E.i. Dupont De Nemours and Company

Dennie Turin Mah

John Scott Newman

Clarence Garlan Law, Jr

Francisco Jose Freire

James Arthur Trainham

Vinci Martinez Felix

Bruce Arthur Kaiser

Stephen Ernest Jacobson

Kenneth B Keating

Douglas John Eames

William H Zimmerman

James Arthur Trainham, Iii

Edward Joseph Fahy

A low temperature electrolysis process that can be used for producing an alkali metal from an alkali metal halide is provided, which comprises electrolyzing an electrolyte composition comprising at least one alkali metal halide and a co-electrolyte comprising (a) a halide or halides of Group IIIA, Group IB, or Group VIII metals and (b) a halide-donating compound.

Low temperature alkali metal electrolysis

A process and a system produces isocyanate and converts anhydrous hydrogen chloride, which is a by-product of isocyanate production, to chlorine gas in an electrochemical cell. The chlorine is recycled to the isocyanate process. Any unreacted anhydrous hydrogen chloride may be recycled to the electrochemical cell. By recycling the anhydrous hydrogen chloride and the chlorine, the process and system are able to reduce the cost of producing isocyanate. In addition, this process and system process eliminate or at least substantially minimize the problems associated with disposal of anhydrous hydrogen chloride by turning it into a useful starting material in the isocyanate process.

Production of isocyanate using chlorine recycle

The present invention relates to an electrochemical cell having split fluid and current feed. Specifically, the cathode or anode inlet and outlet fluid may be fed from both, rather than from just one end of the electrolyzer. Alternatively, or additionally, the current may be fed to the anode or cathode side of the cell at one point, but may be removed from the opposite end of cell at two points. By feeding the fluid from both ends of the electrolyzer, the internal shunt current within each manifold is reduced, while the active area in the electrolyzer is increased without increasing the overall area of the current distributors. By removing the current from the electrolyzer at two points rather than just one, the voltage required by the electrolyzer may be reduced by half than if the current were removed at just one point.

Electrochemical cell having split fluid and current feed

The present invention relates to an electrochemical cell, system and process for converting essentially anhydrous hydrogen halide to essentially dry halogen gas. The process of the present invention is useful for converting anhydrous hydrogen halide, in particular, hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to a halogen gas, such as chlorine, fluorine, bromine, or iodine. In particular, in the present invention, water is provided to the cation-transporting membrane at the cathode in various ways. The present invention allows for recovery of a released fluid at the cathode-side of the membrane and recycling of the released fluid back to the cathode side of the membrane. In this way, the recovered, released fluid may be recycled to continuously supply water to the membrane, thereby allowing the limiting current density of the cell to be increased and/or controlled.

Membrane hydration in electrochemical conversion of anhydrous hydrogen

The invention relates to an electrochemical cell which has an electrode, a membrane disposed in contact with one side of the electrode, and a resilient flow field disposed on the other side of the electrode. The resilient flow field provides uniform electrical contact with the electrode. Such a flow field is preferably an elastomer, which can be be made by molding techniques, thereby decreasing the cost and increasing the ease with which such a flow field may be manufactured. The resilient flow field of the present invention is particularly useful in converting anhydrous hydrogen halide directly to essentially dry halogen gas, such as anhydrous hydrogen chloride to chlorine gas, although it may be used in a cell which converts aqueous reactants.

Electrochemical cell having a resilient flow field

A process and a system uses a direct chlorination reactor for producing ethylene dichloride by direct chlorination, without the need for an oxychlorination unit. This ethylene dichloride may be used to make vinyl chloride monomer. In the process for making ethylene dichloride, ethylene and chlorine are both supplied to a direct chlorination reactor. The ethylene reacts with the chlorine to form ethylene dichloride. Chlorine is supplied to the direct chlorination reactor from an electrochemical cell which converts anhydrous hydrogen chloride to dry chlorine gas. This chlorine gas is purified and liquefied to form liquid dry chlorine, and the liquid dry chlorine is recycled to the direct chlorination reactor. The ethylene dichloride may be pyrolyzed to produce vinyl chloride monomer and anhydrous hydrogen chloride.

Production of ethylene dichloride by direct chlorination and production

The invention relates to an electrochemical cell having an electrode with a catalyst layer and a gas diffusion layer. The cell also includes a mass flow field for directing fluid to and away from the electrode. An additional gas diffusion layer is disposed between the gas diffusion layer and the flow field. This increases the diffusion resistance of the fluid. The electrochemical cell of the present invention is particularly useful in a process for electrochemically converting anhydrous hydrogen halide to essentially dry halogen gas, where it is necessary to control and increase limiting current. It is also possible to use the additional gas diffusion layer in an aqueous process electrochemical cell.

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Wilmington, DE, United States of America

Dennie Turin Mah