Endothermic reaction, polymer thermodynamics

The thermodynamic analysis of loannides [193] on SRE in a solid polymer fuel cell indicated that the ethanol steam reforming reaction needs to be carried out in two steps a high-temperature endothermic step (steam reforming), in which ethanol is converted to a gaseous mixtures of H2, CO, CO2, CH4 and unreacted H2O, and a subsequent, low-temperature step (WGSR) in which CO reacts with water to form H2 and CO2. 

The number of phenomena which can be directly studied by thermal analysis (DSC (DTA), TG, TMA, DMTA, TOA and DETA) is impressive. Typical of these methods is that only small amounts of sample (a few milligrams) are required for the analysis. Calorimetric methods record exo- and endothermic processes, e.g. melting, crystallization, liquid-crystalline phase transitions, and chemical reactions, e.g. polymerization, curing, depolymerization and degradation. Second-order transitions, e.g. glass transitions, are readily revealed by the calorimetric methods. Thermodynamic quantities, e.g. specific heat, are sensitively determined. TG is a valuable tool for the determination of the content of volatile species and fillers in polymeric materials and also for studies of polymer degradation. The majority of the aforementioned physical transitions can also be monitored by TMA (dilatometry). DMTA and DETA... 

After CO insertion, CO and C2H4 compete for adsorption on the Pd-center. Although the adsorption equilibrium clearly favors the adsorption of CO, this does not lead to insertion in the polymer, as this reaction step, sketched in Figure 6.31a appears to be strongly endothermic. The ethylene insertion step (Figure 6.31b), however, is thermodynamically favored. Thus, selective polyketon formation by... 

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