Solid-state reaction, design

The third aspect, the stability range of solid electrolytes, is of special concern for alkaline-ion conductors since only a few compounds show thermodynamic stability with, e.g., elemental lithium. Designing solid electrolytes by considering thermodynamic stability did lead to very interesting compounds and the discovery of promising new solid electrolytes such as the lithium nitride halides [27]. However, since solid-state reactions may proceed very slowly at low temperature, metasta-... 

This first industrial device has been designed by MES company [65] for drying. It could be used for solid state reactions with powder reactants. Consequently, the reactor cannot be a classical chemical vessel or a classical chemical reactor with stirrer and others associated technical devices but a container able to enclose a reactant powder layer. The geometrical shape of the microwave applicator is parallelepiped box and the reactants are supported by a dielectric conveyor belt with edges as described by the Fig. 1.18. 

Increasing the size of PAHs makes their deposition on surfaces difficult because they can neither be sublimed nor made sufficiently soluble for solution processing. A precursor route has thus been designed according to which molecules are deposited on a surface and transformed into the final disc-type adsorbate structures in a thermal solid-state reaction with the substrate surface acting as a template.1261 An exciting example is the hexaether 41 (scheme 11) which is sublimed onto a Cu-(1U) sur-... 

These examples illustrate a number of points. Solid-state reactions can, in many cases, be performed very easily. Their courses are frequently interpretable in terms of straightforward geometrical principles concerning conformation and/or packing of the reactant molecules. It is sometimes possible to design the reactant molecule with suitable substituents to ensure a desired crystal structure... 

Although it is always possible, once the formula of a specific POM is known, to write an equation analogous to Eq. (1) describing its formation, this is often not the appropriate synthetic procedure. In addition to variation of counter-cation, ionic strength and pH in aqueous media, syntheses may be carried out in non-aqueous solvents, via hydro- or solventothermal methods, and by solid state reactions. The starting material may even be a pre-formed stable or metastable POM this is especially the case for tungstates. While in some cases the preparation of a specific POM may be rationally designed, in the majority of systems the synthesis has to be described simply as "self assembly."... 

For the development of a sustainable chemistry based on clean technologies, the best solvent would be no solvent at all. For this reason, considerable efforts have recently been made to design reactions that proceed under solvent-free conditions, using modern techniques such as reactions on solid mineral supports (alumina, silica, clays), solid-state reactions without any solvent, support, or catalyst between neat reactants, solid-liquid phase-transfer catalysed and microwave-activated reactions, as well as gas-phase reactions [37-42]. However, not all organic reactions can be carried out in the absence of a solvent some organic reactions even proceed explosively in the solid state Therefore, solvents will still be useful in mediating and moderating chemical reactions and this book on solvent effects will certainly not become superfluous in the foreseeable future. 

Crystalline pyr-FeFs , a metastable cubic form of FeFs with pyrochlore-related structure, was obtained in a topotactical oxidation reaction of NH4Fe2F6 with Br2 in acetonitrile. At this example, the designation "chimie douce (soft chemistry) for this type of solid-state reaction under low-temperature conditions was propagated in the 1980s. ... 

The development of the principles of solid-state reactions of substituted cinnamic acids was pioneered by Gerhard M. J. Schmidt. The trans-SLcid was found to be polymorphic, and three different crystal forms (designated a, and 7) were identified by him. The finding that the nature of the cyclobutane derivatives formed by the solid-state photochemical reaction on crystals of frans-cinnamic acid depend on which polymorph is irradiated was of great interest. The products of the photo-... 

Most solid-state reactions investigated up to the late 1960s were observed mainly by accident, without design, a major difficulty being the absence of a general method for producing crystals that have desired characteristics. 

When greater selectivity is required in the solid-state reaction, host-guest chemistry techniques can be applied efficaciously. Reaction in the solid state of the guest compound as its inclusion complex crystal with a chiral host can give an optically active reaction product. Various host compounds have been designed by us to follow this simple principle. 

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