Liquid clathrates analysis

Analysis. The liquid clathrates were analyzed by the integration of NMR spectra recorded on a Perkin-Elmer R20-B instrument. The aromatic stoichiometries in Table II are in most cases the average of three preparations and integrations a realistic standard deviation would be 0.2 molecules. The chemical shifts are accurate to better than 0.02 ppm. 

Knowing the thermal stability of clathrates permits the prediction of experimental conditions for polymerization (8). A detailed analysis of this problem requires the examination of all the involved phases, particularly the solid and liquid phases. Equations for phase equilibria were derived from within the framework of the regular solution theory they contain an interaction parameter W, (whose value is always positive or zero for ideal solutions), which measures the tendency of host and guest to segregate in the liquid phase. The melting or decomposition point is very sensitive to the value of W, especially when it exceeds 2 RT, i.e. when a miscibility gap is observed in the liquid phase. For this reason the PHTP-hydrocarbon clathrates melt congruently between 115 and 180 C, whereas the urea-hydrocarbon... 

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