Organosulfur oxidation process

Abstract

This invention is a method of oxidizing organosulfur impurites found in fuel streams. The method comprises reacting the organosulfur impurities with an organic hydroperoxide in the presence of a titanium-containing catalyst. The titanium-containing catalyst is obtained by impregnating a siliceous solid with a titanium halide in a hydrocarbon solvent, or a vapor stream of titanium tetrachloride, followed by calcination. The resulting sulfones are more readily removed from the fuel stream than the non-oxidized organosulfur impurities.

We claim:  
     
         1 . A process comprising contacting a fuel stream containing organosulfur impurities with an organic hydroperoxide in the presence of a catalyst obtained by a method comprising the steps of: 
 (a) impregnating an inorganic siliceous solid with a titanium source selected from the group consisting of: 
 (1) a solution of a titanium halide in a non-oxygenated hydrocarbon solvent; and  
 (2) a vapor stream of titanium tetrachloride;  
   (b) calcining the impregnated siliceous solid to form the catalyst; and    (c) optionally, heating the catalyst in the presence of water;    wherein a substantial portion of the organosulfur impurities are converted into sulfones.    
     
     
         2 . The process of  claim 1  wherein the titanium halide is titanium tetrachloride.  
     
     
         3 . The process of  claim 1  wherein impregnation step (a)(1) is accomplished by combining a solution of the titanium halide in the non-oxygenated hydrocarbon solvent with the inorganic siliceous solid and thereafter removing the hydrocarbon solvent.  
     
     
         4 . The process of  claim 1  wherein the inorganic siliceous solid is selected from the group consisting of silica and MCM-41.  
     
     
         5 . The process of  claim 1  wherein the non-oxygenated hydrocarbon solvent is selected from the group consisting of C 5 -C 12  aliphatic hydrocarbons, C 6 -C 12  aromatic hydrocarbons, C 1 -C 10  halogenated aliphatic hydrocarbons, C 6 -C 10  halogenated aromatic hydrocarbons, and mixtures thereof.  
     
     
         6 . The process of  claim 1  wherein water is substantially excluded until after step (b) is completed.  
     
     
         7 . The process of  claim 1  wherein the method of obtaining the catalyst comprises an additional step after step (c) of treating the catalyst with a silylating agent.  
     
     
         8 . The process of  claim 1  wherein calcination step (b) is performed at a temperature of at least 500° C.  
     
     
         9 . The process of  claim 1  wherein step (b) is performed in a substantially oxygen-free atmosphere.  
     
     
         10 . The process of  claim 1  wherein the organic hydroperoxide is t-butyl hydroperoxide.  
     
     
         11 . The process of  claim 1  wherein the organic hydroperoxide is substantially free of alcohol.  
     
     
         12 . A process comprising contacting a diesel fuel stream containing organosulfur impurities with t-butyl hydroperoxide in the presence of a catalyst obtained by a method comprising the steps of: 
 (a) impregnating an inorganic siliceous solid with a titanium source selected from the group consisting of: 
 (1) a solution of a titanium chloride in a non-oxygenated hydrocarbon solvent; and  
 (2) a vapor stream of titanium tetrachloride;  
   (b) calcining the impregnated siliceous solid to form the catalyst; and    (c) optionally, heating the catalyst in the presence of water;    wherein a substantial portion of the organosulfur impurities are converted into sulfones.    
     
     
         13 . The process of  claim 12  wherein impregnation step (a)(1) is accomplished by combining a solution of the titanium halide in the non-oxygenated hydrocarbon solvent with the inorganic siliceous solid and thereafter removing the hydrocarbon solvent.  
     
     
         14 . The process of  claim 12  wherein the inorganic siliceous solid is selected from the group consisting of silica and MCM-41.  
     
     
         15 . The process of  claim 12  wherein the non-oxygenated hydrocarbon solvent is selected from the group consisting of C 5 -C 12  aliphatic hydrocarbons, C 6 -C 12  aromatic hydrocarbons, C 1 -C 10  halogenated aliphatic hydrocarbons, C 6 -C 10  halogenated aromatic hydrocarbons, and mixtures thereof.  
     
     
         16 . The process of  claim 12  wherein water is substantially excluded until after step (b) is completed.  
     
     
         17 . The process of  claim 12  wherein the method of obtaining the catalyst comprises an additional step after step (c) of treating the catalyst with a silylating agent.  
     
     
         18 . The process of  claim 12  wherein calcination step (b) is performed at a temperature of at least 500° C.  
     
     
         19 . The process of  claim 12  wherein step (b) is performed in a substantially oxygen-free atmosphere.  
     
     
         20 . The process of  claim 12  wherein the t-butyl hydroperoxide is substantially free of t-butyl alcohol.