SE434515B - PROCEDURE FOR POLYMERIZATION OF PROPEN USING CATALYSTS CONTAINING TITAN, MAGNESIUM, ALUMINUM AND HALOGENS - Google Patents

Description

a0o16ss ~ s' 2 When, by analogy, the catalytic component containing a Nesium halide in activated form is prepared by bringing Tlqlê to react with a magnesium compound of the formula RMgX, in which R is a hydrocarbon radical and X may be R or a halogen, is active and the stereobondency of the catalyst thus obtained not entirely satisfactory. 7 It has now surprisingly been found that it is possible to merise propylene with catalysts, which have improved properties in terms of activity and stereo regularity, despite the fact that is based on a catalytic "component" in which magnesium halide in activated form is prepared from Mg alcoholate.

The catalysts used in the process of the present invention according to the present invention, comprises the reaction products between A) a product comprising complexes between an ester and an aluminum trialkyl, in which the alkyl groups are straight or branched and contain holds up to 20 carbon atoms, the aluminum trialkyl compound in complex form is 0.01 to less than 1 mole per mole of starting aluminum. nium compound, and B) a compound and / or composition obtained by bringing (bl) an aluminum alkyl halide or aluminum trihalide with the formula AlR'mX3_m, in which X is halogen and R 'is one alkyl group containing up to 10 carbon atoms, and m is 0 or a number less than 3, in contact with the reaction product between (b3) a titanium alcoholate and (bz) a magnesium halide or (az) a magnesium dialcoholate Mg (OR '), wherein R' is an alkyl group with 1-10 carbon atoms, the atomic ratio of halogen / magnesium in the compound or composition B) is at least 1: 1.

Typical examples of esters in component A are ethyl anisate, ethyl paratoluate, ethyl benzoate, ethyl p-methoxybenzoate, diethyl carbonate, ethyl acetate, dimethyl maleate, triethyl borate, ethyl o-chlorobenzoate, ethyl naphthenate, ethyl toluate, ethyl p-butoxybenzoate, ethyl cyclohexanoate, ethyl pivalate.

The preferred ester / aluminum trialkyl ratio varies from 0.1 to 0.6.

Usually, the activity of the catalyst and the stereospecific in the opposite direction xv molar ratio ester / aluminum trialkyl, in the sense that the higher this ratio is, the lower it becomes activity and vice versa in terms of stereospecificity. and 8001155-3 The aluminum trialkyls which can be used in the present invention invention, can be selected within a wide range of compounds.

Particularly suitable compounds are those which include alkyls with a linear or branched chain, containing up to 20 carbon atoms.

Some typical examples of such compounds are aluminum triethyl, aluminum trimethyl, aluminum n-butyl, aluminum tri-n-propyl, aluminum minium triisohexyl, aluminum triisooctyl, Al (Cl2H25) 3, aluminum isoprenyl and the like.

Component A of the catalyst of the present invention may produced according to different methods. A preferred one is that first cause the ester to react with aluminum trialkyl in a suitable manner molar ratio and then bring the component thus obtained A to react with component B. Q Another method is to bring aluminum trialkyl to I do with component B and then add the ester to it thus obtained the reaction product.

The aluminum, magnesium and titanium compounds, which are suitable to form component B of the catalysts of the present invention invention, can be selected within a wide range of compounds.

Some typical examples of compounds of type (b1) are aluminum alkyl halides of the formula AlR'mX3_m, in which X is chlorine and R ' is an alkyl radical having a linear or branched chain containing up to 10 carbon atoms and in particular aluminum ethyl sesquichloride and aluminum ethyl dichloride.

Other typical examples of compounds of type (b1) are aluminum trihalides and in particular AlCl3.

A typical example of type (b2) compounds is magnesium chloride.

Some typical examples of compounds of type (b3) are Ti (O-iC3H7) 4, Ti (O-nC3H7) 4, Ti (O-iC4H9) 4, Ti (O-nC4H9) 4 and Ti2O (O-iC3H7) 6.

