Electron behavior in mixed solvents: optical spectra and reactivities in water/alkane diols

1984 ◽  
Vol 62 (11) ◽  
pp. 2217-2222 ◽  
Author(s):  
K. M. Idriss-Ali ◽  
Gordon R. Freeman
Keyword(s):  
Optical Absorption ◽  
Reaction Rate ◽  
Composition Range ◽  
Mixed Solvents ◽  
Solvated Electrons ◽  
Reaction Rate Constants ◽  
Diffusion Controlled ◽  
Entropy Of Activation ◽  
Lower Entropy ◽  
The Difference

Investigation of the effect of solvent structure on the optical absorption spectrum and reactivity of solvated electrons has been extended to diol/water mixed solvents, using 1,2-ethanediol (12ED) and 1,4-butanediol (14BD). The large effects that had been found in mono-ol/water mixed solvents did not occur in diol/water. Although addition of 3 mol% of a diol to water increased the optical absorption energies of e−s by 0.06 eV, similar to the shift caused by addition of 3 mol% of a mono-ol, the variation of the spectrum over the rest of the composition range was nearly ideal in diol/water, in contrast to the very non-ideal variation in mono-ol/water. Reaction rate constants kS at 298 K in the diol/water mixed solvents vary approximately as the inverse viscosity,η−1.0, in the diffusion-controlled limit. However, when reactions are two or three orders of magnitude slower than diffusion controlled, kS at 298 K is independent of η. Toluene reacts with e−s at a 10−3-fold smaller rate than does nitrobenzene; the difference is nearly completely due to a ~50 J/mol K lower entropy of activation of the former reaction.

scholarly journals Optical absorption spectra of solvated electrons in 1-butylamine–water mixed solvents

1995 ◽  
Vol 73 (12) ◽  
pp. 2126-2130 ◽  
Author(s):  
Yixing Zhao ◽  
Gordon R. Freeman
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Pure Water ◽  
Mixed Solvents ◽  
Binary Solvents ◽  
Optical Absorption Spectra ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Selective Solvation ◽  
Ideal Mixing

The optical absorption spectra of es− in 1-butylamine–water mixed solvents increase smoothly in energy and intensity as the water content is increased, with the exception of a small decrease in intensity on going from 95 to 100 mol% water. At 298 K the value of Gεmax increases from 1.42 × 10−21 m2/16 aJ (8.6 × 103 es−L/100 eV mol cm) in pure 1-butylamine to 8.3 × 10−21 m2/16 aJ (50 × 103 es−L/100 eV mol cm) in pure water, and the value of EAmax increases from 115 zJ (0.72 eV) to 278 zJ (1.74 eV). In the pure amine, if G(es−) = 0.27, then εmax = 5.3 × 10−21 m2/es− (3200 m2/mol). The solvent composition dependences of Gεmax and EAmax indicate little selective solvation of es− by water; this might be due to relatively "ideal" mixing of water and amine in the binary solvents. The temperature coefficient −dEAmax/dT = 0.43 zJ/K in pure 1-butylamine, 0.47 in pure water, and has a minimum of 0.27 in the 50:50 mixture. Keywords: 1-butylamine–water mixed solvents, optical absorption spectra, solvated electron, temperature dependence.

scholarly journals Positronium in a Liquid Phase: Formation, Bubble State and Chemical Reactions

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Sergey V. Stepanov ◽  
Vsevolod M. Byakov ◽  
Dmitrii S. Zvezhinskiy ◽  
Gilles Duplâtre ◽  
Roman R. Nurmukhametov ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Reaction Rate ◽  
Local Heating ◽  
Bubble Radius ◽  
Annihilation Rate ◽  
Electron Pairs ◽  
Reaction Rate Constants ◽  
Slowing Down ◽  
Diffusion Controlled ◽  
Different Temperatures

The present approach describes the e+ fate since its injection into a liquid until its annihilation. Several stages of the e+ evolution are discussed: (1) energy deposition and track structure of fast positrons: ionization slowing down, number of ion-electron pairs, typical sizes, thermalization, electrostatic interaction between e+ and the constituents of its blob, and effect of local heating; (2) positronium formation in condensed media: the Ore model, quasifree Ps state, intratrack mechanism of Ps formation; (3) fast intratrack diffusion-controlled reactions: Ps oxidation and ortho-paraconversion by radiolytic products, reaction rate constants, and interpretation of the PAL spectra in water at different temperatures; (4) Ps bubble models. Inner structure of positronium (wave function, energy contributions, relationship between the pick-off annihilation rate and the bubble radius).

scholarly journals Correlation of Isoprene-Maleic Anhydride Reaction Rate Constants in Mixed Solvents

2006 ◽  
Vol 13 (2) ◽  
pp. 123-127
Author(s):  
Haruo KATO ◽  
Yu ITO ◽  
Setsuko YONEZAWA ◽  
Katsumi HONDA ◽  
Yasuhiko ARAI
Keyword(s):  
Maleic Anhydride ◽  
Rate Constants ◽  
Reaction Rate ◽  
Mixed Solvents ◽  
Reaction Rate Constants

