Abstract: Process for the preparation of copolymers of ethylene and an alpha-olefin having six carbon atoms comprising hexene-1 or 4-methyl-pentene-1 with a density comprised between 0.910 and 0.940, involving a copolymerization of ethylene and an alpha-olefin having six carbon atoms comprising hexene-1 or 4-methyl-pentene-1 in the gas phase by means of a fluidized bed, in the presence of a catalyst system comprising on the one hand a co-catalyst consisting of at least one organo-metallic compound of a metal of Groups, II and III of the Periodic Table of Elements and on the other hand a supported catalyst comprising a special support based essentially on magnesium chloride and optionally aluminum chloride, on which support there has been precipitated a derivative of a transition metal of Groups IV, V and VI of the Periodic Table of Elements.

Abstract: The invention relates to a process making it possible to reduce the corrosion of metals and alloys of heat exchanger circuits where aqueous heat transfer fluids are circulating and which may contain anti-freeze products.The process consists in mixing with these aqueous heat transfer fluids on the one hand from 0.05 to 5 percent by weight of one or more salts of alkali metals or of amines of dicarboxylic aliphatic acids of the formula (CH.sub.2)n(COOH).sub.2 in which n is comprised between 2 and 10 and on the other hand from 0.05 to 2.5 percent by weight of one or more polyols comprising a number of carbon atoms between 5 and 12 and a number of alcohol functions between 5 and 12 and possessing no reducing power.

Abstract: The invention concerns polyethylene compositions particularly adapted for the manufacture of film and hollow bodies by blow-moulding, characterized in that they contain(a) from 50 to 98% by weight of polyethylene of high density, of at least 0.940(b) from 2 to 50% by weight of a linear, low density polyethylene, with a density below 0.930.

Abstract: Process for the preparation of copolymers of ethylene and an alpha-olefin having 6 carbon atoms with a density comprised between 0.910 and 0.940, involving a copolymerization of ethylene and an alpha-olefin having 6 carbon atoms in the gas phase by means of a fluidized bed, in the presence of a catalyst system comprising on the one hand a co-catalyst consisting of at least one organo-metallic compound of a metal of Groups II and III of the Periodic Table of Elements and on the other hand a supported catalyst comprising a special support based essentially on magnesium chloride and optionally aluminium chloride, on which support there has been precipitated a derivative of a transition metal of Groups IV, V and VI of the Periodic Table of elements.

Abstract: Process for the preparation of addition products of epoxides and hydroxylated compounds, characterized by the fact that it comprises the reaction of an epoxide and a hydroxylated compound in the homogeneous liquid phase, in the presence, as catalyst, of a salt of trifluoromethanesulphonic acid.

Abstract: The present invention relates to catalysts which can be used for the polymerization and copolymerization of propylene with other alpha-olefins, characterized in that they comprise a support containing essentially magnesium chloride and possibly a chlorinated aluminium derivative, and occurring in the form of spheroidal particles having a mean diameter by mass comprised between 10 and 100 microns and a particle size distribution such that the ratio of the mean diameter by mass to the mean diameter by number is less than or equal to 3, which support has been treated by an electron donor compound chosen from among the aromatic ethers and aromatic acid esters and which when impregnated with titanium tetrachloride comprises 0.5 to 3% of atoms of titanium per atom of magnesium, and process for utilizing the said catalyst.

Abstract: The present invention relates to catalysts for the polymerization and copolymerization of ethylene, characterized in that they comprise a support based on magnesium chloride and possibly on aluminium chloride, of spheroidal shape, having a mean diameter by mass comprised between 10 and 100 microns and with a narrow particle size distribution, such that the ratio of the mean diameter by mass to the mean diameter by number is less than or equal to 3, on which support there has been precipitated a derivative of a transition metal of groups IV, V and VI of the Periodic Table of Elements, and a polymerization process utilizing the said catalysts.

Abstract: The invention relates to a device and process permitting of the bottom drainage of a fluid-bed polymerization reactor (1) comprising a fluidization plate (2), a gas inlet (3) located between the said plate and the bottom of the reactor and a side pipe (4) located above the said plate and permitting of the evacuation of the fluidized particles, the said device consisting:of a vertical pipe (5) having a top opening at the level of the plate and a bottom end located outside and underneath the bottom of the reactor, which is occluded by a cock (6),and a gas intake tube (7) in the said vertical piping, leading out into the immediate vicinity of the said cock (6).

Abstract: The present invention relates to catalyst supports for the polymerization and co-polymerization of alpha-olefins, especially ethylene and propylene, consisting essentially of magnesium chloride, characterized in that these supports occur in the form of spheroidal particles with a mean particle size by mass comprised between 10 and 100 microns and having a narrow particle size distribution, which can be controlled, such that the ratio of the mean diameter by mass to the mean diameter by number of the particles is less than or equal to 3.0, and the process for the preparation of the said supports.

Abstract: The present invention relates to catalyst supports for the polymerization and co-polymerization of alpha-olefins, especially ethylene and propylene, consisting essentially of magnesium chloride, characterized in that these supports contain a chlorinated compound of aluminium in a quantity such that the atomic ratio of Al/Mg is comprised between 0.001 and 0.1 and that they occur in the form of spheroidal particles having a mean diameter by mass comprised between 10 and 100 microns and a narrow and controllable particle size distribution such that the ratio of the mean diameter by mass to the mean diameter by number of particles is less than or equal to 3, and also a process for the preparation of these supports.

Abstract: The invention relates to a process of thermomechanical treatment in the molten state, in the presence of organic peroxides, of co-polymers with a density less than 0.935, obtained by co-polymerization under a pressure of less than 4 MP.sub.a of ethylene and a higher alpha-olefin. The co-polymers thus treated may advantageously be used for the manufacture of finished objects such as films according to the current techniques of conversion of "high pressure" type polyethylene.

Abstract: The invention is addressed to solid catalysts comprising essentially compounds of magnesium and of transition metals selected from the sub-groups IVa, Va and VIa of the periodic table, applicable to the polymerization of olefins and particularly ethylene, in which the catalyst is obtained by first preparing a solid compound of magnesium, monohalogenated hydrocarbon and halogen and/or organic derivatives of the transition metal in a state of valency of at least 4 and then reacting the solid compound of magnesium and transition metal with an oxidizing compound.