Method for pretreating and using copper-based catalyst
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.
1. A method for pretreating a copper-based catalyst comprising
dehydrating a copper-based catalyst at an elevated temperature,
reducing the dehydrated copper-based catalyst with hydrogen to obtain an activated copper-based catalyst, and
passivating the activated copper-based catalyst to obtain a catalyst suitable for N-alkylation by reacting with a sulfur- or halogen-containing compound,
wherein the copper-based catalyst comprises about 10% to 70% copper oxide; and
concentration of the sulfur- or halogen-containing compound is about 1000 PPM to 10000 PPM for passivation; and
the sulfur- or halogen-containing compound is selected from the group consisting of carbon disulfide, chlorophenylamine, 2-mercaptobenzothiazole, thiophene, 2,4-dichloroaniline, and tetramethyl thiuram disulfide.
2. The method of claim 1 , wherein the copper-based catalyst further comprises a carrier that is ZnO, Al 2 O 3 , SiO 2 , activated carbon, glass fiber net, ceramic ball, layered graphite, natural clay, cerium oxide, or a mixture thereof, and the carrier does not change its contents after the catalyst being pretreated.
3. The method of claim 1 , wherein the copper-based catalyst is dehydrated at the elevated temperature of more than about 100° C. and under pressure of an inert gas at about 1 MPa to 5 MPa.
4. The method of claim 1 , wherein the temperature is elevated at about 5° C. to 10° C. per hour during dehydration.
5. The method of claim 1 , wherein the dehydrated copper-based catalyst is reduced with hydrogen in a liquid phase or a gas phase.
6. The method of claim 1 , wherein the dehydrated copper-based catalyst is reduced at a temperature of about 110° C. to 280° C. and the hydrogen gas is fed at a volume concentration of about 0.1% to 100%.
7. The method of claim 1 , wherein the temperature for reduction is elevated at about 1° C. to 15° C. per hour.
8. The method of claim 1 , wherein the copper-based catalyst is dehydrated and reduced simultaneously.
9. The method of claim 1 , wherein a ratio of the sulfur- or halogen-containing compound to the copper-based catalyst is about 0.05-1 mole per kilogram catalyst.
10. The method of claim 1 , wherein the copper-based catalyst is passivated in a gas phase, and the sulfur- or halogen-containing compound is fed to the reaction with a carrier.
11. The method of claim 1 , wherein the copper-based catalyst is passivated in a solution, and the sulfur- or halogen-containing compound is dissolved in an alcohol, ketone, or an amine solvent to form the solution for passivating the catalyst.
12. The copper-based catalyst pretreated by the method of claim 1 .
13. The method for making alkylated derivatives of 4-aminodiphenylamine according to claim 1 , comprising
reacting 4-aminodiphenylamine with a ketone in presence of hydrogen and the copper-based catalyst pretreated by the method of claim 1 .
14. The method of claim 13 , wherein the reaction is conducted at a temperature of about 110° C. to 240° C. under a hydrogen pressure of about 2 MPa to 8 MPa.
15. The method of claim 13 , wherein the reaction is conducted continuously, and a total feed amount of 4-aminodiphenylamine and ketone is about 10 to 25% by weight per hour of the weight of the catalyst.