采用共沸间歇精馏从桉叶油母液中回收1,8-桉叶油素

Recovery of 1,8-cineole from byproduct of eucalyptus oil by an azeotrope batch distillation

本文研究了一种从桉叶油副品—桉叶油母液中分离回收1,8-桉叶油素的工艺。通过比较在桉叶油母液中加入不同酚类添加剂对精馏馏出曲线的影响,确定了以苯酚为共沸剂的两步精馏工艺:第一步,在料液中加入苯酚精馏脱除杂质组分,苯酚与料液质量比1∶1,回流比为4∶1,压力3.0kPa;第二步:在第一步的釜底液中加入水,水与釜底液质量比1∶1,常压精馏,回流比2∶2,得苯酚和桉叶油素的共沸物,共沸物分层得1,8-桉叶油素产品,纯度98.8%,回收率68.5%。与已有专利相比,所建立的以苯酚和水为共沸剂两步精馏工艺,不仅获得了高纯桉叶油素和较高回收率,且节省了能量与精馏时间。

Recovery of 1,8-cineole from the mother liquid,a byproduct of eucalyptus oil industry was studied by batch distillation.Effects of different phenolic additives including phenol,p-cresol,m-cresol and resorcinol on effusing curves of the target 1,8-cineole as well as the main impurities of limonene and p-cymene were investigated by batch distillation.The technology of two-steps batch distillation using phenol as an additive was selected.First,phenol was added to remove the light （low-boiling point） impurities and to obtain the residue in pot,and the optimum distillation conditions were：ratio of phenol and the mother liquid in 1 ∶ 1 （w/w）,reflux ratio at 4 ∶ 1,absolute pressure at 3.0 kPa; Second,the azeotrope of 1,8-cineole with water was distilled from the residue in pot,and the optimum distillation conditions were ∶ ratio of water and residue in 1 ∶ 1 （w/w）,reflux ratio at 2 ∶ 2,ordinary pressure.Collecting the upper layer of the azeotrope of 1,8-cineole with water,1,8-cineole was obtained in a purity of 98.8％ and a recovery yield of 68.5％.Compared with what had been patent,the present technology has the advantages of high recovery of pure 1,8-cineole,energy-saving and less time consumed.