Synthesis And Properties Of A Class Of Phosphate Amphoteric Surfactants

Phosphate amphoteric surfactants whose structures are similar to phosphoglyceride in cells not only have the multifunctional properties belonging to amphoteric surfactants,but also show excellent application properties and special smooth feel,such as excellent foaming,detergency,acid and alkali resistance,softness,antistatic and sterilization performance.Thus they are widely applied in daily chemicals fields.Moreover,amide-type phosphate amphoteric surfactant contains amide and phosphate groups in the molecule,exhibiting good compatibility with the skin,mild performance and good biodegradability,making it more generally applicable.With the improvement of living standard,the study of the environmental-friendly surfactant can provide new product with better performance for the surfactant industry,such as replacing some large dosage but not-environmental-friendly ingredients used in industrial formulas.It is of great significance to the sustainable development of resource.Based on the above,this paper synthesized a class of fatty amide phosphate amphoteric surfactants and studied their synthetic process,surface properties,application performance and compounding performance.Moreover,the application of product in shampoo formula had also been studied.The following were the content and results of the study:Phosphate amphoteric surfactants with different carbon chains?abbreviated as C_n-APA?were synthesized by using sodium dihydrogen phosphate,epichlorohydrin,fatty acid and N,N-dimethyl-1,3-propanediamine as raw materials.Among them,the condensation of fatty acid with N,N-dimethyl-1,3-propanediamine obtained intermediate alkyl amide propyl dimethyl tertiary amine?abbreviated as C_n-PKO?with a yield of 94%.The suitable conditions were attained by optimizing the conditions of addition reaction and quaternization reaction.Synthetic conditions of the intermediate sodium 2-hydroxy-3-chloropropyl phosphate?abbreviated as HCP?were as follows:when n?epichlorohydrin?:n?sodium dihydrogen phosphate?=1:1.2,the mass concentration of sodium dihydrogen phosphate was 50%,and the reaction lasted for 5 h at 85oC.Finally,the yield of the HCP could reach 79%.As for the C_n-APA synthetic process:when the temperature was controlled at 120oC,the pressure was0.3 MPa,n?HCP?:n(C₁₂-PKO)=1:1,and the reaction lasted for 5 h.Based on the above conditions,the yield of the C₁₂-APA,C₁₄-APA and C₁₆-APA could reach 94.1%,93.8%and93.5%,respectively;The intermediates and products were purified and characterized by FT-IR,MS,and ¹H-NMR,confirming the successful synthesis of target products.It was found the Krafft points of C₁₂-APA,C₁₄-APA and C₁₆-APA were all below 0oC with a wide applicable range.The cmc of three surfactants was very small and decreased with the increase of the hydrophobic chain length.?_cmc decreased firstly and then increased.The micellization thermodynamic functions of products were calculated from 25oC to 40oC.The results showed that the micellization was an exothermic and spontaneous process driven by both thermal and entropy effects;the rheological properties of the C₁₆-APA/sodium salicylate system were studied and the system exhibited the characteristics as worm-like micelles;three products had poor wetting ability on canvas,good emulsification ability on liquid paraffin,and excellent foaming and foam stabilization properties.The products demonstrated good stain removal effect on sebum stained cloth.The antistatic properties of the three products were outstanding and close.The bactericidal rate of C₁₂-APA against Escherichia coli was less than 90%,and that of Staphylococcus aureus and Candida albicans was both above 99%.It was found that the SDS/C₁₂-APA compounding system had a synergistic effect on reducing cmc,the effectiveness and efficiency of surface tension.The interaction between the molecules of system was moderate,and the application properties of the system had a significant synergistic effects including wetting,emulsification and foaming under certain compounding molar ratios.However,the AEO₉/C₁₂-APA compounding system had no synergistic effect;besides,the micropolarity,aggregation numbers of micelle,and mean hydrodynamic radius of micelles of compounding system were studied.From the obtained results,the SDS/C₁₂-APA system existed synergistic effect,but the AEO₉/C₁₂-APA system had no synergistic effect.Moreover,the morphology of the micelles formed by the two compounding system was simply analyzed;the additon of n-butanol could reduce the?_cmc of C₁₂-APA aqueous solution and increase its cmc.As the n-butanol concentration increased,cmc increased firstly and then decreased,?_cmc decreased;the addition of polyethylene glycol could reduce the?_cmc and increase cmc of C₁₂-APA aqueous solution,and it didn't change much with the increase of the polyethylene glycol concentration.As the polymerization degree of polyethylene glycol increased,cmc continued to increase and?_cmc continued to decrease,but stayed constant when with the high polymerization degrees?2000 and 11000?.C₁₂-APA was applied in a silicone-free and sulfate-free transparent shampoo formula.The pH value of the formula was about 6.0?6.5,and the viscosity was about 3500?4000mPa.s.The heat and cold resistance stability tests all met the national standard.The sensory evaluation of the shampoo showed that it exhibited good performance and obvious slippery feeling,and was expected to be mass-produced.