Abstract: A method and apparatus are described for removing a chemical product species produced by electrochemical action at an electrode or by a chemical reaction which occurs at the surface of a solid catalyst. The method involves providing a flow of a host solution generally parallel to a surface at which a chemical reaction occurs. The flow of the host solution causes the products from the chemical reaction to be entrained in a thin boundary layer which moves along the surface. These products can be removed from a cell by withdrawing the boundary layer from the cell as it reaches the trailing edge of the surface.

Abstract: A method for oxidizing HCl to produce pure chlorine gas by reacting HCl with a mixture of sulfuric and nitric acids. Chlorine gas is evolved. Spent nitric and sulfuric acids are first regenerated by contact with air or oxygen. After regeneration, the entire stream of regenerated acid, or major portion thereof, is reconcentrated. The concentration of sulfuric acid occurs at lower strengths (60%-80%) and temperatures. The concentrated acid may be used to oxidize more HCl. Heat evolved by the regeneration of the spent acids is carried into the acid concentration stage.

Abstract: A continuous process to nitrate a nitratable aromatic compound utilizing nitric acid and sulfuric acid feed stocks is described. The process includes the collecting of NO.sub.x O gases with water under pressure to and treating the NO.sub.x gases with water under pressure to produce weak nitric acid which is recycled to the nitric acid feed stock. The process is efficient, permitting the venting of NO.sub.x free gases to the atmosphere.