The Experimental Research And Exploration Of The Synthesis Of Alkyl Ketene Dimer AKD By Solvent-free Method

Alkyl ketene dimer(AKD),as sizing agent,is widely used in papermaking process.It is usually reacted by triethylamine and aliphatic acyl chloride in toluene and other solvents.Because of the green chemistry and the consideration of human health,it is necessary to reduce or avoid the use of harmful solvents.In view of this problem,this paper carries on the related research,and obtains the following results:1.The molecular structure of amine salts was observed and analyzed by means of SEM,FR-IR,HNMR and Single Crystal XRD.The high viscosity is mainly attributed to the dendritic structure of amine salts,the very fine particle size and the interaction between amine hydrochloride and AKD.2.AKD was synthesized with benzene,toluene,n-hexane and ethyl acetate as solvents.The effects of different solvents on the synthesis of AKD were studied.The viscosity of benzene and toluene as solvents was the lowest and the yield of AKD was the highest.Under the optimum conditions,the purity and yield of AKD could reach 89.6%and 90.7%.3.It is feasible to synthesize AKD from triethylamine by solvent-free method.The purity and yield of AKD are above toluene.It is more environmentally friendly and the post-treatment method is more convenient.Under the optimum conditions,the purity and yield of AKD are 91.3%and 90.9%,respectively.4.It is feasible to synthesize AKD with tri-n-propylamine instead of triethylamine as raw material without solvent.The purity and yield of AKD are above triethylamine,and the change of viscosity is more gentle.Under the optimum conditions,the purity and yield of AKD can reach 92.6%and 91.4%.5.AKD was synthesized from tertiary amine M with low viscosity and easy control.The ratio of raw materials could be carried out at 1:1.It was an optimum material for further study.The purity and yield of AKD were 93.4%and 91.3%respectively under the optimum conditions.6.TEMED as raw material also has the problem of high viscosity.At the same time,some AKD is hydrolyzed in the process of water washing,which makes the mixed solution Milky white.The product AKD appears impurity peaks at 300 nm in ultraviolet spectrophotometry,which indicates that there are a lot of impurities in the product.AKD was synthesized from TEMED with low yield and purity.