Thermal solid

Thermal solid-state reactions were carried out by keeping a mixture of powdered reactant and reagent at room temperature or elevated temperature, or by mixing with pestle and mortar. In some cases, the solid-state reactions proceed much more efficiently in a water suspension medium or in the presence of a small amount of solvent. Sometimes, a mixture of solid reactant and reagent turns to liquid as the reaction proceeds. All these reactions are called solid-state reactions in this chapter. Solid-state reactions were found to be useful in the study of reaction mechanisms, since it is easy to monitor the reaction by continuous measurement of IR spectra. 

Mechanistic Study of Thermal Solid-State Reactions... 

The thermal solid-to-solid cyclization reaction of diallene derivatives also proceeds stereospecifically. Reaction of 1,6-diphenyl-1,6-di(p-tolyl)hexa-2,4-diyne-l,6-diol (113) with HBr gave meso- (114) and rac-3,4-dibromo-l,6-di-... 

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-... 

Volume 58—THERMAL SOLID WASTE UTILISATION IN REGULAR AND INDUSTRIAL FACILITIES... 

Many solid-state reactions may be pictured as proceeding in two steps. First a homogeneous process leads to product molecules dissolved in residual parent matrix. Curtin and Paul, in a review on thermal solid-state reactions (6), divide this step into a number of stages First, there is a loosening of the molecules at the reaction site to be, then molecular change (the true reaction), and finally solid-solution formation. When the concentration of the accumulated product exceeds the solubility limit the second step, the decomposition of this solid solution into separate reactant and product phases, occurs. However, in some cases the solubility limit is very low, so that the overall process appears to become simpler ... 

A reversible thermal solid-state [2-1-2] cyclodimerization which is stereospecific and proceeds in single crystals has been found with (q -C5H5)Co-(S2C6H4) (379). The dimer 380 forms with major conformational changes in... 

A thermal solid-state N-N double inversion between kinetically stable in-vertomers (exo/endo isomerism) was studied by high-temperature X-ray dif-... 

Below we shall consider some experience acquired in carrying out reactions of catalytic and thermal solid-phase hydrosilylation with the participation of hydride-modified silicas, simple terminal olefins, and a number of functional compounds with double bonds. 

Thus, the researches on reactions of thermal solid-phase hydrosilylation (without a catalyst and a solvent) in a surface layer of hydridesilica I and II made it possible to reveal the distinctions in the reactivity both of 1-olefins and hydridesilicas. It has been established that the activity of 1-olefins is symbate to the electron density on a carbon atom of double bonds, and the reactivity of hydridesilicas increases with the electron-accepting ability of substituents at silicon atoms. 

G. Kaupp, Stereoselective thermal solid-state reactions in Topics in Stereochemistry, Vol. 25, Ch. 9, Wiley, 2006, 303-354. 

References G. Kaupp, M.R. Naimi-Jamal, V. Stepanenko, Eur. J. Chetn. 9, 4156 (2003) G. Kaupp, Stereoselective thermal solid-state reactions, in Topics in Stereochemistry, Vol. 25, Wiley Sons, Hoboken USA, 2006, Chapter 9, 303-354. 

FIGURE 33. Phosphorescence excitation and emission spectra of photo- (dotted) and thermally (solid oxidized poly(butadiene) [after figure in Eur. Polym. J., 10, 593 (1974)]. 

This remaining amount of liquid has to be removed in a second, the Thermal Solids-Liquid Separation step which is commonly known as Drying . 

The aim of this Chapter is to review our spectroscopic work towards the analysis of both, the electronic structures and the dynamics of the intermediate reaction products (Fig. 9.2), during the photopolymerization, i. e. after the excitation of the solid state reaction by light. For the entirely thermally activated solid state polymerization detailed spectroscopy of the intermediate states turned out to be difficult or not very efficient. One exception was the identification of carbenes as reactive species during the thermal solid state polymerization of TS6 (Fig. 9.8). 

Table 9.3 Zero-field splitting parameters for the reactive species during the thermal solid state polymerization of TS [20], pme methylene [16], diphenylmethylene [21], and benzene [22] in their first excited triplet state.

Figure 9.34 Thermal solid state polymerization of TS/FBS (PTS is another acronym for TS). (a) Time-conversion curve derived by gravimetrical analysis, (b) Time-permittivity curve derived at 1 kHz for a thin parallel-plate single-crystal capacitor oriented with the polymer chain direction (b-axis) parallel to the electric field, (c) Correlation of conversion and electric permittivity (with time as implicit parameter) obtained by combination of (a) and (b) [73].

The linear relation between permittivity and polymer content is in principle surprising because there is a distribution of chain lengths of solid state polymerization, differing between induction period and autocatalytic range. The linearity, shown in Fig. 9.34c, reveals that the polarizability of the rr-electron system saturates already at chain lengths below the shortest ones occurring during thermal solid state polymerization. 

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