Surfactant Inclusions by Modified β-Cyclodextrins

Abstract

Binding constants for the inclusion of sodium alkane-1-sulfonates (C5-C10, C12) by four modified β- cyclodextrins (2,6-O-dimethyl-β-cyclodextrin, 2,3,6-O-trimethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin and maltosyl-β-cyclodextrin ) were determined conductimetrically at 25°C. Binding increased with increasing length of the alkyl chain. Generally, the substituted β- cyclodextrins were no more effective as encapsulating agents than ordinary β- cyclodextrin with the persubstituted 2,3,6-O-trimethyl-β-cyclodextrin being the weakest.

Determination of Association Constants for Cyclodextrin–Surfactant Inclusion Complexes: A Numerical Method Based on Surface Tension Measurements

“…This demonstrates that b-CD and C 12 As form inclusion complexes, the surface activity of C 12 As decreases with the addition of b-CD, and aqueous solutions of b-CD and the inclusion complexes do not have any surface activity. The same results were found for C 8 As and C 16 As in the presence of different b-CD concentrations.…”

“…Figures 2 and 3 display the variations in the surface tensions for C 12 As and C 16 As in the presence of different b-CD concentrations at 313 and 323 K, respectively. It is found that the surface tension curves of C n As (n Å 8, 12,16) in the presence of b-CD are higher than those in the absence of b-CD. The curves rise much higher with the increase in b-CD concentration.…”

“…The surface tensions at different temperatures for three anionic surfactants, Formation of the Inclusion Complexes sodium alkyl sulfonate, C n As (n Å 8, 12,16), in the absence and presence of different b-CD concentrations, are meaWe have studied the 1 H-NMR spectra of b-CD in the absence and presence of C n As (n Å 8, 12, 16) at 313 K sured. The association constants of b-CD with C n As (n Å 8, 12, 16) at different temperatures are determined.…”

Dissociation constants of host–guest complexes of alkyl-bearing compounds with β-cyclodextrin and "hydroxypropyl-β-cyclodextrin"

“…Apparently, a similar situation exists for other types of guests binding to Hp-P-CD. For example, 4-(2-pyridy1azo)-N,N-dimethylaniline binds equally well to Hp-P-CD and P-CD (30), as do the tetraphenylborate ion and BF,- (15). For two naphthalene derivatives, 1-and 2-naphthyl acetate, binding to Hp-P-CD is about twice as strong as that to P-CD (3 1).…”

“…Table 1 contains Kd values for 18 alcohols and 5 alkanesulfonate ions binding to P-CD and Hp-P-CD, most of which were determined by the inhibition method just outlined. It also contains values taken from the literature, particularly those for P-CD, that were obtained in other ways (13)(14)(15).…”