Abstract: Method for pretreating the copper-based catalyst having the steps of dehydrating the copper-based catalyst at an elevated temperature, reducing the dehydrated copper-based catalyst with hydrogen, and passivating the activated copper-based catalyst to obtain a catalyst suitable for N-alkylation. The dehydration and reduction steps may be conducted simultaneously.

Abstract: A solid base catalyst having a carrier, an organic base, and an inorganic base. Both of the organic base and inorganic base are loaded on the carrier. The solid base catalyst is especially suitable for the synthesis of 4-Aminodiphenylamine (4-ADPA).

Abstract: A sulfur-containing palladium-carbon catalyst prepared by loading palladium on an active carbon, mixing the palladium-carbon catalyst with a solvent to form a slurry, adding a sulfide to the slurry to treat the loaded palladium under a predetermined temperature, and removing liquid and drying to obtain the catalyst. The sulfur-containing palladium-carbon catalyst is suitable for making phenylene diamine rubber antioxidant with improved productivity and selectivity.

Abstract: A process tank for producing insoluble sulfur comprising a tank body having an upper half portion a lower half portion a first end and a second end along the longitudinal axis; an inner semi-cylinder body inside the upper half portion; and a first filter plate in the lower half portion. The space between the inner semi-cylinder body and the tank body is a sandwich structure and an inner cavity independent of the sandwich structure is provided inside the tank body. The first filter plate is wavelike in the cross section which separates from the inner cavity a first filter liquid cavity. A first liquid outlet communicating with the first filter liquid cavity is provided on the tank body.

Abstract: A process for using a solid acid catalyst having a strong acid cation exchange resin having a cross-linking network structure and free aromatic sulfonic acids adsorbed in the network for synthesis of rubber antioxidant RD and other strong-acid catalyzed reactions.

Abstract: A process for preparing alkylated p-phenylenediamine having the steps of reacting aniline and nitrobenzene in presence of a complex base catalyst to obtain 4-aminodiphenylamine intermediates, hydrogenating the 4-aminodiphenylamine intermediates to 4-aminodiphenylamine in presence of a hydrogenation catalyst, and reductively alkylating the 4-aminodiphenylamine to alkylated p-phenylenediamine.

Abstract: Method for pretreating the copper-based catalyst having the steps of dehydrating the copper-based catalyst at an elevated temperature, reducing the dehydrated copper-based catalyst with hydrogen, and passivating the activated copper-based catalyst to obtain a catalyst suitable for N-alkylation. The dehydration and reduction steps may be conducted simultaneously.

Abstract: A method for refining an organic composition containing 4-aminodiphenylamine, aniline, azobenzene, and phenazine, having the steps of feeding the organic composition to a first rectification column, producing a first effluent composition containing aniline, azobenzene, phenazine, and a small amount of 4-aminodiphenylamine at the top of the first rectification column and a second effluent composition containing crude 4-aminodiphenylamine at the bottom of the first rectification column, feeding the second effluent composition to a second rectification column, and producing a 4-aminodiphenylamine composition at the top of the second rectification column and a residual composition at the bottom of the second rectification column.

Abstract: A falling film evaporator having a shell pass, multiple tubes parallel to each other, a condensed steam outlet, an inlet for an aqueous solution on the top of the tube pass, an outlet for the aqueous solution at the bottom of the tube pass, a distributing assembly having a plurality of distributing trays arranged vertically from top to bottom in incremental diameters and each having multiple holes, and a plate for collecting the aqueous solution below the distributing assembly. The tubes are straight and installed vertically in the evaporator; inner wall of the tubes is smooth, and the top portion of the tubes is protruded above a horizontal plane of the plate. The evaporator is particularly useful for concentrating an aqueous solution containing thermosensitive materials.

Abstract: A solid base catalyst having a carrier, an organic base, and an inorganic base. Both of the organic base and inorganic base are loaded on the carrier. The solid base catalyst is especially suitable for the synthesis of 4-Aminodiphenylamine (4-ADPA).

Abstract: A sulfur-containing palladium-carbon catalyst prepared by loading palladium on an active carbon, mixing the palladium-carbon catalyst with a solvent to form a slurry, adding a sulfide to the slurry to treat the loaded palladium under a predetermined temperature, and removing liquid and drying to obtain the catalyst. The sulfur-containing palladium-carbon catalyst is suitable for making phenylene diamine rubber antioxidant with improved productivity and selectivity.

