M. N. Litvina
Russian Academy of Sciences
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by M. N. Litvina.
Radiochemistry | 2002
M.K. Chmutova; L. A. Ivanova; M. N. Litvina; G. A. Pribylov; D. E. Drozhko; I. G. Tananaev; O. A. Artyushin; R. M. Kalyanova; N. A. Pavlova; T. A. Mastryukova; A. D. Kuntsevich; B. F. Myasoedov
Extraction of actinides with dialkyl methylphosphonates was studied with the aim to find a compromise between the use of highly effective but expensive chemicals, on the one hand, and weakly effective but cheap and readily available chemicals, on the other hand, and also to find possible ways of utilization of methylphosphonic dichloride, which is the starting substance in syntheses not only of dialkyl methylphosphonates, but also of chemical weapons. In systems with 3 M HNO3 as the aqueous phase and a solution of tributyl phosphate (TBP), diisoamyl methylphosphonate (DIAMP), or bidentate diphenyl(carbamoylmethyl)phosphine oxide (Ph2Bu2) in dichloroethane as organic phase, at equal concentrations of the organophosphorus compounds, the distribution coefficients of Am(III) increase in the order TBP <; DIAMP < Ph2Bu2 in a proportion of 1 : 50 : 5 × 104. Mixtures of dialkyl methylphosphonates and acidic phosphonates show a synergistic effect, which, however, can be utilized only at [HNO3] > 0.1 M and [HIAMP] < 1.5 M (HIAMP is isoamyl hydrogen methylphosphonate).
Radiochemistry | 2001
M. N. Litvina; M.K. Chmutova; Yu. M. Kulyako; B. F. Myasoedov
Extraction of Am(III) from nitric acid solutions with a liquid complex of diphenyl(dibutylcarbamoylmethyl)phosphine oxide (Ph2Bu2) with nitric acid as influenced by concentration of Al, Ca, Na, Ni, Co, Cr, Fe, Zr, and Mo nitrates was studied. Nonextractable (Al, Ca, Na) and poorly extractable (Ni, Co, Cr) nitrates at their widely varied concentration do not interfere with the exhaustive extraction of americium from 3 M HNO3. These salts facilitate both formation of the extraction-active liquid phase on contact of Ph2Bu2 with 1 M HNO3 and exhaustive extraction of americium from the acid. Extraction of Fe(III) at its widely varied concentration insignificantly interferes with extraction of americium, but this effect increases with increasing acidity and phase contact time. Americium is extracted with a powdered reagent from 0.1 M HNO3 when liquid extractant is not formed in the visible amounts. In extraction of americium from weakly acidic solutions in the presence of salts the solid reagent, apparently, partially transforms into the liquid extractant, and two different extraction mechanisms are operative. It was shown that the neat liquid complex of Ph2Bu2 with HNO3 can be used for exhaustive extraction of americium from high-level saline wastes from plants for processing nuclear fuel.
Radiochemistry | 2007
M. N. Litvina; D. A. Malikov; T. A. Maryutina; Yu. M. Kulyako; B. F. Myasoedov
The separation of U, Pu, and Am recovered from MOX fuel with the adduct of HNO3 with N,N′-dimethyl-N,N′-dioctylhexylethoxymalonamide by countercurrent chromatography (CCC) was studied. Solutions of N,N′-dimethyl-N,N′-dibutyldodecylethoxymalonamide in dodecane were used as stationary phase. The separation of U, Pu, and Am was carried in both isocratic and stepwise elution modes. The better separation of actinides and their higher radionuclidic purity are reached with stepwise elution. The first eluate fraction contained only Am (100%). The second eluate fraction contained U (100%) and Pu (0.7%). The third eluate fraction contained 99.3% of Pu.
Radiochemistry | 2006
M. N. Litvina; D. A. Malikov; T. A. Maryutina; Yu. M. Kulyako; B. F. Myasoedov
The article deals with the use of countercurrent chromatography (CCC), support-free partition chromatography, for separation of U and Pu from the organic extract obtained directly by the dissolution of MOX fuel in supercritical CO2 containing the complex TBP · nHNO3. White spirit solutions with various TBP concentrations were used as a stationary phase. The effects of the compositions of the stationary and mobile phases on the U/Pu partition efficiency are studied. The CCC method allows the separation of U and Pu under conditions of a TBP concentration gradient in the stationary phase and also of an HNO3 concentration gradient in the mobile phase. Chromatographic separation first gives the Pu fraction containing 98.9% of Pu and 0.07% of U, and then the U fraction (99.93% of U and 1.1% of Pu). The separation time is 50 min.
Radiochemistry | 2002
Yu. M. Kulyako; M. D. Samsonov; M. N. Litvina; M.K. Chmutova; B. F. Myasoedov
Interaction of solid diphenyl(dibutylcarbamoylmethyl)phosphine oxide (Ph2Bu2) with perchloric and hydrochloric acid solutions was studied. On contact with the acids, this agent forms a liquid substance (“liquid reagent,” LR) exhibiting extractive power. The conditions of LR formation and extraction of Am(III) from HCl solutions with LR in the absence of organic diluent were studied. The solubility of Ph2Bu2 in 3 M HClO4 is 2.5 mg l-1. The composition of the LR formed in HClO4 solutions is 2Ph2Bu2·HClO4·nH2O. Perchloric acid is quantitatively backwashed from the LR phase with water. Formation of an Nd(III) complex with LR in HClO4 solutions is accompanied by cementation (solidification) of the compound. The resulting complex has the 3 : 1 [Ph2Bu2 : Nd(III)] composition and mp ∼120°C. According to the IR spectrum, the coordination of Ph2Bu2 with the HClO4 molecule is monodentate, and with the Nd(III) ion (in the absence of organic diluent) it is bidentate.
Russian Chemical Bulletin | 1998
B. F. Myasoedov; M.K. Chmutova; M. N. Litvina; Yu. M. Kulyako
The possibility of changing the aggregate state of several solid mono- and bidentate neutral organophosphorus compounds in contact with various mineral acids was demonstrated. The formation of the liquid phase immiscible with water was observed. The, phase exhibits a high extraction capability with respect to actinides in various oxidation states. The diphenyl(dibutylcarbamoylmethyl)phosphine oxide-NHO3 extraction system was studied in detail. The composition of the liquid phase was shown to the Ph2P(O)CH2C(O)NBu2·HNO3·nH2O (n=2 or 3). The kinetics of formation of this phase and extraction of Amiii from solutions of nitric acid and its salts was studied. The organic phase exhibits redox properties, due to which some actinides change the oxidation state during extraction. The “aryl strengthening effect” was suggested to exist for extraction of AmIII in the absence of a solvent.
Radiochimica Acta | 2005
B. F. Myasoedov; T. A. Maryutina; M. N. Litvina; D. A. Malikov; Yu. M. Kulyako; B. Ya. Spivakov; Clément Hill; J.-M. Adnet; Michael Lecomte; Charles Madic
Radiochemistry | 2004
T. A. Maryutina; M. N. Litvina; D. A. Malikov; B. Ya. Spivakov; B. F. Myasoedov; M. Lecomte; Clément Hill; Charles Madic
Radiochemistry | 1998
M.K. Chmutova; Yu. M. Kulyako; M. N. Litvina; D. A. Malikov; B. F. Myasoedov
Radiochemistry | 2004
M. N. Litvina; M.K. Chmutova; Yu. M. Kulyako; B. F. Myasoedov