Process for regenerating ionic liquids by adding light hydrocarbon stream

Abstract

A process for removing at least one impurity from a hydrocarbon feed such as vacuum gas oil in which the process includes the steps of contacting the feed with a hydrocarbon-immiscible phosphonium ionic liquid to produce a hydrocarbon and hydrocarbon-immiscible phosphonium ionic liquid mixture, and separating the mixture to produce a hydrocarbon effluent having a reduced impurity content relative to the hydrocarbon feed.

1 . A process for removing at least one impurity from a hydrocarbon stream comprising:
 (a) contacting a hydrocarbon stream with a hydrocarbon-immiscible phosphonium ionic liquid to produce a mixture comprising the hydrocarbon and the hydrocarbon-immiscible phosphonium ionic liquid;   (b) separating the mixture to produce a hydrocarbon product and a hydrocarbon-immiscible phosphonium ionic liquid effluent, the hydrocarbon-immiscible phosphonium ionic liquid effluent comprising at least one hydrocarbon impurity; and   (c) contacting the hydrocarbon-immiscible phosphonium ionic liquid effluent with water and with a light hydrocarbon stream, separating said hydrocarbon-immiscible phosphonium ionic liquid and said water from the light hydrocarbon stream and the at least one hydrocarbon impurity to produce an extract stream comprising the light hydrocarbon stream and the at least one hydrocarbon impurity and a separate stream comprising said hydrocarbon-immiscible phosphonium ionic liquid and water.   
     
     
         2 . The process of  claim 1  wherein the hydrocarbon stream has a specific gravity from about 0.8 to 1.2. 
     
     
         3 . The process of  claim 1  wherein said light hydrocarbon stream is selected from the group of hydrocarbons having a density lower than the water or the ionic liquid. 
     
     
         4 . The process of  claim 1  wherein said hydrocarbon stream is selected from the group consisting of consisting of naphtha, diesel, light cycle oil, benzene, kerosene, and toluene. 
     
     
         5 . The process of  claim 1  wherein the extract stream comprising the light hydrocarbon stream and the at least one hydrocarbon impurity has a specific gravity difference of at least 0.01 than a mixture of said hydrocarbon-immiscible phosphonium ionic liquid and said water. 
     
     
         6 . The process of  claim 1  wherein the hydrocarbon stream comprises a vacuum gas oil. 
     
     
         7 . The process of  claim 1  wherein the hydrocarbon-immiscible phosphonium ionic liquid comprises at least one ionic liquid from at least one of tetraalkylphosphonium dialkylphosphates, tetraalkylphosphonium dialkyl phosphinates, tetraalkylphosphonium phosphates, tetraalkylphosphonium tosylates, tetraalkylphosphonium sulfates, tetraalkylphosphonium sulfonates, tetraalkylphosphonium carbonates, tetraalkylphosphonium metalates, oxometalates, tetraalkylphosphonium mixed metalates, tetraalkylphosphonium polyoxometalates, and tetraalkylphosphonium halides. 
     
     
         8 . The process of  claim 1  wherein the hydrocarbon-immiscible phosphonium ionic liquid comprises at least one of trihexyl(tetradecyl)phosphonium chloride, trihexyl(tetradecyl)phosphonium bromide, tributyl(methyl)phosphonium bromide, tributyl(methyl)phosphonium chloride, tributyl(hexyl)phosphonium bromide, tributyl(hexyl)phosphonium chloride, tributyl(octyl)phosphonium bromide, tributyl(octyl)phosphonium chloride, tributyl(decyl)phosphonium bromide, tributyl(decyl)phosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, triisobutyl(methyl)phosphonium tosylate, tributyl(methyl)phosphonium methylsulfate, tributyl(ethyl)phosphonium diethylphosphate, and tetrabutylphosphonium methanesulfonate. 
     
     
         9 . The process of  claim 1  further comprising separating said hydrocarbon-immiscible phosphonium ionic liquid and water. 
     
     
         10 . The process of  claim 1  further comprising separating said light hydrocarbon stream and said at least one hydrocarbon impurity 
     
     
         11 . The process of  claim 1  wherein the ratio of the hydrocarbon stream to the hydrocarbon-immiscible phosphonium ionic liquid in the mixture ranges from about 1:1000 to about 1000:1 on a weight basis. 
     
     
         12 . A process for regenerating an ionic liquid comprising sending a mixture of an ionic liquid, water and a hydrocarbon extract containing impurities to a regeneration unit, adding a quantity of a light hydrocarbon having a lower specific gravity than said mixture, and removing said light hydrocarbon together with said hydrocarbon extract containing impurities. 
     
     
         13 . The process of  claim 12  wherein said light hydrocarbon is selected from the group consisting of naphtha, kerosene, light cycle oil, benzene and toluene. 
     
     
         14 . The process of  claim 12  wherein the hydrocarbon stream comprises a vacuum gas oil. 
     
     
         15 . The process of  claim 12  wherein the hydrocarbon-immiscible phosphonium ionic liquid comprises at least one ionic liquid from at least one of tetraalkylphosphonium dialkylphosphates, tetraalkylphosphonium dialkyl phosphinates, tetraalkylphosphonium phosphates, tetraalkylphosphonium tosylates, tetraalkylphosphonium sulfates, tetraalkylphosphonium sulfonates, tetraalkylphosphonium carbonates, tetraalkylphosphonium metalates, oxometalates, tetraalkylphosphonium mixed metalates, tetraalkylphosphonium polyoxometalates, and tetraalkylphosphonium halides. 
     
     
         16 . The process of  claim 12  wherein the hydrocarbon-immiscible phosphonium ionic liquid comprises at least one of trihexyl(tetradecyl)phosphonium chloride, trihexyl(tetradecyl)phosphonium bromide, tributyl(methyl)phosphonium bromide, tributyl(methyl)phosphonium chloride, tributyl(hexyl)phosphonium bromide, tributyl(hexyl)phosphonium chloride, tributyl(octyl)phosphonium bromide, tributyl(octyl)phosphonium chloride, tributyl(decyl)phosphonium bromide, tributyl(decyl)phosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, triisobutyl(methyl)phosphonium tosylate, tributyl(methyl)phosphonium methylsulfate, tributyl(ethyl)phosphonium diethylphosphate, and tetrabutylphosphonium methanesulfonate. 
     
     
         17 . The process of  claim 12  further comprising separating said hydrocarbon-immiscible phosphonium ionic liquid and water. 
     
     
         18 . The process of  claim 12  further comprising separating said light hydrocarbon stream and said at least one hydrocarbon impurity.