Synthesis And Properties Of Metal Extractant Based On Sulfoxide

Rare earth metals are scarce and expensive,and the recovery of rare metals in secondary resources is of great significance for reducing environmental pollution,sustainable socioeconomic development and realizing circular economy.As a mature and effective extraction and separation method in the recycling of rare metal secondary resources,solvent extraction technology has been widely attention.The studies of this technique focus on the selection of highly efficient extraction agent,study the extraction of various metals,accurately grasp the extraction mechanism of the system,the development of efficient extraction and separation process.In this paper,2-(dodecylsulfinyl)acetic acid,2-(dodecylsulfinyl)-N-((tetrahydrofuran-2-yl)methyl)acetamide,2-((dodecylsulfinyl)methyl)-1H-benzo[d]imidazole,these long-chain metal extraction agent containing sulfoxide group was successfully synthesized.A series of long carbon chain metal extraction agents containing sulfoxide groups were synthesized through nucleophilic substitution,oxidation and acylation using dodecanethiol,hydrogen peroxide and alkanes containing different functional groups.The structures of aimed products were all verified by GC-MS,1HNMR,FT-IR.The extraction efficiency of rare earth metal thulium was determined,and the relationship between the extraction rate and the functional groups was studied.The extraction agent(dodecylsulfinyl)-N-((Tetrahydrofuran-2-yl)methyl)acetamide(L8).The effects of pH,diluent,shock time on the extraction rate were investigated,and the saturated extraction capacity of L8 to thulium was explored.The results showed that the thulium ion solution could be completely extracted with L8 in the trichloromethane diluent,the shock time not less than 3min,pH> 4.20.The extraction capacity of 0.01 mol/L L8 solution was about 0.0033 mol/L in an equal volume,and the ratio of L8 to thulium ion is about 3: 1.At pH> 4.25,the extraction performance of several sulfoxides to ytterbium and lutetium was explored.L8 showed good extraction performance on the extraction of ytterbium and lutetium in the trichloromethane diluent.Solution pH has a great effect on the extraction rate,the extraction efficiency of L8 to ytterbium and lutetium is almost zero at high acidity,while at low acidity,ytterbium and lutetium is almost completely extracted by L8.Other functional groups of sulfoxide on ytterbium and lutetium extraction is not good.Under the optimal conditions of extraction thulium,the equal concentration of thulium ytterbium lutetium ion solution was extracted by L8.The experimental results show that L8 has poor performance in the separation of thulium,ytterbium and lutetium.The extraction of noble metal palladium was tested with several different functional groups of sulfoxides,and the results showed that the performance of the sulfoxide extract containing the bifunctional and ester groups was poor,other sulfoxides showed good extraction efficiency of Palladium,while L8 has the most excellent extraction performance.