Selective liquid-liquid extraction of oxidative desulfurization reaction products

Abstract

The present invention provides selective extraction of sulfoxides, or sulfoxides in combination with sulfones, from hydrocarbon mixtures containing these compounds. A significant advantage of the invention is that oxidation products resulting from oxidative desulfurization of hydrocarbon feedstocks are selectively extracted with minimum co-extraction of non-oxidized products such as valuable hydrocarbon fuel components.

We claim: 
     
         1 . A process for extracting sulfoxidation reaction products from hydrocarbon fractions containing sulfoxidation reaction products while minimizing co-extraction of hydrocarbons including aromatic hydrocarbons, comprising:
 contacting a hydrocarbon fraction containing sulfoxidation reaction products with a selective solvent formulation comprising an aqueous solution having a concentration of about 2.5 weight % to about 70 weight % of a polar organic solvent, the polar organic solvent selected from the group consisting of acetone, methanol, acetonitrile, acetic acid, formic acid and combinations comprising at least two of the foregoing polar organic solvents,   wherein the concentration of the aqueous solution is selected to maximize extraction of a target sulfoxidation reaction product and minimize co-extraction of unoxidized organosulfur compounds and hydrocarbons including aromatic hydrocarbons.   
     
     
         2 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 30 weight % to about 70 weight % of polar organic solvent, and the target sulfoxidation reaction product includes
 a. one or more sulfoxidation products derived from aromatic organosulfur compounds including thiophene, benzothiophene, napthothiophene, dibenzothiophene, naptho-benzo-thiophene, or alkyl and dialkyl derivatives of one or more of thiophene, benzothiophene, napthothiophene, dibenzothiophene, or naptho-benzo-thiophene; or   b. a combination of sulfoxides and sulfones.   
     
     
         3 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 50 weight % of acetone. 
     
     
         4 . The process as in  claim 3 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 20 weight % of acetone, and wherein the target compounds for extraction are non-bulky sulfoxide products. 
     
     
         5 . The process as in  claim 3 , wherein the concentration of the aqueous solution is about 20 weight % to about 50 weight % of acetone, and wherein the target compounds for extraction are bulky sulfoxide products. 
     
     
         6 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 70 weight % of methanol. 
     
     
         7 . The process as in  claim 6 , wherein the concentration of the aqueous solution is about 10 weight % to about 30 weight % of methanol, and wherein the target compounds for extraction are non-bulky sulfoxide products. 
     
     
         8 . The process as in  claim 6 , wherein the concentration of the aqueous solution is about 30 weight % to about 70 weight % of methanol, and wherein the target compounds for extraction are bulky sulfoxide products. 
     
     
         9 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 60 weight % of acetonitrile. 
     
     
         10 . The process as in  claim 9 , wherein the concentration of the aqueous solution is about 5 weight % to about 30 weight % of acetonitrile, and wherein the target compounds for extraction are non-bulky sulfoxide products. 
     
     
         11 . The process as in  claim 9 , wherein the concentration of the aqueous solution is about 20 weight % to about 40 weight % of acetonitrile, and wherein the target compounds for extraction are bulky sulfoxide products. 
     
     
         12 . The process as in  claim 9 , wherein the concentration of the aqueous solution is about 40 weight % to about 55 weight % of acetonitrile, and the target sulfoxidation reaction product is a combination of sulfoxides and sulfones. 
     
     
         13 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 70 weight % of acetic acid. 
     
     
         14 . The process as in  claim 13 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 20 weight % of acetic acid, and wherein the target compounds for extraction are non-bulky sulfoxide products. 
     
     
         15 . The process as in  claim 13 , wherein the concentration of the aqueous solution is about 20 weight % to about 40 weight % of acetic acid, and wherein the target compounds for extraction are bulky sulfoxide products. 
     
     
         16 . The process as in  claim 13 , wherein the concentration of the aqueous solution is about 30 weight % to about 70 weight % of acetic acid, and the target sulfoxidation reaction product is a combination of sulfoxides and sulfones. 
     
     
         17 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 70 weight % of formic acid. 
     
     
         18 . The process as in  claim 17 , wherein the concentration of the aqueous solution is about 2.5 weight % to about 30 weight % of formic acid, and wherein the target compounds for extraction are non-bulky sulfoxide products. 
     
     
         19 . The process as in  claim 17 , wherein the concentration of the aqueous solution is about 30 weight % to about 70 weight % of formic acid, and wherein the target compounds for extraction are bulky sulfoxide products. 
     
     
         20 . The process as in  claim 17 , wherein the concentration of the aqueous solution is about 50 weight % to about 70 weight % of formic acid, and the target sulfoxidation reaction product is a combination of sulfoxides and sulfones. 
     
