Abstract: A process for preparing hyperpure propylene (co)polymers comprising polymerizing the monomer(s) in liquid monomer in the presence of a catalyst obtained by reacting an Al-trialkyl compound with a solid catalyst component comprising magnesium dihalide in active form, having supported thereon a titanium chloride or chloroalcoholate, and an ether having the general formula: ##STR1## where R and R" are the same or different and are C.sub.2-18 alkyl, C.sub.3-18 cycloalkyl, C.sub.6-18 aryl, C.sub.7-18 arylalkyl or alkylaryl radicals.

Abstract: Disclosed are catalyst components for the polymerization of olefins which include magnesium halide in active form, and, supported thereon, a titanium halide or titanium halogen alcoholate and an electron-donor compound selected from the group diamines of formula ##STR1## wherein the radicals R.sub.1 to R.sub.10 are the same or different and are hydrogen or C.sub.1 -C.sub.18 hydrocarbon radicals, with the proviso that at least one of the R.sub.7 and R.sub.8 radicals and at least one of the R.sub.9 and R.sub.10 radicals are not hydrogen. Also, disclosed are catalysts obtained from the catalyst components and an Al-alkyl compound, as well as catalysts obtained by reaction of an Al-alkyl compound and a diamine of formula (I) with a solid catalyst component including a titanium halide or a titanium halogen alcoholate, and an electron-donor compound having particular characteristics of extractability with Al-triethyl, supported on magnesium halide in active form.

Abstract: Disclosed is a component for a catalyst for the polymerization of alpha-olefins to stereoregular polymers having narrow molecular weight distribution. The product is formed by the reaction of a solid catalyst-forming component comprising (1) a Ti compound having at least one Ti-halogen bond and (2) optionally, an electron-donor compound, supported on an anhydrous Mg dihalide in active form, with certain amounts of an organic compound (AH) containing at least one active hydrogen atom, in the presence of a liquid medium which is inert with respect to the Ti compound and the other components of the catalyst component, and which has a dielectric constant greater than 2 at 20.degree. C.Catalysts comprising the reaction product of the solid catalyst component prepared as above described, with an Al-alkyl compound and an electron-donor compound are also disclosed.

Abstract: Catalysts for polymerizing ethylene to high yields of polyethylene having a controlled particle size are disclosed. The catalysts are prepared from new catalyst-forming components which are the reaction products of solid halogenated titanium compounds, Grignard compounds and halogenating agents. Said components, on mixing with organometallic compounds of metals belonging to Groups I-III of the Mendelyeev Periodic Table result in the catalysts capable of polymerizing ethylene to polyethylene having a controlled particle size.

Abstract: Disclosed are reverse osmosis anisotropic gel-type membranes having the structure: ##STR1## WHEREIN N IS A WHOLE NUMBER; A is a divalent group derived from piperazine and having the structure: ##STR2## WHEREIN X IS 0 TO 8 AND R is an alkyl group, and Q is at least two divalent organic groups selected from the group consisting of: ##STR3## wherein Y is O or S, ##STR4## Also disclosed are processes for preparing such membranes.