The Reaction of the Hydrated Electron with Amino Acids, Peptides, and Proteins in Aqueous Solution: I. Factors Affecting the Rate Constants

1975 ◽  
Vol 62 (2) ◽  
pp. 337 ◽  
Author(s):  
Y. Tal ◽  
M. Faraggi
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Rate Constants ◽  
Hydrated Electron ◽  
Factors Affecting

Effect of β-cyclodextrin on the reaction of α-amino acid anions with p-nitrophenyl acetate and p-nitrophenyl hexanoate

1997 ◽  
Vol 75 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Oswald S. Tee ◽  
Timothy A. Gadosy ◽  
Javier B. Giorgi
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Data Analysis ◽  
Amino Acid ◽  
Rate Constants ◽  
First Order ◽  
Yield Rate ◽  
Pseudo First Order ◽  
Rate Ratios ◽  
Kinetics Of

The effects of β-cyclodextrin (β-CD) on the kinetics of the reaction of α-amino acid anions with p-nitrophenyl acetate (pNPA) and p-nitrophenyl hexanoate (pNPH) have been investigated. Pseudo-first-order rate constants obtained with various concentrations of nucleophile and β-CD, in aqueous solution at pH 9.88, were analyzed to yield rate constants for reaction of the nucleophiles with free ester (kN) and with ester bound to β-CD (kcN). For pNPA reacting with amino acids that bind weakly to β-CD, if at all, the ratio kcN/kN is very close to one, but for amino acids that bind appreciably to β-CD this ratio is greater than one (up to 3.5). Generally similar behaviour is observed for reactions with pNPH, but the rate ratios are smaller and all less than one. These findings are comparable to those obtained in this laboratory for the CD-mediated reactions of p-nitrophenyl alkanoate esters with other nucleophiles, including simple alkylamines that bind quite strongly to CDs, but they differ from those reported in an earlier study of the reaction of pNPA with amino acid anions (Can. J. Chem. 69, 1124 (1991)) where the data analysis suggested more substantial catalysis by cyclodextrins. Key words: amino acids, cyclodextrin, ester cleavage, kinetics, catalysis.

Radiolysis studies on the corrosion inhibitors 1 -hexyn-3-ol, cinnamonitrile, and 1,3-diethyl-2-thiourea

1995 ◽  
Vol 73 (12) ◽  
pp. 2137-2142 ◽  
Author(s):  
A.J. Elliot ◽  
M.P. Chenier ◽  
D.C. Ouellette
Keyword(s):  
Hydrogen Atom ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Rate Constant ◽  
Rate Constants ◽  
Corrosion Inhibitors ◽  
Hydrated Electron

In this publication we report: (i) the rate constants for reaction of the hydrated electron with 1-hexyn-3-ol ((8.6 ± 0.3) × 108 dm3 mol−1 s−1 at 18 °C), cinnamonitrile ((2.3 ± 0.2) × 1010 dm3 mol−1 s−1 at 20 °C), and 1,3-diethyl-2-thiourea ((3.5 ± 0.3) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile and diethylthiourea, the temperature dependence up to 200 °C and 150 °C, respectively, is also reported; (ii) the rate constants for the reaction of the hydroxyl radical with 1-hexyn-3-ol ((5.5 ± 0.5) × 109 dm3 mol−1 s−1 at 20 °C), cinnamonitrile ((9.2 ± 0.3) × 109 dm3 mol−1 s−1 at 21 °C), and diethylthiourea ((8.0 ± 0.8) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile, the temperature dependence up to 200 °C is also reported; (iii) the rate constant for the hydrogen atom reacting with 1-hexyn-3-ol ((4.3 ± 0.4) × 109 dm3 mol−1 s−1 at 20 °C). Keywords: radiolysis, corrosion inhibitors, rate constants.

Fabrication of monodisperse polypyrrole/SBA-15 composite for the selective removal of Cr(Ⅵ) from aqueous solutions

2021 ◽  
Author(s):  
Liang Wang ◽  
Peng Gao ◽  
Mengxin Liu ◽  
Ziqing Huang ◽  
Shixia Lan ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Adsorption Process ◽  
In Situ Polymerization ◽  
Selective Removal ◽  
Factors Affecting

Monodisperse polypyrrole/SBA-15 composite (PPy/SBA-15) was fabricated by in-situ polymerization and used for Cr(Ⅵ) adsorption from aqueous solution. PPy/SBA-15 was characterized by numerous approaches. Factors affecting the Cr(Ⅵ) adsorption process included...

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