Abstract: A process for the cyclic production of hydrogen peroxide comprising alternating the reduction of oxidation of a quinone in a solvent medium and extracting the hydrogen peroxide. The solvent medium contains a carboxylic acid amide comprising at least one aryl group to satisfy one of the following conditions:(a) an aryl group is attached to the nitrogen or the carbon of the carbonyl; or(b) an aryl group is attached to the nitrogen and another aryl group, which is the same or different, is attached to the nitrogen or to the carbon of the carbonyl.

Abstract: A process is disclosed for the regeneration, by thermal treatment, of used catalysts for a cyclical process for the production of hydrogen peroxide. According to the process, used aluminosilicate type catalyst is subjected to progressive heating up to a temperature between 700.degree. and 850.degree. C., in the presence of an oxidizing atmosphere circulating co-current to the catalyst being regenerated. The process can be carried out in a rotary furnace inclined to the horizontal by 0.7 to 1% and having radial fins on the lower section of its inner wall, and an adjustable diaphragm at its outlet.

Abstract: Improved methods and apparatus for the purification of industrial flue gases, combustion products and gaseous effluents before their rejection to the atmosphere, said gases and effluents containing as impurities especially sulfur oxide and also oxides of nitrogen, sulphuric fogs, dust and soot, said method comprising essentially the steps of: extracting the dust from the gaseous fluid to be purified; proceeding to a chemical purification phase of the gaseous fluid by establishing intimate contact between said fluid and an aqueous solution of hydrogen peroxide at a temperature lower than 80.degree.C.; and carrying out a concentration phase by effecting a direct contact between the gases and the liquid of the gaseous effluents in the hot state, and said liquid being constituted by sulphuric acid formed during said purification phase. The chemical purification phase is carried out on the gaseous effluents when these latter are saturated with water and is effected at a temperature between 55.degree. and 65.

Abstract: A process for regenerating working solutions used in cyclic processes for the manufacture of hydrogen peroxide using anthraquinones, the process consisting of a first distillation stage in which the solvent is separated under a pressure not greater than atmospheric pressure, and a second distillation stage in which the quinones and "light degraded products" are separated under a lower pressure. All the distillation products are used as a new working solution, the vapors of the second distillation stage being condensed on a liquid film of constantly renewed cold solvent originating from condensable vapors of the first distillation stage.