Polyacrylate esters, their preparation and use as a low-temperature flow-improver in middle distillate oils

Abstract

A polymer having structural units derived from an ester ( 1 ) of an aliphatic carboxylic acid with an aliphatic alcohol, wherein either the acid or the alcohol is ethylenically unsaturated and the other of the acid or alcohol has a medium length chain group of 440 carbon atoms; said polymer having a molecular weight of less than 30,000.

1 . A polymer having structural units derived from an ester (1) of an aliphatic carboxylic acid with an aliphatic alcohol, wherein either the acid or the alcohol is ethylenically unsaturated and the other of the acid or alcohol has a medium length chain group of 4-40 carbon atoms; said polymer having a molecular weight of less than 30,000.  
     
     
         2 . A process for the production of the polymer of  claim 1 , said process comprising transesterification of 
 a) at least one polymer of an ester of an aliphatic carboxylic acid and an aliphatic alcohol, wherein either said acid or said alcohol is ethylenically unsaturated and the other of said acid or alcohol has a short chain aliphatic group of 1-4 carbon atoms, with    b) an aliphatic alcohol or carboxylic acid having an aliphatic group of 4-40 carbon atoms.    
     
     
         3 . A process as claimed in  claim 2 , wherein said at least one polymer of an ester of an aliphatic carboxylic acid and an aliphatic alcohol is a polyacrylate.  
     
     
         4 . A process as claimed in  claim 3 , wherein said polyacrylate is polymethacrylate.  
     
     
         5 . A process as claimed in  claim 3  or  4 , wherein the polyacrylate employed has a molecular weight of 1000 to 3000 prior to transesterification.  
     
     
         6 . A process as claimed in any one of  claims 2  to  5 , wherein said a) at least one polymer of an ester of an aliphatic carboxylic acid and an aliphatic alcohol is transesterified with an aliphatic alcohol having 6-16 carbons.  
     
     
         7 . A polymer obtainable by the process of any one of  claims 2  to  6 .  
     
     
         8 . A polymer as claimed in  claim 7 , which 60 to 63% by weight of units derived from polymethacrylate and 37 to 40% of units derived from a C12 to C16 alcohol.  
     
     
         9 . A method of reducing wax formation and/or deposition in a wax-containing middle distillate oil, said method comprising mixing a polymer as claimed in  claim 7  or  8  with said oil.  
     
     
         10 . A method as claimed in  claim 9 , wherein the middle distillate oil selected from the group consisting of kerosene, jet fuel, diesel fuel, heating oil, visbroken gas oil, light cycle oil, vacuum gas oil, light fuel oil and fuel oil.  
     
     
         11 . A mixture comprising a middle distillate oil, a conventional flow improver and a polymer as claimed in  claim 7  or  8 .  
     
     
         12 . A mixture as claimed in  claim 11 , wherein said conventional flow improver comprises ethyl vinyl acetate.  
     
     
         13 . A mixture as claimed in  claim 11  or  12 , wherein the amount of polymer present in said mixture is 2-10,000 ppm.  
     
     
         14 . A mixture as claimed in any one of  claims 11  to  13 , wherein the amount of conventional flow improver present is 10-10,000 ppm.  
     
     
         15 . Use of a polymer as claimed in any one of  claims 7  to  8 , for reducing at least one of the cloud point, CFPP and pour point of a middle distillate oil.  
     
     
         16 . Use of a polymer as claimed in any one of  claims 7  to  8 , for reducing at least one of the cloud point, CFPP and pour point of a mixture comprising a middle distillate oil and a conventional flow improver.  
     
     
         17 . Use as claimed in  claim 16 , wherein said conventional flow improver comprises ethyl vinyl acetate.