Extraction Of Praseodymium And Neodymium Ions With P-Tert-butyl Calixarene Phosphate

In this paper,formaldehyde and p-tert-butyl phenol were used as raw materials to synthesize calix [8] arene phosphate derivatives by the substitution reaction with diethyl chlorophosphate.The products were further characterized by FT-IR,MS ESI,1HNMR,etc.Chloroform selected as solvent for calix [8] arene and its phosphate derivatives.The effects of on the extraction efficiency of praseodymium and neodymium ions in aqueous solution were investigated.Moreover,the effects of synergistic extraction system on the extraction performance and the extraction mechanism were studied.The researches in details were as follows:(1)Methanol and p-tert-butyl phenol,sodium hydroxide used as the raw materials and catalyst,respectively,the calix [8] arene is obtained by condensation reaction.In tetrachloromethane,the calix [8] arene phosphate derivatives were obtained by esterification reaction between calix [8] arene and diethyl chlorophosphate with catalyst TBAB.All of the products were characterized by FT-IR,1HNMR,MS ESI,etc.(2)The effects of calix [8] arene and its phosphate derivatives on the extraction efficiency of praseodymium and neodymium icons such as pH,extraction agent concentration,extraction phase ratio,co-existing icons,etc.were investigated.Furthermore,the extraction ablility of calix [8] arene and its phosphate derivatives were compared.The results showed that the optimal conditions for calix [8] arene to extract praseodymium and neodymium icons were extraction agent concentration: 0.0003mol/L,shock extraction time: 50 min,water oil ratio: 1:1,and extraction solution pH: 1,and the optimal conditions for phosphate derivatives to extract praseodymium and neodymium icons were extraction agent concentration: 0.0004mol/L,shock extraction time: 60 min,water oil ratio: 1:1,and extraction solution pH=1.(3)A new synergistic extraction systems combined common extraction agents P204,P507 and TBP with calix [8] arene and its phosphate derivatives,respectively,can reduce the cost and especially improve the extraction efficiency.The optimal conditions for the extraction of praseodymium and neodymium ions by calix [8] arene-P507 synergistic system were extraction agent concentration: 0.0001mol/L(neodymium ion)and 0.0002 mol/L(praseodymium ion),shock extraction time: 55 min,water oil ratio: 1:1,and extraction solution pH: 1,temperature: 40 and 45? ?.The optimal conditions for the extraction of praseodymium and neodymium ions by calix [8] arene phosphate-P507 synergistic system were extraction agent concentration: 0.0002mol/L,shock extraction time: 60 min,water oil ratio: 1:1,and extraction solution pH: 1,temperature: 40 and 45? ?.In the meanwhile,the effect of metal cations(Na+?Mn2+?Cu2+?Ni2+?Mg2+?Pb2+)on extraction was larger than that of anions(CO32-?SO42-?C2O42-).(4)The coordination of calix [8] arene with metal ions mainly depended on the electrostatic interaction at the bonding site of hydroxyl bonds and the inclusion interaction of cavity of hydrophobic benzene rings,however,calix [8] arene phosphate derivatives with metal ions was mainly dependent on the coordination of phosphorus and oxygen groups.Due to stronger interaction of binding on praseodymium,neodymium ions for phosphorus-oxygen functional groups(P=O),their complexing stability with these metal ions was improved obviously.(5)Based on the experimental results and theoretical calculation,calix [8] arene and its phosphate derivatives possessed the selective separation capability on praseodymium and neodymium icons and were promising for selective separation of praseodymium and neodymium icons by the multi-stage centrifugal extraction.