- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Phosphonylation process
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A process for the production of a phosphono organo carboxylic acid, said process comprising a reaction stage wherein an unsaturated carboxylic acid [or a salt or an anhydride of said acid], is heated with a chlorophosphorus reaction product to produce a mixture including a phosphono organo carboxylic acid chloride, and a hydrolysis stage wherein said mixture is treated with an aqueous medium to produce said phosphono organo carboxylic acid. The process provides a relatively simple means of making the acid in high yields.
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- PHOSPHONYLATION BY TETRAPHOSPHORUS HEXOXIDE
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The general usefulness of P4O6 as starting material for the preparation of inorganic and organic phosphorus compounds is demonstrated by reactions of P4O6 with nucleophilic and electrophilic compounds.
- Schuelke, Ulrich
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p. 623 - 626
(2007/10/02)
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- Complexation Properties of Phosphonocarboxylic Acids in Aqueous Solutions
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The concentration formation constants of phosphonoacetic acid (PAA) complexes with the Ca(2+) and Mg(2+) ions were determined in aqueous solution at 25 deg C by potentiometric and coulometric titrations at different ionic strengths and were extrapolated to I = 0 in order to obtain thermodynamic values of the formation constants.Complexes were formed by the completely deprotonated Kf(ML) and monoprotonated Kf(MHL) forms of the PAA anion.The respective values for the complexes are: log Kf(CaL) = 4.68 +/- 0.03, log Kf(CaHL) = 2.61 +/- 0.08; log Kf(MgL) = 5.58 +/- 0.09, log Kf(MgHL) = 3.0 +/- 0.3.The enthalpy and entropy of complexation for the deprotonated Ca(2+) and Mg(2+) PAA species, determined from the temperature dependence of the log Kf(ML), are: ΔHo(Ca) = 0.6 +/- 0.2 kcal-mol-1, ΔSo(Ca) = 21.4 +/- 0.6 cal-mol-1-K-1, ΔHo(Mg) = 3.0 +/- 0.7 kcal-mol-1, and ΔSo(Mg) = 35 +/- 2 cal-mol-1-K-1.It is seen therefore, that the complexes are entropy stabilized but enthalpy destabilized.Formation constants were also determined for Ca(2+) and Mg(2+) complexes with PAA analogs, phosphonoformic and 3-phosphonopropionic acids and the complexation of PAA was also studied at a single ionic strength, with Na(1+), Ag(1+), Tl(1+), Sr(2+), Ba(2+), Cd(2+), Cu(2+), and Pb(2+) ions.
- Farmer, Richard M.,Heubel, P.-H.C.,Popov, Alexander I.
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p. 523 - 532
(2007/10/02)
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- Effect of Phosphono Substituents on Acyl Transfer Reactions
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The rate of release of p-nitrophenoxide from esters of phosphono-substituted carboxylic acids was examined as a function of pH(D), temperature, divalent metal ion (Mg2+ and Ca2+) concentration, and acyl acceptor (-OH and the thiolate of N-acetylcysteine).The hydrolysis of p-nitrophenyl 3-phosphonopropionate involves intramolecular nucleophilic catalysis by the dianionic phosphono substituent (pKa2(*) = 7.5) and is characterized by a first-order rate constant of 94 min-1 at 37 deg C.A comparison of the rate constant of the unimolecular reaction with that of the corresponding bimolecular reaction (corrected for the inductive effect of the acyl substituent and for the phosphonate basicity) yields a rate constant ratio of kuni/kbi = 7(+/-6)*103 M.The magnitude of this rate enhancement is similar to those of analogous intramolecular reactions (e.g., hydrolysis of mono-p-nitrophenyl succinate or of p-nitrophenyl 4-(N,N-dimethylamino)butyrate but, unlike these reactions, the rate acceleration resulting from intramolecular nucleophilic catalysis by the dianionic phosphono group is enthalpic in origin (Δ(*) ca. 8 kcal/mol).The entropy of activation for the intramolecular reaction is less favorable than that for the bimolecular reaction (Δ(*) ca. 9 eu).The alkaline hydrolysis and the thiolysis rates of p-nitrophenyl phosphonoacetate are accelerated over 100-fold by the association of Mg2+ or Ca2+ with the ester.This rate acceleration is attributed to the formation of a six-membered bidentate coordination complex between the divalent cation and the incipient tetrahedral intermediate.The metal-promoted acyl transfer reactions of p-nitrophenyl phosphonoacetate provide a convenient system for the quantitative assessment of the role of metal ions in the catalysis of aqueous reactions.
- Shames, Spencer L.,Byers, Larry D.
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p. 6177 - 6184
(2007/10/02)
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