Patent ID: 7449528
Filing Date: 2008-11-11
Classification: C07C,C07F,C08F

Abstract:
1. A catalyst supported on silica, active in the polymerization, copolymerization and terpolymerization of olefin-unsaturated compounds, wherein the silica has a surface area of ≧200 m 2 /g, a total cumulative pore volume greater than 1 ml/g, as measured by the BET method, a quantity of total surface hydroxyls (isolated, vicinal, geminal) of less than 1.0 milliequivalents (meq)/g, an average particle diameter ranging from 5 μm to 100 μm, a free humidity content lower than or equal to 2% by weight, and wherein the catalyst contains from 0.5 to 3.0% by weight of titanium with respect to the total weight of the catalyst, and further contains Si, Mg, Al and Cl in the following atomic composition with respect to titanium: and is obtained by means of a process which comprises: (i) deposition in the pores of the above silica of at least one solution of (i1) at least one derivative of magnesium selected from bis magnesium chlorocarboxylates and halogen magnesium chlorocarboxylates having general formula (II) wherein X′ is a halogen, excluding iodine; m is selected from 0 to 1; R′ is a chlorinated monofunctional hydrocarbyl radical having from 1 to 20 carbon atoms and from 1 to 6 chlorine atoms; and of (i2) at least one derivative of titanium selected from titanium chlorocarboxylates having general formula (I): wherein: p+n=2, 3, 4; n≧1; R has the same meaning as R′; X is selected from chlorine, bromine, alkoxyl, carboxyl, beta-dicarbonyl group; and wherein the atomic ratio between the Mg in (II) and Ti in (I) ranges from 0.5/1 to 10/1; (ii) subsequent deposition, on the silica containing derivatives of magnesium and titanium obtained at the end of step (i), of a solution of one or more halogen alkyl derivatives of aluminum selected from those having general formula (III) and (IV): wherein R″ is a C X″ is chlorine or bromine; and wherein the ratio between the sum of the halogen atoms in (III) and/or (IV) and the total carboxyl groups in (I) and (II) varies from 0.3/1 to 10/1; (iii) reaction, inside the silica pores containing derivatives of Ti, Mg, Al obtained at the end of step (ii), between the one or more halogen alkyl derivatives of aluminum and compounds (I) and (II), thus obtaining a supported catalyst consisting of porous silica containing, inside the pores, derivatives of magnesium, titanium, aluminum and by-products essentially based on aluminum; (iv) recovery of the supported catalyst obtained at the end of step (iii), after elimination by washing the aluminum-based by-products.