Abstract: The complex stability constants for the 1∶1 inclusion complexation of various dihydroxybenzenes (pyrocatechol, hydroquinone, resorcinol) with cellulose fibre grafted β-cyclodextrin have been determined by means of spectrophotometric titrations at different temperatures in aqueous solutions with different pH values. The molecular recognition mechanism for various complexes of dihydroxybenzenes and β-cyclodextrin is discussed from the viewpoint of stability constants, apparent thermodynamic parameters, the size/shape-fit, multiple recognition, and pH value of inclusion systems of dihydroxybenzenes between the host cavity and the guest molecules. The results show that the cellulose fibre grafted β-cyclodextrin possesses a special binding ability and molecular selectivity for dihydroxybenzenes, the complex stability constants of dihydroxybenzenes are Ka(resorcinol)>Ka(hydroquinone)>Ka(pyrocatechol), apparent thermodynamic parameters of dihydroxybenzenes are ΔH(resorcinol )<ΔH(hydroquinone)<ΔH(pyrocatechol) and ΔS(resorcinol)<ΔS(hydroquinone)< ΔS(pyrocatechol).

Key words: β-cyclodextrin, Cellulose fibre, Inclusion properties, Molecular recognition, Dihydroxybenzenes