Process for converting hydrocarbon feedstocks with electrolytic and photoelectrocatalytic recovery of halogens

Abstract

A method for converting a hydrocarbon feedstock into higher hydrocarbons is provided comprising reacting a hydrocarbon feedstock with a molecular halogen to form alkyl halides; reacting at least a portion of the alkyl halide in the presence of a catalyst to form higher hydrocarbons and a hydrogen halide; and converting at least a portion of the hydrogen halide into the molecular halogen via photoelectrocatalysis. Additional methods are also provided.

1 . A method for converting a hydrocarbon feedstock into higher hydrocarbons, comprising:
 reacting a hydrocarbon feedstock with a molecular halogen to form alkyl halides;   reacting at least a portion of the alkyl halide in the presence of a catalyst to form higher hydrocarbons and a hydrogen halide; and   converting at least a portion of the hydrogen halide into the molecular halogen via photoelectrocatalysis.   
     
     
         2 . The method of  claim 1  wherein the hydrocarbon feedstock comprises natural gas. 
     
     
         3 . The method of  claim 1  wherein the hydrocarbon feedstock comprises methane. 
     
     
         4 . The method of  claim 1  wherein the higher hydrocarbons comprise fuel grade hydrocarbons, aromatic hydrocarbons, or a combination thereof. 
     
     
         5 . The method of  claim 4  wherein the aromatic hydrocarbons comprise benzene, toluene, and xylene. 
     
     
         6 . The method of  claim 1  further comprising reusing the molecular halogen obtained from converting the hydrogen halide as the molecular halogen in the reaction with the hydrocarbon feedstock. 
     
     
         7 . The method of  claim 1  wherein the hydrogen halide is converted into the molecular halogen by neutralizing the hydrogen halide to a halide salt and electrolyzing the halide salt in a photoelctrocatalytic cell to form the molecular halogen. 
     
     
         8 . The method of  claim 1  wherein the hydrocarbon feedstock is derived from a biomass. 
     
     
         9 . The method of  claim 1  wherein the hydrocarbon feedstock comprises coal. 
     
     
         10 . The method of  claim 1  wherein the hydrogen halide is converted into the molecular halogen in a photoelctrocatalytic cell to form the molecular halogen, the method further comprising feeding carbon dioxide to the photoelctrocatalytic cell and forming methanol, formic acid, or a mixture thereof via photoelectrocatalysis. 
     
     
         11 . The method of  claim 1  wherein the hydrogen halide is converted into the molecular halogen by neutralizing the hydrogen halide to a halide salt and electrolyzing the halide salt in a photoelctrocatalytic cell to form the molecular halogen, the method further comprising feeding carbon dioxide to the photoelctrocatalytic cell and forming methanol, formic acid, or a mixture thereof via photoelectrocatalysis. 
     
     
         12 . The method of  claim 1  wherein the photoelectrocatalysis is performed in a photoelectrocatalyic cell including an electrolyte, an anodic electrode and a cathodic electrode. 
     
     
         13 . The method of  claim 12  wherein the anodic electrode and/or the cathodic electrode has a flat sheet-like configuration. 
     
     
         14 . The method of  claim 12  wherein the anodic electrode and/or the cathodic electrode has a tubular configuration. 
     
     
         15 . The method of  claim 12  wherein the anodic electrode and/or the cathodic electrode has a particulate configuration. 
     
     
         16 . A method for converting a hydrocarbon feedstock into methanol, comprising:
 reacting a hydrocarbon feedstock with a molecular halogen to form alkyl halides;   reacting at least a portion of the alkyl halide with an alkali to form methanol and a halide salt; and   converting at least a portion of the halide salt into the molecular halogen via photoelectrocatalysis.   
     
     
         17 . The method of  claim 16  wherein the hydrocarbon feedstock comprises natural gas. 
     
     
         18 . The method of  claim 16  wherein the hydrocarbon feedstock comprises methane. 
     
     
         19 . The method of  claim 16  further comprising reusing the molecular halogen obtained from converting the halide salt as the molecular halogen in the reaction with the hydrocarbon feedstock. 
     
     
         20 . A method for converting a hydrocarbon feedstock into alkyl amines, comprising:
 reacting a hydrocarbon feedstock with a molecular halogen to form alkyl halides;   reacting at least a portion of the alkyl halides with ammonia or an ammonium species to form alkyl amines and a halide salt; and   converting at least a portion of the halide salt into the molecular halogen via photoelectrocatalysis.   
     
     
         21 . The method of  claim 20  wherein the ammonium species comprises NaNH 2 . 
     
     
         22 . The method of  claim 20  wherein at least a portion of the alkyl halides comprises ethyl bromide and at least a portion of the ammonium species comprises NaNH 2 . 
     
     
         23 . The method of  claim 20  further comprising reusing the molecular halogen obtained from converting the halide salt as the molecular halogen in the reaction with the hydrocarbon feedstock. 
     
     
         24 . A method for converting coal into coke, comprising:
 reacting coal with a molecular halogen to form halogenated coal intermediates;   reacting at least a portion of the halogenated coal intermediates in the presence of a catalyst to form coke and a hydrogen halide; and   converting at least a portion of the hydrogen halide into the molecular halogen via photoelectrocatalysis.   
     
     
         25 . The method of  claim 24  further comprising reusing the molecular halogen obtained from converting the hydrogen halide as the molecular halogen in the reaction with the coal. 
     
     
         26 . The method of  claim 24  wherein the hydrogen halide is converted into the molecular halogen by neutralizing the hydrogen halide to a halide salt and electrolyzing the halide salt in a photoelctrocatalytic cell to form the molecular halogen. 
     
     
         27 . A method for converting coal or a biomass-derived hydrocarbon feedstock into polyols, comprising:
 reacting coal or a biomass-derived hydrocarbon feedstock with a molecular halogen to form alkyl halides;   reacting at least a portion of the alkyl halides with an alkali to form polyols and a halide salt; and   converting at least a portion of the halide salt into the molecular halogen via photoelectrocatalysis.   
     
     
         28 . The method of  claim 27  further comprising reusing the molecular halogen obtained from converting the halide salt as the molecular halogen in the reaction with the coal or biomass-derived hydrocarbon feedstock.