Analysis of Dibenzyltoluene Mixtures: From Fast Analysis to In-Depth Characterization of the Compounds

The so-called dibenzyltoluene (H0-DBT) heat transfer oil contains numerous isomers of dibenzyltoluene as well as (benzyl)benzyltoluene (methyl group on the central vs. the side aromatic ring). As it is used as a liquid organic hydrogen carrier (LOHC), a detailed analysis of its composition is crucial in assessing the kinetic rate of hydrogenation for each constituent and studying the mechanism of H0-DBT hydrogenation. To identify all of the compounds in the oil, an in-depth analysis of the GC-MS spectra was performed. To confirm peak attribution, we synthesized some DBTs and characterized the pure compounds using NMR and Raman spectroscopies. Moreover, a fast-GC analysis was developed to rapidly determine the degree of hydrogenation of the mixture.

Easy preparation of small crystalline Pd2Sn nanoparticles in solution at room temperature

We describe here a simple protocol yielding small (<2 nm) crystalline Pd₂Sn nanoparticles (NPs) along with Pd homologues for sake of comparison. These NPs were obtained via an organometallic approach using Pd₂(dba)₃·dba (dba = dibenzylideneacetone) in THF with 2 equivalents of tributyltin hydride under 4 bars of H₂ at room temperature. The Pd NP homologues were prepared similarly, using Pd₂(dba)₃·dba with 2 equivalents of n-octylsilane. These NPs were found to be crystalline and very small with a similar mean size (ca. 1.5 nm). These NPs were finally used as nanocatalysts in solution for a benchmark Suzuki-Miyaura cross-coupling reaction. The Pd₂Sn NPs were found to be more active than Pd NPs analogues, exhibiting remarkable performances with Pd loading as low as 13 ppb. This result demonstrates a beneficial effect of tin on palladium in catalysis.

Alkene hydrosilylation with supported and unsupported Ni nanoparticles: strong influence of the Ni environment on activity and selectivity

Isolated nickel nanoparticles in suspension or supported on silica are efficient catalysts for inactivated alkene hydrosilylation.

A Solid Iridium Catalyst for Diastereoselective Hydrogenation

An Ir(NHC) supported catalyst is used in the selective hydrogenation of terpinen-4-ol to cis p-menthan-4-ol. Its activity, selectivity and stability are compared to those of a homogeneous homologue [IrCl(COD)MesImPr] and to a commercial Pd/C. The solid Ir catalyst is much more selective than the Pd catalyst (92 vs. 42 % at 80 °C) but also more active, more selective and more stable than the iridium complex in solution. For the first time, a supported catalyst shows an enhanced activity with respect to a complex in a diastereoselective hydrogenation reaction.

Pt nanoparticles immobilized in mesostructured silica: a non-leaching catalyst for 1-octene hydrosilylation

A catalyst containing platinum nanoparticles embedded into the walls of a mesostructured silica framework is highly active in alkene hydrosilylation and does not lead to Pt leaching.

Platinum nanoparticles in suspension are as efficient as Karstedt's complex for alkene hydrosilylation

1–2 nm Pt nanoparticles and Karstedt's catalyst were used in the hydrosilylation of 1-octene with a polymethylhydrosiloxane and showed a very similar behaviour (the same TONs and the same selectivity towards 1-octene isomerization). This further assesses that Karstedt's catalyst is not truly homogeneous, but rather colloidal, during catalysis at high TONs.

Gas–liquid and gas–liquid–solid catalysis in a mesh microreactor

A microstructured mesh contactor that can offer residence time of more than minutes is used for gas-liquid-solid hydrogenations and gas-liquid asymmetric hydrogenations. Applications for catalyst/chiral inductor screening and for kinetic data acquisition are demonstrated.