54436-53-2Relevant academic research and scientific papers
Kinetics and adsorption calculations: insights into the MgO-catalyzed detoxification of simulants of organophosphorus biocides
Almerindo, Gizelle I.,Buratto, Suelen C.,Caramori, Giovanni F.,Fiedler, Haidi D.,Medeiros, Michelle,Micke, Gustavo A.,Nicolazi, Lucas M.,Nome, Faruk,Parreira, Renato L. T.,Sangaletti, Patrícia,Schneider, Felipe S. S.,Wanderlind, Eduardo H.
supporting information, p. 19011 - 19021 (2020/10/02)
We report the targeted decomposition of the organophosphate methyl paraoxon by means of its transesterification with 1-propanol catalyzed by magnesium oxide. Catalyst characterization by energy dispersive X-ray fluorescence (EDXRF), nitrogen adsorption/desorption measurements (BET and BJH methods), and temperature programmed desorption of CO2(CO2-TPD) showed that the employed MgO presents properties favorable for the methyl paraoxon adsorption and transesterification to occur. A thorough kinetic investigation showed that rate enhancements up to 3 × 106-fold can be achieved in comparison with the spontaneous propanolysis of the substrate, and that the material can be used in additional cycles without loss of catalytic activity, with the catalyst recovery achieved through a simple washing procedure. Energies for adsorption of 1-propanol and methyl paraoxon onto a MgO model surface were obtained by density functional theory calculations, which showed that the latter displays a stronger affinity for the catalyst surface, and that the reaction should proceed with methyl paraoxon and 1-propanol molecules juxtapositioned at adjacent Mg2+sites, with nucleophilic and electrophilic centersca.2.4 ? away from each other. Additionally, MgO also promoted rate enhancements up to 5 × 104-fold in the propanolysis of a further range of representative phosphate triesters, and in most of the cases the final transesterified products are trialkyl phosphates structurally related to a family of flame-retardants. The results thus provide insights into the development of novel systems for the targeted conversion of organophosphorus compounds into value-added products by employing simple, highly efficient, and low-cost metal oxide catalysts.
Dual nucleophilic substitution reactions of O,O-diethyl 2,4-dinitrophenyl phosphate and thionophosphate triesters
Aguayo, Raul,Arias, Felipe,Canete, Alvaro,Zuniga, Carolina,Castro, Enrique A.,Pavez, Paulina,Santos, Jose G.
, p. 202 - 211 (2013/03/14)
The reactions of the title compounds with phenoxides, secondary alicyclic (SA) amines, and pyridines, in 44 wt% ethanol-water, at 25°C and an ionic strength of 0.2 M, were subjected to kinetic and product studies. From analytical techniques (HPLC and NMR), two pathways were detected (nucleophilic attack at the phosphoryl center and at the C-1 aromatic carbon) for the reactions of all the nucleophiles with the phosphate (2) and for the pyridinolysis of the thionophosphate (1). Only aromatic nucleophilic substitution was found for the reactions of 1 with phenoxides and SA amines. For the dual reactions, the nucleophilic rate constants (kN) were separated in two terms: documentclass{article}usepackage{amssymb} pagestyle{empty}begin{document}k-{rm N}^{rm P}end{document} and documentclass{article}usepackage{amssymb}pagestyle{empty}begin{document}k-{ rm N}^{{rm Ar}}end{document}, which are the rate constants for the corresponding electrophilic centers. The absence of a break in the Bronsted-type plots for the attack at P is consistent with concerted mechanisms. The Bronsted slopes, βAr 0.32-0.71, for the attack at the aromatic C-1, are in agreement with stepwise mechanisms where formation of a Meisenheimer complex is the rate-determining step. 2013 Wiley Periodicals, Inc. Int J Chem Kinet 45: 202-211, 2013 Copyright
Transfer of the Diethoxyphosphoryl Group between Imidazole and Aryloxy Anion Nucleophiles
Ba-Saif, Salem,Williams, Andrew
, p. 2204 - 2209 (2007/10/02)
Rate constans have been measured for reaction of imidazole with aryl diethyl phosphate (k1) and of aryloxy anions with N-(diethoxyphosphoryl)imidazolium ion (k-1) in aqueous solution at 25 deg C; they obey the following linear Broensted equations: log k1 = -1.02pKArOH + 1.83 (n = 6, r = 0.989); log k-1 = 0.85pKArOH - 0.48 (n = 10, r = 0.957).The value of βeq (1.87) obtained from βlg and βnuc supports a previously determined value (1.83) for the transfer of the neutral phosphoryl group from phenolate ion nucleophiles.The pKaof (diethoxyphosphoryl)imidazolium ion is 6.04.The equilibrium constant for reaction of 4-nitrophenyl diethyl phosphate with imidazole is 5.9 x 10-6; in the case of the aryl ester from phenol with pKArOH = 4.34 the equilibrium constant is calculated to be unity.The Broensted βeq data are used to calibrate effective charges derived from previously measured βlg values for attack of nucleophiles at phosphorus bearing phenolate ion leaving groups.
Cleavage of Phosphate Esters by Hydroxyl-Functionalized Micellar and Vesicular Reagents
Moss, Robert A.,Ihara, Yasuji
, p. 588 - 592 (2007/10/02)
In order to compare the kinetic efficiencies of hydroxyl-functionalized surfactant vesicles with those of comparably functionalized micellar reagents, we studied the cleavages of p-nitrophenyl diphenyl phosphate (2) at pH 9.0 and lithium 2.4-dinitrophenyl
