Extraction Equilibria of Formic and Acetic Acids from Aqueous Solution by Phosphate-Containing Extractants

2001 ◽  
Vol 46 (6) ◽  
pp. 1472-1475 ◽  
Author(s):  
Weibin Cai ◽  
Shenlin Zhu ◽  
Xianglan Piao
2006 ◽  
Vol 419 (1-3) ◽  
pp. 240-244 ◽  
Author(s):  
Takumi Hori ◽  
Hideaki Takahashi ◽  
Masayoshi Nakano ◽  
Tomoshige Nitta ◽  
Weitao Yang

2012 ◽  
Vol 35 (13) ◽  
pp. 1675-1981 ◽  
Author(s):  
Xinqing Lee ◽  
Daikuan Huang ◽  
Dawei Lou ◽  
Janusz Pawliszyn

1997 ◽  
Vol 86 (11) ◽  
pp. 1210-1214 ◽  
Author(s):  
Ashwini Gadre ◽  
Kenneth A. Connors

1964 ◽  
Vol 42 (4) ◽  
pp. 878-884 ◽  
Author(s):  
M. Halpern ◽  
T. Kim ◽  
A. S. Kertes ◽  
N. C. Li

The extraction equilibria in the system aqueous hydrochloric acid – uranyl chloride –undiluted tri-n-butoxyethyl phosphate, TBEP, were examined as a function of increasing uranyl concentration (0.44 to 4.41 M) in the initial aqueous solution, the acid content of the initial aqueous solution being kept constant at 6.76 M. The extraction behavior of TBEP is found to be different from that of tributyl phosphate. Evidence has been presented to show that the three ethereal oxygen atoms in the TBEP molecule are, under high organic phase loading conditions, available for participation in complexation. The hydrochloric acid promoted hydrolysis of TBEP and the instability toward light of the TBEP layer containing hydrochloric acid and uranium were also examined.


1976 ◽  
Vol 54 (2) ◽  
pp. 202-209 ◽  
Author(s):  
J. Peter Guthrie

The equilibrium constant for the addition of sodium methoxide to methyl trifluoroacetate, in methanol as solvent, has been measured by 19F nmr, and is 7 M−1. From this was calculated an equilibrium constant, 2 × 10−4 M−1, for addition of methanol to the ester. The equilibrium constant for formation of methyl trifluoroacetate in aqueous solutions is 0.06 M−1. These results, with literature data, permit calculation of the free energies of formation in aqueous solution of orthotrifluoroacetic acid and its mono-, di-, and trimethyl esters. These in turn permit calculation of the standard free energy changes for addition of water and methanol to trifluoroacetic acid and its methyl ester. These combined with the analogous values for formic and acetic acids permit evaluation of ρ* values for these addition reactions. Linear plots are obtained if correction is made for steric effects, and the ρ* values are somewhat larger, 2.1–2.9, than was observed for the analogous carbonyl addition reactions.


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