Abstract: A process for preparing alkylated p-phenylenediamine having the steps of reacting aniline and nitrobenzene in presence of a complex base catalyst to obtain 4-aminodiphenylamine intermediates, hydrogenating the 4-aminodiphenylamine intermediates to 4-aminodiphenylamine in presence of a hydrogenation catalyst, and reductively alkylating the 4-aminodiphenylamine to alkylated p-phenylenediamine.

Abstract: A process tank for producing insoluble sulfur comprising a tank body having an upper half portion, a lower half portion, a first end and a second end along the longitudinal axis; an inner semi-cylinder body inside the upper half portion; and a first filter plate in the lower half portion. The space between the inner semi-cylinder body and the tank body is a sandwich structure, and an inner cavity independent of the sandwich structure is provided inside the tank body. The first filter plate is wavelike in the cross section which separates from the inner cavity a first filter liquid cavity. A first liquid outlet communicating with the first filter liquid cavity is provided on the tank body.

Abstract: A process for using a solid acid catalyst having a strong acid cation exchange resin having a cross-linking network structure and free aromatic sulfonic acids adsorbed in the network for synthesis of rubber antioxidant RD and other strong-acid catalyzed reactions.

Abstract: The present invention provides spherical rubber chemicals and the method for preparing the same. The spherical rubber chemicals of the present invention include spherical antioxidants, spherical vulcanization agents, spherical processing aids, spherical reinforcing agents, or spherical adhesive agents. With the spherical rubber chemicals of the present invention, the shortcomings of powdery or semi-spherical rubber chemicals are overcome, including eliminating the dust pollution during granulation procedure and avoiding the raw material loss and the environmental pollution, while solving the quality problem of lower melting point of product caused by the presence of fine powder crystal. Furthermore, the resultant rubber chemicals has an improved smoothness of surface, which is helpful to improve the flowing and mixing behaviors of the rubber chemicals in mixing or open milling process with rubbers.

Abstract: Method for pretreating the copper-based catalyst having the steps of dehydrating the copper-based catalyst at an elevated temperature, reducing the dehydrated copper-based catalyst with hydrogen, and passivating the activated copper-based catalyst to obtain a catalyst suitable for N-alkylation. The dehydration and reduction steps may be conducted simultaneously.

Abstract: A complex base catalyst comprising tetraalkyl ammonium hydroxide and tetraalkyl ammonium salt for the condensation reaction of aniline and nitrobenzene.

Abstract: A solid acid catalyst having a strong acid cation exchange resin having a cross-linking network structure and free aromatic sulfonic acids adsorbed in the network. The solid acid catalyst is prepared by treating a strong acid cation exchange resin with aromatic sulfonic acids in a solution. The catalyst is useful for synthesizing rubber antioxidant RD and other strong-acid catalyzed reactions.

Abstract: The present invention relates to a magnetic separation apparatus for continuous separating and recovering magnetic solid particles from a solid-liquid mixture. The apparatus includes at least one magnetic separation unit and each unit includes: an outer cylindrical vessel having a material inlet, a first outlet, and a second outlet; an inner cylindrical vessel, at least part of which extends along the axis inside the first cylindrical vessel without contacting with the inner surface of the outer cylindrical vessel; and a magnet, rendering the bottom of the inner cylindrical vessel magnetism during the first period and making the part of the surface lose its magnetism during a second period. When the solid-liquid mixture flows through the magnetic surface of the inner cylindrical vessel in the passage, the magnetic solids are absorbed and separated from the mixture.

Abstract: A method for refining an organic composition containing 4-aminodiphenylamine, aniline, azobenzene, and phenazine, having the steps of feeding the organic composition to a first rectification column, producing a first effluent composition containing aniline, azobenzene, phenazine, and a small amount of 4-aminodiphenylamine at the top of the first rectification column and a second effluent composition containing crude 4-aminodiphenylamine at the bottom of the first rectification column, feeding the second effluent composition to a second rectification column, and producing a 4-aminodiphenylamine composition at the top of the second rectification column and a residual composition at the bottom of the second rectification column.