Solid component of catalyst for the (co) polymerization of ethylene and process for its use

Abstract

Catalyst and solid component of catalyst for the (co)polymerization of ethylene, comprising titanium, magnesium, chlorine, a protic organo-oxygenated compound D p and a neutral aprotic electron-donor compound D, in the following molar ranges: Mg/Ti=1.0-50; D/Ti=1.0-15; Cl/Ti=6.0-100; Dp/D=0.05-3; and a process for obtaining said component.

1 . A solid component of catalyst for a (co)polymerization of ethylene, comprising titanium, magnesium, chlorine, an organo-oxygenated protic compound D p , and a neutral electron-donor aprotic compound D, in the following molar ratio ranges:
 Mg/Ti=1.0-50; D/Ti=1.0-15;   Cl/Ti=6.0-100; D p /D=0.05-3.   
     
     
         2 . The solid component according to  claim 1 , additionally comprising an inert granular solid, in a quantity ranging from 10 to 90% by weight with respect to the total weight of the solid component. 
     
     
         3 . The solid component according to  claim 2 , wherein said inert granular solid is in a quantity ranging from 25 to 50% by weight. 
     
     
         4 . The solid component according to  claim 2 , wherein said inert granular solid is selected from the group consisting of: silica, titania, silico-aluminates, calcium carbonate, and magnesium chloride, and having average dimensions of the inert granule solid ranging from 10 μm to 300 μm. 
     
     
         5 . The solid component according to  claim 4 , wherein said inert granular solid consists of microspheroidal silica having an average diameter ranging from 20 to 100 μm, a BET surface area ranging from 150 to 400 m 2 /g, a total porosity equal or higher than 80% and an average pore radius of 50 to 200 Å. 
     
     
         6 . The solid component according to  claim 1 , wherein the molar ratio ranges are:
 Mg/Ti=1.5-10; D/Ti=3.0-8.0;   Cl/Ti=10-25; D p /D=0.1-2.0.   
     
     
         7 . The solid component according to  claim 1 , wherein said ratio D p /D ranges from 0.2 to 1.0. 
     
     
         8 . The solid component according to  claim 1 , wherein said organo-oxygenated protic compound D p  is selected from compounds having the following formula (II):
   R-(A) m -OH   (II)
   
       wherein:
 R is an aliphatic, cyclo-aliphatic or aromatic radical, optionally fluorinated, containing from 1 to 30 carbon atoms; 
 A is one of divalent groups having the formula CR 1 R 2 , CO, SCO and SO, wherein each R 1  and R 2  is independently hydrogen or an aliphatic or aromatic group having from 1 to 10 carbon atoms; and 
 m is 0 or 1. 
 
     
     
         9 . The solid component according to  claim 1 , wherein said organo-oxygenated protic compound D p  is selected from the group consisting of aliphatic or aromatic alcohols and organic acids, having from 2 to 10 carbon atoms. 
     
     
         10 . The solid component according to  claim 1 , wherein said aprotic electron-donor compound D is a coordinating organic compound having from 3 to 20 carbon atoms, comprising at least one heteroatom of non-metallic compounds of groups 15 and 16. 
     
     
         11 . The solid component according to  claim 1 , wherein said electron-donor compound D is at least one selected from the group consisting of ketones, ethers, esters, amines, amides, thioethers, and xanthates, linear or cyclic, and aliphatic or aromatic, having from 4 to 10 carbon atoms. 
     
     
         12 . The solid component according to  claim 10 , wherein said compound D is selected from the group consisting of dibutyl ether, dihexyl ether, methylethyl ketone, diisobutyl ketone, tetrahydrofuran, dioxane, ethyl acetate, butyrolactone. 
     
     
         13 . The solid component according to  claim 1 , wherein said titanium is present in a quantity ranging from 1 to 10% by weight. 
     
     
         14 . A process for the preparation of a solid component comprising titanium, magnesium, chlorine, an organo-oxygenated protic compound D p , and a neutral electron-donor aprotic compound D, in the following molar ratio ranges:
 Mg/Ti=1.0-50; D/Ti=1.0-15;   Cl/Ti=6.0-100; D p /D=0.05-3,   comprising reacting, in an inert liquid medium, a solid precursor containing titanium, magnesium, chlorine, an aprotic electron-donor compound D and optionally an inert granular solid in the following molar ratios:   Mg/Ti=1-50; D/Ti=2.0-20; Cl/Ti=6-100   with protic organo-oxygenated compound D p , in such a quantity that the molar ratio D p /D ranges from 0.1 to 1.2, until equilibrium is reached, wherein said inert granular solid is in a quantity ranging from 0 to 95%.   
     
     
         15 . The process according to  claim 14 , wherein said molar ratios are:
 Mg/Ti=1.5-10; D/Ti=4.0-12; Cl/Ti=10-30, and   wherein said inert granular solid is in a quantity ranging from 20 to 60% by weight with respect to the total weight of the precursor.   
     
     
         16 . The process according to  claim 14 , wherein the molar ratio D p /D ranges from 0.2 to 1.2. 
     
     
         17 . The process according to  claim 14 , wherein said reaction is carried out at a temperature ranging from 40 to 100° C., for a period varying from 5 minutes to 5 hours. 
     
     
         18 . The process according to  claim 17 , wherein said reaction is carried out at a temperature ranging from 60 to 80° C., for a period of 5 to 60 minutes. 
     
     
         19 . A catalyst for the (co)polymerization of ethylene, where the catalyst is obtained by a process comprising reacting said solid component according to  claim 1  with a co-catalyst comprising a hydrocarbyl compound of a metal selected from the group consisting of Al, Ga, Mg, Zn and Li. 
     
