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  • Author or Editor: Yan-Zhao Yang x
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Abstract  

The catalytic synthesis of 2-amino-1-butanol from 1,2-butanediol and ammonia was studied in a continuous fixed-bed reactor. The catalysts prepared by doping Co–Ba/γ-Al2O3 with Sr, Ni, Ca, Zn, La, Fe, Mg, Zr, Mn, Cr were examined, among which the Co–Ba–Fe/γ-Al2O3 catalyst showed the best catalytic performance. These catalysts were characterized by XRD, XPS, and TPR. It was found that the addition of iron led to the formation of crystalline Co7Fe3, which modified the catalytic activity of Co species, inhibited the generation of CoAl2O4, improved the stability and enhanced the reduction of the Co–Ba–Fe/γ-Al2O3 catalyst. The conversion of 1,2-butanediol was 72.9% and the selectivity of 2-amino-1-butanol achieved 73.3% under the optimum reaction conditions.

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Summary  

The synergistic extraction of uranium(VI) from aqueous nitric acid solution with a mixture of tri-n-butyl phosphate (TBP) and i-butyldodecylsulfoxide (BDSO) in toluene was investigated. The effects of the concentrations of extractant, nitric acid, sodium nitrate and sodium oxalate on the distribution ratios of uranium(VI) have been studied. The values of enthalpy change for the extraction reactions with BDSO, TBP and a mixture of TBP and BDSO in toluene were -23.2±0.8 kJ/mol, -29.2±1.4 kJ/mol and -30.6±0.6 kJ/mol, respectively. It has been found that the maximum synergistic extraction effect occurs when the molar ratio of TBP to BDSO is close to 1. The composition of the complex of the synergistic extraction is UO2(NO3)2 . BDSO . TBP.

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Abstract  

The influence of the concentration of sodium oleate (NaOL), alcohol and the nature of the internal water phase on the water content of microemulsion was studied. The effect of the concentration of NaOL, sodium stearate, alcohol, salting-out agent, Alamine 336 added and of the contact time, volume ratio of the aqueous to microemulsion (R) and temperature on the extraction yield of samarium was investigated. The result shows that the extraction of samarium is effective under well-defined conditions utilizing WinsorII microemulsion systems.

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Abstract  

The kinetics and mechanism of uranium(VI) extraction from nitric acid solution by bis(octylsulfinyl)methane (BOSM) are studied with the method of stationary interface cell. The effects of temperature, extractant and nitric acid concentrations are discussed. The results showed that the extraction process is controlled by the following reaction: UO2(NO3)2 + BOSM(i)k1 k-1UO2(NO3)2BOSM(i). The variation of enthalpy associated with the extraction is -22.1±2.1 kJ/mol.

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Summary  

The parameters affecting the formation of the microemulsion were investigated and the microemulsion region was determined. The extraction of uranium(VI) from HNO3 solution into a water in oil microemulsion was studied. The effects of the concentration of extractant (TRPO), the volume ratio of oil to water and the acidity of outer water phase on the extraction equilibrium of uranium(VI) are discussed and the appropriate conditions are obtained. The result showed the microemulsion has great efficiency for uranium(VI) extraction.

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Abstract  

The liquid-liquid extraction behavior of octyldodecylsulfoxide (ODoSO) towards uranium(VI), contained in nitric acid aqueous solution, has been investigated. It was found that the extraction increased with increasing nitric acid concentration up to 2.0 mol/l and then decreased. Extraction also increases with increasing extractant concentration. The extracted species appears to be UO2(NO3)2 .2ODoSO. The influences of temperature, sodium nitrate and oxalate concentrations on the extraction were also investigated and the thermodynamic functions of the extraction reaction were obtained.

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Abstract  

The synergistic extraction of uranium(VI) from aqueous nitric acid solution with mixtures of bis(hexylsulfinyl)ethane (BHxSE) and petroleum sulfoxides (PSO) in 1,1,2,2-tetrachloroethane was studied. It has been found that the maximum synergistic extraction effect occurs when the molar ratio of PSO to BHxSE is close to 1. The composition of the complex of synergistic extraction was estimated as UO2(NO3)2 .BHxSE.PSO. The formation constant of the complex was equal to KBP = 4.23±0.03. The effects of extractant, nitric acid, salting-out agent, and complex anion concentrations and temperature on the extraction equilibrium of uranium(VI) were also studied.

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Abstract  

The i-butyldodecylsulfoxide (BDSO) was synthesized. The extraction of uranium(VI) has been carried out with BDSO in toluene from various HNO3 concentrations. It was found that the distribution ratio increases with increasing nitric acid concentration up to 3.0 mol/l and then decreases. The distribution ratios also increase with increasing extractant concentration. The extracted species appears to be UO2(NO3)2·2BDSO and the equilibrium constant value is 15.2. The influence of temperature, sodium nitrate and oxalate concentrations on the extraction was also investigated, and the thermodynamic functions of the extraction reaction were obtained.

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Abstract  

The influence of the concentration of nitric, hydrochloric and phosphoric acids, petroleum sulfoxides (PSO), salting-out agent, kind of diluent and temperature on the distribution ratio of U(VI) and Th(IV) has been systematically studied. It is found that the extraction regularity of PSO is similar to that of TBP. The distribution ratio in phosphoric acid is lower, but it increases with the increase of hydrochloric acid concentration and reaches a high value. The U(VI) exhibits the maximum distribution ratio at 3–4 mol/l HNO3. The distribution ratio of U(VI) and Th(IV) increases rapidly in the presence of a salting out agent. The extracted compounds are determined to be UO2(NO3)22PSO and Th(NO3)42PSO. The extraction enthalpies of U(VI) and Th(IV) with PSO were also calculated.

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