IONIZATION OF ORGANIC COMPOUNDS: III. BASICITIES OF PROPIONIC ACID AND PROPIONAMIDE

1962 ◽  
Vol 40 (5) ◽  
pp. 966-975 ◽  
Author(s):  
J. T. Edward ◽  
I. C. Wang
Keyword(s):  
Sulphuric Acid ◽  
Propionic Acid ◽  
Organic Compounds ◽  
Acid Concentration ◽  
Ultraviolet Absorption ◽  
Protonation Constants ◽  
Acidity Function ◽  
Hammett Acidity Function ◽  
Ionization Ratio

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.

IONIZATION OF ORGANIC COMPOUNDS: II. THIOACETAMIDE IN AQUEOUS SODIUM HYDROXIDE. THE H− ACIDITY FUNCTION

1962 ◽  
Vol 40 (3) ◽  
pp. 399-407 ◽  
Author(s):  
J. T. Edward ◽  
I. C. Wang
Keyword(s):  
Sodium Hydroxide ◽  
Organic Compounds ◽  
Aqueous Sodium Hydroxide ◽  
Ion Concentration ◽  
Acidity Function ◽  
Concentrated Solutions ◽  
Salting Out ◽  
Hydroxide Ion ◽  
Aqueous Sodium ◽  
Ionization Ratio

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.

scholarly journals Protonation constants of hydroxybenzenes in hydrochloric acid

1999 ◽  
Vol 64 (9) ◽  
pp. 533-538
Author(s):  
D.S. Veselinovic ◽  
M.V. Obradovic ◽  
S.B. Tosic
Keyword(s):  
Hydrochloric Acid ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Protonation Constants ◽  
Acidity Function ◽  
Absorption Bands ◽  
Graphic Dependence ◽  
Mineral Acids ◽  
Hammett Acidity Function

The absorption spectra of monohydroxybenzene (Fen), 1,3-dihydroxybenzene (Rez), 1,4-dihydroxybenzene (Hi), 1,2,3-trihydroxybenzene (Pg) and 1,3,5-trihydroxy-benzene (Fg) in aqueous solutions of hydrochloric acid with different values of the Hammett acidity function(H0) have two absorption bands in the region between 190-220 nm and 260-290 nm. This behavior is similar in another mineral acids (H2SO4, H3PO4, HClO4). The absorbance decreases with increasing of acidity (with decreasing of H0 values) because of O-protonation. The absorption maxima shift to longer wave-lengths, and the graphic dependence of the absorption of the second band as a function of H0 gives characteristic S-curves. These curves show the different effect of the acid on the form the protonation of the investigated hydroxybenzenes. The potonation constants of the hydroxybenzenes were calculated: pKFen=-1.95; pKRez=-2.40; pKHi= -1.93; pKPg=-2.95; pKFg=-1.83.

IONIZATION OF ORGANIC COMPOUNDS: V. THIOLACTAMS IN SULPHURIC ACID

1963 ◽  
Vol 41 (3) ◽  
pp. 721-725 ◽  
Author(s):  
J. T. Edward ◽  
H. Stollar
Keyword(s):  
Sulphuric Acid ◽  
Organic Compounds ◽  
Ring Size ◽  
Ionization Ratio

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.

Rates of formation of isoperthiocyanic acid (5-Amino-1,2,4-dithiazole-3-thione) from thiocyanate in aqueous solution

1969 ◽  
Vol 22 (3) ◽  
pp. 513 ◽  
Author(s):  
WH Hall ◽  
IR Wilson
Keyword(s):  
Aqueous Solution ◽  
Sulphuric Acid ◽  
Rate Constant ◽  
Linear Dependence ◽  
Potassium Thiocyanate ◽  
Acidity Function ◽  
Third Order ◽  
Hammett Acidity Function ◽  
Thiocyanate Concentration ◽  
Arrhenius Expression

The rates of formation of 5-amino-1,2,4-dithiazole-3-thione from potassium thiocyanate in aqueous sulphuric acid have been studied spectrophotometrically. They show close to third-order dependence on thiocyanate concentration and linear dependence on the Hammett acidity function, h-. Between 25 and 45� the rate constant is given by the Arrhenius expression k = 9.27 x 10-5exp(-8800/T) 1.2 mole-2 sec-1 A mechanism is proposed.

A New Iterative Method of Construction of the Hammett Acidity Function

1997 ◽  
Vol 62 (4) ◽  
pp. 645-655 ◽  
Author(s):  
Oldřich Pytela
Keyword(s):  
Acid Concentration ◽  
Moving Average ◽  
Acidity Function ◽  
Hammett Acidity Function ◽  
Fourth Step ◽  
The Mean ◽  
The Given ◽  
Gradual Transformation ◽  
New Iterative Method ◽  
Weighted Moving Average

A new iterative algorithm has been devised for construction of the H acidity function. The procedure is based on gradual transformation of the dependence of log I vs acid concentration into the dependence of H vs acid concentration, and it involves four steps. In the first step a continuous acidity function is obtained by taking the average of log I values for the same acid concentrations. The second step of the algorithm is smoothing out of the acidity function by means of smoothing the H value by weighted moving average. In the third step, the mean distances between the log I values and the corresponding values of the smoothed acidity function H are calculated for the given indicator, and in the fourth step these distances are used together with log I values for calculating a new acidity function. The procedure designed was converted into a programme in the Delphi 2 language for PC Pentium and was successfully validated on literature data.

