N‐Methylation of N‐Methylaniline with Carbon Dioxide and Molecular Hydrogen over a Heterogeneous Non‐Noble Metal Cu/TiO2 Catalyst. Issue 16 (20th May 2019)

• Record Type: Journal Article
• Authors: Liu, Ke; Zhao, Zhenbo; Lin, Weiwei; Liu, Qiang; Wu, Qifan; Shi, Ruhui; Zhang, Chao; Cheng, Haiyang; Arai, Masahiko; Zhao, Fengyu
• Is Part Of: ChemCatChem. Volume 11:Issue 16(2019)
• Page Start: 3919
• Page End: 3926
• Publication Date: 2019-05-20
• Subjects: N-Methylation -- N-methylaniline -- CO2 -- Copper -- Heterogeneous catalysis; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201900582
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: A non‐noble heterogeneous catalyst of Cu/TiO2 was prepared for N ‐methylation of N ‐methylaniline (MA) with CO2 and H2 . 5 wt.–% Cu loaded TiO2 (P25) catalyst exhibited a high performance, with 82 % MA conversion and 98 % N, N ‐dimethylaniline (DMA) selectivity under the reaction conditions used (4 MPa H2, 2 MPa CO2, 180 °C, 36 h). The Cu/TiO2 catalyst was more effective with respective to the total conversion and the DMA selectivity as compared to 5 wt.–% Cu loaded catalysts on CeO2, ZnO and activated carbon materials. The possible active species of Cu/TiO2 catalyst should be both Cu + and Cu 0 which contributed to the high activity as the reaction conversion increased linearly with them exposed on the surface of catalyst. Moreover, the reaction pathways involved were studied; it was likely that the reaction took place via an intermediate of formaldehyde that was formed from CO2 and H2, as confirmed by in situ diffuse reflectance Fourier‐transform infrared spectroscopy, then it reacted with MA to give N ‐methylformanilide (MFA), and finally MFA was hydrogenated to DMA. Abstract : Another drop of copper : A non‐noble metal catalyst of Cu/TiO2 is effective for the heterogeneous N ‐methylation of N ‐methylaniline with CO2 and H2, in which CHO* is formed as methyl reagent, and it reacts with N ‐methylaniline to produce intermediate N ‐methylformanilide followed by its hydrogenation to N, N ‐dimethylaniline.