Herein we reported a method for copper pivalate mediated, directed functionalization of ortho C−H bonds in (2-methylthio)aniline benzamides. Diaryl disulfides were used for thiolation, while successful phenoxylation was obtained with phenol as the coupling agent. Our report marks a rare example for flexible transformation of benzamide C(sp 2 )−H bonds into the corresponding unsymmetrical diaryl ethers and thioethers.
Pt/HSSZ-13 with 0.5–3 wt % Pt load and PtCu/HSSZ-13 with 1–7 wt % Cu load were prepared by the initial wetness impregnation method. Without compromising the original crystal structure and surface texture characteristics, doped Pt and Cu are dispersed uniformly throughout the surface. The Si/Al molar ratio affected not only the texture of the crystal but also the number of acid sites on the catalyst surface. The appropriate addition of Cu significantly increased the dispersion of Pt. The addition of Cu also provided electrons to Pt, affected the electron cloud density on the surface of Pt, and then reduced the adsorption of propylene and improved the selectivity of propylene. Cu can also decrease the number of acidic sites on the catalyst surface, thus slowing the deactivation rate of the catalyst and the amount of carbon deposition during the reaction. 1.0Pt3.0Cu/HSSZ-13(40) had a small number of strong acid sites (3.89 μmol/g) and showed the best propane initial conversion (73.95%), excellent propylene selectivity (97.60%), lowest deactivation constant (0.33 h–1), and good regeneration robustness.
Rui Zou,Chenyang Shen,Kaihang Sun,Xinbin Ma,Zhuoshi Li,Maoshuai Li,Chang-Jun Liu
The metal promoted In 2 O 3 catalysts for CO 2 hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity. However, there was still no experimental confirmation if copper could be a good promoter for In 2 O 3 . Herein, the Cu promoted In 2 O 3 catalyst was prepared using a deposition-precipitation method. Such prepared Cu/In 2 O 3 catalyst shows significantly higher CO 2 conversion and space time yield (STY) of methanol, compared to the un-promoted In 2 O 3 catalyst. The loading of Cu facilitates the activation of both H 2 and CO 2 with the interface between the Cu cluster and defective In 2 O 3 as the active site. The Cu/In 2 O 3 catalyst takes the CO hydrogenation pathway for methanol synthesis from CO 2 hydrogenation. It exhibits a unique size effect on the CO adsorption. At temperatures below 250 °C, CO adsorption on Cu/In 2 O 3 is stronger than that on In 2 O 3 , causing higher methanol selectivity. With increasing temperatures, the Cu catalyst aggregates, which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity. Compared with other metal promoted In 2 O 3 catalysts, it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.
Direct conversion of syngas into aromatics (STA) on the tandem catalyst containing Fischer-Tropsch (F-T) synthesis catalysts and acid zeolites, especially Fe-based catalysts and ZSM-5, has been attracting significant attention due to the higher cost efficiency. Even though promoters have frequently been added into the Fe-based part to improve the performance of STA reaction, its motivating mechanism is still unclear in the tandem catalyst system. Herein, the influence of the Cu promoter was evaluated for the catalytic activity of Fe-based/zeolite tandem catalysts in the STA process. Moreover, the working mechanism of the Cu promoter had been systematically investigated by adding different copper amounts and deliberately designed experiments. It was demonstrated that the addition of copper could improve aromatic selectivity because the Cu promoter could facilitate CO to participate in the conversion of olefins into aromatics over the tandem catalyst. In addition, the Cu promoter doped into the Fe-based catalyst drastically suppressed methane formation and enhanced the stability of the catalyst in the STA reaction. These findings provide insights into the effect of the Cu promoter on producing aromatics from syngas over the Fe-based/zeolite tandem catalyst system.
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