Abstract: A process for the electrolysis of aqueous solutions of sodium chloride in an electrolytic cell separated into an anode chamber and a cathode chamber by a perfluorocarbon copolymer cation exchange membrane having pendant carboxylic acid groups. The process is characterized by reducing the calcium content of the aqueous sodium chloride solution charged into the anode chamber to less than 1 p.p.m. High current efficiencies are obtained utilizing membranes having an ion exchange capacity of carboxylic acid groups of from 0.5 to 2.1 milliequivalents per gram of dry resin.

Abstract: A process for the electrolysis of aqueous solutions of sodium chloride in an electrolytic cell separated into an anode chamber and a cathode chamber by a cation exchange membrane consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, said membrane having an ion exchange capacity of sulfonic and carboxylic acid groups of from 0.5 to 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin.

Abstract: A multi-cell electrolyzer comprising a plurality of unit cells, each of which is composed of an anode chamber containing an anode and a cathode chamber containing a cathode and a cation exchange membrane for partitioning said unit cell into said anode chamber and said cathode chamber, and each of which is adapted to have an internal pressure maintained at a level higher than the atmospheric pressure in operation of the electrolyzer, said plurality of unit cells being arranged in series and adapted to be energized through a plurality of current lead plates, and rigid multi-contact electrically conductive means provided between the adjacent unit cells and/or between each current lead plate and the unit cell adjacent thereto, thereby establishing electrical connection between the adjacent unit cells and/or between each current lead plate and the unit cell adjacent thereto.

Abstract: Cation exchange membranes characterized by carboxylic or carboxylic and sulfonic acid groups pendant from a fluorocarbon polymer are utilized for the electrolysis of aqueous sodium chloride.

Abstract: A mixture containing formaldehyde and water is separated effectively by contacting with adsorbents of specific type A zeolites containing exchanged cations of the elements from Group IA (4) to (6) or Group IIA (6) or mixture thereof of the Periodic Table of Elements.

Abstract: High purity aqueous alkali hydroxide solutions containing predetermined, low concentrations of alkali metal halide are obtained in the anode compartment of an electrolytic cell using a cationic ion exchange membrane by conducting the electrolysis under controlled conditions such that the difference between the concentration of alkali metal halide in the anode compartment and the limiting concentration of alkali metal halide in the anode compartment is within a defined range.

Abstract: An improved process for the production of a high purity terephthalic acid by a liquid phase oxidation reaction of para-xylene by means of molecular oxygen or a molecular oxygen-containing gas in an aliphatic monocarboxylic acid solvent in the presence of a cobalt-manganese-bromine catalyst system, characterized in that as the cobalt-manganese-bromine catalyst system there is used a catalyst system of a specific composition at a specific concentration, and the liquid phase oxidation reaction is effected in the presence of acetaldehyde in addition to the cobalt-manganese-bromine catalyst system under relatively mild temperature (170.degree.-190.degree. C.) and pressure conditions while maintaining the water concentration in the reaction system at a specified low level.

Abstract: An electrolytic cell having anode and cathode chambers separated by a cation exchange membrane comprising a fluorocarbon polymer containing pendant carboxylic acid or salt groups of the formula ##STR1## wherein R is a group containing perfluoroalkyl or perfluoroalkoxy having 1 to 5 carbon atoms and M is hydrogen, an alkali or alkaline earth metal or ammonium as a surface stratum on the cathode side of the membrane.

Abstract: In a process for electrolysis of sodium chloride in an electrolytic cell divided into the anode chamber and the cathode chamber by a cation exchange membrane, well brine is used as the starting material for the electrolysis and the dilute aqueous sodium chloride solution formed as the result of the electrolysis is subjected to concentration for re-use as the starting material.

Abstract: Cation exchange membranes characterized by carboxylic or carboxylic and sulfonic acid groups pendant from a fluorocarbon polymer are utilized for the electrolysis of aqueous sodium chloride.

Abstract: A hydrocarbon mixture is fed to a system of adsorbents in a plug flow so as to form at least one displacement boundary in the system to accumulate the composition in the vicinity of the boundary. The process is simple to operate and suitable for separation of a hydrocarbon mixture containing components with similar physical and chemical properties such as a mixture of hydrocarbon isomers.

Abstract: A mixture containing formaldehyde and water is separated effectively by contacting with adsorbents of specific type A zeolites containing exchanged cations of the elements from Group IA (4) to (6) or Group IIA (6) or mixture thereof of the Periodic Table of Elements.

Abstract: A fluorocarbon polymer membrane having pendant sulfonamide groups is first treated with anion radicals and then hydrolyzed for conversion into a cation exchange membrane having carboxylic groups and sulfonic acid groups.

Abstract: An aqueous alkali metal halide solution is electrolyzed in an electrolytic cell using a cation exchange membrane which is a fluorocarbon polymer containing sulfonic acid groups and at least one cation exchange group which is less acidic than the sulfonic acid group with higher proportion of the latter in surface stratum on the cathode side of the membrane than in the entire membrane, while controling proton concentration in the anolyte at not higher than critical proton concentration at which no substantial amount of protons in the anolyte penetrate into the membrane.This invention relates to a process for electrolysis of an aqueous alkali metal halide solution using a cation exchange membrane comprising a fluorocarbon polymer containing sulfonic acid groups and at least one cation exchange group with weaker acidity than the sulfonic acid group.

Abstract: An anion exchange resin particle provided with specific structure as well as specific functional groups is found to be suitable for uranium technology, especially for separation of uranium isotopes.

Abstract: Uranium-235 is efficiently concentrated using a solution containing uranium-238 and uranium-235 by passing a solution containing uranium (VI) complex anions through a body of an anion exchange material to adsorb uranium (VI) complex anions on a portion of the anion exchange material and then passing a solution of a reducing agent through the anion exchange material thus retaining uranium in the form of the uranium (VI) complex anions to elute the uranium ions while reducing the uranium (VI) complex anions to uranium (IV) complex ions.

Abstract: A process for separation of uranium isotopes by chromatography through an anion exchange material is found to be improved in efficiency of separation as well as in productivity by addition of a catalyst for accelerating electron exchange reactions occurring in the system under conditions to retain uranyl ions on the anion exchange material preferentially over uranous ions.

Abstract: A bipolar system electrolytic cell having a partition wall made of explosion-bonded titanium plate and iron plate which is electrically connected to anode of titanium substrate at its titanium side and to cathode of iron at its iron side, space is preferably given between anode and the partition wall and also between cathode and the partition wall. An assembly having a number of such unit cells arranged in series is useful for electrolysis of sodium chloride which can be performed under a low voltage per unit cell.

Abstract: In an electrolytic cell having cation exchange membrane as diaphragm to partition said cell into cathode and anode chambers, electrolysis of an electrolyte aqueous solution is conducted while generating gas from anode by keeping the inner pressure in cathode chamber higher than that in anode chamber. Some disadvantages caused in the case of electrolyzing an aqueous alkali metal halide solution to form alkali metal hydroxide in cathode chamber are overcome by adjusting the anolyte at pH <3.5. The electrolytic cell preferably employable for the present process is also disclosed.

Abstract: A perfluorocarbon type cation exchange membrane prepared by treatment with an oxidizing agent of a cation exchange membrane containing perfluorocarbon polymers having specific pendant N-sulfonamide groups has improved electrochemical characteristics when used as a membrane in electrolysis of aqueous alkali halide solution.