60239-18-1 Purity
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Specification
An effective method for separating Np in the Plutonium Uranium Reduction EXtraction (PUREX) process involves converting Np(VI) to Np(V) using free-salt reductants like hydrazine and its derivatives. Recently, carbohydrazide (CO(N2H3)2), which is a derivative of hydrazine and urea, has gained significant attention for its ability to reduce Np(VI) to Np(V) during the reprocessing of spent nuclear fuel. This study examined the reduction mechanism of four Np(VI) ions by a single carbohydrazide molecule, based on experimental findings and various theoretical calculations.
Key Findings
· The reduction of the fourth Np(VI) ion, with an energy barrier of 22.26 kcal mol-1, is identified as the rate-determining step, consistent with the observed experimental value of 20.54 ± 1.20 kcal mol-1.
· Spin density analysis indicates that the first and third Np(VI) reductions occur through outer-sphere electron transfer, while the second and fourth reductions involve hydrogen transfer.
· Localized molecular orbitals (LMOs) reveal that the breaking of the N-H bond and the formation of the Oyl-H bond occur during the transition from initial complexes (ICs) to intermediates (INTs).
· This research provided foundational insights into the reduction mechanism of Np(VI) to Np(V) by CO(N2H3)2, paving the way for the development of effective free-salt Np(VI) reductants for enhanced separation in the PUREX process.
Selective Non-Catalytic Reduction (SNCR) faces limitations when using NH3 or urea-narrow effective temperature windows and reduced NOx abatement under high O2 conditions. This case study investigates carbohydrazide as an alternative reducing agent to enhance SNCR performance in flue gas treatment.
Experimental Approach
Testing in a pilot-scale flow reactor assessed carbohydrazide's NOx reduction efficiency across temperatures (650-850°C), normalized stoichiometric ratios (NSR), and O2 levels (11.5-16.6%) at initial NOx concentrations of 635 mg/m3, while co-injection trials evaluated its synergy with NH3/urea solutions.
Key Findings
· Carbohydrazide achieved effective NO reduction within 650-850°C (peak efficiency at 730°C, NSR=2.0), but while it shifted NH3's temperature window downward, it provided no conversion efficiency improvement for NH3-based systems and had no positive effect on urea deNOx performance.
· Carbohydrazide functions as a viable standalone reducing agent in high-oxygen flue gas environments within its operational temperature range, offering an alternative pathway for NOx abatement where traditional reagents underperform, despite demonstrating no synergistic benefits with existing NH3/urea systems.
The molecular formula of carbohydrazide is CH6N4O.
The molecular weight of carbohydrazide is 90.09 g/mol.
Carbohydrazide was created on March 26, 2005.
The IUPAC name of carbohydrazide is 1,3-diaminourea.
The InChIKey of carbohydrazide is XEVRDFDBXJMZFG-UHFFFAOYSA-N.
The CAS number of carbohydrazide is 497-18-7.
The European Community (EC) number of carbohydrazide is 207-837-2.
The UNII of carbohydrazide is W8V7FYY4WH.
The hydrogen bond donor count of carbohydrazide is 4.
Carbohydrazide is a liquid.