Time independent diffusion controlled reaction rate constants

1977 ◽  
Vol 99 (19) ◽  
pp. 6454-6455 ◽  
Author(s):  
Malcolm Dole ◽  
J. Salik
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constants ◽  
Diffusion Controlled ◽  
Diffusion Controlled Reaction

Effects of solvent structure on electron reactivity and radiolysis yields: 2-propanol/water mixed solvents

1984 ◽  
Vol 62 (7) ◽  
pp. 1265-1270 ◽  
Author(s):  
Joanna Cygler ◽  
Gordon R. Freeman
Keyword(s):  
Pure Water ◽  
Mixed Solvents ◽  
Water Structure ◽  
Trap Depth ◽  
Solvent Structure ◽  
Solvated Electrons ◽  
Absorption Energy ◽  
Diffusion Controlled ◽  
Free Ion ◽  
Different Temperatures

Reaction of solvated electrons with nitrobenzene, N, is nearly diffusion controlled in both pure solvents; kN ~ 1010 dm3/mol s. The value of kN is approximately proportional to the inverse viscosity η−1 in the pure solvents, and in the mixed solvents at different temperatures. However, on going from zero to 74 mol% water at the same temperature kN is independent of the 40% increase of η. Electron diffusion in the mixed solvents is not a simple function of fluidity.Reaction with the inefficient scavengers tryptophane (kS ~ 109 dm3/mol s) and phenol (kS ~ 107–108 dm3/mol s) correlates inversely with the electron optical absorption energy. The latter is related to the trap depth in the solvent; electrons in deeper traps have less tendency to react with molecules of low electron affinity.Addition of 3 mol% 2-PrOH to water at 296 K increases the value of Gεmax by 16%, although the value in pure 2-PrOH is three-fold smaller than that in pure water. The increase is attributed to an increase in the free ion yield, caused by an increase in the product of the electron thermalization range and the microscopic dielectric constant of the fluid between the ion and electron, averaged over the time that they exist as a correlated pair. Addition of a small amount of alcohol to water increases the orderliness of the water structure.

scholarly journals Near diffusion-controlled reaction of a Zn(Cys)4 zinc finger with hypochlorous acid

2016 ◽  
Vol 7 (8) ◽  
pp. 5508-5516 ◽  
Author(s):  
Vincent Lebrun ◽  
Jean-Luc Ravanat ◽  
Jean-Marc Latour ◽  
Olivier Sénèque
Keyword(s):  
Zinc Finger ◽  
Rate Constants ◽  
Reaction Rate ◽  
Hypochlorous Acid ◽  
Zinc Fingers ◽  
Reaction Rate Constants ◽  
Diffusion Controlled ◽  
Diffusion Controlled Reaction

Reaction rate constants of HOCl with zinc-bound cysteines are determined, demonstrating that zinc fingers are potent targets for HOCl and may serve as HOCl sensors.

scholarly journals Reduction kinetics of lead-rich slag with carbon in the temperature range of 1073 to 1473K

2013 ◽  
Vol 49 (2) ◽  
pp. 201-206 ◽  
Author(s):  
X. Hou ◽  
K.C. Chou ◽  
B. Zhao
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Graphite Crucible ◽  
Reduction Reaction ◽  
Synthetic Slag ◽  
Reduction Kinetics ◽  
Temperature Range ◽  
Diffusion Controlled ◽  
The Difference ◽  
Increasing Temperature

Extensive experiments have been carried out on the reduction of lead-rich slag in graphite crucible at temperature range of 1073 to 1473K. The reduction kinetics was also compared between industrial sinters and synthetic slags. The extent of reduction was measured by the volume of CO-CO2 gas produced at a given temperature and time. It was found that, at a given temperature, the reaction rate between the slag and carbon was initially fast and then slow as the extent of the reaction increases. Only limited reaction between slag and carbon occurred at temperatures below 1173K. At temperatures above 1173K, the reaction rate increased significantly with increasing temperature. The reduction reaction was found to be mainly liquid-solid reaction, which was chemically controlled at initial stage and diffusion controlled at later stage. The apparent activation energy was calculated to be 83.8 kJ/mol at chemically controlled stage and 224.9 kJ/mol at diffusion controlled stage for reduction of industrial sinter. For the synthetic slag, the reaction activation energy was 102.9 kJ/mol at chemically controlled stage and 259.4 kJ/mol at diffusion controlled stage. The difference of the activation energy between industrial sinter and synthetic slag can be explained by the difference in their CaO/SiO2 ratios.

scholarly journals Application of Transition State Theory to Estimate Diffusion Controlled Bimolecular Reaction Rate Constants.

1981 ◽  
Vol 35b ◽  
pp. 529-531 ◽  
Author(s):  
Vernon D. Parker ◽  
Ann-Marie Eklund ◽  
Toshiaki Nishida ◽  
Curt R. Enzell ◽  
Curt R. Enzell
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Reaction Rate ◽  
Bimolecular Reaction ◽  
State Theory ◽  
Reaction Rate Constants ◽  
Diffusion Controlled
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