Continuous flow hydroformylation using supported ionic liquid phase catalysts with carbon dioxide as a carrier.

A supported ionic liquid phase (SILP) catalyst prepared from [PrMIM][Ph2P(3-C6H4SO3)] (PrMIM = 1-propyl-3-methylimidazolium), [Rh(CO)(2)(acac)] (acacH = 2,4-pentanedione) [OctMIM]NTf2 (OctMIM = 1-n-octyl-3-methylimidazolium, Tf = CF3SO2) and microporous silica has been used for the continuous flow hydroformylation of 1-octene in the presence of compressed CO2. Statistical experimental design was used to show that the reaction rate is neither much affected by the film thickness (IL loading) nor by the syngas: substrate ratio. However, a factor-dependent interaction between the syngas: substrate ratio and film thickness on the reaction rate was revealed. Increasing the substrate flow led to increased reaction rates but lower overall yields. One of the most important parameters proved to be the phase behaviour of the mobile phase, which was studied by varying the reaction pressure. At low CO2 pressures or when N-2 was used instead of CO2 rates were low because of poor gas diffusion to the catalytic sites in the SILP. Furthermore, leaching of IL and Rh was high because the substrate is liquid and the IL had been designed to dissolve in it. As the CO2 pressure was increased, the reaction rate increased and the IL and Rh leaching were reduced, because an expanded liquid phase developed. Due to its lower viscosity the expanded liquid allows better transport of gases to the catalyst and is a poorer solvent for the IL and the catalyst because of its reduced polarity. Above 100 bar (close to the transition to a single phase at 106 bar), the rate of reaction dropped again with increasing pressure because the flowing phase becomes a better and better solvent for the alkene, reducing its partitioning into the IL film. Under optimised conditions, the catalyst was shown to be stable over at least 40 h of continuous catalysis with a steady state turnover frequency (TOF, mol product (mol Rh)(-1)) of 500 h(-1) at low Rh leaching (0.2 ppm). The selectivity of the catalyst was not much affected by the variation of process parameters. The linear: branched (1:b) ratios were ca. 3, similar to that obtained using the very same catalyst in conventional organic solvents.

Why do they go? Empirical evidence of employees' motives for seeking or accepting relocation

This study addresses one of the shortcomings apparent in previous research on expatriate job-transfers, namely the lack of exploratory, empirical groundwork into the motives of expatriates to seek or accept international assignments. The relocatee population of a large German MNC was surveyed for their motives to seek or accept their transfer, using an open-response format. Responses were content analysed in order to arrive at an empirically grounded set of motives. The findings provide a very detailed picture of employees' motives to seek or accept international assignments and thus an important interim result that, when used as input in subsequent investigations, promises highly relevant results due to established content validity.

Selective oxidation of a pyrimidine thioether using supported tantalum catalysts

Ta2O5-SiO2 catalysts were prepared by a sol-gel method using tetraethyl orthosilicate (TEOS) and tantalum (V) ethoxide as the sources of silicon and tantalum, and two families of quaternary ammonium salts, [CnH(2n+1)(CH3)(3)N]Br (n = 14, 16, 18) and [(CnH(2n+1))(4)N]Br (n = 10, 12, 16, 18) as surfactants. The catalysts were compared for the selective suffoxidation of 4,6-dimethyl-2-thiomethylpyrimidine using peroxide as an oxidising agent in a range of ionic liquids and organic solvents. The sol-gel catalysts were also compared with tantalum on MCM-41 prepared by grafting. The catalysts were characterized from adsorption-desorption isotherms of N-2, XRD patterns, small-angle X-ray scattering, IR spectra from adsorbed pyridine and CDCl3, XPS spectra, and Si-29 magic angle spinning (MAS) NNIR experiments. The effect of recycling on the catalyst leaching and selectivity/activity was also studied. High activities and selectivities were found in [NTf2](-) based ionic liquids and organic solvents with good recyclability of the catalyst. Tantalum was found in the solution after reaction; however, this was determined to be due to entrapment of catalyst particulates, as opposed to leaching of the active metal. (c) 2005 Elsevier Inc. All rights reserved.

Asymmetric Carbon-Carbon Bond Forming Reactions Catalysed by Metal(II) Bis(oxazoline) Complexes Immobilized using Supported Ionic Liquids

A series of bis(oxazoline) metal(II) complexes has been supported on silica and carbon supports by non-covalent immobilisation using an ionic liquid. The catalytic performance of these solids was compared for the enantioselective Diels-Alder reaction between N-acryloyloxazolidinone and cyclopentadiene and the Mukaiyama-aldol reaction between methyl pyruvate and 1-methoxy-1-trimethylsilyloxy-propene. In both reactions the enantioselectivity was strongly influenced by the choice of support displaying enantioselectivies (ee values) up to 40% higher than those conducted under homogeneous reaction conditions.

Measuring workforce segregation: religious composition of private-sector employees at individual sites in Northern Ireland

In this paper I examine the scope of publicly available information on the religious composition of employees in private-sector companies in Northern Ireland. I highlight the unavailability of certain types of monitoring data and the impact of data aggregation at company as opposed to site level. Both oversights lead to underestimates of the extent of workplace segregation in Northern Ireland. The ability to provide more-coherent data on workplace segregation, by religion, in Northern Ireland is crucial in terms of advancing equality and other social-justice agendas. I argue that a more-accurate monitoring of religious composition of workplaces is part of an overall need to develop a spatial approach in which the importance of ethnically territorialised spaces in the reproduction of ethnosectarian disputation is understood.

