Carbamoyl extractant

Waste Handling for Unirradiated Plutonium Processing. Higher capacity, better-performing, and more radiation-resistant separation materials such as new ion exchange resins(21) and solvent extractants, similar to dihexyl-N,N-di ethyl carbamoyl methylphosphonate,(22) are needed to selectively recover actinides from acidic wastes. The application of membranes and other new techniques should be explored. 

Carbamate herbicides, 13 320 Carbamates, 13 108 amine, 16 359 Carbamic acid nitrile, 3 158 Carbamide derivatives, as cellulose solvents, 11 272 Carbamodiimide, 8 158 Carbamoylated gelatin, 12 444 Carbamoyl-methylphosphoryl family, extractants of, 10 789 Carbamyl chlorides, 12 180 Carbanion coordination, 13 656—657 Carbanions, 21 101... 

Reeves and Woodham [83] have described a gas chromatographic method for the determination of Methomyl (S-methyl-N-(methyl carbamoyl)oxy thioacetimidate) insecticide in sediments. The residues were extracted with dichloromethane, and the extracts were purified on a column of Florisil. The purified and concentrated extracts were then examined by gas chromatography. The limits of detection were 0.05mg kg-1 and the recoveries were 91%. 

Synthesis. Oxidation of -alkyl or -benzyl IJ,IJ-dialkylthio-carbamates with one equivalent of m-chloroperoxybenzoic acid (MCPBA) in chloroform or methylene chloride at -25° to 25°C yields the corresponding carbamoyl sulfoxide (3) in essentially quantitative yield (3-5). The -chloroallyl thiocarbamate sulfoxides (e.g., 4-7) are obtained in the same manner except that the temperature is maintained between -20°C and 0°C for the oxidation and extraction of the reaction mixture with 5% sodium carbonate aqueous solution (7, 8). 

Recently, another class of neutral organophosphorus compounds, namely, N,N-dialkyl carbamoyl methyl phosphonate (CMP) (59) and its phosphine oxide analog (CMPO) have received attention due to their ability to extract even trivalent actinides from acidic solutions along with the hexa- and tetravalent actinide ions. These biden-tate phosphorus-based neutral extractants are reported to be stronger extractants as compared to TOPO (59-62). Pu(IV) and U(VI) are extracted as per the following extraction equilibria ... 

Kannan, S. Chetty, K.V. Venugopal, V. Drew, M.G.B. Extraction and coordination studies of the unexplored bifunctional ligand carbamoyl methyl sulfoxide (CMSO) with uranium(VI) and cerium(III) nitrates. Synthesis and structures of [U02(N03) 2(PhSOCH2CONiBu2)] and fCe(NOi)i(PhSOCn2CONBLi2)2, Dalton Trans. (2004) 3604-3610. 

Bidentate oxygen-donor extractants include the neutral diamide compounds, such as the malonamides used in the French DIAMEX and DIAMEX-SANEX processes, RR N(C=0)-CHR"-(C=0)NRR the bisphosphine oxides, RR (P=0)- CIIR"-(P=0) RR the carbamoyl-(methyl)-phosphinates, R0R 0(P=0)-(CI I On o 0rr(C=0)NRR or the more efficient carbamoyl-methyl-phosphine oxides, RR (P=0)-CHR"-(C=0)... 

Carbamoyl methyl Phosphine Oxide Derivatives The physicochemical properties of various aryl derivatives of CMPO have been investigated at the Vernadsky Institute of Geochemistry and Analytical Chemistry. Extraction of americium and lanthanides from nitric acid with solutions of diphenyl- and dibutyl-(diethylcarbamoylmethyl) phosphine oxides (Ph2Et2-CMPO and Bu2Et2-CMPO) in dichloroethane have been investigated as a function of the concentrations of the extractants and nitric acid (110, 111). The observed dependences are characterized... 

Carbamoyl-5-methylpyrazine 4-oxide (5.0 g) was added to 10% by weight sodium hydroxide (50 ml) and then refluxed for 30 min. The reaction mixture was acidified with dilute hydrochloric acid and extracted in a continuous extractor with ethyl acetate. The ethyl acetate extract was concentrated to small volume and gave, after filtration 2-carboxy-5-methylpyrazine 4-oxide (3.2 g), melting point 178°-180°C. 

The reaction solution was stirred at room temperature for 4 h, and then condensed to a half volume in vacuo. The residual solution, added with 100 ml of water, was extracted with chloroform. The chloroform extract was washed with water, dried over anhydrous magnesium sulfate and evaporated in vacuo to give 4.8 g of 2-(3 -t-butylamino-2 -hydroxypropylthio)-4-(5 -carbamoyl-2 -thiophenyl)thiazole, as crystals, melting point 234°-235.5°C (dec., recrystallized from methanol/water). 

