Study On The Synthesis And Surfactivity Of N-sodium Medium Chain Fatty Acyl Glutamate

N-medium chain fatty acid amino acid surfactant is a kind of amino acid surfactant which is directly prepared by fatty acyl chloride and amino acid salt. It not only has good detersive power, solubleness, bactericidal activity, antistatic activity,anti-corrosion and so on.but also has biodegradability, biological interm-iscibilit and etc. So developing such surfactants has the very vital significance.Camphor tree seed kernel oil can be prepared compound medium chain fatty acid (MCFA) which the purity is over95%by saponification and acidification, using molecular distillation to obtaine lauric acid and decylic acid that the purity was over95%. Saponification process conditions:Reaction temperature was80-85℃, adding the amount of NaOH was3times mole of oil and10%more, the reaction time was3-4h. Acidification process condition:adding6mol/L HC1, standing for layering and taking the supernatant, using80℃water to wash it until the water was neutral. Molecular distillation condition is:under the0.75mbar, steamed out decanoic acid at103.6℃; steamed out of lauric acid at121.4℃.Decanoic acid, lauric acid and decanoic/lauric acid respectively react with thionyl chloride, perparing fatty acid chloride after vacuum distillation. The suitable process conditions are as follows:reaction temperature was80±5℃, raw material ratio(thionyl chloride:MCFA) was1.5-2(mol/mol),instill the thionyl chloride,reaction time was2-3h.Using four factors three levels orthogonal test optimize preparation process conditions of N-sodium medium chain fatty acyl glutamate. The consequences were as follows:①sodium caprinoyl glutamate:the temperature was55℃,reaction medium: acetone/water (mL/mL) was2:1, raw ratio (the molar ratio of acyl chloride and sodium glutamate) was1:2and time was3h.②sodium lauroyl glutamate:the temperature was45℃, reaction medium:acetone/water (mL/mL) was2:1, raw ratio (the molar ratio of acyl chloride and sodium glutamate) was1:3and time was4h.③sodium caprinoyl and lauroyl glutamate:reaction temperature was45℃,reaction medium:acetone/water (mL/mL) was2:1, raw ratio (the molar ratio of acyl chloride and sodium glutamate) was1:2and time was3h. To verify the optimize process conditions, the results showed that the yield of N-decyl acyl glutamic acid sodium was91.3%, N-laurel acyl glutamic acid sodium93.2%, N-decyl/sodium laurel acyl glutamic acid of89.2%.Using the kjeldahl test analyse the products purity; infrared and mass spectrometry analysis verify the product structure. The results show that three kind’s materials were high concentrations and little impurity peak. The purity of sodium caprinoyl glutamate were92.53%, sodium lauroyl glutamate were94.73%, sodium caprinoyl and lauroyl glutamate were91.26%Refer to GB/T5549-2010, testing the surface tension y of N-sodium fatty acyl glutamate. γsodium caprinoyl glutamate=27.9085mN/m; Ysodium lauroyl glutamate=25.5478mN/m; Ysodium decanoyl and lauroyl glutamate=24.0026mN/m.Refer to GB/T6371-2008and the synthetic detergent industry analysis [M], to determine the whiteness and brightness of dirty cloth before and after the water washing, found sodium caprinoyl glutamate had a good decontamination effect; sodium lauroyl glutamate had a good degreasing effect.Using the2152ROSS-Miles test the foaming ability. Sodium caprinoyl glutamate foam height was5.6cm, sodium lauroyl glutamate foam height was8.3cm, sodium caprinoyl and lauroyl glutamate foam height was6.5cm,5minutes later the foam height was4.6cm,7.7cm,5.6cm. Results show that sodium lauroyl glutamate has good foam properties. According to GB/T11983-2008and the synthetic detergent industry analysis [M], sodium caprinoyl glutamate wetting time was57.7s; sodium lauroyl glutamate wetting time was34.4s; sodium caprinoyl and lauroyl glutamate wetting time was51.4s. Results show that sodium lauroyl glutamate has good wettability. According to GB/T6369-2008the emulsifying ability of sodium medium chain fatty acyl glutamate was determined. The results are as follows:Remulsifying power of sodium caprinoyl glutamate=11.87%, Remulsifying power of sodium lauroyl glutamate=33.17%, Remulsifying power of sodium decanoyl and lauroyl glutamate=21.93%. Results show that sodium lauroyl glutamate has a good emulsification among the three products.