Fischer-Tropsch synthesis over unpromoted Co/ɣ-Al2O3 catalyst: effect of activation with CO compared to H2 on catalyst performance

Abstract : The effect of activating Co/Al2O3 catalyst by diluted CO or H2 on catalyst performance for Fischer-Tropsch reaction was investigated. The catalyst was prepared by incipient wetness impregnation of the support and characterized using BET N2 physisorption, SEM and XRD analyses. The reduction behavior of the catalyst in presence of CO and H2 individually was evaluated using TPR analyses. The data reveal that CO activates Co/Al2O3 catalyst at a lower temperature than H2 and produces a catalyst with higher rate for liquid product formation. It also leads to higher methane selectivity probably due to some cobalt carbide formation

trans-Dichloridobis[dicyclo­hex­yl(phen­yl)phosphane-κP]palladium(II)

The title compound, [PdCl2{P(C6H11)2(C6H5)}2], forms a monomeric complex with a trans-square-planar geometry. The Pd—P bond lengths are 2.3343 (5) Å, as the Pd atom lies on an inversion centre, while the Pd—Cl bond lengths are 2.3017 (4) Å. The observed structure was found to be closely related to [PdCl2{P(C6H11)3}2] [Grushin et al. (1994 ▶). Inorg. Chem. 33, 4804–4806], [PdBr2{P(C6H11)3}2] [Clarke et al. (2003 ▶). Dalton Trans. pp. 4393–4394] and [PdCl2P(C6H11)2(C7H7)}2] [Vuoti et al. (2008 ▶). Eur. J. Inorg. Chem. pp. 397–407] (C6H11 is cyclo­hexyl and C7H7 is o-tol­yl). One of the cyclo­hexyl rings is disordered with the phenyl ring in a 0.587 (9):413 (9) ratio. Five long-range C—H⋯Cl inter­actions were observed within the structure

CO2 hydrogenation to liquid hydrocarbons via modified Fi scher Tropsch over alumina supported cobalt catalyst s : effect of operating temperature, pressure and potassium loading

Abstract: The effect of promoting 15%Co/Al2O3 catalyst with potassium on CO2 hydrogenation to longer-chain hydrocarbons was investigated. The catalysts used in this study were synthesized using an incipient wetness impregnation of the support with nitrate solutions. All catalysts were supported on γ-alumina and promoted with potassium (0 – 8%). The synthesized catalysts were characterized by XRD, BET, XPS, TPR and CO2-TPD analyses. The catalysts were evaluated for CO2 hydrogenation using a fixed-bed tube reactor. The CO2 conversion was found to increase with both the reaction temperature and pressure. The TPR data revealed that potassium limited the reduction of the catalyst, decreased the selectivity to methane and increased the selectivity to C2+ hydrocarbons. The maximum C2+ yield of 10.2%, with CO2 conversion of 42.3%, was obtained when 6 wt.% of potassium was added to the catalyst. It is believed that during the CO2 hydrogenation process over the catalysts that were promoted with potassium, CO2 is first converted to CO via reverse–water–gas–shift reaction, followed by subsequent hydrogenation of CO to hydrocarbons

Synthesis, crystal structure and hydroformylation activity of triphenylphosphite modified cobalt catalysts

The dinuclear complex [Co2(CO)6{P(OPh)3}2] (2) has been synthesised and was fully characterised. The solid state structure revealed a trans diaxial geometry, no bridging carbonyls, and Co–Co and Co–P bond lengths of 2.6722(4) and 2.1224(4) Å, respectively. Catalysed hydroformylation of 1-pentene with 2 was attempted at temperatures in the range 120 to 210 °C and pressures between 34 and 80 bar. High pressure spectroscopy (HP-IR and HP-NMR) was used to detect hydride intermediates. High pressure infrared (HP-IR) studies revealed the formation of [HCo(CO)3P(OPh)3] (4) at ca. 110 °C, but at higher temperatures absorption bands corresponding to [HCo(CO)4] (3) were observed. The hydride intermediate 4 has also been synthesised and characterised. Upon increased ligand concentration, HP-IR studies showed the formation of new carbonyl absorption bands due to a higher substituted cobalt carbonyl complex-[HCo(CO)2{P(OPh)3}2] (5), which is believed to be catalytically less active. Complex 5 has been synthesised independently and was fully characterised. A low temperature crystal structural study of 5 revealed a trigonal bipyramidal structure with a trans H–Co–CO arrangement and two equatorial phosphite ligands, the Co–P bond lengths being 2.1093(8) and 2.1076(8) Å, respectively

