New environmentally friendly catalysts containing Pd–interstitial carbon made from Pd–glucose precursors for ultraselective hydrogenations in the liquid phase

Abstract

We report a novel preparation of a Pd nanocatalyst modified with subsurface C via blending a glucose precursor at the molecular level: the catalyst is demonstrated for the first time to be stereoselective in the hydrogenation of alkynes to cis-alkenes in the liquid phase.

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

“…It is interesting that virtually no over-hydrogenation products were observed for Pd-int B/C as no hexanol (HAL) was detected. The selectivity towards CHEL and cis/trans ratio are apparently higher than that of Pd-int C catalysts we reported earlier (91.9% CHEL, cis/trans ratio of 10.8) under the comparable conditions 9,10 suggesting that int B is more effective than int C in subsurface modification of Pd for this reaction. On the other hand, both 3% Pd/C and surface poisoned Lindlar catalyst suffered from the significant over-hydrogenation to HAL as well as a rapid isomerization to trans-hexen-1-ol.…”

“…The changes in lattice parameter and charge transfer between the host-guest may also alter the band structure, hence catalytic properties of the supported Pd metal [5][6][7][8][9][10] . It is therefore interesting to develop new Pd nanocatalysts modified with interstitial atoms as a greener alternative to Lindlar catalysts for selective hydrogenation reactions.…”

A non-syn-gas catalytic route to methanol production

“…Hydrogen temperature-programmed reduction (TPR) in Fig. 4a Figure 4b clearly shows the absence of typical hydrogen evolution peak of β-Pd hydride 15 (pure Pd particles should readily take up hydrogen to form hydride at room temperature) as compared with alumina-supported Pd at around 70 °C (negative peak) in the second TPR profile of the same Pd/'Fe 2 O 3 ' sample without exposure to air, the fact is again consistent with the formation of highly-dispersive PdFe clusters in the sample.…”

Chemicals from Alkynes with Palladium Catalysts

“…Furthermore, PdNPs modified with subsurface carbon via blending a glucose precursor, have been used as catalyst in the liquid-phase hydrogenation of 3-hexyn-1-ol under hydrogen (3 bar) in isopropanol at 30 ºC, achieving 92% selectivity towards the corresponding alkene in a 10.8 Z/E ratio. 195 Interestingly, the use of commercial 5% Pd/C as catalyst under these conditions gave no selectivity at all towards the alkene.…”