Synthesis Of Calix[8]arene Phosphorate Derivatives For Extraction Of La(?) And Ce(?)

High-purity light rare earth has become an important field of research in rare earth industry.In this paper,calix[8]arene was synthesized as the starting material,then calix[8]arene derivatives with phosphine oxide-binding groups were also obtained.The calix[8]arene phosphorate derivatives were used as extractants to separate lanthanum and cerium for the first time.The results show that the calix[8]arene phosphorate derivatives can be used to separate lanthanum and cerium,which is expected to be a new extractant for the separation of light rare earth.The primary research contents are listed as the following:1.The 4-tert-butylcalix[8]arene was synthesized from 4-tert-butylphenol and para-formaldehyde,and its structure was characterized.The effects of raw materials,catalyst,reaction time and reaction temperature on the yield were investigated.The yield was 67% in the optimum condition,which was higher than that reported in the literature.2.Using 4-tert-butylcalix[8]arene and diethyl chlorophosphate as the starting material,calix[8]arene phosphorate derivatives were synthesized by a series steps.The best experimental productivity was 92%.3.The extraction of lanthanum and cerium was studied by using 4-tert-butyl calix [8] arene and its phosphate derivatives as extractants.The extraction effects of various experimental parameters such as metal iron concentration,extractant concentration,W/O ratio,aqueous acidity,reaction time and temperature were also investigated and extraction stoichiometry deduced.The results showed that pH = 6.5,experiment time was 1h,the extraction efficiency is the highest,and the extraction reaction is an endothermic and spontaneous process.The extraction of lanthanum and cerium using calix[8]arene phosphorate derivatives is higher than calix[8]arene,indicating that the introduction of phosphate groups increases the extraction efficiency.The 4-tert-butyl calix[8]arene phosphorate derivatives can be used for separation.The preliminary calculation shows that the high purity lanthanum and cerium are obtained by multi-stage centrifugal fractionation.4.At the same time,the extraction mechanism of calix[8]arene and its phosphorate derivatives on metal ions was studied.The results show that calix[8]arene phosphorate derivatives have ability to recognize light rare earths.Afterthe phenolic hydroxyl groups are replaced by phosphate ester groups,the cavity size is closer to rare earth ions.And the introduction of new groups has stronger coordination ability,so the selectivity and extraction efficiency are higher.