Preparation And Properties Of Amphoteric Phosphate Fatliquor Based On FTE

Based on the strong chemical interaction between the phosphate ion and the metal ion,there is excellent bond between phosphate surfactants and leather fiber.Meanwhile phosphate surfactants can be efficiently absorbed and biodegraded,meeting the basic requirements of green development of leather chemicals.Therefore,structure-novel and functional phosphate surfactants have become one of the hotspots in the development of leather chemicals.In this paper,a series of new amphoteric phosphate surfactants were synthesized from the triethanolamine ester?FTE?intermediates prepared from different fatty acids such as lauric acid,palmitic acid,stearic acid and oleic acid.The correlation between the basic surface activity and the structure of the series products was studied.The fatliquoring performance of the series of mixtures was studied systematically through the leather fatliquoring application experiments and analysis.First,the fatty acid triethanolamine monoester?FTM?and the fatty acid triethanolamine diester?FTD?were phosphorylated with phosphorus pentoxide as a phosphorylating reagent respectively to obtain a series of fatty acid triethanolamine monoester phosphate sodium salt?FMPS?and fatty acid triethanolamine diester phosphate sodium salt?FDPS?.The optimal conditions of phosphorylation reaction were explored.The structures of the synthesized products were characterized by FT-IR.The ionicity of the products was determined.The effects of the length and degree of unsaturation of the lipophilic group on the basic surface activity?CMC and corresponding surface tension?and emulsifying ability of the product were investigated.The results show that:?1?The optimal phosphorylation condition for FMPS synthesis is n?ROH?:n?P₂O₅?=2.2,T=75?,t=3h,the corresponding reaction conversion rate is 90.6%,and the phosphoric acid monoester content in the obtained product is 77.5%.The optimal phosphorylation condition for FDPS synthesis is n?ROH?:n?P₂O₅?=2.2,T=80?,t=4h,the corresponding reaction conversion rate is 87.5%,and the phosphoric acid monoester content in the obtained product is 76.3%.?2?Both FMPS and FDPS have zwitterionic characteristics.And their surface activity and emulsifying ability have a consistent relationship with the structure.With the growth of lipophilic carbon chain,their surface activity and emulsifying ability decrease.The increase of unsaturation can improve their surface activity and emulsifying ability to some extent.When the fatty acid structure is the same,the surface activity and emulsifying ability of FMPS are better than FDPS.?3?Among FMPS,FMPS-1 has the strongest surface activity,the CMC is 39.8 mg/L,and the surface tension is 37 mN/m.Using liquid wax as the oil phase,the emulsifying ability of FMPS-1 having a phase separation time of 127.8s is better than sodium dodecyl sulfate having a phase separation time of 114.5s.?4?Among FDPS,FDPS-1 has the strongest surface activity,the CMC is 51.3 mg/L and the surface tension is 43.1 mN/m.Having a phase separation time of 121.8s,its emulsifying ability is better than sodium dodecyl sulfate.Secondly,a series of intermediates were prepared with different fatty acids such as lauric acid,palmitic acid,stearic acid and oleic acid,and triethanolamine as raw materials under the conditions of molar ratio of fatty acid to triethanolamine of 1.0,1.5 and 2.0,respectively.The intermediates were phosphorylated with P₂O₅ to prepare a series of amphoteric phosphate fatliquors?APF?containing FMPS and FDPS as emulsified component and fatty acid triethanolamine triester?FTT?as neutral oil component.The composition of APF and its emulsion particle size,emulsion stability and isoelectric point were determined.In order to explore the effects of fatty acid carbon chain length and molar ratio of fatty acid to triethanolamine on its fatliquoring and dyeing performance,APF was applied to the fatliquoring treatment of chrome tanned leather and TWT tanned leather respectively.The results show that:?1?As the molar ratio of fatty acid to triethanolamine increases,the content of FMPS in APF decreases,the contents of FDPS and FTT increase.?2?As the length of fatty acid carbon chain increases,the average particle size of APF emulsion increases,and the stability of the emulsion decreases.The 1:9 emulsions of APF products prepared from lauric acid and palmitic acid do not layer after 24 hours.The average particle size and particle size distribution of APF prepared by the same fatty acid increase and broaden as the molar ratio of fatty acid to triethanolamine increases.?3?The isoelectric points of series APF are between2.5 and 4.0,which is suitable for the fatliquoring process of chrome tanned leather and TWT tanned leather.?4?A FTE was prepared with palmitic acid and triethanolamine as raw materials under the molar ratio of fatty acid to triethanolamine of 1.5,and its corresponding APF-5 had the best fat-softening effect.The fatliquoring effect of series APF-5 on chrome tanned leather is basically the same as that of commercially available anionic phosphate ester fatliquor,and its fatliquoring effect on TWT tanned leather is obviously better than the later.?5?In the application experiment of dyeing and fatliquoring,the dye uptake rate of chrome tanned leather reached 97.75%,the K/S value of dyed crust leather reached 11.37,and the dyeing rate of TWT leather dye reached94.98%,the dyed crust leather has a K/S value of 8.83 when using APF-5 for fatliquoring.The dye uptake rate of chrome tanned leather reached 94.21%,the K/S value of dyed crust leather reached 7.58,and the dyeing rate of TWT leather dye reached 91.52%,the dyed crust leather has a K/S value of 5.06 when using commercially available anionic phosphate ester fatliquor for fatliquoring.Finally,the biodegradability of APF fatliquor was studied by BOD₅/COD_Crr method and COD₃₀0 method.The experimental results show that the BOD₅/COD_Crr values of APF are all greater than 0.45,the 30-day COD removal rates of APF are higher than 90%,which means APF has good biodegradability.