scholarly journals Diffusion of mineral acids into an epoxy coating. Phosphoric acid diffusion model

2021 ◽  
Vol 10 (4) ◽  
Keyword(s):  
Phosphoric Acid ◽  
Diffusion Model ◽  
Epoxy Coating ◽  
Acid Diffusion ◽  
Mineral Acids

Solvation properties in iso-acidic media involving phosphoric acid

1988 ◽  
Vol 66 (9) ◽  
pp. 2422-2427 ◽  
Author(s):  
C. Louis ◽  
A. Bebba ◽  
J. Bessière
Keyword(s):  
Carbon Tetrachloride ◽  
Phosphoric Acid ◽  
Water Activity ◽  
Ionic Species ◽  
Concentrated Solutions ◽  
Acidic Media ◽  
Acidic Solutions ◽  
Mineral Acids ◽  
Acidity Level ◽  
Silver Extraction

Concentrated solutions of mineral acids (phosphoric, hydrochloric, perchloric, sulfuric) are characterized, for an equal value of their water activity, by an equal R0(H) acidity level (iso-acidic solutions). By mixing them, we prepare what we call iso-acidic mixtures which keep the same acidity level as the constitutive solutions whatever the proportions; their redox and solvating properties depend both on the nature and on the ratio of the constitutive solutions. Reactivity variations for ionic species: Cl−, Br−,I−, diethyldithiophosphate (LET−), Si(W3Ol0)44−, Si(W3O10)45−, Cu2+, Cu+, Pb2+, Sn2+, Cd2+, Zn2+, Ag+, Fe3+, Fe2+, UO22+, U4+ in the iso-acidic mixtures are characterized by their ƒ solvation-transfer activity coefficients. Relations between ƒ coefficient values and complexation properties are established and it is shown that phosphoric acid has comparatively weak solvating properties toward most species. The possibility for anticipating reaction changes with the iso-acidic mixture composition by using the ƒ coefficients is demonstrated in the case of cadmium ionic flotation with diethyldithiophosphate and silver extraction with dithizone in carbon tetrachloride.

scholarly journals Kinetic Study of the Dissolution of Tunisian Natural Phosphate or Francolite in Industrial Phosphoric Acid

2017 ◽  
Vol 6 (1) ◽  
pp. 908-916 ◽  
Author(s):  
Ahmed CHAABOUNI
Keyword(s):  
Activation Energy ◽  
Phosphoric Acid ◽  
Kinetic Study ◽  
Rate Constant ◽  
Calcium Sulfate ◽  
Shrinking Core Model ◽  
Natural Phosphate ◽  
Rate Of Dissolution ◽  
Mineral Acids ◽  
Shrinking Core

A kinetic study of dissolution of Tunisian natural phosphate or francolite whose particles have a mesoporous texture inindustrial phosphoric acid is carried out. Therefore, We focused on the study of the influence of certain parameters thatare close to those used in plants producing phosphoric acid which are the stirring speed (300, 500 and 700 rounds perminute), concentration of phosphoric anhydride (25, 30 and 35 percent of P2O5), and the temperature (60, 70 and 80degrees Celsius); we note that the rate of dissolution of this phosphate rises by increasing the precedent parameters.Because of the complexity of the study of the dissolution of phosphate in mineral acids. Several different published kineticmodels giving different expressions of speed versus time. The shrinking core model is the appropriate model used in ourwork in a solution where there is no calcium sulfate to calculate the rate constant k and the activation energy Ea = 3.3946Kcal/mol of this phosphate.

scholarly journals Studies on Chitin V. The Action of Mineral Acids on Chitin

1962 ◽  
Vol 15 (3) ◽  
pp. 526 ◽  
Author(s):  
RH Hackman
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Sulphuric Acid ◽  
Chain Length ◽  
Colloidal Chitin ◽  
Mineral Acids ◽  
Extensive Degradation

Chitin undergoes rapid and extensive degradation at 20�C when dissolved in ION hydrochloric acid, 21N sulphuric acid, or 85% phosphoric acid. Most of the degradation occurs in the first few minutes after the chitin is dissolved and the products formed are oligosaccharides (which are to some extent deacetylated) and N�acetyl-D.glucosamine. Glucosamine was not found except possibly in the smallest traces. "Colloidal" chitin, prepared by precipitation of chitin from solution in cold 21N sulphuric acid, has a very much shorter chain length than the chitin from which it was prepared. Chitin is more stable in dilute (2N) hydrochloric acid.

