The Partial Hydrogenation of 1,3‐Dienes Catalysed by Soluble Transition‐Metal Nanoparticles

Abstract

ChemCatChem 2014, 6, 702 -710 702 CHEMCATCHEM MINIREVIEWS Scheme 1. Full and partial hydrogenation products formed from 1,3-butadiene, 1,3-cyclohexadiene, 1,3-cyclooctadiene and cyclopentadiene.Scheme 2. Single-site mechanism of full and partial hydrogenation of 1,3-cyclohexadiene catalysed by a single atom. Adapted from Ref. [13].Scheme 3. Multi-site mechanism of full and partial hydrogenation of 1,3-cyclohexadiene catalysed by an ensemble of surface atoms.

Tuning the hydrogen donor/acceptor behavior of ionic liquids in Pd-catalyzed multi-step reactions

“…As it is shown in Table 3, the presence of L on nanoparticles inhibited the trans-4-phenyl-3-buten-2-one I reduction; therefore it was necessary to increase the temperature and also the H 2 pressure to improve the activity. The reaction proceeded in a heterogeneous fashion at moderately harsh conditions (Table 3, entries 1 and 2; black solutions were observed during all the reaction time) meanwhile, at 80°C and 40 bar of H 2 pressure, orange colored resulting solutions suggested the formation of molecular systems which are favored by the ligand presence and high temperature ( Table 3, entries [3][4][5]. TEM studies of the orange solution revealed the absence of nanoparticles.…”

“…PdNPL (L = 1-3) were prepared from decomposition of [Pd 2 (dba) 3 In all cases, the obtained black solutions were analyzed by TEM ( Fig. 1) and EDX (see Appendix A).…”

“…One of the main applications of metal nanoparticles (MNP) relies on their ability to achieve homo-or heterogenous catalytic transformations [1][2][3][4]. The modulation of size, shape and catalytic performance of MNP is one of the main challenges in this area [5][6][7][8]; nevertheless, the surface-like reactivity of the MNP with organic molecules cannot be ruled out, since it has been found that PdNP activate C-S and C-P bonds' cleavage [9].…”

Arene Hydrogenation by Metal Nanoparticles in Ionic Liquids

“…The catalytic activity of both SCILL and SILP catalysts in the hydrogenation of benzene was mainly investigated by Ru‐, Rh‐ and Pt‐based catalysts (Table entries 9, 10, 11, 13, 15, 21, 26, 27, and 28) and is apparently dependent on the size of metal NPs as well as on the hydrophobicity of the IL, although the available data are limited ,,,,. For example, Ru NPs are mainly generated in situ from organometallic precursors in water soluble ILs such as BMIm.BF 4 (entries 10, 11 and 13, Table ) and TMG.TFA (entry 26, Table ).…”

“…This could also be evidence of the effect of the solvent used to ‘‘extract’’ the cycloalkene during the reaction, since benzene is, in most cases, at least four times more soluble than its partially hydrogenated product. Nevertheless, the IL may also behave as a ligand on the metal surface, as observed for reactions in which a simple thin layer of the IL is thought to be responsible for selectivity control ,, , . Although the full hydrogenation of arenes is no challenge and a large‐scale industrial process, classical Ru and Ni NPs in ILs are strong candidates for the partial hydrogenation of benzene to cyclohexene at an industrial scale ,…”