised between 5 and 25%, and from 30 to 90% by weight of a boiling n-heptane-insoluble fraction, soluble in xylene at 135.degree. C., said fraction having a content of isotactic pentads (mmmm) comprised between 50 and 99%, are disclosed. These polymers are suitable as thermoplastic-elastomeric materials. A process for the preparation of these polymers and a process for the preparation of 2-aryl-substituted indenyl metallocene ligands is also disclosed.

Abstract: A class of metallocene compounds having two substituted cyclopentadienyl rings bridged by an alkylidene group wherein the cyclopentadienyl groups can be indenyl groups. The metallocene compounds have the following structures: ##STR1## The metallocenes are characterized by three principal features: (i) the cyclopentadienyl groups are substituted at the 3-position with a substituent other than hydrogen, while R.sup.2 in the 2-position bears a hydrogen (formula (I)) or is part of a condensed benzene ring (formula (II)); (ii) the bridge is a substituted-methylene bridge, i.e. a methylene group bearing at least one substituent other than hydrogen (R.sup.6 is always different from hydrogen); and (iii) the cyclopentadienyl groups are identically substituted (page 2, line 23). These metallocene compounds can be suitably used as catalyst components for the polymerization of olefins.

Abstract: Copolymers of ethylene with comonomers selected from (a) alpha-olefins, (b) cycloolefins and/or (c) dienes, characterized by the fact that:the molar percentage of the comonomer (% .alpha.) and the density of the copolymer (D) satisfy the relation % .alpha.+150D.ltoreq.141.

Abstract: A catalyst for the polymerization of olefins comprises the product obtained by contacting:(A) a titanium, zirconium or hafnium mono- or bis-cyclopentadienyl compound, this latter optionally containing a bridging group which links the two cyclopentadienyl compounds;(B) an alkyl aluminium wherein at least one alkyl is different from a straight alkyl; and(C) water.The molar ratio aluminium/water is higher than 1:1 and lower than 100:1.

Abstract: Homo- and copolymers of ethylene endowed with very high molecular weights and narrow molecular weight distributions are obtainable by carrying out the polymerization reaction in the presence of a metallocene-based catalyst wherein the metallocene is stereorigid and it is in its meso isomeric form.

Abstract: Fractionable, reactor blend polypropylenes, directly obtainable from the polymerization reaction of propylene, having:(a) content of isotactic pentads (mmmm) comprised between 25 and 85%;(b) ratio M.sub.w,/M.sub.n <5;containing from 10 to 70% by weight of a fraction soluble in boiling diethyl ether, said fraction having a content of isotactic pentads (mmmm) comprised between 5 and 25%, and from 30 to 90% by weight of a boiling n-heptane-insoluble fraction, soluble in xylene at 135.degree. C., said fraction having a content of isotactic pentads (mmmm) comprised between 50 and 99%, are disclosed. These polymers are suitable as thermoplastic-elastomeric materials. A process for the preparation of these polymers and a process for the preparation of 2-aryl-substituted indenyl metallocene ligands is also disclosed.

Abstract: Homo- and copolymers of ethylene endowed with very high molecular weights and narrow molecular weight distributions are obtainable by carrying out the polymerization reaction in the presence of a metallocene-based catalyst wherein the metallocene is stereorigid and it is in its meso isomeric form.

Abstract: Highly crystalline high melting 1,5-hexadiene cyclopolymers are prepared by carrying out the polymerization in the presence of a catalyst comprising a specific Zr or Hf metallocene compound and specific alumoxane compounds.