A solution of 642 mg of thioacetic acid in 14 ml of dried dimethylformamide was added to a suspension of 374 mg of 50% sodium hydride in 13 ml of dried dimethylformamide in a nitrogen stream, followed by stirring at room temperature for 25 minutes. To the mixture were added 975 mg of sodium iodide and then a solution of 2.52 g of trans-l-(p-nitrobenzyloxycarbonyl)-4-methanesulfonyloxy-L-prolineamide in 12 ml of dried dimethylformamide, and the resulting mixture was heated to 70°C for 6 hours while stirring. The reaction mixture was poured into a cool aqueous solution of sodium chloride and extracted with benzene. The extract was washed successively with a 10% aqueous solution of sodium sulfate and a sodium chloride aqueous solution, dried over sodium sulfate and distilled off to remove the solvent. The resulting crude crystals were washed with a warm mixed solvent of tetrahydrofuran and benzene to obtain (2S,4S)-l-(p-nitrobenzyloxycarbonyl)- 2-carbamoyl-4-acetylthio-L-prolineamide. Melting point 168.5-169.5°C. 

Muscatello, A.C., Horwitz, E.P., Kahna, D.G., and Kaplan, L., The extraction of Am(III) and Eu(III) from aqueous ammonium thiocyanate by dihexyl-VJV-diethyl carbamoyl methyl phosphonate and related compounds. Sep. Sci. Tech., 1982, 17 859-875. 

Horwitz, E.P. and Kalina, D.G., The extraction of Am(III) from nitric acid by octyl(phenyl)-iVJV-diisobutyl carbamoyl methyl phosphine oxide (CMPO)—tri butyl phosphate mixtures. Solv. Extr. Ion Exch., 1984, 2 179-200. 

Extraction processes (TRUEX, PUREX, Talspeak, DIAMEX, PARC, etc.) generally involve complexation of transplutonium elements by alkyl phosphines, phosphine oxides, phosphoric acids, carbamoyl phosphonates, diamides, and thiophosphinates in aqueous/organic extractions, within derivatized solid supports, or on coated particles. There are excellent reviews of the processes and significant complexes by Mathur et al. and selected chapters in The Chemistry of the Actinide and Transactinide Elements to be published in 2003. " Work on the separation for nuclear waste management in the United States, France, and Russia have been reviewed. " ... 

The extraction of Cm and Es by dibutyl(diethylcarbamoyl)-phosphonate (DBDECP), which has no bridging methylene group between the carbamoyl and phosphoryl groups, is in the order ... 

The natural function of the carboxymethylhydantoinase (E. C. 3.5.2.2) is postulated to be the hydrolysis of 5-carboxymethylhydantoin, which is described to be the product of a non-enzymatic cyclization of N-carbamoyl-i-aspartic acid123, 241 and to occur as a side-product in the metabolism of the pyrimidine nucleotide dihydroorotic acid1251. This enzyme often occurs in combination with a ureidosuccinase (E.C. 3.5.1.7)[2S1, which catalyzes the cleavage of the resulting N-carbamoyl aspartic acid to L-aspartic acid (see Fig. 12.4-5). L-5-Carboxymethylhydantoin was first isolated after incubating orotic acid, a six-membered cyclic amide, with crude cell extracts of the anaerobic bacterium Clostridium oroticum125, 261. 

More recently, a series of irreversible aryl-carbamates inhibitors were described (Mor et al., 2004). URB597 (cyclohexyl carbamic acid 3 -carbamoyl-biphenyl-3-yl ester) (Table 4.1), the most potent member of this family, inhibited FAAH activity with an IC50 value of 4.6 nM in rat brain extracts (Mor et al,... 

In the nematodes the five soluble enzymes of pyrimidine de novo biosynthesis were found in crude extracts of Nippostrongylus brasiliensis and Trichuris muris (81). The first enzyme of de novo synthesis, glutamine-dependent carbamoyl-phosphate synthetase, was deteeted in Ascaris ovary extracts (115), and aspartate transcarbamoylase activity, the second enzyme of de novo synthesis, was found in A. suum (113). 

Later, Lawrence and Niedzwiadek [37] modified the method to improve its performance (repeatability, ruggedness, recovery) for routine regulatory purposes. Earlier chromatographic conditions (gradient and flow) were changed to reduce the analysis time. The oxidation reaction conditions were modified to achieve the best compromise possible for all the PSP toxins, since it has been shown that the optimum pH for the oxidation of individual toxins varies considerably [38]. A matrix modifier (blank oyster extract) was added to improve the yield and repeatability for the periodate derivatization of standards and sample extracts. Finally, the performance of the second cleanup with SPE-COOH cartridges, which enables the separation of the sulfocarbamoyl toxins from their carbamoyl counterparts, was reevaluated. 

Reaction 5 is catalyzed by arginine decarboxylase which has been found in barley (Smith, 1963). Agmatine can be converted to A-carbamoyl putrescine (reaction 6) by agmatine iminohydrolase (E.C. 3.5.3.12). This enzyme has been found in extracts of maize leaves and sunflower (Smith, 1969). The further hydrolysis of A/ -carbamyl putrescine to putrescine (reaction 7) is catalyzed by A-carbamyl putrescine amidohydrolase which has been found in barley leaf extracts (Smith, 1965). The enzyme activities catalyzing reactions 5 and 7 are increased several-fold in K-deficient barley leaves (Smith, 1963, 1965) which correlates well with the high level of putrescine accumulation in K-deficient barley. Further metabolism of putrescine is discussed by Smith, this series, Vol. 7, Chapter 9. 

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