二次萃取蒸馏法提取废次烟叶中烟碱的研究

采用二次萃取蒸馏法,提取废次烟叶中的烟碱。废次烟叶经过浸提、萃取、硫酸反萃、二次萃取和减压蒸馏等处理以提取烟碱,用紫外分光光度法分析了烟碱含量。结果表明,较佳的工艺条件为:以4.5 g/L的NaOH溶液浸泡粉碎后的烟叶,置于60℃水浴中振荡3.5 h,过滤得浸提液;滤渣再次浸提,并将两次浸提液合并。调节浸提液pH≥13,用正己烷按照体积比1∶2萃取浸提液3次。有机相用20%硫酸溶液反萃,调节pH≥13后,用正己烷二次萃取,合并有机相,减压蒸馏,以回收有机溶剂,残液即为含量40%的烟碱产品,提取率达75%。

Study on extraction of nicotine from inferior tobacco by twice extraction and distillation method

In order to reuse inferior tobacco,twice extraction and distillation method has been introduced in this paper for the extraction of nicotine.This method includes several processes,such as immersing,solvent extraction,sulphuric acid extraction in reverse,second solvent extraction and vacuum distillation.The content of nicotine is determined by the ultraviolet spectrophotometry.The experiment results showed that proper conditions should be fixed as below.The tobacco dipped in the 4.5 g/L sodium hydroxide solution was put in 60℃ water,surged for 3.5 h and then taken out.The obtained liquid was adjusted to pH≥13 by sodium hydroxide solution and then extracted for three times with n-hexane.The organic phase was extracted in reverse with 20% H_2SO_4 solution and then adjusted to pH≥13 again.After that,the second extraction was carried out with n-hexane.Then vacuum distillation was adopted at last to callback organic solvent.Finally,nicotine was obtained with 40% concentration and 75% yield.