Imperial Chemical Industries Limited

John W Kelland

John P Candlin

Peter L Law

Anthony D Caunt

Roy John Sampson

Frank T Kiff

Silica supports for use in the production of catalysts for olefin polymerization, in particular where the surface is substantially free from reactive hydroxyl groups, comprise (RCOO).sub.2 Mg deposited on the surface of the silica and/or groups of the general formula R(CO.sub.2 MgO).sub.n linked to surface silicon atoms, where R is a hydrocarbon radical and n=1 to to 6. Such supports are suitable for the production of stereospecific catalysts of high activity in the polymerization of olefins especially propylene.

Catalyst supports

Silica supports for use in the production of catalysts for olefin polymerization, in particular where the surface is substantially free from reactive hydroxyl groups, comprise (RCOO).sub.2 Mg deposited on the surface of the silica and/or groups of the general formula R(CO.sub.2 MgO).sub.n linked to surface silicon atoms, where R is a hydrocarbon radical and n=1 to 6. Such supports are suitable for the production of stereospecific catalysts of high activity in the polymerization of olefins especially propylene.

A transition metal composition is obtained by reacting the magnesium salt of a cycloalkyl carboxylic acid with a transition metal compound, and optionally a Lewis Base compound. The product may be used to produce an olefin polymerization catalyst by addition of for example an aluminium trialkyl and the resulting catalyst has a high activity and stereospecificity in an olefin polymerization process.

Transition metal composition

A suspension which comprises an inert liquid medium, a solid material, and a transition metal compound is dried using a spray-drying technique. The spray-drying is effected under conditions of temperature and pressure which are such as to cause evaporation of the liquid medium. The solid material is preferably in a finely-divided form. The solid material may consist essentially of a transition metal compound or may be a transition metal compound which is supported on a suitable solid inert matrix material. Alternatively, a suspension of a solid support material in a solution of a transition metal compound may be used. The dried solid is obtained as an agglomerate. The agglomerated solid can be mixed with an organic compound of a non-transition metal to give an olefin polymerisation catalyst system.

Drying process and product

A suspension which comprises an inert liquid medium, a solid material, a transition metal compound and an agglomeration aid is dried using a spray-drying technique. The spray-drying is effected under conditions of temperature and pressure which are such as to cause evaporation of the liquid medium. The solid material is preferably in a finely-divided form and may consist essentially of a transition metal compound or may be a transition metal compound which is supported on a suitable solid inert matrix material. Alternatively, a suspension of a solid support material in a solution of a transition metal compound may be used. The agglomeration aid may be polystyrene dissolved in the inert liquid medium. The dried solid is obtained as an agglomerated solid which can be mixed with an organic compound of a non-transition metal to give an olefin polymerization catalyst system.

Process for polymerizing olefins with a spray-dried catalyst

A titanium containing composition is obtained by contacting a magnesium halide with a non-metallic halide such as thionyl chloride, for example by grinding, and contacting the product with a titanium tetrachloride-containing material, preferably undiluted liquid titanium tetrachloride. The treatment with titanium tetrachloride may be effected by milling or by suspending the solid in the titanium tetrachloride. The solid product can be washed at least once. An ester is preferably contacted with the magnesium halide. The product obtained may be used with an organic metal compound such as aluminum triethyl and preferably a Lewis Base such as ethyl benzoate or an organic silicon compound to give olefin polymerization catalyst. When used to polymerise propylene the product obtained is highly stereoregular and the level of residual catalyst is low.

Composition production and use

A suspension which comprises an inert liquid medium, a solid material, and a transition metal compound is dried using a spray-drying technique. The spray-drying is effected under conditions of temperature and pressure which are such as to cause evaporation of the liquid medium. The solid material is preferably in a finely-divided form. The solid material may consist essentially of a transition metal compound or may be a transition metal compound which is supported on a suitable solid inert matrix material. Alternatively, a suspension of a solid support material in a solution of a transition metal compound may be used. The dried solid is obtained as an agglomerate. The agglomerated solid can be mixed with an organic compound of a non-transition metal to give an olefin polymerization catalyst system.

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Middlesborough, United Kingdom

John W Kelland