TY - JOUR

T1 - One-Pot Synthesis of Secondary Amines from Nitroarenes and Aldehydes on Supported Copper Catalysts in a Flow Reactor

T2 - The Effect of the Support

AU - Artyukha, E. A.

AU - Nuzhdin, A. L.

AU - Bukhtiyarova, G. A.

AU - Derevyannikova, E. A.

AU - Gerasimov, E. Yu

AU - Gladkii, A. Yu

AU - Bukhtiyarov, V. I.

N1 - Publisher Copyright: © 2018, Pleiades Publishing, Ltd.

PY - 2018/9/1

Y1 - 2018/9/1

N2 - The effect of the support on the properties of copper catalysts supported on γ-Al2O3, SiO2, and TiO2–SiO2 with a ~5 wt % Cu content was studied in the one-pot synthesis of N-heptyl-p-toluidine from p-nitrotoluene and n-heptanal. The catalysts were characterized by elemental analysis, X-ray diffraction analysis, transmission electron microscopy, temperature-programmed reduction, and low-temperature nitrogen adsorption. The reaction was carried out in a flow reactor with the use of molecular hydrogen as a reducing agent. It was established that the nature of the support exerts a profound effect on the yield of the target secondary amine; in this case, 5%Cu/Al2O3 was found the most active catalyst. A combination of high catalyst activity in the hydrogenation of a nitro group to an amino group with the presence of acid sites, which facilitate imine formation as a result of the interaction of n-heptanal with p-toluidine, on the catalyst surface is necessary for reaching the greatest yield of N-heptyl-p-toluidine. The study of reaction mechanism on the 5%Cu/Al2O3 catalyst showed that p-nitrotoluene inhibits the hydrogenation of n-heptanal, and aldehyde hydrogenation into alcohol begins only after the conversion of the major portion of p-nitrotoluene as a result of the selective adsorption of the nitroarene under the conditions of the simultaneous presence of p-nitrotoluene and n-heptanal in the reaction mixture.

AB - The effect of the support on the properties of copper catalysts supported on γ-Al2O3, SiO2, and TiO2–SiO2 with a ~5 wt % Cu content was studied in the one-pot synthesis of N-heptyl-p-toluidine from p-nitrotoluene and n-heptanal. The catalysts were characterized by elemental analysis, X-ray diffraction analysis, transmission electron microscopy, temperature-programmed reduction, and low-temperature nitrogen adsorption. The reaction was carried out in a flow reactor with the use of molecular hydrogen as a reducing agent. It was established that the nature of the support exerts a profound effect on the yield of the target secondary amine; in this case, 5%Cu/Al2O3 was found the most active catalyst. A combination of high catalyst activity in the hydrogenation of a nitro group to an amino group with the presence of acid sites, which facilitate imine formation as a result of the interaction of n-heptanal with p-toluidine, on the catalyst surface is necessary for reaching the greatest yield of N-heptyl-p-toluidine. The study of reaction mechanism on the 5%Cu/Al2O3 catalyst showed that p-nitrotoluene inhibits the hydrogenation of n-heptanal, and aldehyde hydrogenation into alcohol begins only after the conversion of the major portion of p-nitrotoluene as a result of the selective adsorption of the nitroarene under the conditions of the simultaneous presence of p-nitrotoluene and n-heptanal in the reaction mixture.

KW - aldehydes

KW - flow reactor

KW - molecular hydrogen

KW - nitroarenes

KW - one-stage synthesis

KW - secondary amines

KW - support effect

KW - supported copper catalysts

KW - HYDROGENATION

KW - CARBONYL-COMPOUNDS

KW - SELECTIVE REDUCTIVE AMINATION

KW - AROMATIC-AMINES

KW - NANOPARTICLES

KW - MILD CONDITIONS

KW - RECOVERABLE CATALYST

KW - SUBSTITUTED NITROAROMATICS

KW - METAL

KW - AU/AL2O3 CATALYST

UR - http://www.scopus.com/inward/record.url?scp=85053897737&partnerID=8YFLogxK

U2 - 10.1134/S0023158418050014

DO - 10.1134/S0023158418050014

M3 - Article

AN - SCOPUS:85053897737

VL - 59

SP - 593

EP - 600

JO - Kinetics and Catalysis

JF - Kinetics and Catalysis

SN - 0023-1584

IS - 5

ER -