Abstract: Process for the continuous preparation of halopolymers, comprising the radical-mediated polymerization of halomonomers in a medium comprising liquid or supercritical carbon dioxide in at least two mixed reactors under pressure in series. Halopolymers obtained.

Abstract: Process for inhibiting crust formation in reactors used for polymerising alpha-olefines, such as ethylene and propylene, in the presence of particles of catalytic solids containing titanium and chlorine in the combined state.The polymerisation is carried out in the presence of an amount of a silicone oil which is less than 1% by weight, relative to the weight of catalytic solid.

Abstract: Catalyst systems for the polymerization of .alpha.-olefins, as well as process for making and using the same, which comprises an organometallic compound, like an organoaluminum compound, and a solid catalyst complex formed by reacting together at least one compound selected from organic oxygen-containing and halogen-containing compounds of each of the metals of magnesium and titanium and at least one aluminum halide selected from organoaluminum chlorides of formula AlR.sub.n Cl.sub.3-n wherein R is an alkyl radical featuring at least 4 carbon atoms and 1.ltoreq.n.ltoreq.2. Particles of polyolefins of higher average dimension are recoverable, when polymerized in the presence of such catalyst systems.

Abstract: A process for low temperature polymerization and copolymerization of alpha-olefins comprising conducting the polymerization in the presence of a catalytic system comprising an organic compound of a metal of Group IA, IIA, IIB, IIIA and IVA of the Periodic Table and a solid catalytic complex which is prepared by reacting a compound of a metal of Groups IVB, VB and VIB of the Periodic Table with a porous aluminum oxide on which a magnesium compound is deposited.

Abstract: Alumina-supported halogen-containing transition metal compounds prepared in such manner that (a) the transition metal compound is chemically bound to and supported by an activated alumina having a high surface area and an internal pore volume greater than 0.8 cc/g., (b) the concentration of the transition metal compound chemically bound to the support is greater than 10 grams of transition metal per kilogram of activated alumina, and (c) the atom ratio of halogen to transition metal on the support is higher than that of the halogen-containing transition metal compound which is used and preferably greater than 3:1, have been found to be unusually effective cocatalysts for the polymerization of ethylene and other .alpha.-olefins. These supported cocatalysts, which may be used to produce polyethylene as well as interpolymers of ethylene with other .alpha.-olefins and with diolefins, are prepared by heating an alumina hydrate (such as boehmite) to a temperature in the range from about 500.degree. C. to 900.

Abstract: Catalyst systems for the polymerization and copolymerization of .alpha.-olefins, as well as process for making and using the same, which comprises an organo-metallic compound of a metal of Groups Ia, IIa, IIb, IIIb and IVb of the Periodic Table and a solid catalyst complex formed by reacting together at least one compound selected from organo oxygen-containing and halogen-containing compounds of each of the metals of magnesium, titanium and zirconium and at least one aluminum halide.

Abstract: Catalyst systems for the polymerization and copolymerization of .alpha.-olefins, as well as process for making and using the same, which comprises an organo-metallic compound of a metal of Groups Ia, IIa, IIb, IIIb and IVb of the Periodic Table and a solid catalyst complex formed by reacting together at least one compound selected from organo oxygen-containing and halogen-containing compounds of each of the metals of magnesium, titanium and zirconium and at least one aluminum halide.

Abstract: This invention relates to novel catalysts and cocatalysts for use in the polymerization and copolymerization of .alpha.-olefins, to a process of using such catalysts to polymerize and copolymerize .alpha.-olefins, and to a process of making such cocatalysts. The .alpha.-olefins are polymerized or copolymerized in the presence of a catalytic amount of a catalyst comprising an organometallic compound of a metal of Groups I a, II a, II b, III a, or IV a of the Periodic Table and a cocatalyst comprising the reaction product of an activated halogenated alumina having an atomic ratio of halogen/aluminum of from 0.1 to 1 and a derivative of a transition metal.

Abstract: This invention relates to novel catalysts and cocatalysts for use in the polymerization and copolymerization of .alpha.-olefins, to a process for using such catalysts to polymerize and copolymerize .alpha.-olefins, and to the process of making such cocatalysts. The .alpha.-olefins are polymerized or copolymerized in the presence of a catalytic amount of a catalyst system comprising an organometallic compound of a metal of Groups Ia, IIa, IIb, IIIa, or IVa of the Periodic Table and a cocatalyst comprising the reaction product of a halogenated alumina and a derivative of a transistion metal of Groups IVb, Vb, and VIb of the Periodic Table, said halogenated alumina being formed by halogenating a complex oxide of aluminum and at least one other metal.