Abstract: A gas diffusion electrode is used as a cathode for an electrolysis of an alkali metal chloride or an electrode in a fuel cell etc. A gas diffusion electrode has a porous layer made of a sintered mixture of a filler, a catalyst and a hydrophobic material which is formed by decomposing a pore forming agent selected from the group consisting of nickel, cobalt or iron salts of a carboxylic acids which is incorporated in a mixture of said filler, said catalysts and said hydrophobic material.

Abstract: A gas and liquid permeable cathode is bonded on an ion-exchange membrane and the composite electrode is used in an electrolytic cell for a production of sodium hydroxide by an electrolysis of an aqueous solution of sodium chloride. The cathode comprises a thermally decomposed nickel obtained from a nickel salt of fatty acid, Raney nickel, stabilized Raney nickel or carbonyl nickel and a polytetrafluoroethylene.

Abstract: An electrode is prepared by plating on an electrode substrate in a dispersion coating method to form a metal layer partially exposed porous particles of Ag on the electrode substrate, and, if desired, a middle layer is formed between the electrode substrate and the metal layer. The porous particles can be formed by etching an alloy of the particles.

Abstract: A macromolecular adsorbent is suitable for recovering heavy metal ions such as uranium ions from a dilute solution such as sea water and is a polymer having pendant groups having the formula ##STR1## wherein R.sup.1 represent a C.sub.1 -C.sub.8 divalent organic group; R.sup.2 and R.sup.3 respectively represents a C.sub.1 -C.sub.5 divalent organic group; p, q, r and l respectively represent 0 or 1; R.sub.f represents a C.sub.1 -C.sub.10 divalent perfluoro group; X.sup.1 and X.sup.2 respectively represent hydroxyl group or a hydroxyl convertible group or atom.

Abstract: An electrolysis of an aqueous solution of potassium chloride is carried out by employing a fluorinated cation exchange membrane having an ion-exchange capacity of 0.8 to 2.0 meq/g dry polymer and having carboxylic acid groups as functional groups and maintaining a concentration of an aqueous solution of potassium hydroxide in a cathode compartment in a range of 20 to 45 wt. % and maintaining a calcium concentration in the aqueous solution of potassium chloride to lower than 0.05 mg/liter.The purification of the aqueous solution of potassium chloride to reduce the calcium concentration is carried out in a system comprising a chelate ion-exchange substance.

Abstract: An electrode is prepared by etching an alloy substrate comprising a first metallic component selected from the group consisting of chromium, manganese, tantalum, niobium, vanadium, titanium, silicon, zirconium, germanium, scandium, yttrium and lanthanum and a second metallic component selected from the group consisting of iron, nickel, tungsten, copper, silver, cobalt and molybdenum to remove at least part of the first metallic component.

Abstract: An electrolysis of an aqueous solution of sodium chloride is carried out by employing a fluorinated cation exchange membrane having an ion-exchange capacity of 0.8 to 2.0 meq/g dry polymer and having carboxylic acid groups as functional groups and maintaining a concentration of an aqueous solution of sodium hydroxide in a cathode compartment in a range of 20 to 45 wt. % and maintaining a calcium concentration in the aqueous solution of sodium chloride to lower than 0.08 mg/liter.The purification of the aqueous solution of sodium chloride to reduce the calcium concentration is carried out in a system comprising the first and second chelate ion-exchange towers which are connected through a detector for detecting impurities in the aqueous solution.

Abstract: 5-Fluorouraacil is produced by reacting orotic acid with a fluorinating agent and then, decarboxylating the resulting 5-fluoro-orotic acid.

Abstract: A process for a separation of hexafluoropropylene oxide from hexafluoropropylene by an extractive distillation in the presence of a normally liquid inert compound such as 1,2-dichloroethane, monochlorobenzene, di-isopropyl ether and 1,1,2-trichloroethane.

Abstract: In a process for producing an alkali metal hydroxide which comprises electrolysis of an aqueous solution of an alkali metal chloride in an electrolytic cell having an anode compartment and a cathode compartment which are partitioned by a fluorinated cation exchange membrane, the improvement which comprises a fluorinated cation exchange membrane made of a fluorinated copolymer having carboxylic acid groups as the ion exchange group and having an ion exchange capacity of 0.5 to 2.0 meq/g dry polymer and a concentration of carboxylic acid groups of 8 to 30 meq/g water absorbed by the membrane when contacted with an aqueous solution of the alkali metal hydroxide having about the same concentration of alkali metal hydroxide as that of catholyte during said electrolysis.

Abstract: An unsaturated aldehyde having three to four carbon atoms is prepared by reacting the corresponding olefin with molecular oxygen in the vapor phase at a temperature of from 350.degree. to 520.degree. C in the presence of a metal oxide catalyst comprising the metallic components: (a) molybdenum; (b) at least one metal selected from the group consisting of niobium and tantalum; (c) tellurium; and (d) at least one metal selected from the group consisting of alkali metals, copper, arsenic, antimony, iron and nickel.

Abstract: Methacrylic acid is prepared by reacting methacrolein with molecular oxygen in the presence of a catalyst comprising (a) molybdenum, (b) phosphorus, (c) at least one element selected from the group consisting of thallium and cesium, (d) at least one element selected from the group consisting of vanadium, zirconium, tin, niobium, nickel, tantalum and iron, and (e) oxygen.

Abstract: Unsaturated carboxylic acids are prepared by reacting the corresponding unsaturated aldehyde with molecular oxygen in the presence of a catalyst of (a) molybdenum, (b) phosphorus, (c) antimony, (d) at least one element selected from the group consisting of tungsten, barium, chromium, lead, niobium, tantalum, tin, nickel, iron and zirconium, and (e) oxygen, and optionally (f) at least one element selected from the group consisting of strontium, titanium, germanium, cerium, and silver.

Abstract: An unsaturated aldehyde having three to four carbon atoms is prepared by reacting the corresponding olefin with molecular oxygen in the vapor phase at a temperature of from 350.degree. to 520.degree. C in the presence of a metal oxide catalyst comprising the metallic components: (a) molybdenum; (b) at least one metal selected from the group consisting of niobium and tantalum; and (c) at least one metal selected from the group consisting of tellurium, bismuth, cobalt, tungsten, indium, and titanium.

Abstract: Perfluoroaklyl iodides are prepared by reacting iodine, iodine pentafluoride and tetrafluoroethylene in the presence of a fluoride catalyst selected from the group consisting of niobium fluoride, tantalum fluoride, boron fluoride, and molybdenum fluoride.