Abstract:
The invention relates to a method for reactivating homogeneous catalyst systems from organic reaction mixtures. The catalyst systems are suitable for oxidating organic compounds such as, for example cyclododecene. The reactivation is carried out by means of an aqueous base.
Abstract:
The present invention provided a process for regenerating a deactivated heteropolymolybdophosphoric acid catalyst comprising the steps of grinding the deactivated catalyst into particles having a particle size of 40 mesh or less, mixing same with a mixture consisting of aqua ammonia, an aqueous solution containing ammonium ion and organic auxiliaries and kneading same in a kneader to obtain a paste, drying the paste and molding into cylindrical particle with a through hole in its longitudinal axis, and heating in atmosphere at 350 - 450°C for 1 ~ 10 hours to produce the generated catalyst. The catalytic capacity of such a catalyst having keggin structure of heteropoly acid fully recovered is fully restored for selective oxidation of lower unsaturated aldehydes (such as acrolein or isobutyraldehyde) to produce unsaturated acids. The regeneration is conducted under mild condition by a simple and easy process with good reproducibility.
Abstract:
A process for regenerating one or more deactivated cobalt comprising Fischer-Tropsch catalyst particle (s) in situ in a reactor tube, said process comprising the steps of : (i) oxidising the catalyst particle(s) at a temperature between 20 and 400 °C; (ii) treating the catalyst particle (s) for more than 5 minutes with a solvent, (iii) drying the catalyst particle (s); and (iv) optionally reducing the catalyst with hydrogen or a hydrogen comprising gas. This process may be preceded by a step in which Fischer-Tropsch product is removed from the catalyst particle(s).
Abstract:
The present invention provides a process for regenerating a catalyst for producing e-caprolactam comprising the steps of adsorbing a silicon compound on a zeolite catalyst that had been used for a Beckmann rearrangement reaction of cyclohexanone oxime and contacting the catalyst with an aqueous solution containing a compound selected from a quaternary ammonium compound, lower alkylamines and ammonia. The present invention also provides a process for producing e-caprolactam comprising subjecting cyclohexanone oxime to the Beckmann rearrangement reaction in the presence of the catalyst thus regenerated.
Abstract:
A process for enhancing metal catalysts for carbon monoxide hydrogenation comprising reducing the catalyst so that at least a portion is in the metallic state, impregnating under a non-oxidative atmosphere with a solution of a salt of at least one metal, optionally in combination with at least one of an ammonium salt, an alkyl ammonium salt, a weak organic acid and ammonia, oxidizing with a gaseous oxidant in the presence of the impregnating solution, and reducing to form an active catalyst. used catalysts enhanced by the process are initially treated to decrease their hydrocarbon content. The treatment may be carrier out in a single reactor, or by carrying out up to all steps after catalyst may be withdrawn from a reactor and returned to at least one reactor, both preferably during operations. Up to all steps may be effected in a subsequent reactor, or in specialized apparatus.
Abstract:
A method for producing ε-caprolactam and a method for reactivating a zeolite catalyst for producing ε-caprolactam are provided. In the reactivation step, a zeolite catalyst is allowed to contact a gas containing a carboxylic acid, water and a compound selected from ammonia and amines. In accordance with the present invention, the catalytic activities of a zeolite catalyst used for the Beckmann rearrangement reaction of cyclohexanone oxime can be effectively restored. Consequently, ε-caprolactam may be produced with a high production yield for a long period of time by reusing the catalyst by the method described above.
Abstract:
Provided are high activity catalysts based upon gamma alumina containing substrates impregnated with one or more catalytically active metals, which catalysts in addition contain a nanocrystalline phase of alumina of a crystallite size at the surface of less than 25 Å. Also provided are processes for preparing such high activity catalysts and various uses thereof.
Abstract:
An epoxidation reaction product formed by the molybdenum catalyzed reaction of propylene with tertiary butyl hydroperoxide to provide propylene oxide and tertiary butyl alcohol is separated by distillation into a propylene fraction, a propylene oxide fraction, a tertiary butyl alcohol fraction and a heavy liquid distillation fraction composed primarily of tertiary butyl hydroperoxide, tertiary butyl alcohol, dissolved molybdenum catalyst, and impurities including lower aliphatic C₁-C₄ carboxylic acids, and the heavy liquid distillation fraction is saturated with ammonia to precipitate the molybdenum therefrom for recovery.