The Study On The Synthesis Of Organic-phosphoric Extractant About The Rare Earth Metals

Rare earth element has special physical properties and chemical properties due to its unique electronic structure, which laid a foundation for the wide application of rare earth elements. The demand of single rare earth products is increasing. New effectively separated method is also evolving. Solvent extraction is one of the most important separated methods of rare earth element. The early researchers have extracted Ce4+successfully from nitric acid solution that is separated from rare earth metal ions by using tributyl phosphate. Since then, organic-phosphoric extractant caused widespread concern. Diffrent kinds of new extractant hae been found. In this paper category, rare earth separation method has been introduced, especially the application of rare earth extraction. On this basis, the study on the design and synthesis of neutral organophosphorus extractants has been researched in this paper which is combined with business needs. Specific contents as follows:Firstly, the method which has been synthesized for P350were compared and verified. We find with some problems. We proposed the method which has short reaction time, high conversion rate and good product purity. It is suitable for industrial production. In this paper, P350was synthesized by using PCl3、CH3Cl、2-octanol as the raw materials. The improvements of this synthesis process is useing the solvent method with increase the air press to get CH3PCl3·AlCl4.It can be used for the synthesis of P350by alcoholysis reaction. This method can improve the quality and exterior. The yellow or light yellow product P350can be synthesised by two reactions with59%overall yield and the purity of the product is99.0%. In our research we find mother liquor which is used for the preparation of intermediate compounds can be repeatedly used. It greatly improve the conversion yield of the raw materials. We can get pure P350by vacuum distillation which removes the low boiling point under a certain temperature.Then,14difunctional rare earth metal extractant were designed and synthesized. Each one contains both phosphoryl group and carbonyl group. It’s named N, N-dialkyl carbamoyl methyl phosphonic ester. These compounds has been synthezisd by dialkyl phosphite and N, N-dialkyl-chloroacetamide. The reaction yields is from29%to65%. Phosphorous acid dialkyl ester is converted to the sodium salt with the using of Na in toluene. Then the sodium salt reacted with N, N-dialkyl-chloroacetamide.to form the products. Their structures were confirmed by IR,1H-NMR,13C-NMR, GC-MS and elemental analysis. Preliminary solvent extraction experiments indicated that the compound lac showed high extraction efficiency towards La(Ⅲ).Trifunctional rare earth extractant we synthezisd. It contains a phosphoryl group, an amide carbonyl group and an ether group (or thioether group). It is successful to get compounds Ⅰ and Ⅱ. And it’s thankful that we got trifunctional compounds Ⅲ and IV of new structures by accident. They can also be useed as rare earth extractant. Their structures were confirmed by IR,1H-NMR,13C-NMR,GC-MS and elemental analysis.