These titanium compounds can optionally be used in admixture with minor amounts of vanadium compounds such as VOCl3 and VCl4.

The titanium alcoholate (b3) may optionally be used in admixture with (b4) in aluminum alcoholate.

Some typical examples of compounds of type (bq) are aluminum alcoholates, in which the alkylene contains up to 10 carbon atoms and in in particular aluminum triisobutylate.

The final ratios of Ti, Mg and Al in component B of the catalyst The compounds of the present invention can vary widely area.

SÜOlÖES-š In case I) (reaction products between b1 and (bz + b3 and val- free b4)), particularly valuable results are obtained with Mg / Ti ratios in the range 0.5-30, preferably 0.5-20, with Mg / Al ratios holdings in the range 0.5-15, preferably 0.8-10, and with Ti / Al ratios (as b9 in the range 0.01-2, preferably 0.01-0.5.

In case II) (reaction product between b1 and (az + b3)) is obtained always particularly valuable results with Mg / Ti ratios within range 0.5-50, preferably 1-30, and with Mg / Al ratios within range 0.5-15, preferably 1-10. _ In the catalysts of the present invention, Al / Ti holding higher than l; particularly advantageous results are obtained with Al / Ti ratios in the range 10-10 000.

The polymerization conditions are well known to those skilled in the art. Council and covers temperatures in the range ~ 80oC - + 150oC, preferably OQC - 100OC, the partial pressure of propylene being higher than atmospheric pressure. The polymerization can be carried out either in liquid phase, in the presence or absence of an inert hydrocarbon diluent or in the gas phase.

In the polymerization of propylene, particularly satisfactory results by working in the presence of an inert aliphatic liquid or aromatic hydrocarbon diluent under the polymerization conditions, or by working in liquid propylene as a reaction medium.

The following examples are provided to better illustrate the main features in the present industrial invention without, however, limiting this. ' In the examples given below, the melt flow index (MIL) is determined according to methods ASTM-D-1238/73; the flexural stiffness is measured according to the method ASTM-D-747/70 on samples prepared by molding by means of a plate press at 200 ° C and by curing at 140 ° C for 2 hours.

The intrinsic viscosity is measured by standard methods, ie at 135C in the tetrahydronaphthalene as solvent.

Bulk density, always determined on the polymer in powder form, and surface area, on the other hand, is measured using non-standard methods. 8001355-3 U * gïtnprl. L a) Preparation of component B in the catalyst , 4 g of Ti (Onbu) 4 (titanium tetranormal butylate) were mixed with 11.4 G anhydrous MgCl 2 in powder form and kept at a temperature of l65 ° C 1 3 h. A semi-liquid product was obtained in which a part of the the cium chloride was present in solution; Under cold conditions The above reaction product was added to 240 ml of n-hexane and was carefully decomposed by stirring. The suspension was mixed with 38.2 g of AlC2H5Cl2 (aluminum ethyl dichloride) in an n-heptane solution with a concentration of 478 g / l. The mixing temperature was brought to 70 ° C and kept at this value for 1 hour. After cooling, it was decanted the solid precipitate until the excess aluminum alkyl had settled disappeared. The solid product was dried under vacuum at 50 ° C.

Elemental analysis gave the following results: 11.45 g / 100 g Ti 12.1 g / 100 g 3.45 g / 100 g Cl 63.75 g / 100 g Polymerization of propylene in a liquid monomer M9 Al b) kg of propylene together with 12.5 g of Al (C2H5) 3 in 90 ml of n-heptane, 6.36 g of ethyl anisate in 120 ml of n-heptane, 860 mg of the solid product (Example 1a) in 130 ml of n-heptane and 15 N1 of hydrogen were introduced into a 30 l stainless steel autoclave. The temperature was brought up to 65 ° C and the pressure was adjusted to an overpressure of 26.5kp / cmz.

