Electrochemical reactor for upgrading methane and small alkanes to longer alkanes and alkenes

Abstract

This application relates to new process that utilizes electrodes that incorporate acids that facilitate upgrading of methane and other low molecular weight alkanes to higher order hydrocarbon molecules, such as paraffins, olefins, and aromatics, at temperatures less than 250° C. A primary focus of the invention includes methane conversion to ethylene. The first step of the process includes acid containing electrodes that facilitate the activation of the alkane in the anode layer of the electrochemical reactor. Subsequent steps include the separation of protons from produced longer chain hydrocarbons followed by subsequent electrochemical reduction of the protons to yield hydrogen at the cathode or protons combined with oxygen at the cathode to yield water. The reaction steps in the anode upgrade methane to higher order hydrocarbon products.

We claim: 
     
         1 . An apparatus for synthesizing higher order hydrocarbons from low molecular weight alkanes comprising:
 (a) an anode;   (b) a cathode;   (c) an acid electrolyte separator;   (d) a catalyst;   (e) electrode binders that feature acids in the anode and cathode;   a low molecular weight hydrocarbon;   (g) wherein the anode and the cathode are in electronic communication to allow flow of electrons from the anode to the cathode;   (h) wherein the low molecular weight hydrocarbon is in contact with the anode;   and, wherein synthesis of a higher order hydrocarbon occurs at a temperature less than 400° C.   
     
     
         2 . The apparatus of  claim 1  wherein the low molecular weight alkane is selected from a group consisting of methane, ethane, propane, and butane (or mixtures of). 
     
     
         3 . The apparatus of  claim 1  wherein the low molecular weight alkane is methane. 
     
     
         4 . The apparatus of  claim 1  wherein the higher order hydrocarbon is an alkane, alkene, or aromatic product. 
     
     
         5 . The apparatus of  claim 1  wherein a hydrogen molecule is produced at the cathode. 
     
     
         6 . The apparatus of  claim 1  wherein the acid is selected from the group consisting of trifluoroacetic acid, perchloric acid, sulfuric acid, phosphoric acid, chlorosulfonic acid, perchloric acid, hydrofluoric acid, triflic acid, and fluorosulfonic acid. Other acid candidates may include: antimony pentafluoride, tantalum pentafloride, FeOxCly, triantimony (V) oxide-floride, perfluorosulfonic acid, tantalum oxyfloride. 
     
     
         7 . The apparatus of  claim 6  wherein the acid is in liquid form. 
     
     
         8 . The apparatus of  claim 6  wherein the anode and cathode further comprises an electrically conductive support material, catalyst, and an acid containing ionomer binder. 
     
     
         9 . The apparatus of  claim 6  wherein the synthesis reaction occurs at a temperature between 100° C. and 250° C. 
     
     
         10 . The apparatus of  claim 9  wherein the cathode and anode comprise a catalyst that is selected from a group consisting of ruthenium, rhodium, palladium, osmium, iridium, and platinum metal or the metal in its oxide form. 
     
     
         11 . The apparatus of  claim 10  wherein the acid containing ionomer comprises a polymer host such as polybenzimidazole, polycations, and blends of polybenzimidazole-polycations. 
     
     
         12 . The apparatus of  claim 11  wherein the polycation material is selected from a group consisting of polyaromatic or perfluorinated backbones with tethered cation groups such as quaternary ammoniums, imidazoliums, phosphoniums, or ternary sulfoniums or sulfoxniums, or tethered metal cation centers (i.e., metallocenes).