摘要
以羟甲基-12-冠-4和1,6-二溴己烷、1,10-二溴癸烷为原料,在KH催化下,分别合成一溴己氧基12-冠-4和一溴癸氧基12-冠-4;将一溴癸氧基12-冠-4与硫脲加到无水乙醇中,反应过夜合成至今还未见报道的巯基癸氧基12-冠-4,并对其进行表征确认。在不同的pH条件下,分别比较了3种化合物对Li+和Na+的选择配合情况。结果表明,一溴己氧基12-冠-4和一溴癸氧基12-冠-4对Li的配合比都是1∶1,在氯仿中的萃取率不随冠醚环上支链的长短变化而变化,但随pH的增大而增大,达峰值97.69%后趋于稳定;巯基癸氧基12-冠-4由于巯基水解的效应对Li配合物的萃取能力稍差,且随pH的增大而减小,在75.76%后趋于稳定。同时它们对钠的萃取能力则较差。由此可见,12-冠-4对Li具有很好的选择配合能力,该研究为冠醚更广应用提供了一定的基础。
2-[（6-Bromohexyl）oxy]methyl-12-crown-4 and 2-[（10-bromodecyl）oxy]methyl-12-crown-4 were synthesized under certain conditions when 2-（hydroxymethyl）-12-crown-4,1,6-dibromohexane and 1,10-dibromodecane used as raw materials and KH as catalyst.And 2-[（10-bromodecyl）oxy]methyl-12-crown-4 further reacts with thiourea in a solvent of anhydrous ethanol to produce the target compound of 2-[（10-Mercaptodecyl）oxy]methyl-12-crown-4 which has never been reported before.The composition and structure are characterized.Their competitive complexation between Li＋ and Na＋ in different pHs are studied.It is revealed that all chained 12-crown-4 derivatives show 1∶1 coordination ratio with lithium.The pH does not have any influence on the extraction efficiency when 2-[（6-bromohexyl）oxy]methyl-12-crown-4 and 2-[（10-bromodecyl）oxy]methyl-12-crown-4 are compared in the consideration of alkyl chain elongation.However,both increase as pH increases,leveling off at 97.69%.In contrast to 2-[（10-bromodecyl）oxy]methyl-12-crown-4,2-[（10-mercaptodecyl）oxy]methyl-12-crown-4 shows low extraction efficiency for Li＋ due to its ionization of thiol group,decreasing as increase of pH and leveling off at 75.76%.All the derivatives demonstrate poor extraction efficiency for sodium,revealing 12-crown-4 with an excellent selectivity for lithium.This work provides a new basic chemical for the crown ether family.
出处
《化学试剂》
CAS
CSCD
北大核心
2012年第7期637-639,661,共4页
Chemical Reagents
基金
国家自然科学基金资助项目(51168001)