After 5 hours of polymerization and after removal of propylene in excess 0.6 kg of polypropylene was obtained (yield 5770 g polymer / g Ti) which had an extraction residue with boiling heptane of 68.6 % and one bulk density of 0.20 kg / l.

EXAMPLE 2 a) Preparation of component B in the catalyst 11.65 g of anhydrous MgCl 2 in powder form was mixed with 29.55 g Al (0sec.Bu) 3 (aluminum secondary tributylate) and 4.08 g of Ti (0n.Bu) 4 (titanium-n-tetrabuthyate) and processed at 165 ° C for one hour.

A paste, semi-solid under hot conditions and solid under cold conditions, were thus obtained.

This solid product was decomposed by stirring in a solution. ln-hexane: 240 ml) under cold conditions.

At a temperature of 20 ° C, the above suspension was added with 38.15 g of AlCl 2 H 5 Cl 2 at a concentration of 478 g / l. The mixing temperature was brought (aluminum ethyl dichloride) in an n-heptane solution to 70 ° C and kept at this value for 1 hour; after cooling decant- the solid product was washed repeatedly with n-hexane IN åüülêšå fl š by decantation to remove excess aluminum alkyl.

The solid product was dried under vacuum at 50 ° C. Elemental ~ the analysis gave the following results: Mg = 16.15 g / 100 g, Ti = 3 g / 100 g A1 = 7.05 g / 1000 g 'cl 57.45 g / 100 g The surface area was 46 m2 / g. b) Polymerization of propylene in a solvent 119 mg of the solid product (Example 2a) were introduced into a 2.5 L stainless steel autoclave containing 1 1 n-heptane and 1,135 g Al (C2H5) 3, premixed with 447 mg of ethyl anisate.

The polymerization was carried out at 60 ° C under an overpressure of kp / cm2 with propylene and hydrogen (1.5 vol% of the gas phase) for 5 h. Pressure kept constant by continuous supply of propylene.

At the end after removal of the solvent by stripping with steam, 74 g of dry polypropylene with an extraction residue with boiling heptane equal to 77.6%, the yield being 20,700 g polymer / g Ti in 5 hours. c) Polymerization of propylene in a liquid monomer A stainless steel autoclave with a capacity of 30 liters was charged with 10 kg of propylene, 12.5 g of Al (C 2 H 5) 3 in 90 ml of n-heptane, 6.36 g of ethyl anisate in 120 l of n-heptane, 856 mg of the solid product (Example 2a) in 130 ml of n-heptane and 15 Nl of hydrogen.

The polymerization temperature was brought to 65 ° C and the pressure was adjusted to an overpressure of 26.5 kp / cm ?.

After 5 hours, 1.61 kg was obtained when excess propylene had been removed polypropylene (yield: 62 600 g polymer / g Ti), which had an extractant with boiling heptane equal to 78.5%, a bulk density of 0.29 kg / l, an intrinsic viscosity of 2 dl / g, a melt flow index of 3.7 g / 10 min and a flexural stiffness of 10 310 kp / cmg.

EXAMPLE 3 a) Preparation of component B in the catalyst 23 g of anhydrous MgCl 2 in powder form were mixed with 59 g of Al (0 sec-Bu) 3 (aluminum sec. tributylate) and with 4.08 g of Ti (OnBu) 4 (titanium-n-tetra- butylate) and processed at 65 ° C for 6 hours. A semi-solid paste was obtained thus, which was cold dispersed by stirring in 180 ml of n-hexane.

At a temperature of 20 ° C, 76.2 g of AlC 2 H 5 Cl 2 (aluminum ethyl dichloride) in an n-heptane solution at a concentration of 478 g / l with the suspension. The temperature was brought to 70 ° C under intense stirring for 1 hour. After cooling, the solid product was decanted and 8001655-3 * J was washed repeatedly with n-hexane by decantation to remove excess aluminum alkyl. The solid product is dried was then charged under vacuum at 50 ° C.

