THE IONIZATION BEHAVIOR OF AMIDES IN CONCENTRATED SULFURIC ACIDS: III. INDICATOR ACTIVITY COEFFICIENT VARIATION

1966 ◽  
Vol 44 (20) ◽  
pp. 2395-2404 ◽  
Author(s):  
Linda M. Sweeting ◽  
Keith Yates
Keyword(s):  
Sulfuric Acid ◽  
Activity Coefficient ◽  
Acid Concentration ◽  
Acidity Function ◽  
Total Acidity ◽  
Relative Importance ◽  
Ionic Activity ◽  
Tetraethylammonium Ion ◽  
Ionization Behavior ◽  
Substituted Benzamides

Activity coefficient data for ten substituted benzamides and two benzamide salts have been obtained from solubility measurements in 0–70% sulfuric acid. The ionic activity coefficients have been referred to a standard ion, the tetraethylammonium ion. The variations of activity coefficient with acid concentration are discussed and compared with available data for anilines and anilinium ions. Estimates have been made of the relative importance of the various terms contributing to the total acidity function for sulfuric acid. Up to 40% acid the order of importance of these terms is [Formula: see text] and in more concentrated acids becomes [Formula: see text].

Dissociation Degree of HSO-4 and Mean Ionic Activity Coefficient of Aqueous Sulfuric Acid of Different Molalities up to 473 K and 975 bar

1994 ◽  
Vol 49 (10) ◽  
pp. 939-942
Author(s):  
B. A. Bilal ◽  
E. Müller
Keyword(s):  
Sulfuric Acid ◽  
Activity Coefficient ◽  
Thermodynamic Data ◽  
Formation Constant ◽  
Saturation Pressure ◽  
Ionic Activity ◽  
The Real ◽  
Aqueous Sulfuric Acid ◽  
Dissociation Degree

AbstractThe apparent formation constant and the dissociation degree of HSO-4 in aqueous H2SO4 of the molalities 0.1, 0.5, and 1.0 m, as well as the real mean ionic coefficient have been calculated up to 473 K and 975 bar using the thermodynamic data reported by Holmes and Mesmer at saturation pressure and those given by the authors at higher pressure.

scholarly journals Corrosion Behavior of AA 1100 Anodized in Gallic-Sulfuric Acid Solution

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 405
Author(s):  
Marlon L. Mopon ◽  
Jayson S. Garcia ◽  
Dexter M. Manguerra ◽  
Cyril John C. Narisma
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Gallic Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Solution ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Anodized Aluminum ◽  
The Common

Sulfuric acid anodization is one of the common methods used to improve corrosion resistance of aluminum alloys. Organic acids can be added to the sulfuric acid electrolyte in order to improve the properties of the anodized aluminum produced. In this study, the use of gallic acid as an additive to the sulfuric acid anodization of AA1100 was explored. The effect of varying anodization current density and gallic acid concentration on the properties of anodized aluminum samples was observed using electrochemical impedance spectroscopy, linear polarization, and scanning electron microscopy. It was observed that the corrosion resistance of samples anodized in gallic-sulfuric acid solution at 10 mA·cm−2 is lower than samples anodized in sulfuric acid. It was also observed that higher anodization current density can lead to lower corrosion resistances for aluminum samples anodized in gallic-sulfuric acid solution. However, samples anodized at 5 mA·cm−2 and at a gallic acid concentration of 5 g·L−1 showed better corrosion performance than the samples anodized in sulfuric acid only. This suggests that the use of low amounts of gallic acid as an additive for sulfuric acid anodization can lead to better corrosion resistances for anodized aluminum.

