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Phosphinic Acid (phosphinic + acid)
Selected AbstractsAn Efficient Route for the Synthesis of Glycosyl Phosphinic Acids.CHEMINFORM, Issue 8 2004Charla A. Centrone Abstract For Abstract see ChemInform Abstract in Full Text. [source] Perfluoroalkyl Phosphonic and Phosphinic Acids as Proton Conductors for Anhydrous Proton-Exchange MembranesCHEMPHYSCHEM, Issue 13 2010Mahesha B. Herath Abstract A study of proton-transport rates and mechanisms under anhydrous conditions using a series of acid model compounds, analogous to comb-branch perfluorinated ionomers functionalized with phosphonic, phosphinic, sulfonic, and carboxylic acid protogenic groups, is reported. Model compounds are characterized with respect to proton conductivity, viscosity, proton, and anion (conjugate base) self-diffusion coefficients, and Hammett acidity. The highest conductivities, and also the highest viscosities, are observed for the phosphonic and phosphinic acid model compounds. Arrhenius analysis of conductivity and viscosity for these two acids reveals much lower activation energies for ion transport than for viscous flow. Additionally, the proton self-diffusion coefficients are much higher than the conjugate-base self-diffusion coefficients for these two acids. Taken together, these data suggest that anhydrous proton transport in the phosphonic and phosphinic acid model compounds occurs primarily by a structure-diffusion, hopping-based mechanism rather than a vehicle mechanism. Further analysis of ionic conductivity and ion self-diffusion rates by using the Nernst,Einstein equation reveals that the phosphonic and phosphinic acid model compounds are relatively highly dissociated even under anhydrous conditions. In contrast, sulfonic and carboxylic acid-based systems exhibit relatively low degrees of dissociation under anhydrous conditions. These findings suggest that fluoroalkyl phosphonic and phosphinic acids are good candidates for further development as anhydrous, high-temperature proton conductors. [source] Green, Palladium-Catalyzed Synthesis of Benzylic H -Phosphinates from Hypophosphorous Acid and Benzylic AlcoholsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2008Laëtitia Coudray Abstract Benzylic alcohols cross-couple directly with concentrated H3PO2 by using Pd/xantphos (1 or 2 mol-%). Depending on the substrate, DMF at 110 °C or t -AmOH at reflux with a Dean,Stark trap can be used. A broad range of benzylic alcohols react successfully to give moderate to good yields of the products. The preparation of other organophosphorus compounds (phosphinic and phosphonic acids) is also demonstrated. Asymmetric reaction with (R)-1-(2-naphthyl)ethanol provids the corresponding H -phosphinic acid in 77,% ee. The methodology provides a green, PCl3 -free route to benzylic- H -phosphinic acids.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Enantioselective Synthesis of Phospholenes via Asymmetric Organocatalytic Alkene IsomerizationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2008Lukas Hintermann Abstract An asymmetric synthesis of the 2,5-diphenylphosphol-2-ene fragment (,95% ee) has been realized via enantioselective Cinchona -alkaloid catalyzed double bond isomerization of a meso -2,5-diphenylphosphol-3-ene amide to a 2,5-diphenylphosphol-2-ene amide (up to 83% ee), followed by enantiomeric enrichment to ,95% ee by crystallization. The 2,5-diphenylphosphol-2-ene amide (a cyclic phosphinic acid amide) was hydrolyzed to the 2,5-diphenylphosphol-2-ene acid (a cyclic phosphinic acid) with retention of configuration at C-5. [source] Toward greener separations of rare earths: Bifunctional ionic liquid extractants in biodieselAICHE JOURNAL, Issue 9 2010Yinghui Liu Abstract Ionic liquids (ILs) containing quaternary phosphonium cations and phosphonic acid anions were explored as novel extractants for rare earths (RE) separation. They were considered to be bifunctional ionic liquid extractants (bif-ILEs), since both cations and anions of ILs were involved in the extraction. Trihexyl(tetradecyl)phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104), as a bif-ILE, together with propylene carbonate (PC), dimethyl carbonate (DMC), and soybean oil methyl ester (SBME, biodiesel) as diluents was employed in the extraction of RE(III) from aqueous solutions. Acidified Cyphos IL 104 (HNO3 -Cyphos IL 104) exhibited high solubility in three diluents, and higher extraction efficiency than bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) because of the coextraction of RE(III) by quaternary phosphonium cation and phosphonic acid anion in organic phase. Additionally, this coextraction mechanism could eliminate the loss of IL. The physical properties and miscibility test results indicated that SBME was an excellent solvent for RE(III) extraction. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Hydrogen bonding and short contacts in [2,4,6-tris(trifluoromethyl)phenyl]phosphinic acidACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Stéphanie M. Cornet In the title compound, C9H4F9O2P, molecules are linked by a single O,H...O hydrogen bond into chains related to those in phenylphosphinic acid. There are short intramolecular F...P contacts. [source] Synthesis of cyclic aminomethylphosphonates and aminomethyl-arylphosphinic acids by an efficient microwave-mediated phospha-mannich approachHETEROATOM CHEMISTRY, Issue 2 2008György Keglevich Microwave-assisted condensation of 1,3,-2-dioxaphosphinane 2-oxide (1), paraformaldehyde and secondary amines including 5- and 6-membered N -heterocycles at 55°C gave cyclic aminomethylphosphonates (2), whereas an analogous reaction involving dibenzo[c.e][1,2]oxaphosphinane 2-oxide (3) resulted in the corresponding aminomethyl-2-(2,-hydroxybiphenyl)phosphinic acids (4) as a consequence of a hydrolytic ring opening following the condensation. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:207,210, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20387 [source] Perfluoroalkyl Phosphonic and Phosphinic Acids as Proton Conductors for Anhydrous Proton-Exchange MembranesCHEMPHYSCHEM, Issue 13 2010Mahesha B. Herath Abstract A study of proton-transport rates and mechanisms under anhydrous conditions using a series of acid model compounds, analogous to comb-branch perfluorinated ionomers functionalized with phosphonic, phosphinic, sulfonic, and carboxylic acid protogenic groups, is reported. Model compounds are characterized with respect to proton conductivity, viscosity, proton, and anion (conjugate base) self-diffusion coefficients, and Hammett acidity. The highest conductivities, and also the highest viscosities, are observed for the phosphonic and phosphinic acid model compounds. Arrhenius analysis of conductivity and viscosity for these two acids reveals much lower activation energies for ion transport than for viscous flow. Additionally, the proton self-diffusion coefficients are much higher than the conjugate-base self-diffusion coefficients for these two acids. Taken together, these data suggest that anhydrous proton transport in the phosphonic and phosphinic acid model compounds occurs primarily by a structure-diffusion, hopping-based mechanism rather than a vehicle mechanism. Further analysis of ionic conductivity and ion self-diffusion rates by using the Nernst,Einstein equation reveals that the phosphonic and phosphinic acid model compounds are relatively highly dissociated even under anhydrous conditions. In contrast, sulfonic and carboxylic acid-based systems exhibit relatively low degrees of dissociation under anhydrous conditions. These findings suggest that fluoroalkyl phosphonic and phosphinic acids are good candidates for further development as anhydrous, high-temperature proton conductors. [source] | ||||||||||