Catalyst system for alpha-olefin oligomerization

Abstract

It is disclosed a new catalyst system, having high catalytic activity in the oligomerization of α-olefins, comprising a bridged bis-amido Group 4 metal compound of formula (I): wherein M is Ti, Zr or Hf; Y is Si, Ge or Sn; X is a hydrogen, halogen or an hydrocarbon radical; R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are hydrocarbon radicals, optionally containing Si, Ge, O, S, P, B or N atoms; Q is a neutral Lewis base; and m is 0-2; in association with a boron activating compound, and with one or more branched alkylaluminiums and/or alumoxanes of branched alkylaluminiums: said catalyst system allows oligomers to be obtained in high yields, with a high selectivity towards α-oligomers.

1 . A catalyst system for α-olefin oligomerization comprising the product obtainable by contacting the following components: 
 (A) one or more bis-amido compounds having formula (I):  
                     
 wherein M is Ti, Zr or Hf;  
 N is a trivalent nitrogen atom;  
 the Y atoms, the same or different from each other, are selected from the group consisting of Si, Ge and Sn;  
 the X groups, the same or different from each other, are selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated C 1 -C 20  alkyl, C 1 -C 20  alkoxyl, C 3 -C 20  cycloalkyl, C 6 -C 20  aryl, C 6 -C 20  aryloxyl, C 7 -C 20  alkylaryl and C 7 -C 20  arylalkyl radicals, optionally containing one or more Si, Ge, O, S, P, B or N atoms; or two X groups form a ring having from 4 to 8 members;  
 R 1 , R 2 , R 3 , R 4 , R 5  and R 6 , the same or different from each other, are linear or branched, saturated or unsaturated C 1 -C 20  alkyl, C 3 -C 20  cycloalkyl, C 6 -C 20  aryl, C 7 -C 20  alkylaryl or C 7 -C 20  arylalkyl radicals, optionally containing one or more Si, Ge, O, S, P, B or N atoms; or are Si(R 7 ) 3  groups, wherein the groups R 7 , the same or different from each other, are linear or branched, saturated or unsaturated C 1 -C 10  alkyl, C 3 -C 10  cycloalkyl, C 6 -C 15  aryl, C 7 -C 15  alkylaryl or C 7 -C 15  arylalkyl groups; or two or four substituents of R 1 , R 2 , R 3 , R 4 , R 5  and R 6 , linked to two vicinal atoms, form one or two rings having from 4 to 8 members;  
 Q is a neutral Lewis base; and  
 m is an integer ranging from 0 to 9;  
 said bis-amido compound being optionally present in the form of a dimer;  
 (B) one or more activating cocatalysts selected from:  
 compounds having formula Y + Z − , wherein Y +  is a cation capable of reacting irreversibly with a substituent X of the compound of formula (I), and Z −  is a compatible non-coordinating anion comprising at least one boron atom; and  
 neutral strongly Lewis acidic compounds comprising at least one boron atom;  
 (C) one or more compounds selected from the following classes:  
 (a) organometallic aluminium compounds having formula (II):  
 Al(CH 2 —CR 8 R 9 R 10 ) x R 11   y H z   (II)  
 wherein, in the (CH 2 —CR 8 R 9 R 10 ) groups, the same or different from each other, R 8  is a linear or branched, saturated or unsaturated C 1 -C 10  alkyl, C 3 -C 13  cycloalkyl or C 7 -C 16  alkylaryl radical;  
 R 9  is a saturated or unsaturated C 1 -C 50  alkyl, C 3 -C 50  cycloalkyl, C 6 -C 50  aryl, C 7 -C 50  alkylaryl or C 7 -C 50  arylalkyl radical, said radical being different from a straight alkyl or alkenyl group;  
 or R 8  and R 9  form together a ring having from 4 to 6 carbon atoms;  
 R 10  is hydrogen or a linear or branched, saturated or unsaturated C 1 -C 10  alkyl, C 6 -C 15  aryl, C 7 -C 16  alkylaryl radical or arylalkyl radical, optionally containing one or more Si or Ge atoms;  
 R 11  is a linear or branched, saturated or unsaturated C 1 -C 10  alkyl, C 3 -C 15  cycloalkyl, C 6 -C 15  aryl, C 7 -C 16  alkylaryl or C 7 -C 16  arylalkyl radical;  
 x is an integer ranging from 1 to 3; z is 0 or 1; and y is 3−x−z; and  
 (b) the reaction products of water with organometallic aluminium compounds of formula (III):  
 AlR 12   3−w H w   (III)  
 wherein the substituents R 12 , the same or different from each other, are selected from the group consisting of linear or branched, saturated or unsaturated C 1 -C 50  alkyl, C 3 -C 50  cycloalkyl, C 6 -C 50  aryl, C 7 -C 50  alkylaryl and C 7 -C 50  arylalkyl radicals, optionally containing one or more Si or Ge atoms, wherein at least one of said substituents R 12  is different from a straight alkyl group; and w is 0 or 1;  
 the molar ratio between said organometallic aluminium compound and water being comprised between 1:1 and 100:1.  
 