Imaging of Brain Connectivity in Dementia: Clinical Implications for Diagnosis of its Underlying Diseases

In this thesis we investigated the use of advanced magnetic resonance imaging (MRI) techniques in identifying subtle brain abnormalities, associating brain abnormalities with disease symptomatology, and improving early (differential) diagnosis in several diseases underlying dementia. Presenile dementia (occurring before 65 years of age) is a neurodegenerative disorder affecting white matter (WM) and grey matter (GM) in different regions of the brain. The two most common underlying diseases are Alzheimer’s disease (AD) and frontotemporal dementia (FTD). FTD is the umbrella term for several types of dementia, such as behavioural variant FTD (bvFTD) and semantic dementia (SD). Additionally, phenocopy frontotemporal dementia (phFTD), a rare syndrome clinically similar to bvFTD, may also belong to this FTD spectrum. In early stages of these diseases, symptoms may still be mild or unspecific. Consequently, early-stage (differential) diagnosis can be difficult. MRI of the brain supports diagnosis, but may still appear normal or show unspecific brain abnormalities in early stages of dementia. More advanced MRI techniques may aid diagnosis by detecting subtle abnormalities that remain unrevealed using conventional (structural) MRI. Additionally, advanced MRI can be quantified, which allows for comparing patients to reference values of the healthy population, and allows for combining WM and GM measures to investigate relations between subtle WM and GM changes in dementia. In this thesis several advanced MRI techniques were explored, specifically diffusion tensor imaging (DTI), resting state functional MRI (rs-fMRI) and arterial spin labelling (ASL). DTI and rs-fMRI can be used to assess brain connectivity in terms of respectively WM microstructure and functional connectivity of resting state networks. Arterial spin labelling can be used to assess whole-brain or region-specific perfusion in GM. Additionally, advanced post-processing tools can be applied to conventional (structural) MRI, which may allow for identifying smaller GM volume changes. The main findings of this thesis allow for the conclusion that advanced MRI techniques identify subtle brain abnormalities in AD, bvFTD, SD and phFTD, that are not otherwise detected using conventional (structural) MR imaging. These subtle brain abnormalities aid to the understanding of brain processes in dementia, and especially DTI and ASL may aid clinical diagnosis and differentiation of the dementia subtypes

Triethyl­ammonium hexa-μ2-acetato-κ12 O:O′-diacetato-κ2 O-aqua-μ3-oxido-triferrate(III) toluene monosolvate

The title compound, (C6H16N)[Fe3(CH3CO2)8O(H2O)]·C7H8, was serendipitously crystallized from a reaction of disilanol with iron(II) acetate. The trinuclear acetatoferrate(III) anion has a triethyl­ammonium cation as the counterion. The three Fe atoms lie on the vertices of a regular triangle and are octa­hedrally coordinated. The complete coordination of the anion includes shared ligands among the three metal ions: a central tribridging O atom and six bidentate bridging acetyl groups. The six-coordinations of two of the metal ions are completed by a monodentate acetate ligand, whereas that of the third metal ion is completed by a water mol­ecule. The uncoordinated triethyl­ammonium cation is involved in N—H⋯O hydrogen bonding to a singly coordinated acetyl group. The coordinated aqua mol­ecule is involved in bifurcated O—H⋯O hydrogen bonding. C—H⋯O inter­actions are also observed. The toluene solvent molecule is disordered over two sets of sites in a 0.609 (11):0.391 (11) ratio

trans-Carbonylchloridobis[tris(4-chlorophenyl) phosphane]rhodium(I) acetone monosolvate

