Catalytic activity of a spent precious metal-iron catalyst is restored by combining the spent catalyst with an iron (III) compound. This can be performed by adding the iron (III) compound into a chemical reaction that contains the spent precious metal-iron catalyst. It is unnecessary to add more of the precious metal. The process is especially useful in a continuous process for converting a nitro compound such as nitrobenzene to the corresponding amine.

Catalytic activity of a spent precious metal-iron catalyst is restored by combining the spent catalyst with an iron (III) compound. This can be performed by adding the iron (III) compound into a chemical reaction that contains the spent precious metal-iron catalyst. It is unnecessary to add more of the precious metal. The process is especially useful in a continuous process for converting a nitro compound such as nitrobenzene to the corresponding amine.

A method of preparing a 2,6 disubstituted anilines includes, reacting a 2-amino isophthalic acid diester with sufficient Grignard reagent R.sub.2CH.sub.2MgX to form the corresponding diol product, dehydrating the diol product to the corresponding dialkene; and hydrogenating the diol product to form the corresponding aniline. The 2,6 disubstituted anilines can be used to produce N-Heterocyclic Carbenes (NHCs). The NHCs can find application in various fields such as organic synthesis, catalysis and macromolecular chemistry. Palladium catalysts containing the NHCs are also described.

A method of preparing a 2,6 disubstituted anilines includes, reacting a 2-amino isophthalic acid diester with sufficient Grignard reagent R.sub.2CH.sub.2MgX to form the corresponding diol product, dehydrating the diol product to the corresponding dialkene; and hydrogenating the diol product to form the corresponding aniline. The 2,6 disubstituted anilines can be used to produce N-Heterocyclic Carbenes (NHCs). The NHCs can find application in various fields such as organic synthesis, catalysis and macromolecular chemistry. Palladium catalysts containing the NHCs are also described.

The invention relates to a method for the purification of aniline, comprising the following steps: a) providing a raw aniline fraction; b) extracting the raw aniline fraction with an aqueous extractant containing, in relation to the total mass of the aqueous extractant, an alkali metal hydroxide in a concentration range from 0.009 to 2.05 mass % and an alkali metal salt that is different from an alkali metal hydroxide in a concentration range from 2.40 to 25.0 mass %, wherein an organic aniline phase and an aqueous amino phenolate phase are obtained after a phase separation; c) distilling the organic aniline phase from step b), obtaining a flow of purified aniline, a gaseous flow that boils at a lower temperature than aniline and containing organic impurities, and a liquid flow that boils at a higher temperature than aniline and containing organic impurities and aniline.

The invention relates to a method for the purification of aniline, comprising the following steps: a) providing a raw aniline fraction; b) extracting the raw aniline fraction with an aqueous extractant containing, in relation to the total mass of the aqueous extractant, an alkali metal hydroxide in a concentration range from 0.009 to 2.05 mass % and an alkali metal salt that is different from an alkali metal hydroxide in a concentration range from 2.40 to 25.0 mass %, wherein an organic aniline phase and an aqueous amino phenolate phase are obtained after a phase separation; c) distilling the organic aniline phase from step b), obtaining a flow of purified aniline, a gaseous flow that boils at a lower temperature than aniline and containing organic impurities, and a liquid flow that boils at a higher temperature than aniline and containing organic impurities and aniline.

The present disclosure relates to a multi-sandwich composite catalyst and a preparation method and application thereof. The present disclosure provides a preparation method of a multi-sandwich composite catalyst, comprises the following steps: sequentially depositing a first layer oxide, a first active metal, an oxide interlayer, a second active metal and a surface oxide on a template, and sequentially performing calcination and reduction, thereby obtaining a multi-sandwich composite catalyst; wherein the first active metal and the second active metal are different kinds of active metals. In the present disclosure, a multi-sandwich structure is formed by depositing the oxides and active metals alternately, so that the position and spacing distance of the active centers can be precisely controlled. The multi-sandwich composite catalyst prepared by the method provided described herein has a higher conversion than that of a catalyst without an interlayer when used for the catalytic reaction.

The present disclosure relates to a multi-sandwich composite catalyst and a preparation method and application thereof. The present disclosure provides a preparation method of a multi-sandwich composite catalyst, comprises the following steps: sequentially depositing a first layer oxide, a first active metal, an oxide interlayer, a second active metal and a surface oxide on a template, and sequentially performing calcination and reduction, thereby obtaining a multi-sandwich composite catalyst; wherein the first active metal and the second active metal are different kinds of active metals. In the present disclosure, a multi-sandwich structure is formed by depositing the oxides and active metals alternately, so that the position and spacing distance of the active centers can be precisely controlled. The multi-sandwich composite catalyst prepared by the method provided described herein has a higher conversion than that of a catalyst without an interlayer when used for the catalytic reaction.

A novel promotor which contains an aniline derivative is introduced. By using the promotor alone, the time and temperature of the curing reaction of the vinyl ester resin can be controlled by the unique steric effect and electronic properties of the aniline derivative. A method for preparing the above promotor is also introduced.

A novel promotor which contains an aniline derivative is introduced. By using the promotor alone, the time and temperature of the curing reaction of the vinyl ester resin can be controlled by the unique steric effect and electronic properties of the aniline derivative. A method for preparing the above promotor is also introduced.