Study On The Properties And Prediction Of D-gluconic Acid Derivatives As Gelator

In this work,three structurally different compounds 2,4-(3,4-dichlorobenzylidene)-Methy-D-Gluconate(compound A),2,4-(3,4-dichlorobenzylidene)-N-(3-aminopropyl)-D-gluconamide(compound B)and 2,4-(3,4-dichlorobenzylidene)-N-(3-aminooctyl)-D-gluconamide(compound C)were synthesized.35 pure solvents were selected based on the solubility parameters and solvent properties.The gelation behaviors of three gelators in 35 solvents were examined.It was found that samples dissolved at low concentrations became gels or precipitates at higher concentrations.SEM images and rheological tests suggested that gels formed at higher concentrations were true gels.In order to find a universal prediction model,Hansen solubility parameters,F-H parameters,Teas plot and 3-D Hansen space were employed to correlate the gelation behaviors with solvent properties,but with no success.To shed light on the relationship between the gelation behaviors in single solvents and mixed solvents,mixed solvents were determined based on the gelation behaviors in pure solvents and the Teas plot.It was found that the tendency of a gelator to form a gel in mixed solvents is strongly correlated with its gelation behaviors in good solvents.If the gelation occurs in a good solvent at higher concentrations,it will take place as well in a mixed solvent(the good solvent plus a poor solvent)at a certain volume ratio.In contrast,if the gelator forms a precipitate in a good solvent at higher concentrations,no gelation is to be observed in the mixed solvents.In addition,a gelator may form a gel in a solvent at higher pressure when it was insoluble at atmospheric pressure,so the gelator could form gels in mixed solvents.A gelation rule for mixed solvents is thus proposed,which may facilitate decision making with regard to solvent selection for gel formation in the solvent mixtures in practical applications.