Study of inclusion complex formation between a homologous series of n-alkyltrimethylammonium bromides and β-cyclodextrin, using conductometric technique

The behaviour of the inclusion complex based on a homologous series of n-alkyltrimethylammonium bromides and β-cyclodextrin (β-CD) were studied using conductometric technique. Association constants have been determined for S(CD) and S(CD)2 complexes. It has been found that DETAB and DOTAB form only the 1:1 complexes, while TTAB forms 1:1 1:2 TTAB/CD complexes. The results are explained in terms of the difference in chain length of surfactants and dimensions of the β-CD cavity. The experiments were carried out at different temperatures. The association constant values are used for evaluation of thermodynamic parameters of complexation, such as ΔG°, ΔH° and ΔS°.