Synthesis And Properties Of Sodium N-lauroyl Sarcosinate

With the development of the national economy,people have the better living standards,increase their own environmental awareness and people have stricter requirements for chemicals,but the oil resources are increasingly scarce,so it becomes a hot topic and trend in the industry to develop the efficient,green,sustainable and versatile surfactants.Sodium N-lauroyl sarcosinate?LS?is a kind of amino acid type anionic surfactant with low-stimulus and good biodegradable properties.LS is widely applied in the food,cosmetics,pharmaceutical,petroleum exploitation and other industries,which shows good surface activity,water solubility and hard water resistance,also has strong foaming power,good wetting property,characteristics of anti caries,better compatibility and so on.Nowadays the industrial production of sodium N-acyl sarcosine is mainly based on the Schotten-Banmann method using acetone-water as the mixed phase,adding fatty acid chloride and sodium hydroxide solution,the process is relatively complicated,existing certain risks and the costs of production are relatively high.When acetone is as organic solvent,it is prone to self-condensation under alkaline conditions to generate impurities which causes the change of products'color;acetone has a certain toxicity;a low boiling point and is volatile,which causes the loss of raw materials and higher risk of the production process.From the future development trend of surfactants and the concept of green chemistry,this paper use a safer organic solvent in the synthesis of LS by the Shotton-Bowman method and study the method systematically.This paper systematically study the synthesis conditions of LS using acetone or ethanol as organic solvent separately,optimize the reaction conditions and find the best results.Then LS is mixed with other types of surfactants and the properties of blended systems are studied and the application performance of the blend systems are tested.The specific research contents are as follows:The reaction conditions for the synthesis of lauroyl chloride were optimized by single factor experiments.As a result,the optimal conditions for the synthesis of lauroyl chloride were as follows:molar ratio of reactants n?lauric acid?:n?thionyl chloride?=1:1.4,reaction time was 5 h,and the yield could reach 96.74%.LS was synthetised by using acetone-water as mixed phase.In the beginning,a single factor experiment was conducted to examine different reaction conditions on the yield of the condensation reaction product.Then an orthogonal test was performed to optimize the synthesis process.The optimal reaction conditions were:when n?sarcosine sodium?:n?lauroyl chloride?=1.3:1,the reaction temperature was 25 ^oC,the reaction time was 3.5 h,and the yield of LS reached 97.15%under the optimized conditions.Changing the organic solvent in the condensation reaction,ethanol was used instead of acetone.And the orthogonal test was carried out,the optimal reaction conditions for using ethanol as the organic solvent were:n?sarcosine sodium?:n?lauroyl chloride?=1.4:1,reaction time was 3.5 h,V?ethanol?:V?water?=2:1,the yield of LS reached 95.86%under optimized conditions.The structure of product LS was characterized by IR,¹H NMR and MS detection methods.Surface chemical properties and interaction of binary surfactant systems of LS with nonionic surfactant fatty alcohol polyoxyethylene ether?AEO₉?,cationic surfactant dodecyl trimethyl ammonium chloride?DTAC?and Amphoteric surfactants dodecyl dimethyl betaine?BS-12?had been investigated respectively.And last,the application performance of LS/AEO₉,LS/DTAC and LS/BS-12 three compound systems were studied,including wetting,emulsification,foam and solubilization properties.The results showed that the three compound systems have better surface activity and synergistic effect under certain conditions,the interactions between the mixed surfactants will result in a change in the application performance of the three compound systems compared to the application performance of a single surfactant.It provides some certain theoretical references for the application of LS and similar amino acid surfactants in industry or products.