Cerium organic colloidal dispersion and element selected from rhodium and palladium and use thereof as additive to diesel fuel for internal combustion engines

Abstract

The inventive colloidal dispersion comprised cerium compound particles, an acid and an organic phase and is characterized in that it also comprises a compound of at least one element selected from rhodium and palladium. According to variants, the dispersion comprises particles of a compound of cerium, another rare earth and/or iron. The inventive dispersion can be used as an additive to diesel fuels for diesel engines

1 - 14 . (canceled)  
   
   
       15 . A colloidal dispersion comprising particles of a cerium compound, an acid and an organic phase, and comprising a compound of at least one element selected from the group consisting of rhodium and palladium.  
   
   
       16 . The dispersion as claimed in  claim 15 , comprising particles of a compound of cerium and of another rare earth.  
   
   
       17 . The dispersion as claimed in  claim 16 , wherein it comprises particles of a compound of cerium, of another rare earth, and of iron.  
   
   
       18 . The dispersion as claimed in  claim 17 , wherein the element is presets a content of not more than 5% with respect to the combination of the elements cerium, other rare earth and iron of the particles.  
   
   
       19 . The dispersion as claimed in  claim 17 , wherein the content of the element is not more than 0.5% with respect to the combination of the elements cerium, other rare earth and iron of the abovementioned particles.  
   
   
       20 . The dispersion as claimed in  claim 15 , wherein the compound of the element is bound to the particles.  
   
   
       21 . The dispersion as claimed in  claim 17 , wherein cerium is present in a proportion of not more than 50%, optionally not more than 20% in moles of cerium oxide CeO 2  with respect to the total number of moles of cerium oxide and iron oxide Fe 2 O 3 .  
   
   
       22 . The dispersion as claimed in  claim 16 , wherein the other rare earth is lanthanum or praseodymium.  
   
   
       23 . The dispersion as claimed in  claim 15 , wherein the acid is an amphiphilic acid.  
   
   
       24 . The dispersion as claimed in  claim 15 , wherein at least 90% of the particles are single crystal particles.  
   
   
       25 . The dispersion as claimed in  claim 15 , wherein the particles have a d 50  of between 1 and 5 nm, optionally between 2 and 4 nm.  
   
   
       26 . A method for preparing a dispersion as claimed in  claim 15 , comprising the steps of: 
 a) preparing an aqueous mixture comprising at least one cerium salt, optionally a salt of a rare earth other than cerium and an iron salt, and a salt of at least one element selected from the group consisting of rhodium and palladium;    b) contacting the aqueous mixture of step (a) with a basic medium to form a reaction mixture whose pH is maintained at a basic pH, thereby producing a precipitate; and    c) the precipitate obtained in step b) is contacted with the acid and the organic phase, to obtain an organic colloidal dispersion.    
   
   
       27 . A fuel additive for internal combustion engines comprising a colloidal dispersion as defined in  claim 15 .  
   
   
       28 . A fuel for internal combustion engines, obtained by mixing a standard fuel with a colloidal dispersion as claimed in  claim 15.