Purification Of Acenaphthene And Emodin By Crystallization From The Systerm Of Solvent/Surfactant

Novel purifying processes of crystallization of crude acenaphthene and crude emodin from solvent/surfactant system were studied.According to the properties of crude material,suitable solvent and surfactant were screened out.In the purifying process,impurities were emulsified and dissolved into the system,while target product was crystallized and precipitated.The enfluencing factors such as surfactant,mixed solvent and ratio,time and stirring on the purifications were investigated based on the single factor experiment and orthogonal experimentals.The findings were listed as follows:(1)Purification of acenaphtheneIt was screened out that cationic surfactant DDBAC had good purification effect with the mixed solvent water and methanol.The parameter optimization was established: the of crude acenaphthene 0.4 g,DDBAC 0.08 mL,mixed solvent 8 mL,the water/methanol volume ratio was 8:2,stirring at 400 r·min-1 for 70 min.Acenaphthene was purified from crude product in a purity above 99% and a yield up to 93%.(2)Purification of emodinEmodin were crystalized from ethanol/water system,with 2,6-lutidine as co-solvent,dodecyldimethylamine oxide as surfactant,glycerol as co-emulsifier.Optimization parameter was established: emodin 0.5 g,surfactant 0.22 mL,co-solvent 20 ?L,mixed solvent ethanol/water 12 mL at the ratio of 6:4,0.15 mL co-emulsifier,and stirred at a rate of 220 r·min-1for 65 min.Under the optimum conditions,emodin was purified from crude product in a purity above 90% and a yield up to 83%.Through the experiment,two different kinds of surfactants were selected for purifying crude acenaphthene and emodin,respectively;and the possible mechanisms were proposed.It was predicted that this novel method could be applied in wider area in purification field than the two cases demonstrated in this study.