Complexation of some univalent organic cations with benzo-18-crown-6 in nitrobenzene saturated with water

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C+(aq) + 1·Na+(nb) 1·C+ (nb) + Na+(aq) taking place in the two-phase water-nitrobenzene system (C+ = methylammonium, ethylammonium, propylammonium, ethanolammonium, diethanolammonium, triethanolammonium, cation TRIS+, hydrazinium, hydroxylammonium; 1 = benzo-18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the 1·C+ cationic complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: triethanolammonium +

Porous copolymers of methacrylic acid with N-(2-hydroxypropyl) methacrylamide and (2-hydroxyethyl) methacrylate. Study of sorption properties

Porous crosslinked copolymers of methacrylic acid with N-(2-hydroxypropyl) methacrylamide (HPMA) or (2-hydroxyethyl) methacrylate were prepared, and the relationship between their structure and the sorption of papain, bovine serumalbumin, chymotrypsinogen, pepsin, ovalbumin, insulin, novocain and oleandomycin were investigated. The presence of hydrophilic components in the gel structure makes possible additional interactions between sorbent and the compound sorbed. The occurrence of additional interactions (probably hydrogen bonds) is more pronounced with cation exchangers containing the (2-hydroxyethyl) methacrylate monomeric unit, which favourably affects the sorption of univalent organic cations but at the same time contributes to the denaturation of sorbed proteins. In contrast to univalent organic cations, cation exchangers containing the N-(2-hydroxypropyl) methacrylamide monomeric unit are more advantageous in the sorption of proteins, because due to the lower extent of additional interactions no irreversible denaturation of sorbed labile proteins takes place in this case.