Synthesis of Phosphine Trans-Substituted Derivatives of Iron Pentacarbonyl

The synthesis of trans-Fe (CO)3(PR3)2 (PR3 = PPh3, PPh2Me, PPh2CHCH2, P(c-C6H11)3, P(n-C4H9)3, PPh2H) can be achieved by refluxing iron pentacarbonyl under reducing conditions in the presence of ligand in 1-butanol. Addition of iron pentacarbonyl to a 1-butanol solution of sodium borohydride at room temperature results in a quantitative conversion of the iron carbonyl complex to the corresponding mononuclear formyl complex. Upon heating the initially formed formyl species decomposes to form the tetracarbonylhydridoferrate(0) anion . This hydride is believed to undergo reaction with the phosphine ligand to yield the isolated trans-substituted iron complex. Even though traces of monosubstituted product were detected in the crude reaction mixture by infrared spectroscopy, uncontaminated trans-substituted complexes were isolated after crystallization from dichloromethane/methanol. All complexes have been found to be sensitive to oxygen if in solution, with the rate of decomposition depending on the kind of ligand. However, if they are dry and under vacuum no apparent decomposition takes place. All synthesized complexes have been characterized by IR spectroscopy, 31P NMR, and by their melting points. The value of the presented synthesis is based on its high selectivity, extremely short reaction time, good to very good yields, and its simplicity

Synthesis of Phosphine Trans-Substituted Derivatives of Iron Pentacarbonyl

The synthesis of trans-Fe (CO)3(PR3)2 (PR3 = PPh3, PPh2Me, PPh2CHCH2, P(c-C6H11)3, P(n-C4H9)3, PPh2H) can be achieved by refluxing iron pentacarbonyl under reducing conditions in the presence of ligand in 1-butanol. Addition of iron pentacarbonyl to a 1-butanol solution of sodium borohydride at room temperature results in a quantitative conversion of the iron carbonyl complex to the corresponding mononuclear formyl complex. Upon heating the initially formed formyl species decomposes to form the tetracarbonylhydridoferrate(0) anion . This hydride is believed to undergo reaction with the phosphine ligand to yield the isolated trans-substituted iron complex. Even though traces of monosubstituted product were detected in the crude reaction mixture by infrared spectroscopy, uncontaminated trans-substituted complexes were isolated after crystallization from dichloromethane/methanol. All complexes have been found to be sensitive to oxygen if in solution, with the rate of decomposition depending on the kind of ligand. However, if they are dry and under vacuum no apparent decomposition takes place. All synthesized complexes have been characterized by IR spectroscopy, 31P NMR, and by their melting points. The value of the presented synthesis is based on its high selectivity, extremely short reaction time, good to very good yields, and its simplicity

Die Keilschrifttexte der Universitätsbibliothek Giessen : unter Benutzung nachgelassener Vorarbeiten von Julius Lewy

Fossil fuels are used widely for energy production and are likely to continue to play a major role world wide for many years to come. Much work has been done on the technology for capturing CO₂ from gaseous industrial e ffluent. For large-scale applications like coal or natural gas-fired power plants, using amine solvents to capture post-combustion CO₂ is the most mature CO₂ capture technology. This technique can be used to retro fit existing plants by treating the flue gas after combustion. This thesis contains a dynamic mathematical model for the absorber column that can be used to include more detailed reaction chemistry for the absorption of CO₂ into an amine in the presence of O₂ as it becomes available. The dynamic model is constructed from first principles and, while it is built using MEA as the absorbent to remove CO₂, it can be adjusted to cater for the removal of different industrial gases with various absorbents. The model is solved using a commercial solver, MATLAB Ode15s when reduced to a system of ODE's by finite difference in the spatial dimension. The flux of MEA, CO₂, O₂ and H₂O across the phase interface in either direction has been included and more components can be added as required. The loss of MEA through oxidative degradation has been quantified which is currently not available using commercial packages. Reaction rate kinetics have been employed to predict the accumulation of oxidation products which is limited by the incomplete knowledge of the dominant reactions between O₂ and MEA. When research has produced more detailed information about the products formed during this oxidation, it can be inserted easily into the model. Validation has been performed using data from the CSIRO PCC pilot plant at AGL Loy Yang. A limited parametric study of the impact of operating conditions on oxidation was performed

Multi-Agent Distributed Reinforcement Learning for Making Decentralized Offloading Decisions

We formulate computation offloading as a decentralized decision-making problem with autonomous agents. We design an interaction mechanism that incentivizes agents to align private and system goals by balancing between competition and cooperation. The mechanism provably has Nash equilibria with optimal resource allocation in the static case. For a dynamic environment, we propose a novel multi-agent online learning algorithm that learns with partial, delayed and noisy state information, and a reward signal that reduces information need to a great extent. Empirical results confirm that through learning, agents significantly improve both system and individual performance, e.g., 40% offloading failure rate reduction, 32% communication overhead reduction, up to 38% computation resource savings in low contention, 18% utilization increase with reduced load variation in high contention, and improvement in fairness. Results also confirm the algorithm's good convergence and generalization property in significantly different environments

Spatial processes in category assignment

Investigates the hypothesis that spatial processes are involved in judgments on membership in a category. It is argued that membership versus nonmembership of an object or a concept, in a category, is spatially simulated in mental space by a minimal continuum with 2 levels, left for membership and right for nonmembership. In analogy to other embodied dimensions (e.g., time line or number line), the orientation of membership levels on the mental dimension is assumed to follow the acquired reading/writing schema, with procedural primacy implying dominance, hence leftward positioning of dominant elements. This rationale is tested in 7 experiments. A recognition memory paradigm (modified 2AFC paradigm, Experiment 1) revealed that participants were faster indicating the location of an old word on the screen when displayed left within a pair of words, indicating a spatial representation of category membership (“member” = left, “nonmember” = right). For category discrimination (Experiment 2) we found faster and more accurate performance when a target word is presented left as compared with right. This pattern is replicated in Experiments 4a and 4b, with different response alternatives. Discriminating categories in a stimulus-response compatibility paradigm (Experiment 3), participants were faster making correct responses with their left hand than with their right hand in target category trials. In contrast, no differences were found for distractor trials. Experiments 5a and 5b address the spatial bias in spontaneous sorting situations. Overall, this pattern of results across the 7 experiments provides evidence in support of a spatial simulation of category assignmen

A robust anchoring effect in linear ordering

The robustness of effects indicating a spatial component associated with abstract reasoning is tested. Judgements regarding hierarchical orderings tend to be faster and more accurate when the dominant element in any pair from the order (e.g., the older, richer) is presented on the left of the screen as compared with the right (left-anchoring effect). This signature effect is investigated in three conditions (Experiment 1), each implementing a different timing regime for the elements in each pair, during learning. Thereby, the construction of a mental representation of the ordering was exposed to a potentially competing spatial simulation, that is, the well-known "mental timeline" with orientation from left (present) to right (future). First, the left-anchoring effect for order representations remained significant when timeline information was congruent with the presumed left-anchoring process, that is, the dominant element in a pair was always presented first. Second, the same effect remained also significant when the timeline-related information was random, that is, the dominant element being presented either first or second. Third, the same effect was found to be still significant, when the timeline-related information was contrary to the left-anchoring process, that is, the dominant element being presented always second. Experiment 2 replicates the target effect under random timeline information, controlling for colour as a stimulus feature. The results are discussed in the context of a theoretical model that integrates basic assumptions about acquired reading/writing habits as a scaffold for spatial simulation and primacy/dominance representation within such spatial simulations