The Dow Chemical Company

H-d Tech Incorporated

Dow Chemical Canada Limited

Indresh Mathur

Allan James

Kenneth J Stutts

Derek J Rogers

Edward B Noonan

Mou S Chao

Ramanathan Gopal

Allan R Knight

Dale M Bristow (nee Elley)

Ram Gopal

Robert D Klassen

David Bissett

A method of producing sodium dithionite comprising electrolyzing a catholyte solution of sulfur dioxide in an electrolytic cell at a pH of at least about 3, the electrolytic cell having a carbonaceous cathode, is disclosed. Particularly high current efficiencies can be attained using a high surface area carbon material for the cathode. The use of a stabilizer to inhibit decomposition of the sodium dithionite to form sodium thiosulfate is also disclosed. The stabilizer is added to the catholyte and is selected from the group consisting of phosphoric acid, sodium tripolyphosphate, acid phosphates and mixtures thereof.

Method of producing sodium dithionite by electrochemical means

An electrochemical cell having improved current efficiency and a method for electrochemically reacting a liquid electrolyte with a gas in an electrochemical cell. The cell has at least two electrodes separated by a cell separator wherein at least one of said electrodes is a porous, self-draining, gas diffusion electrode. In one embodiment of the invention, an electrolyte is flowed through said cell separator into a porous, self-draining electrode and simultaneously the electrode is fed with a mixture of a reactive gas and water or an electrolyte. In another embodiment of the invention in which the cell separator is an ion exchange permselective membrane, a mixture of a reactive gas and an electrolyte are fed to the porous, self-draining electrode. Preferably said porous, self-draining electrode is a cathode.

Cell and method of operating a liquid-gas electrochemical cell

A bipolar, filter press type cell is disclosed having a liquid permeable diaphragm which is particularly suited for the electrolysis of a brine solution to produce chlorine and caustic or the electrolysis of an aqueous alkali metal hydroxide to produce an aqueous alkaline hydrogen peroxide solution. The cell can include a multiplicity of cell units extending generally in a vertical as well as a horizontal direction. A porous, self-draining electrode assembly includes a current distributor in contact with a side of the electrode opposite the electrolyte active side of the electrode.

Bipolar electrolyzer

This invention relates to novel electrocatalyst coated electrodes and to a method for the preparation thereof for use in electrochemical cells, particularly those employing alkaline electrolytes in the anolyte compartment of the cell. The electrodes disclosed are coated with the oxides of cobalt and tungsten and are particularly suitable as anodes since the electrocatalyst coatings resist destruction by oxygen.

Low over-voltage electrodes for alkaline electrolytes

A process for selectively removing sodium sulfate and sodium hydroxide from an aqueous slurry containing sodium chloride, sodium sulfate and sodium hydroxide, which comprises contacting the slurry in a countercurrent wash step with cool water to remove sodium sulfate and sodium hydroxide therefrom.

Process for selective removal of sodium sulfate from an aqueous slurry

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Sarnia, Canada

Indresh Mathur