Thermodynamics of protonation of N,N-dimethylthioamides in aqueous sulfuric acid

1990 ◽  
Vol 68 (10) ◽  
pp. 1746-1749 ◽  
Author(s):  
Alessandro Bagno ◽  
Vlttorio Lucchini ◽  
Glanfranco Scorrano
Keyword(s):  
Sulfuric Acid ◽  
Temperature Range ◽  
Aqueous Sulfuric Acid ◽  
Solvation Thermodynamics ◽  
External Stabilization

The protonation (m* and [Formula: see text]) and thermodynamic (ΔG°, ΔH°, ΔS°) parameters of ionization of four thioamides RCSNMe2 (R = Me, Et, i-Pr, t-Bu) have been determined in aqueous sulfuric acid in the 25–60 °C temperature range with a UV technique. The title compounds are relatively strong bases; 100% protonation is reached in 47% H2SO4. Their solvation is lower than for primary thioamides and sulfides, as indicated by the higher values of m*, and close to the range of carbon bases. Base strengths are discussed in terms of the competition between internal and external stabilization. Keywords: basicity, protonation, solvation, thermodynamics, thioamides.

Electrochemistry of Gold in Aqueous Sulfuric Acid Solutions under Neural Stimulation Conditions

2005 ◽  
Vol 152 (7) ◽  
pp. E212 ◽  
Author(s):  
Daniel R. Merrill ◽  
Ionel C. Stefan ◽  
Daniel A. Scherson ◽  
J. Thomas Mortimer
Keyword(s):  
Sulfuric Acid ◽  
Neural Stimulation ◽  
Acid Solutions ◽  
Aqueous Sulfuric Acid ◽  
Sulfuric Acid Solutions

Highly gas permselective polyetherketone hollow fibre membranes using aqueous sulfuric acid solution as coagulant

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Jiping Yang ◽  
Philip J Brown
Keyword(s):  
Mechanical Properties ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Gas Separation ◽  
Sulfuric Acid Solution ◽  
Hollow Fibre ◽  
Injection Rate ◽  
Fluid Injection ◽  
Aqueous Sulfuric Acid ◽  
Membrane Morphology

AbstractHollow fibre membranes with more sponge-like morphology and improved gas permeation performance were spun from 20% polyetherketone (PEK) /sulfuric acid (H2SO4) dope solution with aqueous sulfuric acid solution as coagulant using dry-jet wet spinning process. The membrane morphology, mechanical properties and gas separation performance (hydrogen, methane and carbon dioxide) of as-spun PEK hollow fibres have been measured using SEM, Instron and gas test rig. Better cross section structures and mechanical properties in as-spun PEK hollow fibres were observed when aqueous sulfuric acid solution replaced water as coagulant (internal and external). The hydrogen/methane selectivity of up to 40 and hydrogen permeation rate of 3.65 GPU obtained in PEK hollow fibre membranes using 30% sulfuric acid solution as internal and external coagulant simultaneously at the bore fluid injection rate of 30 ml/h are higher than those reported in literatures. Furthermore the effects of bore fluid injection rate and various coagulants on the membrane morphology, mechanical properties and gas separation properties were investigated, as well.

Sign in / Sign up

Export Citation Format

Share Document