Polyolefin-derived dispersants

Abstract

Ethylene-C 3 -C 10 alpha olefin copolymers, dispersants and lubricating oils/fuel compositions incorporating dispersants, and related methods are generally described herein. The copolymer may comprise ethylene-derived units and C 3 -C 10 alpha-olefin-derived units. The C 3 -C 10 alpha-olefin-derived units may have a carbon number from three to ten. For example, the C 3 -C 10 alpha-olefin-derived units may be propylene-derived units. The dispersants may be made from copolymers having low metal and/or fluorine contents.

1 . A dispersant prepared by a process comprising: functionalizing a copolymer derived from ethylene and one or more C 3-10  alpha-olefins,
 wherein the copolymer has a number average molecular weight of less than 5,000 g/mol as measured by GPC using polystyrene as a calibration reference;   wherein an ethylene unit content of the copolymer is less than 80 mol %, as measured by  1 H-NMR spectroscopy;   wherein the copolymer has a terminal unsaturation of 70 mol % or greater, as measured by  13 C-NMR spectroscopy, and at least 70 mol % of the terminal unsaturation is selected from terminal vinylidene, one or more tri-substituted isomers of the terminal vinylidene and any combination thereof, as measured by  1 H-NMR spectroscopy;   wherein the copolymer has an average ethylene run length n C2,Actual , as determined by  13 C NMR spectroscopy, of less than 2.6, and wherein:
   n C2,Actual <n C2,Statistical . 
   
     
     
         2 . The dispersant of  claim 1 , wherein the copolymer has a crossover temperature of −25° C. or lower. 
     
     
         3 . The dispersant of  claim 1 , wherein the copolymer has a crossover temperature of −35° C. or lower. 
     
     
         4 . The dispersant of  claim 1 , wherein the ethylene unit content is less than 60 mol %. 
     
     
         5 . The dispersant of  claim 1 , wherein the ethylene unit content is less than 50 mol %. 
     
     
         6 . The dispersant of  claim 1 , wherein the ethylene unit content is at least 10% and less than 80%. 
     
     
         7 . The dispersant of  claim 1 , wherein at least 85 mol % of terminal unsaturation is selected from the terminal vinylidene, one or more of the tri-substituted isomers of the terminal vinylidene and any combination thereof. 
     
     
         8 . The dispersant of  claim 1 , wherein at least 95 mol % of the terminal unsaturation is selected from the terminal vinylidene, one or more of the tri-substituted isomers of the terminal vinylidene and any combination thereof. 
     
     
         9 . The dispersant of  claim 1 , wherein the copolymer has an average ethylene run length of less than 2.4. 
     
     
         10 . The dispersant of  claim 1 , wherein the copolymer has an average ethylene run length of less than 2.2. 
     
     
         11 . The dispersant of  claim 1 , wherein the copolymer has a polydispersity index of less than or equal to 4. 
     
     
         12 . The dispersant of  claim 1 , wherein the copolymer has a polydispersity index of less than or equal to 3. 
     
     
         13 . The dispersant of  claim 1 , wherein the copolymer is an ethylene-propylene copolymer, wherein the ethylene unit content is 30 to less than 80 mol % and a propylene unit content is 20-70 mol %. 
     
     
         14 . The dispersant of  claim 1 , wherein the copolymer is an ethylene-propylene copolymer, wherein the ethylene unit content is 40-60 mol % and a propylene unit content is 40-60 mol %. 
     
     
         15 . The dispersant of  claim 1 , wherein the copolymer is an ethylene-propylene copolymer, wherein the ethylene unit content is about 40-50 mol % and a propylene unit content is about 50-60 mol %. 
     
     
         16 . The dispersant of  claim 1 , wherein the number average molecular weight of the copolymer is less than 3,500 g/mol, as measured by GPC. 
     
     
         17 . The dispersant of  claim 1 , wherein the number average molecular weight of the copolymer is greater than 500 g/mol and less than 3,000 g/mol, as measured by GPC. 
     
     
         18 . (canceled) 
     
     
         19 . The dispersant of  claim 1 , wherein the dispersant is posted treated with anhydride, a boron compound, or a mixture thereof. 
     
