Asahi Kasei Kogyo Kabushiki Kaisha

Maomi Seko

Tetsuya Miyake

Shinsaku Ogawa

Kunihiko Takeda

Hirotsugu Miyauchi

Yasumichi Yamakoshi

Kyoji Kimoto

Reiji Takemura

Tatsushi Saeki

Itaru Watanabe

Akihiko Ikeda

Kazuo Imamura

Kohji Inada

Muneo Yoshida

Mitsunobu Fukumoto

Tomio Sakamoto

Naoki Miyata

Kazushi Ochi

Toshioki Hane

Mitsuo Yoshida

Sakae Tsushima

Masatoshi Tanouchi

Masato Hamada

Yoshinori Masuda

Fumihiko Yamamoto

Hiroshi Takeuchi

Akira Nakamura

Shigeo Yokoyama

Hideharu Miyamori

Tetsuya Miyaki

Akira Kazihara

Takekuni Kobayashi

Nobuo Ajiki

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.

Process for electrolysis of sodium chloride

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.

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. With such a structure, not only is the electrical contact resistance between the adjacent unit cells and between each current lead plate and the unit cell adjacent thereto extremely reduced but also the current density in the unit cells is rendered uniform. Further, the present multi-cell electrolyzer can be easily constructed either in a bipolar form or in a monopolar form using unit cells common to both of the bipolar and monopolar forms.

Multi-cell electrolyzer

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.

Cation exchange membrane and use thereof in the electrolysis of sodium

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.

Purification of formaldehyde by separation

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.

Process for the production of high purity aqueous alkali hydroxide

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. The terephthalic acid produced according to the process of the present invention is of so high a quality that it can be used for the direct production of a polyalkylene terephthalate from the acid and an alkylene glycol or ethylene oxide, which direct production does not need the preparation of an intermediate such as a methyl ester of terephthalic acid.

Process for the production of a high purity terephthalic acid

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. The fluorocarbon polymer may also contain sulfonic acid groups of the formula ##STR2##

Electrolysis of aqueous alkali metal halide solution

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.

Process for electrolysis of sodium chloride by use of cation exchange

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.

Process for separation of hydrocarbon mixture

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.

Method for preparation of cation exchange membranes

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.

Process for electrolysis of aqueous alkali metal halide solution

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.

Growing community of inventors

Tokyo, Japan

Maomi Seko