     
         20 . The catalyst according to  claim 19 , wherein the atomic ratio between the metal in the co-catalyst and titanium in the solid component of catalyst ranges from 10:1 to 500:1. 
     
     
         21 . The catalyst according to  claim 19 , comprising titanium, magnesium, aluminum and chlorine, wherein said co-catalyst comprises an alkylic organometallic compound of aluminum. 
     
     
         22 . The catalyst according to  claim 21 , wherein said organometallic compound of aluminum is at least one aluminum tri-alkyl comprising from 1 to 10 carbon atoms in each alkyl group. 
     
     
         23 . The catalyst according to  claim 19 , wherein the solid component and the co-catalyst are contacted in situ in a polymerization reactor. 
     
     
         24 . The catalyst according to  claim 19 , wherein said solid component is activated before contact with said co-catalyst, by reaction with an aluminum alkyl or alkyl chloride represented by formula (III):
   AlR′ n X (3-n)   (III)
   
       wherein:
 R′ is a linear or branched alkyl radical containing from 1 to 20 carbon atoms; 
 X is H or Cl; and 
 n is a decimal number having a value ranging from 1 to 3; 
 wherein an Al/(D+D p ) ratio between the aluminium moles in said compound having formula (III) and the total of D and D p  moles in said solid component ranges from 0.1 to 1.5. 
 
     
     
         25 . The catalyst according to  claim 24 , wherein said R′ in formula (III) is a linear or branched aliphatic radical, having from 2 to 8 carbon atoms. 
     
     
         26 . The catalyst according to  claim 24 , wherein said Al/(D+D p ) ratio ranges from 0.2 to 1.3. 
     
     
         27 . The catalyst according to 24, wherein said solid component is activated by a first reaction with an aluminum trialkyl (n=3 in formula (III)), and successively in a second reaction with an aluminum dialkyl chloride (n=2, X=Cl, in formula (III)), in such a quantity that the overall molar ratio Al/(D+D p ) ranges from 0.1 to 1.3. 
     
     
         28 . The catalyst according to  claim 27 , wherein, in said first reaction, the molar ratio AlR 3 /(D+D p ) ranges from 0.1 to 0.4 and, in the second reaction, the molar ratio AlR 2 Cl/(D+D p ) ranges from 0.2 to 0.6. 
     
     
         29 . A process for the (co)polymerization of ethylene, comprising reacting ethylene and optionally at least one alpha-olefin, under suitable polymerization conditions, in the presence of said catalyst according to  claim 19 . 
     
     
         30 . The process according to  claim 29 , comprising carrying out a fluid-bed method, wherein a gaseous stream of ethylene and optional alpha-olefin is reacted in the presence of a quantity of catalyst, at a temperature ranging from 70 to 115° C., and at a pressure ranging from 500 to 1000 kPa. 
     
     
         31 . The process according to  claim 30 , wherein said gaseous stream is introduced from the bottom of the polymerization reactor, partially comprising a stream in liquid form. 
     
     
         32 . The process according to  claim 30 , in the presence of a catalyst for the (co)polymerization of ethylene, which is obtained by means of contact and reaction of
 a solid component of catalyst for a (co)polymerization of ethylene, comprising titanium, magnesium, chlorine, an organo-oxygenated protic compound D p , and a neutral electron-donor aprotic compound D, in the following molar ratio ranges:
 Mg/Ti=1.0-50; D/Ti=1.0-15; 
 Cl/Ti=6.0-100; D p /D=0.05-3, 
   with a co-catalyst comprising a hydrocarbyl compound of a metal selected from Al, Ga, Mg, Zn and Li,   wherein said solid component is activated before contact with said co-catalyst, by reaction with an aluminum alkyl or alkyl chloride represented by formula (III):
   AlR′ n X (3-n)   (III)
 
   
       wherein:
 R′ is a linear or branched alkyl radical containing from 1 to 20 carbon atoms; 
 X is H or Cl; and 
 n is a decimal number having a value ranging from 1 to 3; 
 wherein an Al/(D+D p ) ratio between the aluminium moles in said compound having formula (III) and the total of D and D p  moles in said solid component ranges from 0.1 to 1.5. 
 
     
     
         33 . The process according to  claim 29 , wherein the molar ratio with ethylene ranges from 0.1 to 1.0. 
     
     
         34 . The process according to  claim 29 , wherein said α-olefin is selected from the group consisting of 1-butene, 1-hexene and 1-octene and is in a quantity that the molar ratio with ethylene ranges from 0.1 to 0.4. 
     
     
         35 . The process according to  claim 29 , comprising obtaining linear polyethylene having a density ranging from 0.915 to 0.950 g/ml. 
     
     
         36 . The process according to  claim 30 , comprising obtaining linear polyethylene having a density lower than 0.915 g/ml, and co-polymerizing, in gas phase, a gaseous mixture comprising ethylene and at least one alpha-olefin having from 4 to 10 carbon atoms. 
     
     
         37 . The process according to  claim 36 , wherein the gaseous mixture of ethylene and the at least one alpha-olefin is reacted in the presence of a quantity of catalyst, at a temperature ranging from 70 to 95° C., and a pressure ranging from 500 to 1000 kPa. 
     
     
         38 . The process according to  claim 36 , wherein said alphaolefin is selected from the group consisting of 1-butene, 1-hexene and 1-octene, and is in a quantity that the molar ratio with respect to ethylene ranges from 0.1 to 0.4. 
     
     
         39 . The process according to  claim 29 , wherein said catalyst is formed in situ inside the reactor. 
     
     
         40 . The process according to  claim 29 , wherein said linear polyethylene has a weight average molecular weight M w  ranging from 20,000 to 500,000 and a MWD (M w /M n ) distribution ranging from 2.5 to 4.