Catalyst Composition with Phosphorus-Based Donor and Method

Abstract

Disclosed are catalyst compositions having an external electron donor which includes one or more of the following compositions: a phosphite, a phosphonite, a pyrophosphite, and/or a diphosphazane. Ziegler-Natta catalyst compositions containing the present external electron donor exhibit strong activity and produce propylene-based olefins with high isotacticity and high melt flow rate.

1 . A catalyst composition comprising:
 a procatalyst composition comprising a magnesium moiety;   a cocatalyst; and   an external electron donor comprising at least one of a phosphite, phosphonite, pyrophosphite and diphosphazane.   
     
     
         2 . The catalyst composition of  claim 1  wherein the procatalyst composition comprises a component selected from the group consisting of a titanium moiety, an internal electron donor, and combinations thereof. 
     
     
         3 . The catalyst composition of  claim 2  wherein the procatalyst composition comprises an internal electron donor selected from the group consisting of an aromatic acid ester, a diether, a silyl ester, and combinations thereof. 
     
     
         4 . The catalyst composition of  claim 3  wherein the phosphite has the structure (VI) 
       
         
           
           
               
               
           
         
         the phosphonite has the structure (IX) 
       
       
         
           
           
               
               
           
         
         the pyrophosphite has the structure (XI) 
       
       
         
           
           
               
               
           
         
       
       and
 the diphosphazane has the structure (XII) 
 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , R 4  and R 5  are the same or different and each of R 1 -R 5  is selected from the group consisting of a substituted hydrocarbyl group having 1 to 20 carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, and combinations thereof; and
 X is selected from the group consisting of a hydrocarbyl group having 1 to 20 carbon atoms, a substituted hydrocarbyl group having 1 to 20 carbon atoms, a substituted amino group, an unsubstituted amino group, a halide, a pseudohalide, and a hydroxyl group. 
 
     
     
         5 . The catalyst composition of  claim 4  wherein the external donor is a phosphite and R 1 -R 3  are the same or different, and each of R 1 -R 3  is selected from the group consisting of a C 1 -C 6  alkyl group, and combinations thereof. 
     
     
         6 . The catalyst composition of  claim 5  wherein the external donor is a phosphonite and each of R 1 , R 2 , and X is the same or different, and each of R 1 , R 2 , and X is selected from the group consisting of a C 1 -C 6  alkyl group, and combinations thereof. 
     
     
         7 . The catalyst composition of  claim 5  wherein the external donor is a pyrophosphite and R 1 -R 4  are the same or different and each of R 1 -R 4  is selected from the group consisting of a C 1 -C 6  alkyl group, and combinations thereof. 
     
     
         8 . The catalyst composition of  claim 5  wherein the external donor is a diphosphazane and R 1 -R 5  are the same or different and each of R 1 -R 5  is selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a C 5  ring structure, a C 6  ring structure, and combinations thereof. 
     
     
         9 . The catalyst composition of  claim 4  wherein the external electron donor comprises an alkoxysilane. 
     
     
         10 . The catalyst composition of  claim 4  comprising an activity limiting agent. 
     
     
         11 . The catalyst composition  claim 6  wherein each of R 1 , R 2 , and X is the same or different, and each of R 1 , R 2 , and X is selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a C 5  ring structure, a C 6  ring structure, and combinations thereof. 
     
     
         12 . The catalyst composition of  claim 6  wherein at least one of R 1 , R 2 , and X is a member of a P-ring structure. 
     
     
         13 . The catalyst composition of  claim 7  wherein R 1 -R 4  are the same or different and each of R 1 -R 4  is selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a C 5  ring structure, a C 6  ring structure, and combinations thereof. 
     
     
         14 . The catalyst composition of  claim 13  wherein at least one R group of R 1 -R 4  is a member of a P-ring structure. 
     
     
         15 . The catalyst composition of  claim 8  wherein at least one R group of R 1 -R 5  is a member of a P-ring structure. 
     
     
         16 . A polymerization process comprising:
 contacting, under polymerization conditions, an olefin with a catalyst composition comprising an external electron donor comprising a member selected from the group consisting of a phosphite, a phosphonite, a pyrophosphite, a diphosphazene, and combinations thereof; and   forming an olefin-based polymer.   
     
     
         17 . The process of  claim 16  comprising a catalyst composition of  claim 4 . 
     
     
         18 . The process of  claim 17  wherein the olefin is propylene, the process comprising forming a propylene-based polymer having a melt flow rate from about 0.01 g/10 min to about 2000 g/10 min. 
     
     
         19 . The process of  claim 17  wherein the olefin is propylene, the process comprising forming a propylene-based polymer having a xylene solubles content from about 0.5% to about 10%. 
     
     
         20 . The process of  claim 17  wherein the olefin is propylene, the process comprising forming an propylene-based polymer at production rate from about 10 kg/g/hr to about 50 kg/g/hr.