Pyrochlores. VI. Preparative chemistry of sodium and silver antimonates and related compounds

1970 ◽  
Vol 48 (8) ◽  
pp. 1323-1332 ◽  
Author(s):  
David J. Stewart ◽  
Osvald Knop
Keyword(s):  
Acid Solution ◽  
Alkaline Solution ◽  
Pyrochlore Structure ◽  
Previous Literature ◽  
Significant Part ◽  
Related Compounds

A number of pyrochlore-structure antimonates MSbyOz (M = Na, Ag, K) have been prepared by dry-firing methods. Each M forms a series of compounds which adopt the pyrochlore structure up to a maximum ratio of M:Sb; the ratio depends on M. Antimony in these compounds is usually present simultaneously in trivalent and pentavalent states.The preparation of the above antimonates by wet methods was also examined. The products obtained were found to depend on the pH of the solution. In acid solution a polyantimonate ion exists which on addition of M salts leads to compounds of formula MSb3Oz, while in alkaline solution the Sb(OH)6− ion exists and MSb(OH)6 antimonates are obtained.A previous literature claim that NaSbO3 occurs with the pyrochlore structure has been disproved. It has been shown that NaSbyOz pyrochlore phases exist only for Na:Sb less than 1:1.5.The preparation of antimonates in the presence of Cl− and from hydrated reactants was carried out. It was concluded that neither Cl− nor OH− or H2O play a significant part in causing an antimonate of Na, Ag, or K to adopt the pyrochlore structure.

VIII.—The Stability of Suspensions. I. The Rate of Sedimentation of Kaolin Suspensions by Salts at Varying Hydrogen Ion Concentrations

1926 ◽  
Vol 45 (1) ◽  
pp. 59-70 ◽  
Author(s):  
William Ogilvy Kermack ◽  
William Turner Horace Williamson
Keyword(s):  
Sodium Chloride ◽  
Acid Solution ◽  
Alkaline Solution ◽  
Calcium Sulphate ◽  
Sodium Sulphate ◽  
Aluminium Chloride ◽  
Monocalcium Phosphate ◽  
Sodium Hydrogen Phosphate ◽  
Rate Of Sedimentation ◽  
The Stability

Summary1. The rates of sedimentation of a kaolin suspension in presence of varying concentrations of a salt (sodium chloride, potassium chloride, sodium sulphate, di-sodium hydrogen phosphate, sodium citrate, calcium chloride, calcium sulphate, monocalcium phosphate, “superphosphate”, aluminium chloride, ferric chloride or lanthanum chloride) have been compared at various pH values. Abnormal results are obtained with sodium chloride, monocalcium phosphate, aluminium, ferric and lanthanum chlorides.2. Sodium chloride increases the rate of sedimentation in alkaline solution, but actually inhibits it in acid solution.3. In concentrations of monocalcium phosphate above 0·06 per cent, abnormal sedimentation in alkaline solution takes place, with the result that it is much more complete than at the corresponding concentrations in acid solution.4. In acid solution the tervalent ions, aluminium, ferric and lanthanum have little effect, but a zone of very marked flocculation occurs at pH 7–8. This zone separates a region within which the unsedimented particles are negatively charged from a region within which they are positively charged.

scholarly journals Creep Strain and Permeability Evolution in Cracked Granite Subjected to Triaxial Stress and Reactive Flow

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Fan Zhang ◽  
Jianjian Zhao ◽  
Dawei Hu ◽  
Qian Sheng ◽  
Jianfu Shao
Keyword(s):  
Acid Solution ◽  
Strain Rate ◽  
Creep Strain ◽  
Alkaline Solution ◽  
Confining Pressure ◽  
Creep Strain Rate ◽  
Reactive Flow ◽  
Secondary Creep ◽  
Creep Tests ◽  
Creep Stage

