Interaction between zeolites and cluster compounds. Part 2.—Thermal decomposition of iron pentacarbonyl on zeolites

Thermal decomposition in a thermobalance of Fe(CO)5 adsorbed on alkali-metal, hydrogen-Y, dealuminated Y, L and omega zeolites proceeds stepwise via slow decarbonylation at low and high temperatures, separated by a fast endothermic reaction. Average CO/Fe ratios have been determined after each step. From i.r. results the former intermediates are assigned to species bearing bridging CO, whereas reaction products with CO/Fe < 1 are associated with highly unsaturated carbonyl clusters in strong interaction with the zeolite.The thermal stability of zeolite/Fe(CO)5 adducts as well as of the intermediates increases with the electron-donor properties of the matrix and can be rationalized using the Sanderson electronegativity concept. Iron loadings ranging from 2.4 wt % in zeolite L up to 10 wt % with NaY and HY are obtained by decomposition in inert atmosphere. Under vacuum conditions loss of metal up to 50% is observed. Metallic iron clusters are the final decomposition products in alkali-metal zeolites, as probed by NO adsorption. In HY part of the metallic iron is oxidized to FeII ions, which are located at cation positions

Interaction between zeolites and cluster compounds. Part 1.—Adsorption of iron pentacarbonyl on zeolites

The adsorption isotherms of Fe(CO)5 on NaY, HY and Linde L zeolites obtained in McBain balances show micropore adsorption, whereas additional capillary condensation is found with zeolite omega and Na-mordenite. The pores and/or cages of the zeolites studied are completely filled with the complex upon saturation, with the exception of Na-mordenite. Their behaviour is explained, respectively, by pore blocking and the occurrence of channel openings that are too narrow. The silicalite channel system also is too narrow to accept Fe(CO)5 molecules.Infrared results show that an increasing interaction of the complex with faujasites exists in the sequence: dealuminated Y < CsY < HY < NaY. This is derived from the increasing band half-width of the adsorbed complex in the CO stretching region and from the increasing intensity of the v1 vibration, which upon adsorption becomes i.r. active. The interaction is assumed to be influenced mainly by electrostatic fields in the cages or pores, which can lead to a very restricted mobility for the encaged complex. The complex seems to remain intact upon adsorption at 293 K in all the zeolites studied

Characterization of a new iron-on-zeolite Y Fischer-Tropsch catalyst

Iron pentacarbonyl adsorbed on dry Na-Y zeolite can be oxidized at subambient temperatures into Fe203 located in the zeolite supercages (catalyst I). When catalyst I is hydrogen reduced at 575 K most of the iron has agglomerated externally to the zeolite (catalyst 11). When the iron carbonyl is thermally decomposed in vacuo at 525 K, an iron phase with a very low degree of dispersion is again obtained (catalyst 111). During a Fischer-Tropsch reaction most of the iron is transformed into a Hagg-type carbide phase, located externally to the zeolite. Catalysts I1 and 111 rapidly reach steady state and show a Schulz-Flory-type of product distribution, the Hagg carbide being the active phase. Catalyst I slowly moves to steady state and Schulz-Flory behavior. Product selectivity is only found on this catalyst during transient conditions. The physical information on the three catalysts before and after reaction was obtained with transmission electron microscopy and Mossbauer and EXAFS spectroscopies. These techniques supplied consistent and complementary evidenc

Synergism of He-3 acquisition with lunar base evolution

It is shown how acquisition of He-3 affects Lunar Base development and operation. A four phase evolutionary Lunar Base scenario is summarized with initial equipment mass and resupply requirements. Requirements for various He-3 mining operations are shown and available by-products are identified. Impacts of mining He-3 on Lunar Base development include increases in equipment masses to be delivered to the lunar surface and a reduction of Lunar Base resupply based on availability of He-3 acquisition by-products. It is concluded that the acquisition of this valuable fusion fuel element greatly enhances the commercial potential of a Lunar Base

The Language Diplomats Speak: A Discourse-theoretical Approach to the Negotiations in the EURONEST Parliamentary Assembly. EU Diplomacy Paper 05/2016

Although it is widely accepted that the study of diplomatic negotiations ought to be a multi-disciplinary enterprise, the field’s state of the art does not reflect this need for diversity. Game-theoretical and socio-psychological analyses make up the lion’s share of the research. In contrast, interactions between negotiators, perhaps the most elementary building blocks of negotiations, have received relatively little scholarly attention. This paper inquires how matters of language, communication and discourse can be brought to the front in the study of diplomatic negotiations. It will address this question on a theoretical level, by asking what theoretical preconditions to a discursive and language-based approach to diplomatic negotiations exist, and on an empirical level, by developing a relevant case study demonstrating the potential of this approach. With regards to the first question, it will be argued that Discourse Theory is well-suited to overcome the obstacles that have prevented a focus on communication from taking root so far. The case study will be drawn from the European Neighbourhood Policy and look at the discursive conceptualization of institutional relations, bureaucratic infrastructure and socialization efforts in the EURONEST Parliamentary Assembly

Poststructuralist discourse theory as an independent paradigm for studying institutions : towards a new definition of ‘discursive construction’ in institutional analysis

Poststructuralist discourse theory (DT) is enjoying increasing recognition for its potential to contribute to the study of institutional change and continuity. Yet the most fruitful approach to realizing this potential has hitherto not been found. The main proposition so far has been to operationalize DT's insights and concepts by adopting them into the framework of discursive institutionalism (DI). However, an ongoing debate about the compatibility of the ontologies underlying DT and DI has cast doubts over whether such a combination is theoretically feasible. The critical literature review in the first part of this article indeed finds insurmountable ontological differences between the discourse-theoretical and the discursive-institutionalist traditions, as their clashing notions of what is understood as a 'discourse' result in diverging views on power, agency, and subjectivity. Instead of merging DT into DI, I suggest to empower the former as a self-sufficient paradigm for institutional analysis. To achieve this, the second part of this article re-articulates the 'logics framework' proposed by Jason Glynos and David Howarth (2007) into a middle-range theory for the study of institutionalization and politicization in a discourse-theoretical fashion. The purpose of this re-articulation is to dispel various arguments against the viability of an autonomous poststructuralist approach to institutions