The invention relates to a method of regenerating the catalytic activity of a spent catalyst comprising nickel on a refractory oxide support, said method comprising the steps of contacting the spent catalyst with a nitric acid solution, heat-treating the spent catalyst, calcining and reducing the catalyst.

Implementations of the disclosed subject matter provide a process for producing ethylene glycol from a carbohydrate feed. The process may include contacting, in a reactor under hydrogenation conditions, the carbohydrate feed with a bi-functional catalyst system which may include a heterogeneous hydrogenation catalyst including a magnetically active metal, and a soluble retro-Aldol catalyst including tungstate. A liquid effluent stream may be obtained from the reactor and may include hydrogenation catalyst particles and tungsten oxide precipitate particles. The hydrogenation catalyst particles may be magnetically separated from the tungsten oxide precipitate particles in the liquid effluent stream using a magnet in a separation vessel. The separated hydrogenation catalyst particles may be retained in a separation zone in the separation vessel and may be subsequently removed from the separation zone. A liquid product stream may be obtained from the separation vessel and may include the tungsten oxide precipitate particles and ethylene glycol.

Implementations of the disclosed subject matter provide a process for producing ethylene glycol from a carbohydrate feed. The process may include contacting, in a reactor under hydrogenation conditions, the carbohydrate feed with a bi-functional catalyst system which may include a heterogeneous hydrogenation catalyst including a magnetically active metal, and a soluble retro-Aldol catalyst including tungstate. A liquid effluent stream may be obtained from the reactor and may include hydrogenation catalyst particles and tungsten oxide precipitate particles. The hydrogenation catalyst particles may be magnetically separated from the tungsten oxide precipitate particles in the liquid effluent stream using a magnet in a separation vessel. The separated hydrogenation catalyst particles may be retained in a separation zone in the separation vessel and may be subsequently removed from the separation zone. A liquid product stream may be obtained from the separation vessel and may include the tungsten oxide precipitate particles and ethylene glycol.

Implementations of the disclosed subject matter provide a process for producing ethylene glycol from a carbohydrate feed. The process may include contacting, in a reactor under hydrogenation conditions, the carbohydrate feed with a bifunctional catalyst system which may include a heterogeneous hydrogenation catalyst including a magnetically active metal, and a soluble retro-Aldol catalyst including tungstate. A liquid effluent stream may be obtained from the reactor and may include hydrogenation catalyst particles and tungsten oxide precipitate particles. The hydrogenation catalyst particles may be magnetically separated from the tungsten oxide precipitate particles in the liquid effluent stream using a magnet in a separation vessel. The separated hydrogenation catalyst particles may be retained in a separation zone in the separation vessel and may be subsequently removed from the separation zone. A liquid product stream may be obtained from the separation vessel and may include the tungsten oxide precipitate particles and ethylene glycol.

Implementations of the disclosed subject matter provide a process for producing ethylene glycol from a carbohydrate feed. The process may include contacting, in a reactor under hydrogenation conditions, the carbohydrate feed with a bifunctional catalyst system which may include a heterogeneous hydrogenation catalyst including a magnetically active metal, and a soluble retro-Aldol catalyst including tungstate. A liquid effluent stream may be obtained from the reactor and may include hydrogenation catalyst particles and tungsten oxide precipitate particles. The hydrogenation catalyst particles may be magnetically separated from the tungsten oxide precipitate particles in the liquid effluent stream using a magnet in a separation vessel. The separated hydrogenation catalyst particles may be retained in a separation zone in the separation vessel and may be subsequently removed from the separation zone. A liquid product stream may be obtained from the separation vessel and may include the tungsten oxide precipitate particles and ethylene glycol.

A process is described for improving the performance of certain multiphase reaction systems including a solid catalyst, one or more reactants in the gas phase and one or more reactants in the liquid phase, wherein a targeted maximum concentration of a reactant in the liquid phase is identified for providing improved value in terms of byproduct formation, catalyst deactivation and yields of desired products, and this targeted concentration is closely approached and preferably achieved, but not substantially exceeded, downstream in a continuous process or later in time from the initiation of a batch in a semibatch mode of operation of such processes.

A process is described for improving the performance of certain multiphase reaction systems including a solid catalyst, one or more reactants in the gas phase and one or more reactants in the liquid phase, wherein a targeted maximum concentration of a reactant in the liquid phase is identified for providing improved value in terms of byproduct formation, catalyst deactivation and yields of desired products, and this targeted concentration is closely approached and preferably achieved, but not substantially exceeded, downstream in a continuous process or later in time from the initiation of a batch in a semibatch mode of operation of such processes.

A process for regenerating catalysts that have been deactivated or poisoned during hydrogenation of biomass, sugars and polysaccharides is described, in which polymerized species that have agglomerated to catalyst surfaces can be removed by means of washing the catalyst with hot water at subcritical temperatures. A feature of the process can regenerate the catalysts in situ, which allows the process to be adapted for used in continuous throughput reactor systems. Also described is a continuous hydrogenation process that incorporated the present regeneration process.

A process for regenerating catalysts that have been deactivated or poisoned during hydrogenation of biomass, sugars and polysaccharides is described, in which polymerized species that have agglomerated to catalyst surfaces can be removed by means of washing the catalyst with hot water at subcritical temperatures. A feature of the process can regenerate the catalysts in situ, which allows the process to be adapted for used in continuous throughput reactor systems. Also described is a continuous hydrogenation process that incorporated the present regeneration process.