The elemental analysis gave the following results: Mg 19.5 g / 100 g Ti Al 4.2 g / 100 g Cl The surface area was 70 m2 / g. h) Polymerization of propylene in a solvent 234 mg of the solid product (Example 3a) were introduced into a 2.5 l ll 1.95 g / 1oo 9 65.10 g / ioo g ll Il stainless steel autoclave containing 1 l of n-heptane and 1,135 g 1 (C2H5) 3 premixed with 571 mg of ethyl anisate.

The polymerization was carried out at 60 ° C under an overpressure of kp / cm 2 with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours.

The pressure was kept constant by continuous supply of propylene.

Upon completion, after removal of the solvent was obtained by steam stripping 95 g of polymer - the yield was 20,800 g polypropylene / g Ti for 5 h - with an extraction residue with boiling heptane equal to 80.5% and an average density of 0.355 kg / l. c) Polymerization of propylene in a liquid monomer kg polypropylene together with 12.5 g A1 (C2H5) 3 in 90 ml n-heptane, 7.75 g of ethyl anisate in 120 ml of n-heptane, 1.1 g of the solid the product (Example 3a) in 130 ml of n-heptane and 15 Nl of hydrogen were introduced in a stainless steel autoclave with a capacity of 30 1. Poly- the merisation temperature was brought to 65 ° C and the pressure was adjusted to an overpressure of 26.5 kp / cmz.

After 5 hours, when excess propylene had been removed, 1.5 kg polypropylene with an extraction residue with boiling heptane of 81.5%, the yield being 70,000 g polymer / Ti.

Furthermore, the polymer exhibited the following properties: bulk density 0.21 kg / l viscosity 1.5 dl / g melt flow index 1.34 g / 10 ' flexural stiffness 11 sso kp / Cmz ExEMPgILg a) Preparation of component B in the catalyst 18.12 g Mg (OC 2 H 5) 2 was mixed with 5.4 g of Ti (O-n.C 4 H 9) 4 (titanium -tetrabutylate) in 240 ml of n-hexane at about 70 ° C and processing in 45 my. This mixture was added with 90 g of Al (C2H5) Cl2 (aluminum ethyl dichloride) in an n-heptane solution at a concentration of 478 g / l.

The temperature was brought to 75 ° C and kept at this value for 1 hour. sn @ 16ss ~ s 8 After cooling, the solid precipitate was decanted and washed: repeatedly with n-hexane by decantation to remove excess aluminum alkyl. The solid product was dried under vacuum at 45 ° C.

The elemental analysis gave the following results: Mg 12.25 g / 100 g Ti = 3.6 g / 100 g Al = 8.0 g / 100 g t Cl = 68.8 g / 100 g The surface area was 179 m2 / g. b) Polymerization of propylene in a solvent (l 189 mg of the solid product (Example 4a) were introduced into a stainless steel autoclave with a capacity of 2.5 l, containing 1 l of n-heptane and 1.135 g of Al (C2H5) 3, premixed with 447 mg of ethyl anisat. The polymerization was carried out at 60 DEG C. at an overpressure of 5 kp / cm2 with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours.

The pressure was kept constant by continuous supply of propylene.

Upon completion, after removal of the solvent was obtained by steam stripping, 290 g of polypropylene with an extraction residue with boiling heptane equal to 71%, the yield being 42,600 g polymer / g Ti for 5 hours. c) Polymerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (C2H5) 3 in 90 ml of n-heptane, 6.36 g of ethyl anisate in 120 ml of n-heptane, 790 mg of the solid product (Example 4a) in 130 ml of n-heptane and 15 Nl of hydrogen were introduced into an autoclave of stainless steel with a capacity of 30 1. the temperature was brought to 65 ° C and the pressure was adjusted to a pressure of 26.5 kp / cm2.

After 5 hours was obtained, when the excess of propylene had been removed ~ 3.05 kg polypropylene (yield = 107,000 g polymer / g Ti), which showed an extraction residue with boiling heptane equal to 74%, a bulk density of 0.29 kg / l, a melt flow index of 2.5 g / 10 min and a flexural stiffness of 8730 kp / cm 2.

