Facile Synthesis of Effcient and Selective Ruthenium Olefin Metathesis Catalysts with Sulfonate and Phosphate Ligands

A series of novel, air-stable ruthenium NHC catalysts with sulfonate and phosphate anions have been prepared easily in one pot at high yields using commercially available precursors. The catalysts were found to be effective for ring-opening metathesis polymerization, ring-closing metathesis, and cross-metathesis. The catalysts showed higher cis-selectivity in olefin cross-metathesis reactions as compared to earlier known ruthenium-based olefin metathesis catalysts, with allylbenzene and cis-1,4-diacetoxybutene as substrates

Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts

Even though platinum is known as an active electro-catalyst for ethanol oxidation at low temperatures (< 100 oC), choosing the electrode material for ethanol electro-oxidation is a crucial issue. It is due to its property which easily poisoned by a strong adsorbed species such as CO. PtSn-based electro-catalysts have been identified as better catalysts for ethanol electro-oxidation. The third material is supposed to improved binary catalysts performance. This work presents a study of the ethanol electro-oxidation on carbon supported Pt-Sn and Pt-Sn-Ni catalysts. These catalysts were prepared by alcohol reduction. Nano-particles with diameters between 2.5-5.0 nm were obtained. The peak of (220) crystalline face centred cubic (fcc) Pt phase for PtSn and PtSnNi alloys was repositioned due to the presence of Sn and/or Ni in the alloy. Furthermore, the modification of Pt with Sn and SnNi improved ethanol and CO electro-oxidation. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 1st February 2016; Accepted: 1st February 2016 How to Cite: Hidayati, N., Scott, K. (2016). Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1): 10-20. (doi:10.9767/bcrec.11.1.394.10-20) Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.394.10-2

Electrochemical Reduction of CO2 using Cu-Pd clusters on Graphene

In this study, five copper-palladium clusters supported on defective graphene were investigated as catalysts for the electrochemical reduction of CO2 using the first-principles approach and the computational hydrogen electrode model. The limiting potential to reduce CO2 to CH4 using five different copper-palladium catalysts was determined. Of all the catalysts studied, the best one was the Cu2Pd cluster. This cluster showed the lowest necessary overpotential (0.93 V) out of all the catalysts examined to produce CH4. Reaction pathways to produce a variety of C1 products CO, HCOOH, HCHO, CH3OH and CH4 was studied in detail for Cu2Pd. From the pathways, it was determined that it will likely produce CH4 and HCOOH

Hydrogen production by methanol steam reforming on NiSn/MgO-Al 2O3 catalysts: The role of MgO addition

The effect of the magnesia loading on the surface structure and catalytic properties of NiSn/MgO-Al2O3 catalysts for hydrogen production by methanol steam reforming has been investigated. The catalysts have been obtained by impregnation of γ-Al2O3 by the incipient wetness method, with variation of the MgO content. X-ray diffraction (XRD), BET surface area and H2-temperature programmed reduction (TPR) have been used to characterise the prepared catalysts. From this, it has been concluded that the incorporation of MgO results in the formation of MgAl 2O4 spinel, which modifies the acid-base properties of the catalysts. The formation of Ni-Sn alloys after the reductive pre-treatment has also been evidenced. The influence of the temperature of reaction and of the MgO loading on the hydrogen production by reforming of methanol has been established. Moreover, tests of catalytic stability have been carried out for more than 20 h. The carbonaceous deposits have been examined by temperature-programmed oxidation (TPO). The analysis of the catalysts after reaction has confirmed the low level of carbon formation on these catalysts. In no case, carbon nanotubes have been detected on the solids.Junta de Andalucía TEP106Ministerio de Ciencia e Innovación ENE2009-14522-C05-0

Solvent effects on Grubbs’ pre-catalyst initiation rates

Initiation rates for Grubbs and Grubbs-Hoveyda second generation pre-catalysts have been measured accurately in a range of solvents. Solvatochromic fitting reveals different dependencies on key solvent parameters for the two pre-catalysts, consistent with different mechanisms by which the Grubbs and Grubbs-Hoveyda pre-catalysts initiate

Well-defined silica-supported olefin metathesis catalysts

Two triethoxysilyl-functionalized N-heterocyclic carbene ligands have been synthesized and used to prepare the corresponding second-generation ruthenium olefin metathesis catalysts. These complexes were then grafted onto silica gel, and the resulting materials were efficient heterogeneous catalysts for a number of metathesis reactions. The solid-supported catalysts were shown to be recyclable over a number of reaction cycles, and no detectable levels of ruthenium were observed in reaction filtrates (ruthenium concentration of filtrate <5 ppb)

Ti–Pd Alloys as Heterogeneous Catalysts for Hydrogen Autotransfer Reaction and Catalytic Improvement by Hydrogenation Effects

Ti−Pd alloys were investigated as heterogeneous catalysts for hydrogen autotransfer reactions. This is the first reported study of alloys as catalysts for hydrogen‐borrowing reactions using alcohols. We improved the catalytic activities of alloys by increasing their specific surface areas via a hydrogenation−powdering process. The reactivities and selectivities of hydrogenated Ti−Pd alloys [Ti−Pd (Hy) ] were higher than those of non‐hydrogenated alloy catalysts in N‐alkylation by hydrogen autotransfer using alcohols. A plausible catalytic cycle is proposed based on control studies and deuterium labelling experiments