     
         20 . The dispersant of  claim 1 , wherein the dispersant has one of the following formulas: 
       
         
           
           
               
               
           
         
         wherein R 1  is an hydrocarbyl radical derived from the copolymer; R 2  is a divalent C 1 -C 6  alkylene; R 3  is a divalent C 1 -C 6  alkylene; each of R 4  and R 5 , independently, is H, C 1 -C 6  alkyl, 
       
       
         
           
           
               
               
           
         
       
       or, together with the N to which they are attached to, form a 5 or 6-membered ring optionally fused with an aromatic or non-aromatic ring; R 6  is H or C 1 -C 6  alkyl, or —CH 2 —(NH—R 2 ) n —NR 4 R 5 ; Y is a covalent bond or C(O); and n is 0, 1, 2, 3, 4, 5, 6, 7, or 8. 
     
     
         21 . The dispersant of  claim 1 , wherein the terminal vinylidene and the tri-substituted isomers of the terminal vinylidene of the copolymer have one or more of the following structural formulas (A)-(B): 
       
         
           
           
               
               
           
         
         wherein R represents a C 1 -C 8  alkyl group and 
       
       
         
           
           
               
               
           
         
       
       indicates the bond is attached to the remaining portion of the copolymer. 
     
     
         22 . The dispersant of  claim 1 , wherein the copolymer has a total Zr, Ti, Al and B content of 25 ppmw or less, based on the total weight of the copolymer, wherein the Zr, Ti, Al, and B is derived from a single-site catalyst and an optional co-catalyst. 
     
     
         23 . The dispersant of  claim 1 , wherein the copolymer has a total Zr, Ti, Al, and B content of 10 ppmw or less, based on the total weight of the copolymer, wherein the Zr, Ti, Al, and B is derived from a single-site catalyst and an optional co-catalyst. 
     
     
         24 . The dispersant of  claim 1 , wherein the copolymer has a fluorine content of less than 10 ppmw, based on the total weight of the copolymer. 
     
     
         25 . A lubricating oil, comprising:
 at least 50 wt. % of a base oil;   3-20 wt. % of a viscosity index improver selected from the group consisting of polyolefins, olefin copolymers, hydrogenated styrene-isoprene polymers, styrene/maleic ester copolymers, hydrogenated styrene/butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkyl styrenes, hydrogenated alkenyl aryl conjugated diene copolymers, star polymers, ethylene-propylene copolymers that have been functionalized with the reaction product of an acrylating agent and an amine; polymethacrylates functionalized with an amine, esterified maleic anhydride-styrene copolymers reacted with an amine and mixtures thereof;   0-1 wt. % of a pour point depressants selected from polymethylmethacrylates and mixtures thereof; and   0.2-20 wt. % of the dispersant of  claim 1 .   
     
     
         26 . The lubricating oil of  claim 25 , wherein the lubricating oil has a mini-rotary viscometer (MRV) value of 60,000 cP or less at −30° C. as determined by the ASTM D4684 test. 
     
     
         27 . The lubricating oil of  claim 25 , wherein the lubricating oil has a mini-rotary viscometer (MRV) value of 60,000 cP or less at −40° C. as determined by the ASTM D4684 test. 
     
     
         28 . The lubricating oil of  claim 25 , wherein the lubricating oil comprises less than 10 wt. % of the dispersant. 
     
     
         29 . (canceled) 
     
     
         30 . A fuel composition or fuel additive composition, comprising the dispersant of  claim 20 . 
     
     
         31 . The fuel composition or fuel additive composition of  claim 30 , the dispersant having one of the following formulas: 
       
         
           
           
               
               
           
         
         wherein R 1  is an hydrocarbyl radical derived from the copolymer; R 2  is a divalent C 1 -C 6  alkylene; R 3  is a divalent C 1 -C 6  alkylene; each of R 4  and R 5 , independently, is H, C 1 -C 6  alkyl, 
       
       
         
           
           
               
               
           
         
       
       or, together with the N to which they are attached to, form a 5 or 6-membered ring optionally fused with an aromatic or non-aromatic ring; R 6  is H or C 1 -C 6  alkyl, or —CH 2 —(NH—R 2 ) n —NR 4 R 5 ; Y is a covalent bond or C(O); and n is 0, 1, 2, 3, 4, 5, 6, 7, or 8.