     
         21 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 5 weight % to about 30 weight % of acetonitrile and about 5 weight % to about 30 weight % of formic acid. 
     
     
         22 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 5 weight % to about 30 weight % of acetic acid and about 5 weight % to about 30 weight % of acetone. 
     
     
         23 . The process as in  claim 1 , wherein the concentration of the aqueous solution is about 5 weight % to about 30 weight % of acetonitrile and about 5 weight % to about 30 weight % of acetone. 
     
     
         24 . The process as in  claim 1 , wherein the activity coefficient of the target sulfoxidation reaction product is less than about 16.5 and the activity coefficient of the aromatic hydrocarbons is greater than about 16.5. 
     
     
         25 . The process as in  claim 1 , wherein the activity coefficient of the target sulfoxidation reaction product is less than about 16.5 and the activity coefficient of unoxidized organosulfur compounds is greater than about 16.5. 
     
     
         26 . A sulfoxidation process comprising:
 reactively sulfoxidating a hydrocarbon fraction containing organosulfur compounds to produce sulfoxidation reaction products;   extracting sulfoxidation products using an extraction solvent according to the process of  claim 1 ; and   recovering a hydrocarbon product of reduced sulfur content.   
     
     
         27 . The sulfoxidation process as in  claim 26 , further comprising recovering at least a portion of the extraction solvent by heating, whereby the target sulfoxidation reaction product is removed. 
     
     
         28 . The sulfoxidation process as in  claim 27 , wherein the target sulfoxidation reaction product is removed in liquid form. 
     
     
         29 . The sulfoxidation process as in  claim 27 , wherein the target sulfoxidation reaction product is precipitated in solid form. 
     
     
         30 . The sulfoxidation process as in  claim 26 , further comprising polishing the hydrocarbon product of reduced sulfur content. 
     
     
         31 . The sulfoxidation process as in  claim 30 , wherein polishing comprises an aqueous polishing process. 
     
     
         32 . The sulfoxidation process as in  claim 26 , wherein sulfoxidation and extraction occur in the same reaction unit. 
     
     
         33 . The sulfoxidation process as in  claim 26 , wherein sulfoxidation occurs in a reaction unit, further comprising feeding the effluent from the reaction unit comprising treated hydrocarbon and the sulfoxidation reaction products into an extraction unit for extracting sulfoxidation products. 
     
     
         34 . The sulfoxidation process as in  claim 26 , wherein sulfoxidation is effected by an oxidation process selected from the group consisting of photooxidation, photochemical oxidation, ozonation, ionic liquid oxidation, electro chemical oxidation, bio-desulfurization, oxidation by hydrogen peroxide, oxidation by organic peracid, oxidation by peroxomonophosphoric acid, oxidation by nitrogen oxides, oxidation by nitric acid, and a combination of any of the foregoing oxidation processes. 
     
     
         35 . The sulfoxidation process as in  claim 26 , wherein sulfoxidation is conducted at temperatures of about 0° C. to about 40° C. 
     
     
         36 . The sulfoxidation process as in  claim 26 , wherein sulfoxidation is conducted at atmospheric pressure. 
     
     
         37 . The sulfoxidation process as in  claim 26 , wherein sulfoxidation is conducted at temperatures of about 0° C. to about 40° C. and atmospheric pressure. 
     
     
         38 . A method of determining an extraction solvent composition for extracting sulfoxidation reaction products from a hydrocarbon fraction containing sulfoxidation reaction products comprising:
 qualitatively analyzing the hydrocarbon fractions containing sulfoxidation reaction products to determine the type of sulfoxidation reaction products, and the type of aromatic hydrocarbons and/or the type of non-aromatic hydrocarbons;   selecting as a target sulfoxidation reaction product one or more sulfoxides or a combination of one or more sulfoxides and one or more sulfones;   determining the activity coefficient ln γ of a range of extraction solvent compositions for the target sulfoxidation reaction product and at least one type of aromatic or non-aromatic hydrocarbon, the extraction solvent compositions within the range of extraction solvent compositions comprising an aqueous solution having a concentration of about 2.5 weight % to about 70 weight % by weight polar organic solvent in water, the polar organic solvent selected from the group consisting of acetone, methanol, acetonitrile, acetic acid, formic acid and combinations comprising two or more of acetone, methanol, acetonitrile, acetic acid and formic acid;   selecting an extraction solvent composition having an activity coefficient of less than about 16.5 for the target sulfoxidation reaction product that maximizes extraction of the target sulfoxidation reaction product, and an activity coefficient greater than about 16.5 for the at least one type of aromatic or non-aromatic hydrocarbon that minimizes co-extraction of the at least one type of aromatic or non-aromatic hydrocarbon.