Methods for the electrosynthesis of polyols
AssigneeSKA Associates
InventorNorman L. Weinberg
Life of this patent
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Abstract
The electrosynthesis of ethylene glycol conducted with a formaldehyde-containing electrolyte provides unexpectedly higher current efficiencies at pH's maintained above about 5 to below about 7. Performance may be improved further through use of electrolytes having high formaldehyde-low methanol concentrations and with oxygen-containing organic compounds. Cell components such as gas diffusion electrodes and oxidized carbon or graphite cathodes also enhance current efficiencies.
Claims35
In a method of making ethylene glycol by the electrochemical reduction of a formaldehyde-containing electrolyte, the improvement comprising maintaining the pH of the electrolyte from above about 5 to below about 7 to provide an ethylene glycol current efficiency of at least 50 percent.
In a method of making ethylene glycol by the electrochemical reduction of an aqueous formaldehyde-containing electrolyte, the improvement comprising conducting the reaction wherein the pH of the electrolyte is maintained at above about 5 to below about 7 and the elctrolyte is substantially free of methanol.
In a method of making ethylene glycol by the electrochemical reduction of a formaldehyde-containing electrolyte, the improvement comprising conducting the reaction in the presence of a sufficient amount of a quaternary salt to provide an ethylene glycol current efficiency of at least 50 percent.
In a method for the electrosynthesis of ethylene glycol by the reduction of a formaldehdye-containing electrolyte in an electrolytic cell equipped with anodes and cathodes, the improvement comprising conducting the electrosynthesis with graphite or carbon cathodes having a preoxidized surface.
A method for the electrosynthesis of ethylene glycol from the reduction of a formaldehyde-containing electrolyte, which comprises the steps of providing an electrolytic cell equipped with an anode, a graphite or carbon cathode and a separator or membrane positioned between the anode and cathode, and conducting a useful process at the anode simultaneously with the electrosynthesis of ethylene glycol at the cathode.
In a method for electrosynthesis of ethylene glycol by the reduction of a formaldehyde-containing electrolyte, the improvement comprising the step of incorporating into the electrolyte a current efficiency enhancing amount of a glycol catalyzing oxygenated organic compound.
A method for the electrosynthesis of ethylene glycol which comprises conducting the electrosynthesis reaction in an electrolytic cell equipped with an anode and a graphite or carbon cathode wherein said cathode is a gas diffusion type and receives a gaseous feed of anhydrous or wet formaldehyde.
A method for the electrosynthesis of ethylene glycol by the reduction of a formaldehyde-containing electrolyte, which comprises providing an electrolytic cell equipped with a gas diffusion anode and a graphite or carbon cathode, said method including the step of generating at least a portion of the formaldehyde-containing electrolyte by oxidation of methanol at said gas diffusion anode.
Dependencies are inferred from the claim text.