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.

scholarly journals Release of reducing sugars from water hyacinth by thermochemical and enzymatic hydrolysis

2021 ◽  
Vol 6 (1) ◽  
pp. 156-164
Author(s):  
Jessica E. Guzmán-Pérez ◽  
◽  
Oscar J. Salinas-Luna ◽  
Ernesto Favela-Torres ◽  
Nohemi López-Ramírez ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Enzymatic Hydrolysis ◽  
Acid Concentration ◽  
Water Hyacinth ◽  
Dry Matter ◽  
Eichhornia Crassipes ◽  
Reducing Sugars ◽  
Sulfuric Acid Concentration ◽  
Raw Material ◽  
Thermochemical Pretreatment

Water hyacinth (Eichhornia crassipes) is considered a pernicious herb in many parts of the world due to its rapid growth. However, for its high content of cellulose and hemicellulose, it could be considered as raw material to produce fermentable sugars. In this work, the effect of sulfuric acid concentration by thermochemical pretreatment and enzymatic hydrolysis on the release of sugars from water hyacinth was evaluated. Initially, the effect of the sulfuric acid concentration from 1.5 to 9% at 120 ºC was evaluated. With 1.5%, the release of reducing sugars was 160 milligrams of reducing sugars per gram of dry matter (mg red-sug/g dm). After the thermochemical pretreatment, the enzymatic hydrolysis with the cellulase complex (NS22086) allowed obtaining a reducing sugars concentration up to 317 mg red-sug/g dm. These thermochemical and enzymatic approaches to recover reducing sugars from water hyacinth is promising and should be evaluated for bioprocess using reducing sugars as the main source of carbon, such as bioethanol production.

scholarly journals The Effect of Electronic Medical Record Adaptation on Reported Medication Errors in Peripartum Care Areas

2017 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Cellulose Hydrolysis ◽  
Colloidal Dispersions ◽  
Degree Of Polymerization ◽  
Degree Of Crystallinity ◽  
Minimum Level ◽  
Hydrolysis Temperature ◽  
Hydrolysis Conditions ◽  
Negative Zeta Potential

Relationship between concentration of sulfuric acid (C) and temperature (T) required for the cellulose hydrolysis to prepare nanocrystalline cellulose particles (NCP has been studied in this paper. The experiments showed that there is a linear C and T superposition exists, namely: C= Co - n T. The higher the acid concentration, the lower the hydrolysis temperature should be used, and vice versa. The minimum level of acid concentration that can be used for production of CNP is 40 wt. % at optimal temperature of 80o C. If temperature or acid concentration is lower, there is a tendency to form of microparticles. On the other hand, at higher hydrolysis temperatures, carbonized CNP with decreased yield are obtained. The rod-like crystalline nanoparticles of cellulose produced at optimal hydrolysis conditions (C=40 wt. %, T=80o C) have average sizes of 150 x 15 nm, degree of crystallinity of 75- 77% and degree of polymerization of 130-150. The nanoparticles form stable colloidal dispersions in water due to Brownian motion and negative Zeta potential imparting to these particles the mutual electrostatic repulsion. Estimated calculations have also shown that decrease in the concentration of sulfuric acid from 60 to 40 wt. % at production of CNP is economically advantageous despite increase in hydrolysis temperature from 45 to 80o C.

scholarly journals Initial Investigation into the Leaching of Manganese from Nodules at Room Temperature with the Use of Sulfuric Acid and the Addition of Foundry Slag—Part I

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 565 ◽  
Author(s):  
Norman Toro ◽  
Nelson Herrera ◽  
Jonathan Castillo ◽  
Cynthia Torres ◽  
Rossana Sepúlveda
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Room Temperature ◽  
Sulfuric Acid Concentration ◽  
Extraction Rate ◽  
Molar Ratio ◽  
Independent Variables ◽  
Initial Investigation ◽  
Optimization Methodology

In this study, the surface optimization methodology was used to assess the effect of three independent variables—time, particle size and sulfuric acid concentration—on Mn extraction from marine nodules during leaching with H2SO4 in the presence of foundry slag. The effect of the MnO2/Fe ratio and particle size (MnO2) was also investigated. The maximum Mn extraction rate was obtained when a MnO2 to Fe molar ratio of 0.5, 1 M of H2SO4, −320 + 400 Tyler mesh (−47 + 38 μm) nodule particle size and a leaching time of 30 min were used.

Sign in / Sign up

Export Citation Format

Share Document