Theoretical and experimental correlations of gas dissolution, diffusion, and thermodynamic properties in determination of gas permeability and selectivity in supported ionic liquid membranes

Supported ionic liquid membranes (SILMs) has the potential to be a new technological platform for gas/organic vapour separation because of the unique non-volatile nature and discriminating gas dissolution properties of room temperature ionic liquids (ILs). This work starts with an examination of gas dissolution and transport properties in bulk imidazulium cation based ionic liquids [C_nmim][NTf2] (n = 2.4, 6, 8.10) from simple gas H₂, N₂, to polar CO₂, and C₂H₆, leading to a further analysis of how gas dissolution and diffusion are influenced by molecular specific gas-SILMs interactions, reflected by differences in gas dissolution enthalpy and entropy. These effects were elucidated again during gas permeation studies by examining how changes in these properties and molecular specific interactions work together to cause deviations from conventional solution–diffusion theory and their impact on some remarkably contrasting gas perm-selectivity performance. The experimental perm-selectivity for all tested gases showed varied and contrasting deviation from the solution–diffusion, depending on specific gas-IL combinations. It transpires permeation for simpler non-polar gases (H₂, N₂) is diffusion controlled, but strong molecular specific gas-ILs interactions led to a different permeation and selectivity performance for C₂H₆ and CO₂. With exothermic dissolution enthalpy and large order disruptive entropy, C₂H₆ displayed the fastest permeation rate at increased gas phase pressure in spite of its smallest diffusivity among the tested gases. The C₂H₆ gas molecules “peg” on the side alkyl chain on the imidazulium cation at low concentration, and are well dispersed in the ionic liquids phase at high concentration. On the other hand strong CO₂-ILs affinity resulted in a more prolonged “residence time” for the gas molecule, typified by reversed CO₂/N₂ selectivity and slowest CO₂ transport despite CO₂ possess the highest solubility and comparable diffusivity in the ionic liquids. The unique transport and dissolution behaviour of CO₂ are further exploited by examining the residing state of CO₂ molecules in the ionic liquid phase, which leads to a hypothesis of a condensing and holding capacity of ILs towards CO₂, which provide an explanation to slower CO₂ transport through the SILMs. The pressure related exponential increase in permeations rate is also analysed which suggests a typical concentration dependent diffusion rate at high gas concentration under increased gas feed pressure. Finally the strong influence of discriminating and molecular specific gas-ILs interactions on gas perm-selectivity performance points to future specific design of ionic liquids for targeted gas separations.

Bridging the Gap between CO Adsorption Studies on Gold Model Surfaces and Supported Nanoparticles

A happy medium: Volumetric adsorption of carbon monoxide at 308 K and UHR-HAADF-STEM, HREM, and computer modeling techniques were compared. Experimental CO/Au ratios at saturation coverage for two supported gold catalysts were shown to fit very well the predictions of a nanostructural model that considers CO adsorption on gold sites with coordination numbers of less than eight.

Burnout as a predictor of all-cause mortality among industrial employees: A 10-year prospective register-linkage study

Objective: Burnout, a psychological consequence of prolonged work stress, has been shown to coexist with physical and mental disorders. The aim of this study was to investigate whether burnout is related to all-cause mortality among employees. Methods: In 1996, of 15,466 Finnish forest industry employees, 9705 participated in the 'Still Working' study and 8371 were subsequently identified from the National Population Register. Those who had been treated in a hospital for the most common causes of death prior to the assessment of burnout were excluded on the basis of the Hospital Discharge Register, resulting in a final study population of 7396 people. Burnout was measured using the Maslach Burnout Inventory-General Survey. Dates of death from 1996 to 2006 were extracted from the National Mortality Register. Mortality was predicted with Cox hazard regression models, controlling for baseline sociodemographic factors and register-based health status according to entitled medical reimbursement and prescribed medication for mental health problems, cardiac risk factors, and pain problems. Results: During the 10-year 10-month follow-up, a total of 199 employees had died. The risk of mortality per one-unit increase in burnout was 35% higher (95% CI 1.07-1.71) for total score and 26% higher (0.99-1.60) for exhaustion, 29% higher for cynicism (1.03-1.62), and 22% higher for diminished professional efficacy (0.96-1.55) in participants who had been under 45 at baseline. After adjustments, only the associations regarding burnout and exhaustion were statistically significant. Burnout was not related to mortality among the older employees. Conclusion: Burnout, especially work-related exhaustion, may be a risk for overall survival. (C) 2010 Elsevier Inc. All rights reserved.

Organizational Change and Employees' Mental Health: The Protective Role of Sense of Coherence

Objective: To examine the impact of sense of coherence (SOC) on psychiatric events in the context of organizational merger. Methods: Data were derived from a prospective

Lack of Predictability at Work and Risk of Acute Myocardial Infarction: An 18-Year Prospective Study of Industrial Employees

Objectives. We examined whether the distinctive components of job control-decision authority, skill discretion, and predictability-were related to subsequent acute myocardial infarction (MI) events in a large population of initially heart disease-free industrial employees.