Cloud point depressants for middle distiliate fuels

Abstract

An additive for distillate and a fuel composition having improved cloud point depressant properties. The additive is incorporated into a major proportion of distillate fuel and is a maleic anhydride α-olefin copolymer or a polyimide having the following structure: wherein R has at least 80% by weight of a hydrocarbon substituent from about 14 to about 16 carbons, X is oxygen or wherein N is nitrogen and R′ has at least 80% by weight of a hydrocarbon substituent from 16 to 18 carbons, and n is from about 2 to about 30 when X is oxygen, and from about 2 to about 17 when X is Alternatively, the cloud point additive can be an ethylene vinyl acetate isobutylene terpolymer.

What is claimed is:  
     
         1 . A distillate fuel composition haying improved cloud point depressant properties comprising a major proportion of a distillate fuel and an improved cloud point depressant property effective amount of a maleic anhydride α-olefin copolymer having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R has at least 80% by weight of a hydrocarbon substituent from about 14 to about 16 carbons, and n is from about 2 to about 30.  
     
     
         2 . The maleic anhydride α-olefin copolymer of  claim 1  wherein R has at least 90% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         3 . The maleic anhydride α-olefin copolymer of  claim 1  wherein R has at least 95% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         4 . The composition of  claim 1  wherein said distillate fuel is a middle distillate fuel.  
     
     
         5 . The composition of  claim 1  wherein said distillate fuel is No. 2 diesel fuel.  
     
     
         6 . The composition of  claim 1  wherein said distillate fuel is hard-to-treat fuel.  
     
     
         7 . The composition of  claim 1  wherein said maleic anhydride α-olefin copolymer is derived from substantially equimolar proportions of maleic anhydride and α-olefin.  
     
     
         8 . A distillate fuel composition having improved cloud point depressant properties comprising a major proportion of a distillate fuel and an improved cloud point depressant property effective amount of a polyimide having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R has at least 80% by weight of a hydrocarbon substituent from about 14 to about 16 carbons, R′ has at least 80% by weight of a hydrocarbon substituent from 16 to 18 carbons, and n is from about 2 to about 17.  
     
     
         9 . The polyimide of  claim 8  wherein R has at least 90% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         10 . The polyimide of  claim 8  wherein R has at least 95% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         11 . The composition of  claim 8  wherein said distillate fuel is a middle distillate fuel.  
     
     
         12 . The composition of  claim 8  wherein said distillate fuel is No. 2 diesel fuel.  
     
     
         13 . The composition of  claim 8  wherein said distillate fuel is hard-to-treat fuel.  
     
     
         14 . The composition of  claim 8  wherein said polyimide is derived from substantially equimolar proportions of maleic anhydride and α-olefin.  
     
     
         15 . A distillate fuel composition having improved cloud point depressant properties comprising a major proportion of a distillate fuel and an improved cloud point depressant property effective amount of an ethylene vinyl acetate isobutylene terpolymer wherein the weight average molecular weight of said terpolymer is from about 1,500 to about 18,000, the number average molecular weight is from about 400 to about 3,000, the ratio of weight average molecular weight to number average molecular weight is from about 1.5 to about 6, and the vinyl acetate content of said terpolymer is from about 25 to about 55 weight percent.  
     
     
         16 . The composition of  claim 15  wherein said distillate fuel is a middle distillate fuel.  
     
     
         17 . The composition of  claim 15  wherein said distillate fuel is No. 2 diesel fuel.  
     
     
         18 . The composition of  claim 15  wherein said distillate fuel is hard-to-treat fuel.  
     
     
         19 . The terpolymer of  claim 15  wherein said w eight average molecular weight is from about 3,000 to about 12,000 and said number average molecular weight is from about 1,500 to about 2,500.  
     
     
         20 . An additive for improving the cloud point properties of a distillate fuel, said additive comprising a maleic anhydride α-olefin copolymer having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R has at least 80% by weight of a hydrocarbon substituent from about 14 to about 16 carbons, and n is from about 2 to about 30.  
     
     
         21 . The additive of  claim 20  wherein R has at least 90% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         22 . The additive of  claim 20  wherein R has at least 95% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         23 . The additive of  claim 20  wherein said maleic anhydride α-olefin copolymer is derived from substantially equimolar proportions of maleic anhydride and α-olefin.  
     
     
         24 . The additive of  claim 20  having a number average molecular weight in the range of about 700 to about 10,000.  
     
     
         25 . The additive of  claim 20  having a number average molecular weight in the range of about 700 to about 4,000.  
     
     
         26 . An additive for improving the cloud point properties of a distillate fuel, said additive comprising a polyimide having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R has at least 80% by weight of a hydrocarbon substituent from about 14 to about 16 carbons, R′ has at least 80% by weight of a hydrocarbon substituent from 16 to 18 carbons, and n is from about 2 to about 17.  
     
     
         27 . The additive of  claim 26  wherein R has at least 90% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         28 . The additive of  claim 26  wherein R has at least 95% by weight of a hydrocarbon substituent from about 14 to about 16 carbons.  
     
     
         29 . The additive of  claim 26  wherein said polyimide is derived from substantially equimolar proportions of maleic anhydride and α-olefin.  
     
     
         30 . The additive of  claim 26  having a number average molecular weight in the range of about 1,200 to about 10,000.  
     
     
         31 . The additive of  claim 26  having a number average molecular weight in the range of about 1,200 to about 5,000.