Process for preparing low molecular weight olefin (CO) polymer and polymerization catalyst used thereof

Abstract

The present invention provides a process for preparing a low molecular weight olefin (co)polymer having a narrow molecular weight distribution with high productivity, by polymerizing or copolymerizing an olefin in the presence of an olefin polymerization catalyst comprising (A) a specific Group 4 transition metal compound, and (B) at least one compound selected from the group consisting of (B-1) an organometallic compound, (B-2) an organoaluminum compound, (B-3) an organoaluminum oxy-compound, and (B-4) a compound which reacts with the Group 4 transition metal compound (A) to form an ion pair; and compounds useful in that process.

1 . An olefin polymerization catalyst suitable for preparing a low molecular weight olefin (co)polymer by homopolymerizing or copolymerizing an olefin, which comprises:
 (A) a Group 4 transition metal compound represented by the following formula (1), and   (B) at least one compound selected from the group consisting of (B-1) an organometallic compound, (B-2) an organoaluminum compound, (B-3) an organoaluminum oxy-compound, and (B-4) a compound that reacts with the Group 4 transition metal compound (A) to form an ion pair;   
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13  and R 14  are independently selected from the group consisting of hydrogen, a hydrocarbon group, and a silicon-containing group, and are the same or different; and each adjacent pair of substituents R 1  to R 14  may be taken together to form a ring; M is Ti, Zr or Hf; Y is a Group 14 atom; each Q is independently selected from the group consisting of: a halogen, a hydrocarbon group, a neutral conjugated or non-conjugated diene having 10 or fewer carbon atoms, an anionic ligand, and a neutral ligand that can be coordinated with a lone electron pair; n is an integer of from 2 to 4; and j is an integer of from 1 to 4. 
       
     
     
         2 . The olefin polymerization catalyst according to  claim 1 , wherein the Group 4 transition metal compound represented by the general formula (1) is a Group 4 transition metal compound represented by the said formula (1′). 
     
     
         3 . A Group 4 transition metal compound represented by the following formula (1′); 
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11  and R 12  are independently selected from the group consisting of a hydrogen atom, a hydrocarbon group, and a silicon-containing group, and may be the same or different; each of R 13 , R 14 , R 15  and R 16  is independently a hydrogen atom or a hydrocarbon group; n is an integer of from 1 to 3 and when n is 1, not all of the R 1  to R 16  are hydrogen atoms, and each of the R 1  to R 16  may be the same or different; each adjacent pair of substituents R 5  to R 12  may be taken together to form a ring; R 13  and R 15  may be taken together to form a ring, or the pair of R 13  and R 15  and the pair of R 14  and R 16  may be taken together to form rings simultaneously; each of Y 1  and Y 2  is a Group 14 atom, and may be the same or different; M is Ti, Zr or Hf; each Q is independently selected from a group consisting of halogen, a hydrocarbon group, an anionic ligand and a neutral ligand that can be coordinated with a lone electron pair; and j is an integer of from 1 to 4]. 
       
     
     
         4 . The Group 4 transition metal compound according to  claim 3 , wherein n is 1 or 2, and each of Y 1  and Y 2  is a carbon atom or a silicon atom, in the formula (1′). 
     
     
         5 . The Group 4 transition metal compound according to  claim 3 , wherein two or more of the substituents R 6 , R 7 , R 10  and R 11  are hydrocarbon groups having 1 to 20 carbon atoms, in the formula (1′). 
     
     
         6 . The group 4 transition metal compound according to  claim 3 , wherein R 6  and
 R 7  are taken together to form an aliphatic ring, and R 10  and R 11  are taken together to form an aliphatic ring, in the formula (1′).