temperature integrals pm (x)= .eojx e-Xu-2-mdu with m = 0, 1/2 and 1 are apThe proximated using empirical formulae of the type Ax--Be -cx. For estimation of the precision of these approximations, the relative errors were calculated for integral values ofx. It was established that forx < 19 the maximum relative error is 0.26%, while for 19 < x -<50 it is less than 0.1%. The suggested approximations allow a sensible improvement of the integral methods intended to determine the kinetic parameters of the process concerned. The present paper shows that these functions can be approximated with excellent accuracy within the intervals (5, 17) and (17, 50) by using expressions of the type Ax'Be "cx.
KineticsThe thermogravimetric study takes into account the following equation: r / dt = ZTme -EIRT (1-c)n (1)
The vaporization of perhydrotriphenylene and its inclusion compounds with higher evennumbered n-alcohols from C 8 to C16 has been studied using thermogravimetric analysis. For the inclusion compounds of perhydrotriphenylene with the C8, C10 and C12 n-alcohols, kinetic analysis shows that the vaporization processes of the n-alcohol and the perhydrotriphenylene are partially superimposed, while for the inclusion compound perhydrotriphenylene-hexadecanol-1, the above processes are totally superimposed. From the experimental kinetic parameters the values of the preexponential factors corresponding to the vaporization of the n-alcohols and perhydrotriphenylene were calculated, as were the compositions of the inclusion compounds of perhydrotriphenylene with the C8-C12 n-alcohols.The anti-trans-anti-trans-anti-trans equatorial isomer of perhydrotriphenylene (PHTP), I a and Ib, forms stable channel-like inclusion compounds with hydrocarbons, alcohols, esters, monocarboxylic acids, macromolecules, etc. [1][2][3][4]. Within the channels which penetrate the structures of the PHTP inclusion compounds, long-chain guest molecules are isolated from one another longitudinally by the channel walls, but end-group interactions between successive chains are permitted, affording a means of comparing these interactions in different homologous series through their contribution to the thermal stability of the inclusion compound.The thermal decompositions of the inclusion compounds PHTP -higher evennumbered n-alcohols from C 8 to C18, studied by differential thermal analysis [5], revealed that their stabilities become higher as the chain length of the included alcohol increases.This paper deals with a study of the thermal vaporization processes of PHTP and its inclusion compounds with even-numbered aliphatic alcohols from C 8 and C16, using thermogravimetric analysis.
ExperimentalThe inclusion compounds PHTP -n-alcohols were prepared by mixing saturated solutions of PHTP and n-alcohols, C8-C16 , in methyl ethyl ketone, at 60-70 ~ followed by slow-cooling crystallization at room temperature as previously described [5].
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