Preparation And Characterization Of Phase-selective Gelators Based On Glycosy And Amino Acid

In this paper,two different phase-selective gelators(PSGs)based on sorbitol and amino acid were synthesized by the modification of hydrophobic and lipophilic groups.The conditions affecting the yield of gelator were investigated systematically,and optimized to obtain a higher yield of gelator.Furthermore,the porperties of the gelator,including the minimum gelation concentration(MGC),complete gelling time,phase-selectivety and reusablity were tested,and the gelator with good performances was obtained.Firstly,the sorbitol based phase-selective gelator was synthesized by the reaction of sorbitol and benzaldehyde in one step and its structure was confirmed by ~1H-NMR and FTIR techniques.A maximum yield of 88.5%was obtained under optimal reaction conditions:the mass ratio of methanol to raw materials was 2.0:1,the reaction temperature was 80?,the reaction time was 3 h,the molar ratio of benzaldehyde to sorbitol was 2.2:1.The sorbitol based gelator could form organogels in a wide range of oils and organic solvents with MGC values ranging from 0.04-0.10g/mL.Besides,the complete gelling time ranged from 5-15 minutes.Additionally,the gelator exhibited good phase-selectivety and the biphasic minimum gelation concentration(BMGC)values ranged from 0.04-0.10 g/mL.The gelator and oil could be recovered with high ratios up to 99%and 75%,and the gelator could be repeatedly used for ten more times.Then,the amino acid based phase-selective gelator was synthesized by the reaction of N-carbobenzyloxy-L-alanine and octylamine in one step and its structure was confirmed by ~1H-NMR and FTIR techniques.A maximum yield of 92.5%was obtained under the optimal reaction conditions:the reaction time was 1 h,the mass ratio of dichloromethane to N-carbobenzyloxy-L-alanine was 60:1,the molar ratio of octylamine to N-carbobenzyloxy-L-alanine was 1.2:1,the molar ratio of(Benzotriazol1yloxy)tris(dimethylamino)phosphonium hexafluophosphate(BOP)to N-Carbobenzyloxy-L-alanine was 1.4:1.The amino acid based gelator could form organogels in a wide range of oils and organic solvents with MGC values ranging from 0.01-0.03 g/mL.Besides,the complete gelling time ranged from 2-10 minutes.Additionally,the gelator exhibited good phase-selectivety and the BMGC values ranged from 0.01-0.03 g/mL.The gelator and petrol could be recovered with high ratios up to 99%and 70%,and the gelator could be repeatedly used for ten more times.