- Organophosphorus Intermediates. VI. The Acid-Catalysed Reaction of Trialkyl Orthoformates with Phosphinic Acid
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Trialkyl orthoformates react with phosphinic acid to give the corresponding alkyl phosphinate and alkyl mono- or bis-(dialkoxymethyl)phosphinates; dialkyl phosphonites and phosphine, PH3, are also formed.The formation of P-alkylated products is acid-catalysed and is believed to proceed by alkylation of the trivalent tautomer of phosphinic acid (or its ester) by the dialkoxymethyl carbonium ion arising from the ortho ester in the presence of acid.A comparison with the corresponding reactions of phosphonic acid suggests that the trivalent tautomer of phosphinic acid is formed much more readily than the trivalent form of phosphonic acid and this is accounted for by proposing that the equilibria RPH(O)OR' + H+ RP+H(OH)OR' RP(OH)OR' + H+ (R=H,OH; R'= H, alkyl) lie further to the right for R=H than for R=OH because of inductive effects. 31P and 1H n.m.r. data are reported
- Gallagher, Michael J.,Honegger, Herbert
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p. 287 - 294
(2007/10/02)
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- Properties and Reactions of Trimethyl Phosphite, Trimethyl Phosphate, Triethyl Phosphate, and Trimethyl Phosphorothionate by Ion Cyclotron Resonance Spectroscopy
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The gas-phase ion-molecule reactions occurring in trimethyl phosphite, trimethyl phosphate, triethyl phosphate, and trimethyl phosphorothionate have been investigated by ion cyclotron resonance spectroscopy.Protonated parent ions, tetracoordinated phosphonium ions, and cluster ions are the reaction products observed.The proton affinities of these compounds have been determined to be 222.9, 214.2, 218.7, and 216.6 kcal/mol, respectively (relative to PA(NH3) = 207.0 kcal/mol).Homolytic bond dissociation energies of the protonated species are calculated using adiabatic ionization potentials determined by photoelectron spectroscopy.The trends in these quantities are discussed.A reasonable value for the correlated homolytic bond dissociation energy of trimethyl phosphite indicates that the first ionization potential of this molecule should be assigned to the phosphorus lone pair.The application of chemical ionization mass spectrometry to the analysis of phosphorus esters is briefly discussed.
- Hodges, Ronald V.,McDonnell, T. J.,Beauchamp, J. L.
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p. 1327 - 1332
(2007/10/02)
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