Uranyl polyesters

High activity of uranyl acetate as crosslinking sensitizer should be noted. Possibly, this may be explained from different points of view uranyl acetate belongs to the compounds that yield easily to photo-cemical excitation, and also uranyl acetate as radioactive compound may produce itself free radicals in neighboring polyester molecules. 

Along with developing procedures for the removal. Isolation and concentration of the uranyl Ion la the concern for developing less toxic forms of the uranyl Ion (2,12). Thus preliminary biological examination was undertaken on several representative bacteria. The test samples Included uranyl modified PANa, uranyl nitrate hexahydrate, several uranium polyesters and two uranyl polyoximes. 

The uranyl nitrate showed a greater zone of Inhibition than that of any of the uranyl polyesters and polyoximes and the uranyl modified PANa (Table 5). In fact, all but one of the uranyl polyesters show no Inhibition toward the tested species. Thus complexing the uranyl Ion with bidentate salts of carboxylic acids decreases the toxicity of the uranyl Ion (at least for the tested species). These tests were conducted on solid sauries. Further tests are underway. 

More recently we have developed a similar assembly except employing a programmable PY in place of the TG (Vj.). Thus TG are obtained on samples to determine appropriate temperatures for MS to be obtained. Briefly, uranyl polyesters show three somewhat distinct stability plateaus. The PY was programmed to heat the samples to the inception of the stability plateaus plus 50 to 100C . The MS obtained at 250 to 300 C indicated evolution of water accounting for a 5 to 10 weight loss. 

The reason for the decrease in product yield from a 10 mmolar to a 2.5 mmolar uranyl ion reaction system is unknown, but may be due to the need to have a high enough concentration of product to permit nucleation for subsequent precipitation. Another possibility is that there is not enough PANa and/or uranyl ion present to encourage formation of the crosslinking chelations. It is not easy to differentiate between these choices since recovery of PANa, PAA or the uranyl ion from the reaction system is difficult and may affect the actual structures of the particular species. Previous studies with uranyl polyesters showed that even dimeric units precipitated from reaction mixtures at concentrations of 10" molar. 

Previous work involved the s3mthesis and physical characterization of linear uranyl polyesters obtained from both interfacial and aqueous solution polycondensation routes. Uranyl ion complexation, i.e. removal, was effected to a 10" molar (concentration in aqueous solution) level. 

Carraher and Schroeder accomplished the synthesis of uranyl polyesters utilizing both the aqueous interfacial and aqueous solution condensation systems. The aqueous solution system is preferred because of the added effort and cost introduced when employing the interfacial system. Further the aqueous solution system is a more natural system in that a) water is often employed as a coolant in nuclear reactors, b) water is the chief agent for uranium,in the form of the water soluble uranyl ion,movement in mine dumps and uranium rich earth surfaces and, c) water is involved in many of the commercially utilized uranium recovery procedures. 

The uranyl ion-PANa products were insoluble in all liquids tested suggesting that the products are crosslinked since linear uranyl polyesters have been shown to be soluble in dipolar aprotic solvents such as dimethylsulfoxide. 

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