Enthalpy 4-fluorophenol complexes

TABLE 18. Enthalpies of complexation (kJ mol ) of 4-fluorophenol with various bases measured by the pure base method ... 

In this alternative method, referred to as the pure-base calorimetric method , the base is used as the solvent, so complete complexing of the 4-fluorophenol and base can usually be assured. The two heat terms involved are (i) the heat due to the hydrogen-bond formation and (ii) the heat produced by other interactions. The latter contribution is obtained by using 4-fluoroanisole, which resembles 4-fluorophenol in all respects except in its ability to hydrogen bond. The enthalpy is determined through Equation 4.16 by measuring heats of solution, AHs, for 4-fluorophenol and 4-fluoroanisole in the pure base and the reference inert solvent CCI4. 

Figure 4.8 Limited linear enthalpy relationship for formation of hydrogen-bonded complexes of cyanoacetylene and 4-fluorophenol. The upper line represents n bases (benzene, mesity-lene, hexamethylbenzene), the middle line sulfur (tetrahydrothiophene), Nsp (acetonitrile) and O (ethers, CO, SO, PO) bases, and the lower line pyridine and tertiary amine bases.

Determination by FTIR Spectrometry of the Complexation Enthalpy and Entropy of 4-Fluorophenol with Cyclopropylamine... 

In this experiment, the enthalpy and entropy of complexation of 4-fluorophenol with cyclopropylamine is measured from the temperature variation of the complexation constant on the mole fraction scale, Kx. The experimental result is compared with high-level calculations [MP2/aug-cc-pVTZ//B3LYP/6-31- -G(d,p)] of the enthalpy in vacuo. For this reason. 

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