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为研究稀土萃取分离中萃取剂空间位阻的影响,应用烃基膦酸四甲基氢氧化铵盐与溴代辛烷的亲核取代或烃基膦酰二氯的控制醇解反应,合成不同结构位阻的烃基膦酸单辛酯。它们的环己胺盐与铜盐均为短间距熔点的结晶。在测定烃基膦酸单辛酯在苯中的缔合度、萃取稀土分配比与平衡水相酸度和平衡有机相配位体浓度关系的基础上,确定了它们萃取稀土的机理,并据此计算了萃取钕、钐、镱和钇的平衡常数和萃取稀土的分离因数。不同类型的烃基膦酸单辛酯萃取稀土的平衡常数与分离因素的差别和它们的酸解离常数及空间位阻有关,同类型的烃基膦酸单辛酯的辛基结构对其萃取分离稀土的性能也有影响。
In order to study the influence of the steric hindrance of extractant in rare earth extraction and separation, the nucleophilic substitution of alkylphosphonic acid tetramethylammonium hydroxide salt with bromine octane or the control of alcoholysis reaction of hydrocarbyl phosphonochloridic dichloride was carried out to synthesize different structural positions Resistant monooctyl hydrocarbyl phosphonate. Their cyclohexylamine salt and copper salt are short-pitch melting point crystallization. Based on the determination of the association degree of monoalkyl octyl phosphonates in benzene, the relationship between the extraction rare earth distribution ratio and the equilibrium aqueous phase acidity and the equilibrium concentration of organic ligands, the mechanism of rare earth extraction was determined. Neodymium, samarium, ytterbium and yttrium equilibrium constant and separation factor of rare earth extraction. Different types of hydrocarbyl phosphonic acid monooctyl ester extract rare earth equilibrium constant and the separation factor difference and their acid dissociation constant and steric hindrance related to the same type of alkyl octyl phosphonic acid octyl structure of its extraction and separation of rare earth The performance is also affected.