Study On Synthesis And Surfactant Properties Of Lauraldehyde Glycerol Acetal Derivatives

Biodiesel,as a renewable alternative energy,has been widely concerned,researched and used by people in all over the world due to its environmental and renewable feature.With the growing worldwide production of biodiesel,crude glycerol has been obtained widely as the main byproduct from biodiesel.Too much surplus of this glycerol will impact not only the glycerol market but economic feasibility of biodiesel industry.Therefore,how to convert the crude glycerol into value-added chemicals has become a hot topic of thinking and research.In recent years,the researches converting the crude glycerol into value-added chemicals through oxidation,hydrogenation,esterification and etherification have been reported.A new type of green surfactant can be synthesized by using glycerol as a hydrophilic group.Surfactants,known as industrial monosodium glutamate,are indispensable fine chemicals in daily life and industry.With the continued focus on energy,environment and health,the use of renewable biomass as raw materials to synthesize biodegradable,environment-friendly and renewable green surfactants has become an inevitable trend in the development of present and future surfactants industry.The cleavable aliphatic aldehyde glycerol acetals are synthesized from glycerol with aliphatic aldehydes.In this paper,we synthesized three glycerol acetal derivatives using aliphatic aldehydes glycerol acetal as a hydrophobic intermediate,and the surfactants properties were also investigated.The main research contents and conclusions are as follows:1.Lauraldehyde glycerol acetal acetate was obtained in the reaction of lauraldehyde glycerol acetals and acetic anhydride and the structure of product was characterized by IR,GC,GC-MS and elemental analysis.The influence of different factors on the yield of lauraldehyde glycerol acetal acetate was also investigated in this step.The optimum conditions for preparation of were:the amount of catalyst was 1.0 mol% was used with reaction,n(lauraldehyde glycerol acetal):n(acetic anhydride)= 1:2,reacted for 3 hours at 110 oC at this time yield of lauraldehyde glycerol acetal acetate achieved 91.9%.2.Lauraldehyde glycerol acetals were sulfated with sulfur trioxide-pyridine complex then neutralized with sodium hydroxide to obtain sodium lauraldehyde glycerol acetal sulfate(GlyAcS)and its structure was identified by IR,ESI-MS and elemental analysis.The conditions of sulfation processes were optimized by the Single-factor experimental design,and the optimized reaction conditions were as followings: the solvent was CCl4,n(lauraldehyde glycerol acetal):n(sulfur trioxide-pyridine complex)= 1:1.2,reacted for 4 hours at 45 oC.The yield of sodium lauraldehyde glycerol acetal sulfate achieved 82.6%.3.Disodium lauraldehyde glycerol acetal sulfosuccinates(GlyAcSS)were synthesized starting from esterification reaction of lauraldehyde glycerol acetals with maleic anhydride,followed by sulfonation with sodium sulfite.The conditions of esterification processes were also optimized by the single-factor experimental design,and the optimized reaction conditions were as followings: the amount of catalyst was 1.0 mol% was used with reaction,n(lauraldehyde glycerol acetal):n(maleic anhydride)= 1:1.2,reacted for 4 hours at 80 oC at this time yield of disodium lauraldehyde glycerol acetal sulfosuccinates achieved 96.3%.4.Some properties of the synthesized surfactants were measured and compared with the traditional surfactant LAS,such as Krafft point,surface properties,foaming,emulsification,solubilization lime soap dispersibility and salt-tolerance.The experimental results show: GlyAcS and GlyAcSS both have low Krafft points of less than zero degrees;GlyAcS and GlyAcSS both have good performance of reducing surface tension,cmc = 9.99×10-4 mol/L,?cmc = 26.76 mN/m and cmc = 4.67×10-4 mol/L,?cmc = 26.93 mN/m respectively;GlyAcS(4%)have better lime soap dispersibility than GlyAcSS(28%);GlyAcS and GlyAcSS also show better properties in foamability,solubilization and emulsification,but are not as good as LAS;GlyAcS and GlyAcSS have excelent performance on salt-tolerance and can tolerate NaCl concentration of 10% and 8%,far more than LAS(2%).