Synthesis,properties And Application Of Fatty Acid Monoethanolamide Polyoxyethylene Ether

Fatty acid monoethanolamide polyoxyethylene ether（C_n-NEO₉）of four different carbon chain length were prepared by a three-step method.And their surface chemical properties and application properties were studied.Oleic acid monoethanolamide polyoxyethylene ether(C₁₈-NEO₉),which has excellent performance,was selected to be used in microemulsions and laundry detergents.The main contents and results are as follows:C_n-NEO₉ was prepared by esterification reaction,acylation reaction and ethoxylation reaction.The results of static surface chemistry of C_n-NEO₉ measured at 298 K showed that as the number of carbon atoms increased,the critical micelle concentration（cmc）of C_n-NEO₉gradually decreased and the critical surface tension(γ_cmc)gradually increased.The surface adsorption efficiency(pc₂₀)in descending order was palmitic acid monoethanolamide polyoxyethylene ether(C₁₆-NEO₉),myristic acid monoethanolamide polyoxyethylene ether(C₁₄-NEO₉),C₁₈-NEO₉ and laurel Acid monoethanolamide polyoxyethylene ether(C₁₂-NEO₉).The results of dynamic surface chemistry of C_n-NEO₉ measured at 298 K showed that when the mass concentration of C_n-NEO₉ was less than cmc,it was diffusion controlled adsorption in the early stage of adsorption,and hybrid dynamic controlled adsorption in the late stage of adsorption.When its mass concentration was greater than cmc,the adsorption process was controlled by hybrid power.At the same time,the diffusion coefficients in the early and late stages of adsorption decreased with the increase of the carbon number of C_n-NEO₉.But the change rule of the diffusion coefficient in the early stage of adsorption was only reflected when the mass concentration of C_n-NEO₉ was greater than cmc.The research results of application performance of C_n-NEO₉ showed that the cloud point of the series of C_n-NEO₉was higher than 60℃.C₁₈-NEO₉ in the series C_n-NEO₉ had the best water solubility,and there was still no gel phase area at 2℃.With the increase of the carbon chain length,the wettability of C_n-NEO₉ first weakened and then strengthened;the emulsification performance gradually increased;the foaming performance gradually decreased,and the foam stability increased.The order of decontamination ability of C_n-NEO₉ was sebum stained cloth>carbon black stained cloth>protein stained cloth.As the length of the hydrophobic carbon chain increased,the decontamination effect of C_n-NEO₉ on different soiled cloths decreased.C₁₈-NEO₉ was used as emulsifier to prepare oil-in-water（O/W type）microemulsion.The better formula was determined through the pseudo-three-phase diagram,the particle size and its distribution of the microemulsion.The average particle size of O/W-type microemulsion system was 18.6 nm.,and the polydispersity index（value of PDI）was 0.206.When the water content was greater than 70%,the system could form an O/W type microemulsion.Microstructure of microemulsion was photographed by transmission electron microscopy photos.It showed that the microemulsion droplets were uniformly distributed and spherical in shape.The microemulsion of the better formula had good centrifugal stability and high temperature resistance.But it was not resistant to acids,alkalis and electrolytes.Three laundry detergent were prepared with C₁₈-NEO₉ as detergent active.The concentrated laundry detergent was a light yellow transparent liquid.The laundry gel beads and the laundry gel beads containing protease were golden yellow transparent liquids.None of the three formulation samples had a strong pungent odor.The viscosity,p H,heat resistance stability,cold resistance stability and centrifugal stability of the three laundry detergents all met the standard.In terms of foam performance,the foaming properties and foam stabilization of the three formulas were similar.And they were significantly better than standard laundry detergents.In terms of decontamination performance,concentrated laundry detergent had better decontamination performance compared with standard laundry detergent.Laundry gel beads and protease-containing laundry gel beads had excellent stain removal performance compared with standard laundry.With the passage of time,the decontamination performance of protease-containing laundry beads on protein stained cloths had declined,but it was still better than the formulation of protease-free laundry beads.