     
     
         2 . The catalyst system according to  claim 1 , characterized in that said bis-amido compound is present in the form of a dimer having formula (IV):  
       
         
           
           
               
               
           
         
       
       wherein M, Y, X, R 1 , R 2 , R 3 , R 4 , R 5 , R 6  and Q have the meaning reported in  claim 1 , and n is 0 or 1.  
     
     
         3 . The catalyst system according to  claim 1  or  9 , characterized in that, in said bis-amido compound of formula (I) or (IV), M is Zr and the Y atoms are Si atoms.  
     
     
         4 . The catalyst system according to anyone of  claims 1  to  3 , characterized in that, in said bis-amido compound of formula (I) or (IV), X is selected from the group consisting of hydrogen, methyl, ethyl, propyl, n-butyl, phenyl, 4-alkyl-phenyl and benzyl radicals.  
     
     
         5 . The catalyst system according to anyone of  claim 1  to  4 , characterized in that, in said bis-amido compound of formula (I) or (IV), R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are selected from the group consisting of methyl, ethyl, propyl, n-butyl, t-butyl, t-amyl, 1,1,3,3-tetramethyl-butyl, cyclohexyl, phenyl, dimethyl-phenyl, diisopropyl-methyl, trimethyl-silyl, tri-t-butyl-silyl phenylmethyl-ethyl, diphenyl-ethyl and triphenyl-methyl.  
     
     
         6 . The catalyst system according to any one of  claims 1  to  5 , characterized in that, in said bis-amido compound of formula (I) or (IV), Q is selected from the group consisting of diethylether, tetrahydrofuran, dimethylaniline, aniline, n-butylamine and trimethylphosphine.  
     
     
         7 . The catalyst system according to  claim 1 , characterized in that, in said activating cocatalyst of formula Y + Z − , Y +  is a quaternary ammonium cation or a metal cation, and Z −  is a borate of formula [B(R 1 ) 4 ] − , wherein R 1  is selected from the group consisting of hydrogen, C 1 -C 10  alkyl, C 3 -C 10  cycloalkyl, C 6 -C 15  aryl, C 7 -C 15  alkylaryl and C 7 -C 15  arylalkyl groups, optionally substituted with one or more halogens.  
     
     
         8 . The catalyst system according to  claim 7 , characterized in that Y −  is tri-n-butylammonium or dimethylanilinium, and Z −  is selected from the group consisting of [B(C 6 F 5 ) 4 ] − , [R 1 B(C 6 F 5 ) 3 ] − , [B(FC 6 H 4 ) 4 ] − , [KrB(FC 6 H 4 ) 3 ] − , [B{(CF 3 ) 2 (C 6 H 3 )}] and [R 1 B{(CF 3 ) 2 (C 6 H 3 )} 3 ] − , wherein R 1  has the meaning reported in  claim 7 .  
     
     
         9 . The catalyst system according to  claim 1 , characterized in that said activating cocatalyst is a neutral strongly Lewis acidic compound selected from tris(pentafluorophenyl)borane, tris(2,3,5,6-tetrafluorophenyl)borane and trimethylboron.  
     
     
         10 . The catalyst system according to  claim 1 , characterized in that, in said organometallic aluminium compound of formula (II), R 8  is methyl or ethyl; R 9  is a branched C 4 -C 10  alkyl or alkylaryl group, or a phenyl group; R 10  is hydrogen; and R 11  is a C 1 -C 5  alkyl group.  
     
     
         11 . The catalyst system according to  claim 1 , characterized in that, in said organometallic aluminium compound of formula (II), the (CH 2 —CR 8 R 9 R 10 ) groups, the same or different from each other, are β,δ-branched groups.  
     
     
         12 . The catalyst system according to  claim 11 , characterized in that said organometallic aluminium compound of formula (II) is selected from the group consisting of tris(2,4,4-trimethylpentyl)aluminium, bis(2,4,4-trimethylpentyl)aluminium hydride, isobutyl-bis(2,4,4-trimethylpentyl)aluminium, diisobutyl-(2,4,4-trimethylpentyl)aluminium, tris(2,4-dimethylheptyl) aluminium and bis(2,4-dimethylheptyl)aluminium hydride.  
     
     
         13 . The catalyst system according to  claim 11 , characterized in that said β,δ-branched groups correspond to formula (CH 2 —CR 8 R 10 —CH 2 —CR 13 R 14 R 15 ), wherein R 8  and R 10  have the meaning reported in  claim 1;  R 13  and R 14 , the same or different from each other, are linear or branched, saturated or unsaturated C 1 -C 20  alkyl, C 3 -C 20  cycloalkyl, C 6 -C 20  aryl, C 7 -C 20  alkylaryl and C 7 -C 20  arylalkyl radicals; and R 15  is hydrogen or has the same meaning of R 13  and R 14 .  
     
     
         14 . The catalyst system according to  claim 1 , characterized in that, in said organometallic aluminium compound of formula (II), the (CH 2 —CR 8 R 9 R 10 ) groups, the same or different from each other, are β,δ-branched groups.  
     
