Abstract: A process for preparing porous olefin polymers comprising bringing into contact in a polymerization reactor, at a temperature T1, one or more olefins of the formula (I) CH2?CHR1, R1 being hydrogen, a C1–C20-alkyl or a C6–C12-aryl group, with a catalyst obtained by reacting a solid catalyst component in the form of spheroidal particles comprising a compound of Ti or V not containing metal-? bonds and a Mg halide, optionally containing one or more electron donor compounds, with an aluminum-alkyl (Al-alkyl) compound, then raising the temperature up to the polymerization temperature, said process being characterized in that: a) if the temperature T1 is lower than 40° C.

Abstract: Aromatic silane compounds containing at least an aromatic ring bound directly to the silicon atom, wherein the aromatic ring has at least one substituent located in the ortho position selected from C1-10 hydrocarbon groups, are useful as electron donors in olefin polymerization catalysts for the production of polyolefins having a stereoblock content of from about 7 to about 25%.

Abstract: A porous polymer of propylene optionally containing up to 15% by weight of an alpha-olefins of formula CH2?CHR wherein R is a hydrogen atom or a C2-C10 alkyl radical having the following characteristics: a) in the Temperature Rising Elution Temperature analysis (TREF) a fraction eluted at a temperature range front 25° C. to 97° higher than 20% of the total polymer eluted; and b) a pore volume (determined by mercury absorption) greater than 0.45 cc/g.

Abstract: Aromatic silane compounds containing at least an aromatic ring bound directly to the silicon atom, wherein the aromatic ring has at least one substituent located in the ortho position selected from C1-10 hydrocarbon groups, are useful as electron donors in olefin polymerization catalysts for the production of polyolefins having a stereoblock content of from about 7 to about 25%.

Abstract: Aromatic silane compounds containing at least an aromatic ring bound directly to the silicon atom, wherein the aromatic ring has at least one substituent located in the ortho position selected from C1-10 hydrocarbon groups, are useful as electron donors in olefin polymerization catalysts for the production of polyolefins having a stereoblock content of from about 7 to about 25%.

Abstract: Aromatic silane compounds containing at least an aromatic ring bound directly to the silicon atom, wherein the aromatic ring has at least one substituent located in the ortho position selected from C1-10 hydrocarbon groups, are useful as electron donors in olefin polymerization catalysts for the production of polyolefins having a stereoblock content of from about 7 to about 25%.

Abstract: Organosilane compounds having the structural formula ##STR1## wherein R is a linear or branched C.sub.1-4 alkyl, 4-methylpiperidyl, C.sub.6-12 aryl or C.sub.5-7 cycloalkyl; R.sup.1 is hydrogen, methyl or ethyl, R.sup.2 is methyl or ethyl and; n is 4 to 7.These organosilane compounds are useful as electron donors in Ziegler-Natta type catalyst systems.

Abstract: An aminosilane of the formula: ##STR1## where R.sub.1 is a linear or branched C.sub.1-22 alkyl or C.sub.3-22 cycloalkyl, which may be substituted with at least one halogen atom; R.sub.2 is a bis(linear or branched C.sub.1-22 alkyl or C.sub.3-22 cycloalkyl)amino, a substituted piperidinyl, a substituted pyrrolidinyl, decahydroquinolinyl, 1,2,3,4-tetrahydroquinolinyl or 1,2,3,4-tetrahydroisoquinolinyl, with the substituent selected from the group consisting of C.sub.1-8 alkyl, pheny. C.sub.1-8 linear or branched alkylsubstituted phenyl and trimethylsilyl, with the proviso that when the substituent is C.sub.1-8 alkyl, there must be at least two such substituent groups present and R.sub.1 must contain halogen; and R.sub.3 is a linear or branched C.sub.1-8 alkyl or C.sub.3-8 cycloalkyl.

Abstract: Organosilane compounds having the structural formula ##STR1## wherein R is a linear or branched C.sub.1-4 alkyl, 4-methyl-piperidyl, C.sub.6-12 aryl or C.sub.5-7 cycloalkyl; R.sup.1 is hydrogen, methyl or ethyl; R.sup.2 is methyl or ethyl and; n is 4 to 7.These organosilane compounds are useful as electron donors in Ziegler-Natta type catalyst systems.

Abstract: Disclosed are catalysts for the polymerization of alpha-olefins comprising the reaction product of:(A) an Al-alkyl compound;(B) a trifluoropropyl substituted silane compound;(C) a solid component comprising a titanium compound having at least a Ti-halogen bond and an electron donor compound both supported on an activated anhydrous magnesium dihalide, and the process of using said catalysts.