Medium effects on tetraalkylammonium ions in aqueous acid solutions

1976 ◽  
Vol 54 (9) ◽  
pp. 1439-1444 ◽  
Author(s):  
Tomasz A. Modro ◽  
William F. Reynolds ◽  
Keith Yates
Keyword(s):  
Aqueous Solutions ◽  
Chemical Shifts ◽  
Ionic Species ◽  
Acid Solutions ◽  
Medium Effects ◽  
Tetraalkylammonium Ions ◽  
Aqueous Acid ◽  
Low Field ◽  
Cation Hydration ◽  
Strong Acids

Medium effects upon 1H and 13C chemical shifts have been determined for some tetraalkylammonium ions in 0–10 M aqueous solutions of H2SO4, HClO4, and H3PO4. The observed effects are very weak in magnitude, thus justifying the choice of tetraalkylammonium ions as reference standards for studies of ionic species in aqueous solutions of strong acids. The trends in the observed low-field shifts are interpreted in terms of changes in cation hydration and in hydrogen bonding between alkyl hydrogens and acid anions.

Alkylammonium Ions: Chemical Shifts and Interactions with Solvent in Aqueous Acid Solutions

1971 ◽  
Vol 49 (13) ◽  
pp. 2364-2366 ◽  
Author(s):  
J. T. Edward
Keyword(s):  
Sulfuric Acid ◽  
Chemical Shifts ◽  
Acid Solutions ◽  
Aqueous Acid ◽  
Tentative Explanation ◽  
The Difference

The difference between the chemical shifts of the α and β hydrogens of the mono-, di-, tri-, and tetra-ethylammonium ions changes as the concentration of the solvent sulfuric acid is increased from 0 to 94%. A tentative explanation based on hydration of the ions is presented.

H3O+ ions in aqueous acid solutions. The infrared spectra revisited

1976 ◽  
Vol 54 (21) ◽  
pp. 3477-3482 ◽  
Author(s):  
Paul A. Giguère ◽  
Sylvia Turrell
Keyword(s):  
Hydrofluoric Acid ◽  
Ion Pairs ◽  
Acid Solutions ◽  
Ionic Charge ◽  
Experimental Conditions ◽  
Hydrogen Halides ◽  
Aqueous Acid ◽  
Previous Assignment ◽  
Acids And Bases ◽  
Strong Acids

We have re-examined the infrared absorption between 4000 and 800 cm−1 of aqueous solutions of the four hydrogen halides at concentrations up to saturation, and under better experimental conditions than heretofore. The new spectra confirm definitely our previous assignment of the three broad bands around 2900, 1730, and 1200 cm−1 to fundamental vibrations of the H3O+ ion. Other proposed interpretations are shown to be untenable; in particular that of Ackermann, based on alleged similarities in the spectra of strong acids and bases. In hydrofluoric acid, hydrogen-bonded ion pairs are responsible for the shifts of the H3O+ frequencies. There is no evidence in the spectra for higher species, such as H5O2+. We conclude that the H3O+ ion has an appreciably longer lifetime in concentrated aqueous acids than in water. It also forms much stronger hydrogen bonds than H2O because of its ionic charge.

Aqueous acid-aided corrosion products removal from the surface of the brass elements of heat exchangers

2019 ◽  
pp. 110-115
Author(s):  
L. M. Mironovich ◽  
A. Yu. Eliseev ◽  
A. Yu. Eliseeva
Keyword(s):  
Heat Exchangers ◽  
Solution Temperature ◽  
Cleaning Process ◽  
Complex Effect ◽  
Aqueous Acid ◽  
Surface Configuration ◽  
Additional Input ◽  
Heat Exchange Equipment ◽  
Working Solution ◽  
Strong Acids

The paper studies complex effect of various factors on the process of cleaning brass brand L-68, used for the manufacture of heat exchange equipment. It has been established that acids of various strengths can be used as working solutions. The speed of the cleaning process depends on the nature of the acid and its initial concentration. For strong acids, a working solution with low concentration is recommended, followed by an increase in their concentration during the cleaning process. Additional input of oxygen into the system and an increase of the working solution temperature increase the cleaning rate of brass. The cleaning process proceeds without significant changes in the surface configuration, and, consequently, the expenditure of metal.

scholarly journals Selenium and sulphur reactions involved in manganese reduction from sulphate solutions

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25542-25550
Author(s):  
Q. L. Reyes-Morales ◽  
V. E. Reyes-Cruz ◽  
A. Trujillo-Estrada ◽  
J. A. Cobos-Murcia ◽  
G. Urbano-Reyes ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Electrochemical Reduction ◽  
Ionic Species ◽  
Electrochemical Reactor ◽  
Manganese Reduction ◽  
Anionic Exchange ◽  
Manganese Deposition

Electrochemical reduction of ionic species during manganese deposition from sulphated aqueous solutions has been studied in an electrochemical reactor with two anionic exchange membranes.

SYNTHESIS OF N-SUBSTITUTED DIISOPROPANOLAMINES, THEIR SEBACATE POLYESTERS AND POLYURETHANE ELASTOMERS

1958 ◽  
Vol 36 (10) ◽  
pp. 1405-1409 ◽  
Author(s):  
Jean L. Boivin
Keyword(s):  
Aqueous Solutions ◽  
Infrared Absorption ◽  
Propylene Oxide ◽  
Sebacic Acid ◽  
Ionization Constants ◽  
Polyurethane Elastomers ◽  
Molecular Weights ◽  
Slight Excess ◽  
Infrared Absorption Spectra ◽  
Strong Acids

Several N-substituted diisopropanolamines were prepared by reacting aqueous solutions of amines with excess propylene oxide at ordinary pressure but higher N-substituted diisopropanolamines had to be prepared in an autoclave at 200 °C. The ionization constants of these bases were measured and recorded as pKa values. Their infrared absorption spectra gave bands common to all diisopropanolamines mainly at 3.04, 7.14, 7.55, 7.85, 9.45, 10.6, and 11.95 microns. Their condensation with sebacic acid gave the corresponding polyesters, which were soluble in strong acids and had molecular weights of about 1500. The hydroxyl-terminated polyesters were cured with a slight excess of 2,4-tolylene diisocyanate at 100 °C for 2 days to yield elastomers of brittle temperatures in the region of −50 °C.

scholarly journals Voltammetric oxidation of dipyridamole in aqueous acid solutions

2000 ◽  
Vol 11 (2) ◽  
pp. 148-153 ◽  
Author(s):  
Marilza Castilho ◽  
Luiz E. Almeida ◽  
Marcel Tabak ◽  
Luiz H. Mazo
Keyword(s):  
Acid Solutions ◽  
Aqueous Acid
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