Green Synthesis,Characterization, and Properties of Acyl Lysine,Serine, Threonine,and Methionine Derived from Three Types of Natural Oils |
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Authors: | Nan Wang Kaixin Yao Yuzhao Wang Jinhu Ti Jiajing Tan Changyao Liu Guiju Zhang Ce Wang Baocai Xu |
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Affiliation: | 1. Department of Applied Chemistry, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing, 100048 People's Republic of China;2. Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China |
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Abstract: | The development of environmentally benign products has been the subject of growing interest in the field of surfactant chemistry. Acyl amino acid surfactants bearing lysine, serine, threonine, and methionine residues were synthesized using natural oils extracted from coconut, palm kernel, and soybean as acyl donors. The chemical structures were confirmed by high-performance liquid chromatography (HPLC/MS) and infrared (IR) spectra. Their surface activities, ion-specific effects, detergency, and foam properties were studied systematically. The critical micelle concentration (CMC) values depend significantly on amino acid and oil types and follow the orders: (i) Lys > Thr ≈ Ser > Met and (ii) Coconut ≈ Palm kernel > Soybean oil. Interestingly, the ion-specific effects showing that the γCMC value decreases with increasing counterion size and hydrophobicity were observed, and the results were consistent with the famous Hofmeister series. The detergency ability of acyl amino acid surfactants is better than multiple traditional surfactants in distilled water. Although the detergency ability of our products for oil-soiled swatches decreased significantly in hard water, this problem was solved by the C-Lys-Na/AES mixed system showing excellent synergistic effects. Excellent foamability and foam stability were achieved for acyl threonine and serine bearing hydroxyl groups on their headgroups, suggesting that the packing of these surfactants at the air–water interface was assisted by hydrogen bonding. |
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Keywords: | Amino acid surfactants Natural oils Ion-specific effect Detergency Foam |
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