EXAMPLE 5 a) Preparation of component B in the catalyst 39.6 g Mg (OC 2 H 5) 2 was mixed with 5.62 g of Ti (OnC 4 H 9) 4 (titanium-n- tetrabutylate) in 240 ml of n-hexane and worked up at about 70 ° C in 45 min. 183 g Al (C2H5) Cl2 (aluminum ethyl dichloride) in solution in n-heptane at a concentration of 478 g / l was added to this mixture. Tem- the temperature was brought to 75 ° C and kept at this value for 1 hour. 8001655-3 MC? After cooling, the solid precipitate was iced and washed repeatedly by decantation with n-hexane to remove excess aluminum alkyl. The solid product was dried under vacuum at 45 ° C.

The elemental analysis gave the following results: Mg 19.55 g / 100 g Ti = 2 g / 100 g Al 6.30 g / 100 g Cl = 68.35 g / 100 g The surface area was 79 m2 / g. b) Polymerization of the prone in a solvent 173 mg of the solid product (Example 5a) were introduced into a hrs Il stainless steel autoclave with a capacity of 2.5 l, containing 1 l of n-heptane and 1.1 g of Al (C 2 H 5) 3, premixed with 571 mg of ethyl anisate.

The polymerization was carried out at GOOC under an overpressure of kp / cm 2 with propylene and hydrogen (1.5 vo1% in the gas phase) for 5 hours.

The pressure was kept constant by continuous supply of propylene.

At the end, post-removal of the solvent was obtained by steam stripping, 150 g of polypropylene with an extraction residue with a boiling heptane of 72.6% and a bulk density of 0.353 kg / l, the yield being 43,300 g polymer / g Ti for 5 hours. c) Polymerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (C2H5) 3 in 90 ml of n-heptane, 8.75 g of ethyl anisate in 120 ml of n-heptane, 1.05 g of the solid product (Example 5a) in 130 ml of n-heptane and 15 Nl of hydrogen were introduced into an autoclave of stainless steel with a capacity of 30 l. the temperature was brought to 6500 and the pressure was adjusted to a pressure of 26.5 kp / cmz.

After 5 hours, when the excess propylene had been removed, 1.13 kg polypropylene with an extraction residue with boiling heptane of 80.5%, the yield being 53,800 g polymer / g Ti.

The polymer further exhibited the following properties: bulk density 0.33 kg / l melt flow index 5.1 g / 10 ' flexural stiffness 11,500 kp / cmz EXAMPLE 6 ._______----- Polymerization of propylene in a solvent 328 mg of the solid product prepared according to Example 3a) was introduced into a 2.5 L stainless steel autoclave containing 1 L n-heptane and 1.135 g of Al (C2H5) 3, premixed with 450 mg of ethyl para- toluate.

The polymerization was carried out at 60 ° C under an overpressure of kp / cm 2 with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours. soo1ߧs «z 10 The pressure was kept constant by continuous supply of pr ¿-n.

At the end, after removing the solvent was obtained by steam stripping, 296 g of polymer with an extraction residue with boiling heptane equal to 78.6%, a bulk density of 0.38 kg / l and an intrinsic viscosity of 2 dl / 9, the yield being 46,300 g polypropylene / g Ti for 5 hours.

Polymerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (C2H5) 3 in 90 ml of n-heptane, 6 g of ethyl paratoluate in 120 ml of n-heptane, 1.05 g of it according to examples 73a) prepared solid product in 130 ml of n-heptane and 15 Nl of hydrogen was introduced into a stainless steel autoclave with a capacity of 30 l.

The polymerization temperature was brought to 65 ° C and the pressure was adjusted. to an overpressure of 26.5 ~ kp / cm 2.

After 5 hours, when the excess propylene had been removed, 1.9 kg polypropylene - the yield was 97,500 g polymer / g Ti - with a extraction residue with boiling heptane of 80.5%.

