Electrolytic reduction of U

Therefore, many alternatives for the ferrous sulfamate reduction method have been studied(1,2,3) besides, the use of U(IY) as the reductant has actually found some practical application. Since U(IY) is being prepared by means of electrolytic reduction of U(VI)t it is natural to go a step further, namely, to introduce electrolytic reduction to the process stream itself. In such an in-sltu electrolytic process, not only P(IY) would be expected to be directly reduciable to Pu(III), but any U(IY) formed would also be expected to serve as the reductant for Pu(IV). 

ELECTROLYTIC REDUCTION OF U(YI). Since U(VI) in the form of UO2 is present in large amount in the 1B battery in the first cycle of the purex process9 its successful electrolytic reduction to U(IV) would create a most favorable condition for the reduction of Pu(IV). 

Both Heal(1j2) and Finlayson( 1 5) have shown that H ion is involved in the electrolytic reduction of U(YI) to U(IV) as summarised by the following reaction ... 

Figure 5. Electrolytic reduction of U (VI) as a function of cathode potential STi = 20 cm2 V = 20 mL with stirring composition 1M HNOs, 0.2M N2H5 70...

Experiments on the electrolytic reduction of U and Pu in the aqueous phase in presence of hydrazine were carried out to investigate the effect of various factors influencing the rate of reduction. The potentials of the aqueous solution, which can serve to indicate the course of the reduction process, were measured and operating parameters such as acid concentration, hydrazine concentration, applied potential on the cathode, etc., were investigated. Experimental results indicated that, on Ti-cathode nitric acid could be reduced to nitrous even when there is no HN02 in the initial HNO3 solution and, with a u/Pu ratio ranging from 10 2 to 102, Pu(IV) can be reduced readily when the U/Pu ratio is near or more than 1 at low concentration of Pu. In this case, obviously TT(IV) formed in the process plays an important role in the reduction of Pu(IV). 

The source of U(fV) is typically from electrolytic reduction of U(VI) in nitric acid. 

The latest patent for the preparation of artificial thymol is that of E. M. Cole (U.S.P. 1,378,939, 24 May, 1921). His method consists essentially in the electrolytic reduction of nitro-cymene in the presence of sulphuric acid, and the subsequent diazotisation and reduction of the para-amidocymenol produced, by e ctric action, involving the use of stannous chloride. 

Np" + is in many ways the most important oxidation state. It is formed by reduction of the higher oxidation states, and by aerial oxidation of Np +. Strong oxidizing agents like Ce + oxidize it back to [Np02], whilst electrolytic reduction of Np" + affords Np +, which is stable in the absence of air (unlike U). 

Pu(IV) reduction rate were studied Pig.8 shows that at large excess of U and low concentration of Pu, no effect of acid concentration on Pu(IT) reduction rate could he observed. After a period of electrolysis of less than 30 seconds, nearly all of the Pu(IV) could be converted to Pu(III). This fact corresponds to the change of the potential of the electrolyte solution with time, which drops very rapidly after the start of the electrolysis. The effect of 0-concentration on the reduction rate of Pu(IV) is shown in Fig.9, from which it is clearly shown that the reduction rate of Pu(IT) depends very much on the amount of U relative to that of Pu in the electrolyte solution. The upper two curves showed that if the weight ratio of U/Pu is near or more than one, the reduction rate of Pu(IV) could be greatly accelerated. This fact indicates clearly that here U(IV) plays an important role in the reduction of Pu(IV). On the other hand, if the U-oontent in the solution is small compared to that of Pu, the rate of reduction of Pu(IV) is determined chiefly by the electrolytic reduction of Pu(IV) itself which is rather slow. This fact should be borne in mind in designing electrolytic reduction equipments in the purex process. 

Semicarbazide Hydrochloride, Hydrazinecarbox-emide monohydrochloride aminourea hydrochloride carba-myjhydrazitie hydrochloride. CHjCINjO mol wt 111.54. C 10.77%, H 5.42%, Cl 31.78%, N 37.68%, O 14-34%. NHj-NHCONHj.HCl. Prepd by electrolytic reduction of nitro-iirea with cathodes of copper, nickel, lead, and mercury in hydrochloric acid solution [ngersol] et al, Org. Sytt. 5, 93 (1925). Commercial prepn from hydrazine hydrate, iron carbonyl, and carbon monoxide Sampson, U,S. pat. 2,589, 289 (1952 to du Pont). 

Stable to water. Slow oxidation by air to U02. Oxidation in nitrate media catalyzed by UV light. Prepared by oxidation of U by air, by electrolytic reduction of U02 (Hg cathode) and by reduction of UOj by Zn or Hjfg) with Ni catalyst. 

U(DMS0)8][a04l4 [T123] Electrolytic reduction of an aqueous solution of hydrated perchlorate followed by addition of DMSO and filtration of the precipitate formed. 

Zinc sulfide, with its wide band gap of 3.66 eV, has been considered as an excellent electroluminescent (EL) material. The electroluminescence of ZnS has been used as a probe for unraveling the energetics at the ZnS/electrolyte interface and for possible application to display devices. Fan and Bard [127] examined the effect of temperature on EL of Al-doped self-activated ZnS single crystals in a persulfate-butyronitrile solution, as well as the time-resolved photoluminescence (PL) of the compound. Further [128], they investigated the PL and EL from single-crystal Mn-doped ZnS (ZnS Mn) centered at 580 nm. The PL was quenched by surface modification with U-treated poly(vinylferrocene). The effect of pH and temperature on the EL of ZnS Mn in aqueous and butyronitrile solutions upon reduction of per-oxydisulfate ion was also studied. EL of polycrystalline chemical vapor deposited (CVD) ZnS doped with Al, Cu-Al, and Mn was also observed with peaks at 430, 475, and 565 nm, respectively. High EL efficiency, comparable to that of singlecrystal ZnS, was found for the doped CVD polycrystalline ZnS. In all cases, the EL efficiency was about 0.2-0.3%. 

The imido complex [Mo2(cp)2(/r-SMe)3 (/u.-NFl)]" " 25+ undergoes an irreversible one-electron (EC) reduction [70]. Controlled potential electrolysis afforded the amido analog [Mo2(cp)2(/x-SMe)3(/x-NH2)] 26 almost quantitatively after the transfer of IF mol 25+. The amido complex was not the primary reduction product the latter was assigned as a rearranged imide radical (Sch. 18), which is able to abstract a FI-atom from the environment (supporting electrolyte, solvent, or adventitious water) on the electrolysis timescale. In the presence of protons, the reduction of 25+ became a two-electron (ECE) process. This is consistent with the protonation at the nitrogen lone pair of the primary reduction product, followed by reduction of the resulting amido cation... 

Best and coauthors utilized IR spec-troelectrochemistry to study the electrochemical reduction of 1902 " " in aqueous solutions with KNO3 as supporting electrolyte [60]. The pH of the solutions was set with appropriate quantities of HNO3 and KOH. The optimal pH range for the study was 2.8-3.4, since within this range speciation of U(VI) is limited to U02 + and (U02)2(0H)2 " ", disproportionation of the electrogenerated U(V) species is minimized, and the U—O stretches for U(VI) are observable in the IR spectrum. The results from the study indicate that initial reduction of at a platinum elec-... 

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