Effect of Re promoter on the structure and catalytic performance of Ni–Re/Al₂O₃ catalysts for the reductive amination of monoethanolamine

Abstract

Re promoters improve the catalyst performance and stability of Ni–Re/Al2O3 catalysts for the reductive amination of monoethanolamine.

Promotional Effects of Transition Metal Modification over Al2O3 for CH3SH Catalytic Oxidation

“…Figure shown XRD patterns of the pure Al 2 O 3 and metal‐modified Al 2 O 3 . Three diffraction peaks (2 θ =37.4, 45.8, 66.4), which should be indexed to (331), (400), (440) lattice planes of Al 2 O 3 were observed (PDF 88–1609). Furthermore, other additional peaks corresponding to CuO, FeO, CoO, CeO 2 and MnO oxides were observed in the metal‐modified Al 2 O 3 .The representative main peaks of the CeO 2 appear at 2 θ =28.6, 33.2, 47.8, 56.7, 59.5, 76.8, 79.0, 88.8, which should be indexed to (111), (200), (220), (311), (222), (331), (420), (422) lattice planes of cubic fluorite structured CeO 2 , and typical positions for all peaks matched the reference.…”

Effects of Ni particle size on amination of monoethanolamine over Ni-Re/SiO2 catalysts

“…S1, the activity of monometallic Ni/SiO2 decreased rapidly in the initial reaction stage. According to previous studies, the deactivation of Ni/SiO2 catalysts is due to the sintering of metallic Ni particles under H2 and NH3 atmospheres at high pressure [21,52,53]. Therefore, the Re promoter was introduced in the Ni/SiO2 catalyst system in order to maintain the stability of the Ni particle size.…”

“…As shown in Fig. 2, the monometallic Re/SiO2 sample displayed a broad H2 consumption peak in the range of 330-420 °C, corresponding to the reduction process of ReOx with different oxidation states [21,23]. The Ni/SiO2 sample showed two reduction peaks: (I) a broad peak around 412 °C ascribed to the reduction of bulk NiO particles weakly interacting with SiO2, and (II) a small peak at 510 °C that was attributed to highly dispersed Ni 2+ species that were difficult to reduce [24][25][26][27].…”

“…The catalytic performance of the Ni-Re/SiO2 catalysts for MEA amination was evaluated in a trickle-bed reactor. As described previously [21,22], about 3.6 ml (1.9 g) of oxide state catalysts were placed in the center of a stainless steel reaction tube, and the residual space was filled with silica sand. Before reaction, the catalyst was reduced in situ.…”

“…9, while the curve-fitting data are listed in Table 5. The peaks around 860 and 879 eV were ascribed to the shake-up satellite peaks of Ni 2+ 2p3/2 and Ni 2+ 2p1/2, respectively [21,49]. It can be observed that the Ni 0 2p3/2 peak shifts from 853.7 to 852.5 eV with an increase in size of Ni particles, probably due to the different atomic relaxation in large and small nanoparticles [50,51].…”