Synthesis And Properties Of N-acyl Group Polypeptide Surfactant With Different Length Of Carbon Chain Based On Leather Wastes

Different N-acyl compound polypeptide surfactants were synthesized in this paper by using hydrolyzed leather scraps and lauroyl chloride, nutmeg acyl chloride, palmitoyl chloride, oleoyl chloride, dodecyl benzene sulfonyl chloride as raw materials, NaOH as acid acceptor, and water-n-hexane mixture as solvent. The structures and properties of the compound peptide surfactants were analyzed in detail.First, the chrome leather scraps were hydrolyzed by NaOH and the composite hydrolyzed peptides was obtained. The structures and properties of hydrolysate were analyzed by FT-IR, element analysis and other testing methods. The results showed that: the product is composite hydrolyzed peptides, M?=88523 D, hydrolysate solid content is 28.95%, concentration is 0.3175 g/m L, nitrogen content is 14.5%, the carbon content is 40.63%, and hydrogen content is 6.18%;Second, the influence factors on the reaction such as the pH, temperature, time, feeding ratio and the dosage of solvent were explored through the single factor experiment, and the optimal conditions of reaction were identified. The research showed that with the increase of the length of carbon chain, the conversion of the reaction reduced. The conversion rate of(DBSC) system is lowest because of the space steric hindrance is larger compared with linear oleoyl chloride and the matchup sulfonyl makes benzene passivation.Finally, the intrinsic viscosity, infrared spectra, surface tension, wetting ability, foaming ability, emulsion ability and HLB value of the products were characterized. The products were successfully synthesized through the structure characterization. The surface tension under the critical micelle concentration showed the compound polypeptide surfactant could reduce the surface tension of the water effectively. The wetting ability of the surfactants reduced with the increase of carbon chain length. The foaming ability of surfactants was not high and the surfactants have good steady performance. The emulsification effect of n-hexane was better than oleic acid, and the longer length the lipophilic group has, the better emulsifying ability surfactant has. But the emulsification ability of dodecyl benzene sulfonyl compound polypeptide surfactant was weak compared with the oleoyl compound polypeptide surfactant. The laurel acyl and nutmeg acyl compound polypeptide surfactants were suitable for wetting agent and penetrating agent, while palm acyl, oil acyl, and dodecyl benzene sulfonyl compound polypeptide surfactants have the potential as an oil-in-water type emulsifier.