- Synthesis of Trialkyl Phosphates from White Phosphorus
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A new method was proposed for preparing trialkyl phosphates directly from white phosphorus by its electrolysis in a mixture of acetonitrile, alcohol, and water with tetraethylammonium iodide as supporting electrolyte. To increase the amount of the product synthesized in the unit volume of the electrolyte solution and the productivity of the process, phosphorus and water are added to the electrolyte in portions, which allows synthesis of up to 1 mol of trialkyl phosphate in 1 1 of the electrolyte solution.
- Romakhin,Nikitin
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p. 1023 - 1026
(2007/10/03)
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- Organophosphorus Antioxidants. X. The Hydroperoxide Decomposing Action of Phosphites, Phosphonites and Thiophosphites
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The kinetics and mechanism of reactions of phosphites, phosphonites, thiophosphites and hydrogenphosphites with cumyl (CHP), t-butyl (TBHP) and α-tetralyl (THP) hydrogenperoxides has been studied by means of (31)P-n.m.r. spectroscopy, high performance liquid chromatography and iodometric titration.All three valent phosphorus compounds studied initially react with hydroperoxides stoichiometrically to give the corresponding P=O products and alcohol.Some species are able to decompose cumyl hydroperoxide catalytically to form phenol and aceton.Acyloin phosphites decompose CHP catalytically after a stoichiometric reaction as thiophosphites do.Tetramethylpiperidinyl phosphites ("HALS-phosphites") react with hydroperoxides only stoichiometrically but with high velocity.Phosphonites react with hydroperoxides in the same way as the corresponding phosphites.Their reactivity, however, is much higher.Hydrogenphosphites are less reactive than phosphites in the reaction with hydroperoxides.They are able to act catalytically.
- Koenig, T.,Habicher, W. D.,Schwetlick, K.
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p. 913 - 922
(2007/10/02)
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- Reaktionen trivalenter Phosphorverbindungen mit tert-Butoxylradikalen
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The products of the reaction of several alkyl, aryl, sterically hindered aryl and cyclic phosphites, thiophosphites, benzenephosphonites and triphenylphosphine with tert-butoxyl radicals generated by thermolysis of di-tert-butyl peroxalate (DTBPO) in chlorobenzene at 50 deg C was studied. Alkyl phosphites are oxidized to the corresponding phosphates by β-scission of the intermediate phosphoranyl radicals.Phenyl phosphites react under displacement of a phenoxyl to give tert-butyl phosphites by α-scission of the intermediate phosphoranyl radicals.Sterically hindered p-methyl-phenyl phosphites also form the tert-butyl phosphites accompanied by rearranged p-hydroxyphenylmethanephosphonates.Cyclic arylene phosphites are predominantly oxidized, substitution takes place to a minor extent. Benzenephosphonites and phosphines react with tert-butoxyl radicals by oxidation to give the corresponding phosphonates and phosphine oxide, resp. Those phosphorus compounds which are oxidized with the formation of tert-butyl radicals accelerate the thermal decomposition of DTBPO under the condition studied.
- Schwetlick, Klaus,Koenig, Thomas,Rueger, Claus,Pionteck, Juergen
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p. 360 - 366
(2007/10/02)
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