The polymer also had the following properties: 'bulk density 0:21 k9 / 1 intrinsic viscosity 2 dl / g melt flow index 3.1 g / 10 ' flexural stiffness 10,750 kp / cm2 EXAMPLE 7 Polymerization of propylene in a solvent 240 mg of the solid product (prepared according to Example 3a) was introduced into a 2.5 l stainless steel autoclave containing 11 n-heptane and 1.135 g of Al (iC4H9) 3, premixed with 329 mg ethyl anisate.

The polymerization was carried out at 60 ° C under an overpressure of kp / cm 2 with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours.

The pressure was kept constant by continuous supply of propene. At the end, after removing the solution, the agent by stripping with steam, 137 g of polymer with a yield of 29,400 g of polypropylene / g of Ti for 5 hours, which showed an extract ions residue in boiling heptane equal to 72.5%.

Polymerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (iC4H9) 3 in 90 ml of n-heptane, 4.15 g of ethyl anisate in 120 ml of n-heptane, 1 g of that according to Example 3a) prepared solid product in 130 ml of n-heptane and 15 Nl of hydrogen in was carried in a stainless steel autoclave with a capacity of 30 l.

The polymerization temperature was brought to 65 ° C and the pressure was adjusted. to an overpressure of 26.5 kp / cm 2. ~ -..-, «~. ~ 1ue - = -.- n.,“ -., ......... l. ._ .. - 8001655-5 ll After 5 hours, when the excess propylene had been removed, 1.55 kg of polypropylene with a yield of 79,500 g of polymer / g of Ti, which showed an extraction residue in boiling heptane equal to 76%, a melt density of 0.3 kg / l, an intrinsic viscosity of 2 dl / g and a flexural stiffness of saso kp / @ m2.

EXAMPLE Polymerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (iC4H9) 3 in 90 ml of n-heptane, 3.45 g of ethyl paratoluate in 120 ml of n-heptane, 1.06 g of the solid the product (prepared according to Example 3a) in 130 ml of n-heptane and N1 hydrogen was introduced into a stainless steel autoclave with a capacity of 1. The polymerization temperature was brought to 65 ° C and the pressure was adjusted to an overpressure of 26.5 kp / cmz.

After 5 hours, when the excess propylene had been removed, 1.4 kg of polypropylene with a yield of 67,600 g of polymer / g of Ti, which showed an extraction residue with boiling heptane equal to 80.5%, a bulk density of 0.32 kg / l, an intrinsic viscosity of 2 dl / g and a flexural stiffness of 10,200 kp / cmz.

EXAMPLE 9 Polymerization of propylene in a solvent 287 mg of the solid product prepared according to Example 5a was introduced into a 2.5 l stainless steel autoclave, containing 1 l of n-heptane and 1.135 g of Al (C2H5) 3, premixed with 533 mg ethyl paratoluate. 7 The polymerization was carried out at 60 ° C under an overpressure of kp / cm 2 with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours.

The pressure was kept constant by continuous supply of propene. at the end was obtained, after removal of the solvent by steam stripping, 180 g of polymer with a yield of 31,400 g polypropylene / g Ti for 5 hours, which showed an extraction residue with boiling heptane equal to 80% and a bulk density of 0,253 kg / l. polymerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (C2H5) 3 in 90 ml of n-heptane, 6.45 g of ethyl paratoluate in 120 ml of n-heptane, 1 g of it according to example 5a prepared in 130 ml of n-heptane and 15 Nl of hydrogen was introduced into a stainless steel autoclave with a capacity of 30 l.

The polymerization temperature was brought to 65 ° C and the pressure was adjusted. to an overpressure of 26.5 kp / cm 2. 86616555 12 After 5 hours, when the excess propylene was removed, 1.3 kg of polypropylene with a yield of 65,000 g of polymer / g of Ti, which showed an extraction residue with boiling heptane of 84%, a density of 0.27 kg / l, an intrinsic viscosity equal to 2.4 dl / g, a smäitfiöaesinaex of 3.2 g / io 'and a flexural stiffness of 13 szo kp / cmz.