Preparation and Characterization of a Novel Room Temperature Dicationic Ionic Liquid and its Application in the Synthesis of Xanthenediones Under Solvent-Free Conditions

2018 ◽  
Vol 21 (8) ◽  
pp. 602-608 ◽  
Author(s):  
Zainab Ehsani-Nasab ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Reaction Times ◽  
Significant Loss ◽  
Solvent Free ◽  
Acidity Function ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Hammett Acidity Function ◽  
Dicationic Ionic Liquid

Aim and Objective: In the present work, 1, 1’-sulfinyldiethylammonium bis (hydrogen sulfate) as a novel room temperature dicationic ionic liquid was synthesized and used as a catalyst for xanthenediones synthesis. Material and Method: The dicationic ionic liquid has been synthesized using ethylamine and thionyl chloride as precursors. Then, by the reaction of [(EtNH2)2SO]Cl2 with H2SO4, [(EtNH2)2SO][HSO4]2 was prepared and after that, it was characterized by FT-IR, 1H NMR, 13C NMR as well as Hammett acidity function. This dicationic ionic liquid was used as a catalyst for the synthesis of xanthenediones via condensation of structurally diverse aldehydes and dimedone under solvent-free conditions. The progress of the reaction was monitored by thin layer chromatography (ethyl acetate/n-hexane = 3/7). Results: An efficient solvent-free method for the synthesis of xanthenediones has been developed in the presence of [(EtNH2)2SO][HSO4]2 as a powerful catalyst with high to excellent yields, and short reaction times. Additionally, recycling studies have demonstrated that the dicationic ionic liquid can be readily recovered and reused at least four times without significant loss of its catalytic activity. Conclusion: This new dicationic ionic liquid can act as a highly efficient catalyst for xanthenediones synthesis under solvent-free conditions.

Solvolysis kinetics and mechanism of substituted 3-acetyl-1,3-diphenyltriazenes in acid medium; Kinetic acidity function

1987 ◽  
Vol 52 (9) ◽  
pp. 2212-2216
Author(s):  
Oldřich Pytela ◽  
Martin Kaska ◽  
Miroslav Ludwig ◽  
Miroslav Večeřa
Keyword(s):  
Acid Medium ◽  
Sulphuric Acid ◽  
Rate Constants ◽  
Decomposition Kinetics ◽  
Acidity Function ◽  
Hammett Equation ◽  
Kinetic Acidity ◽  
Reaction Constant ◽  
Acid Catalyzed ◽  
Catalytic Rate

The decomposition kinetics has been measured of fourteen 3-acetyl-1,3-bis(subst. phenyl)triazenes in 40% (v/v) ethanol and sulphuric acid. The kinetic acidity function and catalytic rate constants have been determined from the rate constants observed. Mechanism has been suggested for the general acid-catalyzed solvolysis from comparison of the course of the kinetic acidity function and H0 function and from the reaction constant of the Hammett equation.

scholarly journals Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms

2006 ◽  
Vol 6 (12) ◽  
pp. 4079-4091 ◽  
Author(s):  
S.-L. Sihto ◽  
M. Kulmala ◽  
V.-M. Kerminen ◽  
M. Dal Maso ◽  
T. Petäjä ◽  
...  
Keyword(s):  
Time Delay ◽  
Sulphuric Acid ◽  
Acid Concentration ◽  
Particle Formation ◽  
Early Growth ◽  
Activation Mechanism ◽  
Aerosol Formation ◽  
Atmospheric Measurements ◽  
Nucleation Mechanisms ◽  
Sulphuric Acid Concentration

Abstract. We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took place in spring 2003 in Hyytiälä (Finland). During the campaign numerous aerosol particle formation events occurred of which 15 were accompanied by gaseous sulphuric acid measurements. Our detailed analysis of these 15 events is focussed on nucleation and early growth (to a diameter of 3 nm) of fresh particles. It revealed that new particle formation seems to be a function of the gaseous sulphuric acid concentration to the power from one to two when the time delay between the sulphuric acid and particle number concentration is taken into account. From the time delay the growth rates of freshly nucleated particles from 1 nm to 3 nm were determined. The mean growth rate was 1.2 nm/h and it was clearly correlated with the gaseous sulphuric acid concentration. We tested two nucleation mechanisms – recently proposed cluster activation and kinetic type nucleation – as possible candidates to explain the observed dependences, and determined experimental nucleation coefficients. We found that some events are dominated by the activation mechanism and some by the kinetic mechanism. Inferred coefficients for the two nucleation mechanisms are the same order of magnitude as chemical reaction coefficients in the gas phase and they correlate with the product of gaseous sulphuric acid and ammonia concentrations. This indicates that besides gaseous sulphuric acid also ammonia has a role in nucleation.

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