多级错流溶剂萃取分离正丁醇-水混合物

Separation of n-butanol-water mixtures by multi-stage cross-flow solvent extraction

本文针对正辛醇-正丁醇-水三元体系做了液液相平衡研究,并得到了正辛醇-正丁醇-水三元体系在298.15 K下的三元相图。采用溶剂萃取方法,以正辛醇为萃取溶剂,对正丁醇-水混合液进行多级错流萃取分离,结果表明正辛醇可以萃取出正丁醇-水混合液中的正丁醇,且萃取效果随着萃取级数的提高而增大;萃取比对萃取效果的影响先显著增大,而后趋于缓慢;40℃下,当萃取比达到0.3时,三级萃取所对应的正丁醇萃取率与四级萃取所对应的正丁醇萃取率相差很小,萃取率都可以达到98.0%以上,水相中正丁醇的质量分数都低于0.20%,达到了回收正丁醇的目的。

The liquid-liquid ternary phase diagram of the n-octanol-n-butanol-water system at 298.15K has been obtained.n-Octanol was used as the extraction solvent to extract n-butanol from an n-butanol-water mixture.The extractability of n-butanol increased with increasing number of extraction stages.As the extraction ratio increased,extractability increased significantly at first,and then the rate of increase tended to slow down.When the temperature was 40 ℃ and the extraction ratio was 0.3,the extractability difference between the third and the fourth extraction stages was very small.The extractability in both extraction stages reached 98.0%.The mass fraction of n-butanol in the aqueous phase was less than 0.20%.Therefore the aim of recycling n-butanol was achieved.