trans-Tetra­carbonyl­bis­[tris­(4-fluoro­phen­yl)phosphane-κP]chromium(0)

In the title compound, [Cr(C18H12F3P)2(CO)4], the Cr atom is octa­hedrally coordinated by four carbonyl ligands and the two tertiary phosphanes that are trans to each other. The Cr atom and two carbonyl groups are on a twofold axis. The benzene rings attached to the phospho­rus atom make dihedral angles of 80.32 (5), 52.91 (5) and 83.80 (5)° with each other. In the crystal, C—H⋯O and C—H⋯F inter­molecular inter­actions form an infinite three-dimensional network

Synthesis, structure determination and characterization of novel organometallic chromium hexacarbonyl derivatives via ligand (L) substitution /

The objective of the research study is to synthesize novel compounds through substitution process. The carbonyl ligand on chromium complexes is replaced by different tertiary phosphine ligands in order to produce a novel organometallic monocrystal compound. The crystal is characterized in terms of its structure, followed by the physical and chemical properties. Derivatives of Chromium Carbonyl are prepared by reaction with a number of tertiary phosphine ligands which have the potential to result in novel organometallic compounds. There are five attempt substitutions being done using Dicyclophenyiphosphene, Tris-(4fluorophenyl)phosphene, Tris-(3chlorophenyl)phosphine, Diphenylpentafluorophenyiphosphene and 1,2bis(dicyclohexylphosphino)ethane. From these, the substitution reaction using Tris-(4-fluorophenyl)phosphene resulted in the formation of a fine bright yellow crystal. From the monocrystal x-ray diffraction analysis, the resulting novel crystal structure is determined as Trans-bis[tris(4flourophenyl)phosphane]tetracarbonylchromium(0) with molecular formula C40H24CrF60 4P2. Infrared Spectroscopy ([R) and Nuclear Magnetic Resonance (NMIR) further compliment the X-ray diffraction results. For the novel structure, the Cr atom is octahedrally coordinated by four carbonyl ligands and two monodentate phosphorus ligands, which are bonded in a trans position to each other. The compound crystalizes in the monoclinic system, space group C2/c with an average Cr-P bond length of 2.3331 A and average Cr-CO bond length of 1.8808 A

Catalytic Steam Reforming of Toluene for Hydrogen Production over Nickel-Cobalt Supported Activated Carbon

Hydrogen may play a key role in future sustainable energy system as a carrier of renewable energy to replace the conventional fossil fuel. Biomass gasification is the most promising method in renewable hydrogen production technologies. However, the tar by-product poses great obstacle in the realization of commercial biomass gasification. In this work, the performance of Ni and/or Co supported on modified-palm kernel shell-derived activated carbon (AC) catalyst in steam reforming of toluene (SRT) for the production of hydrogen has been investigated. Toluene has been chosen as a model compound since it represents one of the major tar compositions. The effects of nitric acid in the surface pretreatment of AC (ACN) and the influence of Ni and/or Co loading on the catalyst support are studied. The catalysts are characterized using FTIR, BET, XRD, TGA and FESEM-EDX. The modified-AC support shows that the surface area, microporous structure and surface oxygenated functional group (SOFG) increase, leading to a homogeneous distribution of metal particles. The highest toluene conversion (Xtoluene) and hydrogen yield (YH2) obtained over 10%Ni-10%Co/ACN are 70% and 69%, respectively. The catalytic performance of bimetallic Ni–Co/ACN catalyst is more significant compared to monometallic Ni- and Co-supported catalysts. The highest catalytic performance achieved can be attributed to the larger surface area and unique porous structure of the modified-AC support as well as the formation of Ni–Co solid solution alloys that improve its coke-resistant capability with low carbon formation during SRT. The modified palm kernel shell AC-supported bimetal catalyst has high potential as a biomass-based catalyst for the applications in biomass tar removal toward hydrogen production due to its good coke-resistance properties

Optimization of hydrogen production via toluene steam reforming over Ni–Co supported modified-activated carbon using ANN coupled GA and RSM

Hydrogen (H2) is a clean fuel that can be produced from various resources including biomass. Optimization of H2 production from catalytic steam reforming of toluene using response surface methodology (RSM) and artificial neural network coupled genetic algorithm (ANN-GA) models has been investigated. In RSM model, the central composite design (CCD) is employed in the experimental design. The CCD conditions are temperature (500–900 °C), feed flow rate (0.006–0.034 ml/min), catalyst weight (0.1–0.5 g) and steam-to-carbon molar ratio (1–9). ANN model employs a three-layered feed-forward backpropagation neural network in conjugation with the tangent sigmoid (tansig) and linear (purelin) as the transfer functions and Levenberg-Marquardt training algorithm. Best network structure of 4-14-1 is developed and utilized in the GA optimization for determining the optimum conditions. An optimum H2 yield of 92.6% and 81.4% with 1.19% and 6.02% prediction error are obtained from ANN-GA and RSM models, respectively. The predictive capabilities of the two models are evaluated by statistical parameters, including the coefficient of determination (R2) and root mean square error (RMSE). Higher R2 and lower RSME values are reported for ANN-GA model (R2 = 0.95, RMSE = 4.09) demonstrating the superiority of ANN-GA in determining the nonlinear behavior compared to RSM model (R2 = 0.87, RMSE = 6.92). These results infer that ANN-GA is a more reliable and robust predictive steam reforming modelling tool for H2 production optimization compared to RSM model