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.

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.

In one aspect, the disclosure relates to relates to CO.sub.2-free methods of co-producing hydrogen and solid forms of carbon via methane decomposition. The methods are efficient, self-sustaining, and environmentally sound. In a further aspect, the disclosure relates to recyclable and recoverable catalysts supported by solid forms of carbon and methods for recycling the catalysts. In some aspects, the disclosure relates to catalysts that do not require support by solid forms of carbon. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Processes for separating conjunct polymer from an organic phase are described. A mixture comprising an ionic liquid phase and the organic phase into the ionic phase and an organic phase comprising the conjunct polymer and at least one silyl or boryl compound. The organic phase is separated in a fractionation column into an overhead fraction comprising unreacted silane or borane compound and a bottoms fraction comprising the conjunct polymer and the silyl or boryl compound. The bottoms fraction is passed through an adsorption zone, and the silyl or boryl compound is recovered. Alternatively, the organic phase is passed through an adsorption zone first to remove the conjunct polymer and then a fractionation zone to separate the unreacted silane or borane compound from the silyl or boryl compound.

Processes for separating conjunct polymer from an organic phase are described. A mixture comprising an ionic liquid phase and the organic phase into the ionic phase and an organic phase comprising the conjunct polymer and at least one silyl or boryl compound. The organic phase is separated in a fractionation column into an overhead fraction comprising unreacted silane or borane compound and a bottoms fraction comprising the conjunct polymer and the silyl or boryl compound. The bottoms fraction is passed through an adsorption zone, and the silyl or boryl compound is recovered. Alternatively, the organic phase is passed through an adsorption zone first to remove the conjunct polymer and then a fractionation zone to separate the unreacted silane or borane compound from the silyl or boryl compound.

Catalysts, in particular clay catalysts, use in alkylation reaction of aromatic compounds, e.g., aromatic amines, that have lost activity during use, are regenerated by contacting the used catalyst with a mixture of a minor amount of an acid, in a mixture with water and an organic solvent. The regeneration process is readily incorporated into an alkylation process for aromatic amines.

Catalysts, in particular clay catalysts, use in alkylation reaction of aromatic compounds, e.g., aromatic amines, that have lost activity during use, are regenerated by contacting the used catalyst with a mixture of a minor amount of an acid, in a mixture with water and an organic solvent. The regeneration process is readily incorporated into an alkylation process for aromatic amines.

In accordance with one or more embodiments of the present disclosure, a method for regenerating and rejuvenating a spent catalyst comprising coke and contaminant metals includes washing the spent catalyst with a solvent; drying, at least partially, the spent catalyst; partially combusting the spent catalyst to remove a portion of the coke, thereby producing a partially de-coked catalyst; acid washing the partially de-coked catalyst; and fully combusting the partially de-coked catalyst, thereby producing a regenerated and rejuvenated catalyst. The portion of the coke removed during the partial combustion is greater than or equal to 10 wt. % and less than or equal to 60 wt. %. No rare earth elements are added to the partially de-coked catalyst prior to the fully combusting the partially de-coked catalyst.

Provided are a denitration catalyst regeneration method and a denitration catalyst regeneration system, which are capable of recovering denitration performance to a high level and reducing the SO.sub.2 oxidation rate of a catalyst. A denitration catalyst regeneration method according to the present invention includes: a chemical solution cleaning step for immersing a denitration catalyst in a chemical solution containing a fluorine compound and an inorganic acid; a step for extracting the denitration catalyst from the chemical solution; and a finish washing step for washing the denitration catalyst extracted from the chemical solution with a finish cleaning solution containing an organic acid.

Provided are a denitration catalyst regeneration method and a denitration catalyst regeneration system, which are capable of recovering denitration performance to a high level and reducing the SO.sub.2 oxidation rate of a catalyst. A denitration catalyst regeneration method according to the present invention includes: a chemical solution cleaning step for immersing a denitration catalyst in a chemical solution containing a fluorine compound and an inorganic acid; a step for extracting the denitration catalyst from the chemical solution; and a finish washing step for washing the denitration catalyst extracted from the chemical solution with a finish cleaning solution containing an organic acid.