     
         15 . The catalyst system according to  claim 14 , characterized in that said β,δ-branched groups correspond to formula (CH 2 —CR 8 R 10 —CR 13 R 14 R 15 ), wherein R 8  and R 10  have the meaning reported in  claim 1;  R 13  and R 14 , the same or different from each other, are linear or branched, saturated or unsaturated C 1=l -C   20  alkyl, C 3 -C 20  cycloalkyl, C 6 -C 20  aryl. C 7 -C 20  alkylaryl or C 7 -C 20  arylalkyl radicals; and R 15  is hydrogen or has the same meaning of R 13  and R 14 .  
     
     
         16 . The catalyst system according to  claim 15 , characterized in that said organometallic aluminium compound of formula (II) is selected from the group consisting of: 
 tris(2,3 -dimethyl-butyl)aluminium, tris(2,3,3-trimethyl-butyl)aluminium, tris(2,3-dimethyl-pentyl)aluminium, tris(2,3-dimethyl-hexyl)aluminium, tris(2,3 -dimethyl-heptyl)aluminium, tris(2-methyl-3-ethyl-pentyl)aluminium, tris(2-methyl-3-ethyl-hexyl)aluminium, tris(2-methyl-3-ethyl-heptyl)aluminium, tris(2-methyl-3-propyl-hexyl)aluminium, tris(2-ethyl-3-methyl-butyl)aluminium, tris(2-ethyl-3-methyl-pentyl)aluminium, tris(2,3-diethyl-pentyl)aluminium, tris(2-propyl-3-methyl-butyl)aluminium, tris(2-isopropyl-3-methyl-butyl)aluminium, tris(2-isobutyl-3-methyl-pentyl)aluminium, tris(2,3 ,3-trimethyl-pentyl)aluminium, tris(2,3,3-trimethyl-hexyl)aluminium, tris(2-ethyl-3,3-dimethyl-butyl)aluminium. tris(2-ethyl-3 3-dimethyl-pentyl)aluminium, tris(2-isopropyl-3,3-dimethyl-butyl)aluminium, tris(2-trimethylsilyl-propyl)aluminium, tris(2-methyl-3-phenyl-butyl)aluminium, tris(2-ethyl-3-phenyl-butyl)aluminium and tris(2,3-dimethyl-3-phenyl-butyl)aluminium.    
     
     
         17 . The catalyst system according to  claim 1 , characterized in that, in said organometallic aluminium compound of formula (III), R 12  is a substituted or unsubstituted non-straight C 1 -C 10  alkyl or C 7 -C 16  alkylaryl, optionally containing Si or Ge atoms.  
     
     
         18 . The catalyst system according to  claim 17 , characterized in that said organometallic aluminium compound of formula (III) is selected from the group consisting of Al(iBu) 3 , AlH(iBu) 2 , Al(iHex) 3 , Al(C 6 H 5 ) 3 , Al(CH 2 C 6 H 5 ) 3 , Al(CH 2 CMe 3 ) 3 , Al(CH 2 SiMe 3 ) 3 , AlMe 2 iBu and AlMe(iBu) 2 .  
     
     
         19 . The catalyst system according to  claim 17 , characterized in that, in said organometallic aluminium compound of formula (III), at least one group R 12  is a β,δ-branched group.  
     
     
         20 . The catalyst system according to  claim 19 , characterized in that said organometallic aluminium compound is tris(2,3-dimethyl-butyl)aluminium or tris(2,3-dimethyl-hexyl)aluminium.  
     
     
         21 . The catalyst system according to  claim 17 , characterized in that, in said organometallic aluminium compound of formula (III), at least one group R 12  is a β,δ-branched group.  
     
     
         22 . The catalyst system according to  claim 21 , characterized in that said organometallic aluminium compound is tris(2,4,4-trimethylpentyl)aluminium.  
     
     
         23 . The catalyst system according to  claim 1 , characterized in that, in component C, the molar ratio between said organometallic aluminium compound of formula (III) and water ranges from 1:1 to 50:1.  
     
     
         24 . The catalyst system according to  claim 1 , characterized in that the molar ratio between component (A) and component (B) ranges from 0.1:1 to 5:1.  
     
     
         25 . The catalyst system according to  claim 1 , characterized in that the molar ratio between the aluminium of component (C) and the metal M of the component (A) ranges from 10:1 to 500:1.  
     
     
         26 . A process for the oligomerization or co-oligomerization of α-olefins of formula CH 2 ═CHR, wherein R is hydrogen or a C 1 -C 20  alkyl, C 5 -C 20  cycloalkyl or C 6 -C 20  aryl radical, comprising the reaction of oligomerization of one or more α-olefins in the presence of a catalyst system as described in any one of  claims 1  to  25 .  
     
     
         27 . The process according to  claim 26 , characterized in that said α-olefin is selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and allylcyclohexane.  
     
     
         28 . The process according to  claim 26 , characterized by being carried out in the presence of a solvent selected from isopentane, isooctane and toluene.  
     
     
         29 . The process according to  claim 26 , characterized by being carried out at a temperature ranging from 10° C. to 100° C., at a pressure ranging from 200 to 8,000 kPa.