Supported palladium catalysts for the selective conversion of cis-2-butene-1,4-diol to 2-hydroxytetrahydrofuran: effect of metal particle size and support

Hydrodeoxygenation of 5-Hydroxymethylfurfural over Alumina-Supported Catalysts in Aqueous Medium

“…Cu/alumina catalyst presents two overlapping peaks at 217 and 241 °C. In the literature, the low temperature reduction peak is attributed to the reduction of highly dispersed amorphous CuO species and the high temperature peak to the reduction of highly dispersed bulk CuO. ,, The TPR profile of Pd/alumina catalyst shows a small negative peak at 71 °C, assigned to the decomposition of the β-Pd hydride phase. ,, No reduction peak of PdO is detected at the conditions of the TPR experiment because the reduction of these particles has been reported to be achieved at temperatures below 20 °C . Ni/alumina catalyst reduces between 400 and 900 °C.…”

Bimetallic Synergy Effects of Phyllosilicate‐Derived NiCu@SiO2 Catalysts for 1,4‐Butynediol Direct Hydrogenation to 1,4‐Butanediol

“…It can be seen from Figure 6d that acidity of the catalysts remarkably increases with Ni content increasing thanks to the MÀ OH structure variation between Niphy and Cuphy. In our hydrogenation system, these functional acid sites (e. g. surface electron-defect Lewis acid sites which can be proved by Py-IR as reflected in Figure S6) from the surrounding of active NiÀ Cu nanoparticles may act as association sites to attract the electron-rich CÀ OH group at the terminal of adsorbed BED intermediate, [27,[44][45] thus stabilizing the allyl alcohol existing form over the active NiÀ Cu sites and further promoting the selectivity to BDO. 100 and 250°C, corresponding to the desorption of NH 3 from the weak (α) and medium (β) acid sites, respectively.…”

“…For the NiÀ Cu bimetallic catalyst, the weak acid desorption peak shifted slightly toward a higher temperature with the increase of Ni content, indicating that the synergy of NiÀ Cu can cause an increase in the acid strength with the increase of Ni/Cu ratio. In our hydrogenation system, these functional acid sites (e. g. surface electron-defect Lewis acid sites which can be proved by Py-IR as reflected in Figure S6) from the surrounding of active NiÀ Cu nanoparticles may act as association sites to attract the electron-rich CÀ OH group at the terminal of adsorbed BED intermediate, [27,[44][45] thus stabilizing the allyl alcohol existing form over the active NiÀ Cu sites and further promoting the selectivity to BDO.…”

Nanocatalysts for Rearrangement Reactions

“…However, these systems were not selective for the desired cycloisomerization reaction, as they gave as well hydrogenation, hydrogenolysis, and cis-to-trans-isomerization by-products. [95][96][97] The aforementioned Au-NPs stabilized by PVP were also active in the intramolecular hydroamination of alkenes under aerobic conditions, thus leading to a new atomeconomical route to five-membered nitrogen-containing heterocycles. 98 unactivated alkene unit to afford the pyrrolidine derivatives 20 selectively using 5 mol% of the Au/PVP catalyst and excess of Cs 2 CO 3 (Scheme 8.14).…”