A method of fixating CO.sub.2 to form a substituted oxazolidinone is described. The method includes mixing a nickel-based metal-organic framework (Ni-MOF) catalyst of formula [Ni.sub.3(BTC).sub.2(H.sub.2O).sub.3].Math.(DMF).sub.3(H.sub.2O).sub.3, a cocatalyst, an aromatic amine, and at least one epoxide to form a reaction mixture, and further contacting the reaction mixture with a gas stream containing carbon dioxide to react the carbon dioxide in the gas stream with the epoxide and the aromatic amine to form a substituted oxazolidinone mixture. The method further includes adding a polar protic solvent to the substituted oxazolidinone mixture, centrifuging, and filtering to produce a recovered Ni-MOF; and further washing the recovered Ni-MOF with an organochloride solvent and drying for at least 5 hours to produce a recycled Ni-MOF.

A method of fixating CO.sub.2 to form a substituted oxazolidinone is described. The method includes mixing a nickel-based metal-organic framework (Ni-MOF) catalyst of formula [Ni.sub.3(BTC).sub.2(H.sub.2O).sub.3].Math.(DMF).sub.3(H.sub.2O).sub.3, a cocatalyst, an aromatic amine, and at least one epoxide to form a reaction mixture, and further contacting the reaction mixture with a gas stream containing carbon dioxide to react the carbon dioxide in the gas stream with the epoxide and the aromatic amine to form a substituted oxazolidinone mixture. The method further includes adding a polar protic solvent to the substituted oxazolidinone mixture, centrifuging, and filtering to produce a recovered Ni-MOF; and further washing the recovered Ni-MOF with an organochloride solvent and drying for at least 5 hours to produce a recycled Ni-MOF.

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.

Methods for regenerating a spent catalyst are disclosed. Such methods may employ a step of chlorinating the spent catalyst in the gas phase, followed by decoking the chlorinated spent catalyst, and then fluorinating the de-coked catalyst in a fluorine-containing solution of a fluorine-containing compound.

Methods for regenerating a spent catalyst are disclosed. Such methods may employ a step of chlorinating the spent catalyst in the gas phase, followed by decoking the chlorinated spent catalyst, and then fluorinating the de-coked catalyst in a fluorine-containing solution of a fluorine-containing compound.

We provide a process for regenerating a used acidic ionic liquid catalyst which has been deactivated by conjunct polymers in a reactor, by removing at least 57 wt % of the conjunct polymers originally present in the used acidic ionic liquid catalyst in a separate regeneration reactor, so as to increase the activity of the catalyst. We also provide a regenerated used acidic ionic liquid catalyst having increased activity.

We provide a process for regenerating a used acidic ionic liquid catalyst which has been deactivated by conjunct polymers in a reactor, by removing at least 57 wt % of the conjunct polymers originally present in the used acidic ionic liquid catalyst in a separate regeneration reactor, so as to increase the activity of the catalyst. We also provide a regenerated used acidic ionic liquid catalyst having increased activity.

Methods for regenerating a spent catalyst are disclosed. Such methods may employ a step of chlorinating the spent catalyst in the gas phase, followed by decoking the chlorinated spent catalyst, and then fluorinating the de-coked catalyst in a fluorine-containing solution of a fluorine-containing compound.

Methods for regenerating a spent catalyst are disclosed. Such methods may employ a step of chlorinating the spent catalyst in the gas phase, followed by decoking the chlorinated spent catalyst, and then fluorinating the de-coked catalyst in a fluorine-containing solution of a fluorine-containing compound.