Abstract: Organoiodonium salts, including certain novel symmetrical and unsymmetrical diaryliodonium;. polyiodonium and cyclic iodonium salts are synthesized by a significantly improved electrochemical coupling reaction which provides greater control and selectivity over the end product produced. Reaction mixtures comprising aryliodides and/or aromatic substrates are electrolyzed in novel reaction mediums comprising strong acid electrolyte, lower carboxylic acid, and preferably in the presence of acid anhydride in amounts >10 percent by-weight, and up to 50 percent by-weight or more, to provide a high degree of product selectivity, and at yields which can even be quantitative. The methods are conducted by introducing the electrolysis reaction mixture into an undivided electrochemical cell equipped with a cathode and preferably a conductive carbon anode.

Abstract: Methods for the electrolysis of aqueous solutions of alkali metal carbonates and bicarbonates for the production of alkali metal hydroxides at current efficiencies of >85 percent without the simultaneous co-production of halogen or acid can be performed at very low, commercially attractive cell voltages and at high current densities in single or two solution compartment cells with carbon dioxide as the only substantive co-product by maintaining cell pH at >7. The methods are also especially suitable for retrofitting existing chlor-alkali facilities for shifting the balance of production in favor of caustic soda at peak demands. The methods may also be performed with fuel cell configurations for even more attractive operating economics.

Abstract: The present invention provides a sensor, preferably an electrochemical sensor, for detecting acidic gases, e.g. carbon dioxide. The electrochemical sensor has a sensing electrode (20, 22), a counter electrode (37) and a body of electrolyte containing a complex, e.g. copper(II) bis(propanediamine), which has one or more ligands that is displaceable by the presence of the acidic gas in the electrolyte to form a modified complex which can be electrochemically reacted at the sensing electrode at a potential at which the unmodified complex is unreactive. The acidic gas diffuses into the electrolyte through a porous membrane. The modified complex can also be detected colorimetrically because it absorbs light at a different wavelength to the unmodified complex.