Surface modification of inorganic metal oxides for enhanced sulfur selectivity in transportion fuels

Abstract

Disclosed are fuel filters and processes for removing sulfur-containing compounds from a post refinery fuel system. The fuel filter comprises an adsorbent comprising a surface modified inorganic oxide, wherein the surface modified inorganic oxide comprises a surface modifier disposed on an inorganic oxide substrate and the inorganic oxide substrate has a surface acidity characterized by a pK a of less than or equal to −3. The process comprises passing a post refinery liquid fuel through the fuel filter.

1 . A fuel filter comprising an adsorbent comprising a surface modified inorganic oxide, wherein the surface modified inorganic oxide comprises a surface modifier disposed on an inorganic oxide substrate and the inorganic oxide substrate has a surface acidity characterized by a pK a  of less than or equal to −3. 
   
   
       2 . The fuel filter of  claim 1 , wherein the inorganic oxide substrate comprises pores having an average diameter of 1 to 40 angstroms. 
   
   
       3 . The fuel filter of  claim 1 , wherein the inorganic oxide substrate has a surface are of greater than or equal to about 50 square meters per gram. 
   
   
       4 . The fuel filter of  claim 1  wherein the inorganic oxide substrate is at least one of alumina, kaolinite, silica magnesia, alumina-boria, activated alumina, zeolites, aluminosilicates, silica gels, clay, active clay, silicon dioxide, mesoporous silica porous material, silica alumina compounds, silica, alumina phosphate compounds, super acids, super acids-sulfated, titania, sulfated zironia, titanium dioxide, hafnium oxide, and mixtures thereof. 
   
   
       5 . The fuel filter of  claim 1  wherein the inorganic oxide comprises alumina. 
   
   
       6 . The fuel filter of  claim 5  wherein the inorganic oxide comprises gamma alumina, eta alumina, or a mixture thereof. 
   
   
       7 . The fuel filter of  claim 1  wherein the inorganic oxide has a surface acidity characterized by a pK a  of less than or equal to −6. 
   
   
       8 . The fuel filter of  claim 1  wherein the inorganic oxide has a surface acidity characterized by a pK a  of less than or equal to −8. 
   
   
       9 . The fuel filter of  claim 1  wherein the surface modifier is bonded to a pendant hydroxyl group on the surface of the inorganic oxide substrate. 
   
   
       10 . The fuel filter of  claim 1  wherein the surface modifier comprises an organosilane. 
   
   
       11 . The fuel filter of  claim 10  wherein the organosilane is selected from the group consisting of trichloromethylsilane, trichloroethylsilane, trichloropropylsilane, trichlorooctadecylsilane, dimethyloctadecylchlorosilane, isobutyltrichlorosilane, cyclohexyltrichlorosilane, allyltrichlorosilane, phenyltrichlorosilane, p-tolyltrichlorosilane, t-butyldiphenylchlorosilane, trifluoropropyltrichlorosilane, pentafluorophenyldimethylchlorosilane, perfluorodecyltrichlorosilane, perfluorooctyltriethoxysilane, dichlorodimethylsilane, monochlorotrimethylsilane 
   
   
       12 . The fuel filter of  claim 1 , wherein the surface modifier is disposed on a portion of the inorganic oxide substrate. 
   
   
       13 . A method for removing a sulfur containing compound from a post refinery fuel stream, comprising:
 passing the post refinery fuel stream through a fuel filter comprising adsorbent comprising a surface modified inorganic oxide, wherein the surface modified inorganic oxide comprises a surface modifier disposed on an inorganic oxide substrate and the inorganic oxide substrate has a surface acidity characterized by a pK a  of less than or equal to −3.   
   
   
       14 . The method of  claim 13  wherein the post refinery fuel stream comprises sulfur containing compound in an amount of no more than 100 ppm. 
   
   
       15 . The method of  claim 13  wherein the post refinery fuel stream comprises sulfur containing compound in an amount of no more than 15 ppm. 
   
   
       16 . The method of  claim 13  wherein the fuel stream comprises sulfur containing compound in an amount of no more than 3 ppm after passing through the fuel filter. 
   
   
       17 . The method of  claim 13 , wherein the method is performed on board a vehicle. 
   
   
       18 . The method of  claim 13 , wherein the inorganic oxide substrate comprises pores having an average diameter of 1 to 40 angstroms. 
   
   
       19 . The method of  claim 13 , wherein the inorganic oxide substrate has a surface are of greater than or equal to about 50 square meters per gram. 
   
   
       20 . The method of  claim 13 , wherein the inorganic oxide substrate is at least one of alumina, kaolinite, silica magnesia, alumina-boria, activated alumina, zeolites, aluminosilicates, silica gels, clay, active clay, silicon dioxide, mesoporous silica porous material, silica alumina compounds, silica, alumina phosphate compounds, super acids, super acids-sulfated, titania, sulfated zironia, titanium dioxide, hafnium oxide, and mixtures thereof. 
   
   
       21 . The method of  claim 13 , wherein the inorganic oxide comprises alumina. 
   
   
       22 . The method of  claim 21 , wherein the inorganic oxide comprises gamma alumina, eta alumina, or a mixture thereof. 
   
   
       23 . The method of  claim 13 , wherein the inorganic oxide has a surface acidity characterized by a pK a  of less than or equal to −6. 
   
   
       24 . The method of  claim 13 , wherein the inorganic oxide has a surface acidity characterized by a pK a  of less than or equal to −8. 
   
   
       25 . The method of  claim 13 , wherein the surface modifier is bonded to a pendant hydroxyl group on the surface of the inorganic oxide substrate. 
   
   
       26 . The method of  claim 13 , wherein the surface modifier comprises an organosilane. 
   
   
       27 . The method of  claim 26 , wherein the organosilane is selected from the group consisting of trichloromethylsilane, trichloroethylsilane, trichloropropylsilane, trichlorooctadecylsilane, dimethyloctadecylchlorosilane, isobutyltrichlorosilane, cyclohexyltrichlorosilane, allyltrichlorosilane, phenyltrichlorosilane, p-tolyltrichlorosilane, t-butyldiphenylchlorosilane, trifluoropropyltrichlorosilane, pentafluorophenyldimethylchlorosilane, perfluorodecyltrichlorosilane, perfluorooctyltriethoxysilane, dichlorodimethylsilane, monochlorotrimethylsilane 
   
   
       28 . The method of  claim 13 , wherein the surface modifier is disposed on a portion of the inorganic oxide substrate.