Abstract: A process for the oxidation and oxidative dehydrogenation of hydrocarbons, in particular ethylbenzene, to form corresponding oxidized or olefinically unsaturated compounds, in particular styrene, over an oxygen-conferring, oxygen-regenerable catalyst involving a working period, a time-displaced regenerating period and at least one intermediate rinsing period comprises effecting a partial regeneration during the working period by time-displaced addition of a substoichiometric amount of oxygen.

Abstract: An aqueous solution of free hydroxylamine is prepared by a process in which the solution obtained by treating a hydroxylammonium salt with a base is separated into an aqueous hydroxylamine solution and a salt fraction by treatment with water or steam at .ltoreq.80.degree.0 C. The novel process can be carried out in a simple and gentle manner and on a large industrial scale. Owing to the low thermal load, the low concentration of hydroxylamine and the short residence time in the process, the risk of decomposition is minimized.

Abstract: A process for separating chlorine of high purity from a chlorine-containing feed gas by absorption of the chlorine using an inert absorbent and downstream desorption of the chlorine from the absorbent/chlorine mixture drawn off from the absorption stage by the supply of mixture to a desorption distillation column which is coupled to a chlorine separation column in such a way that the top of the chlorine separation column and an upper section of the desorption distillation column and a lower section of the desorption distillation column and the bottom of the chlorine separation column are connected to one another on both the gas and the liquid side, the absorbent/chlorine mixture being supplied exclusively to the desorption distillation column, and high-purity chlorine being drawn off from a middle region of the chlorine separation column.

Abstract: A process for the preparation of olefinically unsaturated compounds by catalytic oxidation, ie oxidative dehydrogenation by transferring oxygen from a previously oxidized oxygen carrier acting as catalyst, in the absence of molecular oxygen, the catalyst being regenerated after exhaustion, wherein, during the operating phase of the catalyst (oxidation/dehydration partial step), the residence time, space velocity and/or temperature of the reactants in the reactor is/are adjusted, ie, controlled, continuously or in discrete steps, in a manner appropiate to the momentary state of activity of the redox catalyst by adjusting--continuously or stepwise--the residence time of the reactants in the freshly regenerated catalyst (ie at the commencement of the reaction) to a shorter time, and/or the temperature to a lower value, than the corresponding parameter(s) in the partially reduced catalyst.

Abstract: A regenerative process for the preparation of olefinically unsaturated compounds by oxidation/dehydrogenation of selectively oxidizable hydrocarbons over an oxygen carrier acting as catalyst, in the absence of molecular oxygen, alternating (in repeated cycles) with regeneration of the spent oxygen carrier with a gaseous molecular oxidizing agent, in which the spent (reduced) catalyst is cooled, prior to introduction of the regenerating gas, to a temperature which is below the temperature of the reaction, regeneration being controlled in such a manner that the highest temperature occurring during regeneration does not exceed the temperature of reaction at which dehydrogenation is commenced.

Abstract: The invention relates to the stabilization of the activity and/or the reactivation of molybdoheteropoly acid catalysts in vapor-phase oxidations, such as the oxidehydrogenation of isobutyric acid or its lower esters to methacrylic acid or its lower esters, by means of an oxidizing treatment of the catalyst in which compounds of catalyst constituents are added, at temperatures ranging from 200.degree. to 400.degree. C., with an oxygen-containing gas.The inventive activation measures can be carried out either during the catalytic vapor-phase reaction, such as oxihydrogenation in particular, or intermittently to alternate therewith, and optionally also physically separated in part from each other.