IONIZATION OF ORGANIC COMPOUNDS: V. THIOLACTAMS IN SULPHURIC ACID

1963 ◽  
Vol 41 (3) ◽  
pp. 721-725 ◽  
Author(s):  
J. T. Edward ◽  
H. Stollar

The ionization in aqueous sulphuric acid of thiolactams consisting of five-, six-, and seven-membered rings has been studied. With increasing concentration of acid the ionization ratio increases more rapidly than h0. A possible explanation involving the hydration of the thio-lactam is given. Changes in the basicity of thiolactams with ring size parallel changes previously found for lactams.

1962 ◽  
Vol 40 (5) ◽  
pp. 966-975 ◽  
Author(s):  
J. T. Edward ◽  
I. C. Wang

Protonation constants (pKBH+) of −6.8 and −0.9 have been determined for propionic acid and propionamide, respectively, from measurements of their ultraviolet absorption in various concentrations of sulphuric acid. The ionization ratio of propionamide and of other amides increases more slowly than the Hammett acidity function, h0, with increase in acid concentration. This may be explained by assuming that in a given concentration of sulphuric acid the protonated amide is more heavily hydrated than the protonated Hammett indicator used to establish the h0 scale for this region of acid concentrations.


1960 ◽  
Vol 38 (11) ◽  
pp. 2109-2116 ◽  
Author(s):  
H. J. Campbell ◽  
J. T. Edward

The changes in the ultraviolet absorption spectra of aliphatic ketones in aqueous sulphuric acid have been followed as the acid strength is increased from 0 to 98%. With increase in strength up to 65% the weak peak at about 270 mμ is shifted to shorter wavelengths by a medium effect. However, with further increase in acid strength the peak disappears altogether because of protonation of the carbonyl group. The pKBH+ values of several ketones have been calculated from the spectrophotometric results to be about −7. The pKBH+ values of cyclic ketones vary systematically with ring size. The significance of the present work to recent studies on the rate of enolization of acetone is discussed.


2014 ◽  
Vol 1040 ◽  
pp. 327-330 ◽  
Author(s):  
Tatyana Volgina ◽  
Viktor T. Novikov ◽  
Oksana Yu. Fedorova

A method of oxidative mineralization of the salicylic acid and its derivatives as well as medicinal products containing salicylic acid as the active ingredient was investigated. Destruction of the organic compounds is possible both in the electrolyte under the oxidant, electrochemically formed in situ in the sulphuric acid solutions, and at the anode so. Simultaneously, at the cathode, reduction of the zinc ions, contained in a number of medicinal products, is possible. Final products of the oxidation are simple non-toxic organic compounds, carbon dioxide, and water. This process is the most effective in the 40% sulphuric acid at the current density of 0.5–0.8 A/cm2 and the temperature of 30–50 °C.


2005 ◽  
Vol 5 (3) ◽  
pp. 2599-2642 ◽  
Author(s):  
A. Petzold ◽  
M. Gysel ◽  
X. Vancassel ◽  
R. Hitzenberger ◽  
H. Puxbaum ◽  
...  

Abstract. The European PartEmis project (''Measurement and prediction of emissions of aerosols and gaseous precursors from gas turbine engines'') was focussed on the characterisation and quantification of exhaust emissions from a gas turbine engine. A comprehensive suite of aerosol, gas and chemi-ion measurements were conducted under different combustor operating conditions and fuel sulphur concentrations. Combustion aerosol characterisation included on-line measurements of mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, cloud condensation nuclei (CCN) activation potential, and off-line analysis of chemical composition. Modelling of CCN activation of combustion particles was conducted using microphysical and chemical properties obtained from the measurements as input data. Based on this unique data set, the role of sulphuric acid coatings on the combustion particles, formed in the cooling exhaust plume through either direct condensation of gaseous sulphuric acid or coagulation with volatile condensation particles nucleating from gaseous sulphuric acid, and the role of the organic fraction for the CCN activation of combustion particles was investigated. It was found that particles containing a large fraction of non-volatile organic compounds grow significantly less at high relative humidity than particles with a lower content of non-volatile OC. Also the effect of the non-volatile OC fraction on the potential CCN activation is significant. While a coating of water-soluble sulphuric acid increases the potential CCN activation, or lowers the activation diameter, respectively, the non-volatile organic compounds, mainly found at lower combustion temperatures, can partially compensate this sulphuric acid-related enhancement of CCN activation of carbonaceous combustion aerosol particles.


1954 ◽  
Vol 8 (1) ◽  
pp. 40 ◽  
Author(s):  
R. J. Gillespie ◽  
J. A. Leisten

1952 ◽  
Vol 52 (3) ◽  
pp. 419-423 ◽  
Author(s):  
H. G. Bray ◽  
Brenda G. Humphris ◽  
W. V. Thorpe ◽  
K. White ◽  
P. B. Wood

1962 ◽  
Vol 40 (3) ◽  
pp. 399-407 ◽  
Author(s):  
J. T. Edward ◽  
I. C. Wang

The ionization ratio of thioacetamide in aqueous sodium hydroxide, determined spectrophotometrically, is proportional to the concentration of hydroxide ion up to a concentration of about 1 M, and indicates a pKHA of 13.4. For more concentrated solutions the ionizing power increases more rapidly than the hydroxide ion concentration; from the experimentally determined ionization ratios the values of the h− acidity function for 1–6 M sodium hydroxide have been calculated. The relation of h− values to the salting-out parameters and water activities of concentrated sodium hydroxide solutions is discussed.


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