The Study Of Amino Acid-based Anionic Surfactants Synthesis And Apply

Nowadays there are two important development trends of surfactant industry in the world: on the one hand, synthesis of environmental friendly surfactants is required as far as environmental protection concerned; on the other hand, with the rising price of petroleum and energy crisis, people are demanded to search new resources of starting materials for synthesizing surfactants. In the view of green chemistry and sustainable development, a series of new easily biodegrading amino acid-based anionic surfactants were prepared by reaction renewable resources as starting materials with amino acids. The study of this issue would be benefit to maintaining environment, improving the efficiency of comprehensive use of natural renewable resources, decreasing the pressure caused by the daily reduction of petroleum source, and satisfying the applied needs of all kinds of industries.In this paper, firstly using natural fatty acids including lauric acid, myristic acid, palmitic acid etc. as starting materials, the acryl reaction of starting materials with SOCl₂ respectively, and then using Schotten-Baumann condensation: on the reaction conditions of alkalescence, condensation of acylchloride with amino acid (sarcosine, glycine, alanine etc.), and then acidification, saltation. Aseries of anionic surfactants were prepared.During the preparation of N-acylamino acid, the reaction conditions of acylchloride with amino acid condensation were identified by optimizing the synthetic conditions of N-lauroylsarcosine: mol ratio of amino acid to acylchloride 2:1, reaction taken place in asolvent composed by acetone/water 2:1, acylchloride and 20% NaOH were slowly added to the reaction mixture at the same time while maintaining the pH at 9～10, after completion of adding maintaining reacting for 2.5h at 25℃. The result proved that through these ways, the process was stable and the product yield of acylamino acid was above 80% at average. Melting point of N-acylamino acids was determined and structure of these compounds was identified by Elementary Analysis, IR, ¹HNMR.Some surface properties of amino acid type negative ion surfactants were studied, in this paper critical micelle concentration (cmc) was determined by surface tension method which was determined by slice method, and some physical chemistry parameters were calculated. The experiment results showed that all the surfactants had excellent surfactivity, and comparing these important parameters, the relationship between chemical structures and surface properties was investigated, which would be helpful to the design and industrialization of surfactant more deeply. Formulation was designed as use of synthetic compounds; the formulation not only has the advantage of the safe, but also was efficacy in defense lose-hair.