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Modular health services:A single case study approach to the applicability of modularity to residential mental healthcare

Background The Dutch mental healthcare sector has to decrease costs by reducing intramural capacity with one third by 2020 and treating more patients in outpatient care. This transition necessitates enabling patients to become as self-supporting as possible, by customising the residential care they receive to their needs for self-development. Theoretically, modularity might help mental healthcare institutions with this. Modularity entails the decomposition of a healthcare service in parts that can be mixed-and-matched in a variety of ways, and combined form a functional whole. It brings about easier and better configuration, increased transparency and more variety without increasing costs. Aim: this study aims to explore the applicability of the modularity concept to the residential care provided in Assisted Living Facilities (ALFs) of Dutch mental healthcare institutions. Methods A single case study is carried out at the centre for psychosis in Etten-Leur, part of the GGz Breburg IMPACT care group. The design enables in-depth analysis of a case in a specific context. This is considered appropriate since theory concerning healthcare modularity is in an early stage of development. The present study can be considered a pilot case. Data were gathered by means of interviews, observations and documentary analysis. Results At the centre for psychosis, the majority of the residential care can be decomposed in modules, which can be grouped in service bundles and sub-bundles; the service customisation process is sufficiently fit to apply modular thinking; and interfaces for most of the categories are present. Hence, the prerequisites for modular residential care offerings are already largely fulfilled. For not yet fulfilled aspects of these prerequisites, remedies are available. Conclusion The modularity concept seems applicable to the residential care offered by the ALF of the mental healthcare institution under study. For a successful implementation of modularity however, some steps should be taken by the ALF, such as developing a catalogue of modules and a method for the personnel to work with this catalogue in application of the modules. Whether implementation of modular residential care might facilitate the transition from intramural residential care to outpatient care should be the subject of future research. Keywords: Mental healthcare, Residential care, Modular healthcare, Service modularity, Healthcare modularity, Assisted living facilities, Chronic psychiatric patient

Bis(dicyclo­hexyl­phenyl­phosphine)silver(I) nitrate

The title compound, [Ag(C18H27P)2]NO3, is a mononuclear salt species in which the Ag atom is coordinated by two phosphine ligands, forming a cation, with the nitrate as the counter-anion, weakly inter­acting with the Ag atom, resulting in Ag⋯O distances of 2.602 (6) and 2.679 (6) Å. The cationic silver–phosphine complex has a non-linear geometry in which the P—Ag—P angle is 154.662 (19)°. The Ag—P bond lengths are 2.4303 (6) and 2.4046 (5) Å

Synthesis and X-ray studies of ruthenium(II) complexes containing hydrazine and benzyl isocyanide ligands

The reaction of the polymeric species [{RuCl2(COD)}x] (1; x > 2; COD = cyclo-octa-1,5-diene) and hydrazine hydrate in methanol under reflux gave a pale pink solution from which the salt [Ru(COD)(N2H4)4][BPh4]2.CH3OH (2) was isolated on addition of NaBPh4. Treatment of 2 in refluxing acetone in the presence of the ligand benzyl isocyanide give a complex of stoichiometry [Ru(NH2N=CMe2)2(PhCH2NC)4][BPh4]2 (3) on the substitution of the labile COD ligand. The two compounds have been characterized by elemental analyses, IR and NMR measurements and single-crystal X-ray diffraction studies. The ruthenium in both compounds has a distorted octahedral coordination geometry. KEY WORDS: Cycloocta-1,5-diene, Hydrazine hydrate, Isocyanide, Ruthenium Bull. Chem. Soc. Ethiop. 2013, 27(3), 405-411.DOI: http://dx.doi.org/10.4314/bcse.v27i3.