Cleavage of 3,3,4-trifluoro-2,2-dimethyloxetane by mineral acids

1985 ◽  
Vol 50 (9) ◽  
pp. 1948-1958 ◽  
Author(s):  
Václav Dědek ◽  
Ivan Veselý
Keyword(s):  
Aqueous Solution ◽  
Phosphoric Acid ◽  
Sulphuric Acid ◽  
Hydrobromic Acid ◽  
Polyphosphoric Acid ◽  
Acetyl Chloride ◽  
Main Product ◽  
Hydrogen Bromide ◽  
Mineral Acids ◽  
Sole Product

Cleavage of 3,3,4-trifluoro-2,2-dimethyloxetane (I) in an aqueous solution of sulphuric acid, phosphoric acid, hydrogen chloride, or hydrogen bromide gave a mixture of 2,2-difluoro-3-methyl-3-butenal (II) and 5,5-difluoro-2-(1,1-difluoro-2-hydroxy-2-methylpropyl)-4-hydroxy-6,6-dimethyl-1,3-dioxane (VIa); in the cleavage effected by hydrochloric or hydrobromic acid the mixture also contained 3-chloro- or 3-bromo-2,2-difluoro-3-methyl-1,1-butanediol (Vb or Vc). In alcoholic solutions of the mineral acids the cleavage afforded the corresponding acetals of butenal II and 2,2-difluoro-3-hydroxy-3-methylbutanal (IIIa). The action of sulphuric acid in the presence of acetyl chloride or acetanhydride led to 1-chloro-2,2-difluoro-3-methyl-3-butenyl acetate (IVd) or 2,2-difluoro-3-methyl-3-butenylidene diacetate (IVe), as the main product. Butenal II was a sole product of the cleavage of oxetane I by polyphosphoric acid at 150-160 °C in the gaseous phase. At temperatures above 180 °C there were also formed (in addition to butenal II) 1,1,5,5-tetrafluoro-2,6-dimethyl-1,6-heptadiene-4-ol (IX) and its formate (X).

IV. On the existence of phosphoric acid in rocks of igneous origin

1844 ◽  
Vol 134 ◽  
pp. 53-56
Keyword(s):  
Phosphoric Acid ◽  
Royal Society ◽  
Elementary Body ◽  
Satisfactory Explanation ◽  
Great Resistance ◽  
Igneous Origin ◽  
Mineral Acids ◽  
White Porcelain

The important although obscure functions attributed to the elementary body phosphorus, both in the vegetable and in the animal kingdoms, and the well-known fact that rocks of nearly every description afford on disintegration soils more or less capable of supporting the life of plants, and from which consequently phosphoric acid cannot possibly be absent, seemed to render a search for that substance in rocks of igneous origin generally very desirable, because if there found, an easy and satisfactory explanation of the origin and first source of the element in question would be given. As I am not aware that any direct researches on this subject have yet been made, or at least placed on record, I venture to submit to the notice of the Royal Society the results of a few experiments made by myself, which, so far as they go, resolve the question in the affirmative. The first substance tried was the fine white porcelain-clay of Dartmoor, Devon, the result of the disintegration of the felspar of the granite of that district. This is one of the chief components of porcelain and of the finer kinds of English earthenware, and was found on analysis to correspond very closely in composition with that of the material employed in the manufacture of the Sèvres porcelain. It was thought that phosphoric acid, if present, would be in combination with a portion of the alumina; and as the phosphate of that earth is readily soluble in dilute mineral acids, while the silicate offers great resistance to these agents, mere digestion with acid would suffice to extract the whole, or the greater part of the phosphate, which could be afterwards precipitated by an alkali, and examined.

Variation of phosphoric acid diffusion coefficient with concentration

AIChE Journal ◽  
1995 ◽  
Vol 41 (1) ◽  
pp. 185-189 ◽  
Author(s):  
F. Ruiz-Beviá ◽  
J. Fernández-Sempere ◽  
N. Boluda-Botella
Keyword(s):  
Diffusion Coefficient ◽  
Phosphoric Acid ◽  
Acid Diffusion
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