Ultrasonic study of hydrochloric acid association in N,N-dimethylformamide

1968 ◽  
Vol 46 (6) ◽  
pp. 853-858 ◽  
Author(s):  
Siu C. Chan ◽  
J. P. Valleau
Keyword(s):  
Hydrochloric Acid ◽  
Sound Velocity ◽  
Hydrogen Chloride ◽  
Rate Constants ◽  
Ultrasonic Absorption ◽  
Frequency Range ◽  
Association Rate ◽  
Reaction Distance ◽  
Ultrasonic Study ◽  
Diffusion Controlled

Ultrasonic absorption and velocity have been measured in anhydrous N,N-dimethylformamide solutions of hydrogen chloride, over the frequency range 13 to 143 mc/s, and the concentration range 0.05 M to 3.5 M. A large relaxation is observed and ascribed to the association of the acid. The rate constants for this reaction are obtained, and their variations with concentration are discussed. The association rate appears to be entirely diffusion controlled, and the corresponding "reaction distance" is large. This may be related to the very large effect on the sound velocity (and hence on the compressibility) that arises from the introduction of these ions.

scholarly journals Effect of heparin on the glia-derived-nexin-thrombin interaction

1989 ◽  
Vol 257 (1) ◽  
pp. 191-196 ◽  
Author(s):  
A Wallace ◽  
G Rovelli ◽  
J Hofsteenge ◽  
S R Stone
Keyword(s):  
Rate Constants ◽  
Antithrombin Iii ◽  
Kinetic Properties ◽  
Association Rate ◽  
High Affinity ◽  
Diffusion Controlled ◽  
Different Types ◽  
Human Thrombin ◽  
Alpha Beta ◽  
Association Rate Constants

In order to determine the specificity of the interaction between thrombin and glia-derived nexin (GdN), the inactivation of proteolytically modified human thrombin species by GdN has been studied. The second-order rate constants for the inactivation of alpha-, beta T-, gamma T- and epsilon-thrombin by GdN were 1.41, 0.63, 0.33 and 1.91 microM-1.s-1 respectively. The kinetic properties of gdN were also investigated in the presence of different types of heparin, fractionated according to antithrombin III-binding affinity. Association rate constants of both gdN and antithrombin III with alpha-thrombin were obtained using unfractionated, low- and high-affinity heparin types. The different heparin types gave optimal rates of inhibition at similar heparin concentrations for both inhibitors. At optimal heparin concentrations, the rate of inactivation of alpha-thrombin by GdN was 0.5-1.2 nM-1.s-1, which suggests that, under these conditions, the interaction is diffusion-controlled.

Proton Transfer Kinetics in Medium-strong Inorganic Acids

1973 ◽  
Vol 51 (14) ◽  
pp. 2297-2305 ◽  
Author(s):  
David Charles Hodgkin ◽  
Peeter Kruus
Keyword(s):  
Proton Transfer ◽  
Aqueous Solutions ◽  
Rate Constants ◽  
Reasonable Agreement ◽  
Ultrasonic Absorption ◽  
Absolute Rate ◽  
Absorption Data ◽  
Inorganic Acids ◽  
Diffusion Controlled ◽  
Excess Absorption

A method of obtaining relative and absolute rate constants for proton transfer equilibria is described. It is suitable for equilibria of the type[Formula: see text]in dilute (< 0.1 M) solutions of medium strong inorganic acids. To obtain absolute values of kd, kr it is necessary to know the value of ΔV0 for the equilibrium. Ultrasonic absorption data for aqueous solutions of H3PO4, H3AsO4, and H2SO4 at 20, 10, and 0 °C are presented together with data at 20 °C for H3PO3, H2SeO3, HIO4, NaHSO4, KHSO4, and NH4HSO4. From analysis of the concentration dependence of the excess absorption, values of Ka are calculated for these acids, and values of kd, kr for those where ΔV0 is available. The Ka obtained are in reasonable agreement with literature values except for HIO4 and H2SeO4. The absolute values of kr for H3PO4, H3AsO4, and HSO4− indicate that the diffusion controlled recombination process postulated is complete when the ions are about 15 Å from each other.

Sound Velocity and Ultrasonic Absorption in High-Tc-Superconductors

1987 ◽  
Vol 26 (S3-3) ◽  
pp. 2139 ◽  
Author(s):  
V. Müller ◽  
K. de Groot ◽  
D. Maurer ◽  
Ch. Roth ◽  
K. H. Rieder ◽  
...  
Keyword(s):  
Sound Velocity ◽  
Ultrasonic Absorption ◽  
High Tc Superconductors ◽  
High Tc
Sign in / Sign up

Export Citation Format

Share Document