4408-78-0Relevant articles and documents
Complexation Properties of Phosphonocarboxylic Acids in Aqueous Solutions
Farmer, Richard M.,Heubel, P.-H.C.,Popov, Alexander I.
, p. 523 - 532 (1981)
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.
The mckenna reaction – avoiding side reactions in phosphonate deprotection
Justyna, Katarzyna,Ma?olepsza, Joanna,Kusy, Damian,Maniukiewicz, Waldemar,B?a?ewska, Katarzyna M.
, p. 1436 - 1446 (2020/07/08)
The McKenna reaction is a well-known and popular method for the efficient and mild synthesis of organophosphorus acids. Bromotrimethylsilane (BTMS) is the main reagent in this reaction, which transforms dialkyl phosphonate esters into bis(trimethylsilyl)esters, which are then easily converted into the target acids. However, the versatile character of the McKenna reaction is not always used to its full extent, due to formation of side products. Herein, demonstrated by using model examples we have not only analyzed the typical side processes accompanying the McKenna reaction, but also uncovered new ones. Further, we discovered that some commonly recommended precautions did not always circumvent the side reactions. The proposed results and recommendations may facilitate the synthesis of phosphonic acids.
Applications of mesoporous titanium phosphonate functionalized with carboxylic groups
Li, Dongdong,Zhang, Yuping
, p. 44229 - 44233 (2014/12/10)
Mesoporous titanium phosphonate functionalized with -COOH was synthesized by a simple co-condensation process with the use of 2-phosphonoacetic acid and titanium tetrachloride under acid conditions. The obtained mesoporous materials show high surface area and large pore volume, which were supported by XRD, TEM, SEM and N2 adsorption analysis. The integrity of the organophosphonate groups were further characterized by FTIR and NMR. Palladium nanoparticles were successfully supported onto the materials combined with a metal adsorption-reduction procedure, showing high activity for the Suzuki reaction. Furthermore, the obtained catalyst can be recovered and reused without significant decrease in catalytic activity. This journal is
