Synthesis Of Pre-organization Conformer Diamide Extractants And Study Of Extraction Properties

The separation and purification of the rare earth elements, which have an important position in the exploration and preparation of new functional materials, can not only meet the demand of the development of science and technology, but also reduce environmental pollution. Solvent extraction technology is currently the best one of high- level radioactive waste reprocessing methods to meet the requirements of sustainable deve lopment.The development of new extraction agent and the design of process have been two important links in the process of solvent extraction. Therefore, optimizing the structure of extractant and extraction conditions is of great significance for the deve lopment of the extraction chemistry discipline. In the field of rare earth separation, amides extractant has been paid much attention because of the advantages of completely burnt-out, simple post-processing, green environmental protection, while the extraction of zirconium and hafnium was not reported. It is difficult to separate zirconium and hafnium because they have a symbiosis and similar nature. Therefore, the separatio n becomes key technique of nuclear level zirconium and hafnium sponge preparation.is. Developing a new type of green environmental protection extractant has important strategic significance. On the basis of the existing extractant structure theory, this paper synthesized a diamide extractant—N, N, N’, N’-tetraoctyl- 3-oxy-glutaramide(TODGA) to study the extraction separation properties of zirconium and hafnium, which expand application of the diamides extractant other than the areas of the rare earths separation. At the same time, this paper also synthesized a kind of 5, 6-benzo-fused bicyclic imides extractant explanatorily, which further perfect the development of diamides extractant in the field of rare earth separation. The main research contents were as follows:1. N, N, N’, N’-tetraoctyl-3-oxy-glutaramide(TODGA) was synthesized with reference to the literature. The products were purified through reduced pressure distillation, column chromatography and other separation methods, and were characterized by using high performance liquid chromatography(HPLC), Fourier infrared spectrum and nuclear magnetic resonance(NMR) method for the product purity and structure. The extraction of zirconium and hafnium from hydrochloric acid was studied in different diluents. The effects of hydrochloric acid concentration, extractant concentration and temperature on distribution ratio were investigated. The results show that the distribution ratio of zirconium and hafnium increases with concentration of hydrochloric acid in the certain acid range. The distribution ratio of zirconium and hafnium increases with the growth of the carbon chain. So does the separation factor. But polarity of extraction is associated with the polarity of the diluents. The distribution ratio increases with the extractant concentration, while separation factor remain unchanged in the certain extractant concentration range. When the concentration of extractant is greater than 0.40 M, the separation factor increased rapidly to indicate that extraction mechanism is change. In the certain temperature range, the results clearly showed that the extraction process of both zirconium and hafnium by TODGA was endothermic and imposes a positive influence with temperature. The enthalpy changes of extraction for zirconium and hafnium were calculated.2. 5, 6-benzo- fused bicyclic imides extractant was prepared exploratory. O-toluidine was used as raw material to react with chloral hydrate, hydrochloride. 7- methyl- isatin was synthesized by Beckmann rearrangement reaction catalyzed by concentrated sulfuric acid. Electrophilic substitution can occur between 7- methyl- isatin and bromine under the action of UV-light to generate 5-bromo-7-bromomethyl- isatin in acetic acid. Nucleophilic substitution was used with dimethyl malonate. Carbonyl reductive can be achieved by strong reducibility of low valence titanium. Finally, the title product was synthesized heated reflux in acetic anhydride using the methods of lipolysis, decarboxylation.