EEI-'IPEL 10 Polymerization of propylene in solvents 204 mg of the solid product prepared according to Example 5a was introduced into a 2.5 L stainless steel autoclave containing 1 L n-heptane and 1.135 g Al (iC4H9) 3, premixed with 215 mg ethyl para- toluate. The polymerization was carried out at 60 ° C at an overpressure of 5 kp / cm 2 with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours.

The pressure was kept constant by continuous supply of propylene.

Upon completion, after removal of the solvent was obtained by stripping with steam, 196 g of polymer with a yield of 19,400 g polypropylene / g Ti for 5 hours, which showed an extraction residue in boiling heptane equal to 69.5%. glygmerization of propylene in a liquid monomer kg of propylene together with 12.5 g of Al (iC4H9) 3 in 90 ml n-heptane, 3.45 g of ethyl paratoluate in 120 ml of n-heptane, 1.04 g of the solid product prepared according to Example 5a in 90 ml of n-heptane and 15 Nl of hydrogen were introduced into a stainless steel autoclave with a capacity of 30 1. The polymerization temperature was brought to 65 ° C and the pressure was adjusted to an overpressure of 26.5 kp / cmz.

After 5 hours, when the excess propylene had been removed, 1.15 kg of polypropylene with a yield of 55 300 g of polymer / g of Ti, which showed an extraction residue in boiling heptane of 76.5%, a density of 0.30 kg / l, an intrinsic viscosity of 1.8 dl / g, a melt flow index of 4 g / 10 min and a height stiffness of 10 460 kp / cmz.

EXAMPLE ll Polymerization of propylene in a solvent 246 mg of the solid product prepared according to Example 5a was introduced into a 2.5 L stainless steel autoclave containing 1 L n-heptane and 1.135 g of Al (C2H5) 3, premixed with 329 mg of ethyl anisate.

The polymerization was carried out at 60 ° C under an overpressure of kp / cm? with propylene and hydrogen (1.5 vol% in the gas phase) for 5 hours.

At the end was obtained, after removal of the solvent by steam stripping, 200 g of polymer with a yield of 41,700 g polypropylene / g Ti for 5 hours, which showed an extraction residue in boiling heptane equal to 71.5%.

Claims (4)

8001655-5 [-4 h; PATENT REQUIREMENTS Process for the polymerization of propylene, characterized in that a catalyst is used which comprises the reaction product between A) a product comprising complexes between an ester and an aluminum trialkyl, in which the alkyl groups are straight or branched and contain up to 20 carbon atoms, the aluminum trialkyl compound in complex form being 0.01 to less than 1 mole per mole of the starting aluminum compound, and B) a compound and / or composition obtained by bringing (b1) an aluminum alkyl halide or aluminum trihalide of the formula AlR'mX3_m, in which X is halogen and R 'is an alkyl group containing up to 10 carbon atoms, and m is 0 or a number less than 3, in contact with the reaction product between (b3) a titanium alcoholate and (bz) a magnesium dihalide or (a2) a magnesium dialcoholate 'Mg (OR') 2, wherein R 'is an alkyl group having 1-10 carbon atoms, the atomic ratio of halogen / magnesium in the compound or composition B) being at least 1: 1, and from polymerization one is carried out at temperatures between -80 ° C and + 125 DEG C., either in the liquid phase, in the presence or absence of an inert hydrocarbon diluent, or in the gas phase, under a partial pressure of propylene higher than atmospheric pressure. 2. A process according to claim 1, characterized in that the magnesium compound (bz) is MgCl 2. 3. A process according to claim 1 or 2, characterized in that the titanium compound (b3) is mixed with (b4) an aluminum alcoholate. Process according to one or more of the preceding claims, characterized in that the compound (b3) has the formula 'ri (o-iC3H7) 4, Ti (o-nC3H7) 4,' ri (o-ic4H9) 4, Ti (o-nc4n9) 4 or Ti2O (O-iC3H7) 6.