Fluid flow and fluid-rock interaction mainly take place in fracture network, consequently resulting in deformation and permeability variation of rock and deterioration of the wellbore performance. Mechanical-reactive flow coupling creep tests are performed on cracked granite under various confining pressures and acid and alkaline solution flows. The testing results show that the confining pressure and solution pH significantly influence the creep deformation, creep strain rate, and permeability. A primary creep stage and secondary creep stage are observed in all creep tests in this study; notably, the sample under a confining pressure of 10 MPa and acid solution injection undergoes creep failure for over 2700 hours. The acid solution has a more obvious influence on the creep behavior than that of the alkaline solution. With an increase in confining pressure, the total creep strain and creep strain rate in the samples gradually decrease during the injection of either solution. The permeability of the samples injected with either solution gradually deceases during the testing process, and this deceasing rate increases with the confining pressure. The scanning electron microscopy observations on the crack surfaces after the creep tests show that the surfaces of the fractures injected with the acid solution are smooth due to the dissolution of the matrix, while those injected with the alkaline solution include voids due to the dissolution of quartz. These experimental results could improve the understanding of the long-term transport and mechanical behaviors of wellbore.

scholarly journals Photolysis of carboxymethylflavin in aqueous and organic solvent: a kinetic study

RSC Advances ◽  
2019 ◽  
Vol 9 (46) ◽  
pp. 26559-26571 ◽  
Author(s):  
Iqbal Ahmad ◽  
Tania Mirza ◽  
Syed Ghulam Musharraf ◽  
Zubair Anwar ◽  
Muhammad Ali Sheraz ◽  
...  
Keyword(s):  
Acid Solution ◽  
Organic Solvent ◽  
Kinetic Study ◽  
Alkaline Solution ◽  
Ring Cleavage ◽  
Side Chain ◽  
Keto Acid ◽  
Side Chain Cleavage ◽  
Chain Cleavage

Carboxymethylflavin (CMF) undergoes photolysis in acid solution to form lumichrome (LC) and in alkaline solution, LC and lumiflavin (LF) by side-chain cleavage and β-keto acid and a dioxoquinoxalaine (DQ) compound by isoalloxazine ring cleavage.

ACCESSORY FOOD SUBSTANCES FOR OSMOPHILIC YEASTS: I. A BIOACTIVATOR IN HONEY STIMULATING FERMENTATION

1931 ◽  
Vol 5 (5) ◽  
pp. 529-538 ◽  
Author(s):  
A. G. Lochhead ◽  
Leone Farrell
Keyword(s):  
Acid Solution ◽  
Alkaline Solution ◽  
Prolonged Exposure ◽  
Selective Adsorption ◽  
Active Principle ◽  
Dry Heat ◽  
Synthetic Media ◽  
Stimulation Of

Honey was found to contain an active principle which stimulated fermentation by certain osmophilic yeasts of the genus Zygosaccharomyces in synthetic media. The substance is dialyzable, insoluble in ether and acetone, not precipitated by 85% alcohol, resistant to heating in acid solution and non-volatile. The activating effect of honey is impaired by heating in alkaline solution and by prolonged exposure to moderate dry heat. The active principle may be separated into two fractions by selective adsorption by charcoal. The adsorbed fraction, which may be recovered by elution with alcohol, and the unadsorbed fraction are relatively inert alone, the presence of both being necessary for the active stimulation of fermentation.

Simple, direct measurement of lipoprotein X in serum.

1982 ◽  
Vol 28 (4) ◽  
pp. 606-608 ◽  
Author(s):  
Y Hashiguchi ◽  
M Kawaguchi ◽  
M Nakanishi ◽  
Y Matsumori ◽  
Y Kaneda ◽  
...  
Keyword(s):  
Acid Solution ◽  
Alkaline Solution ◽  
Gel Electrophoresis ◽  
Phosphotungstic Acid ◽  
Quantitative Estimation ◽  
Magnesium Ion ◽  
Supernatant Fluid ◽  
Agar Gel ◽  
Simple Method ◽  
Agar Gel Electrophoresis

Abstract This relatively simple method for quantitative estimation of lipoprotein X is based on assay of phospholipids in precipitates of lipoprotein X. We first remove other lipoproteins by precipitation with phosphotungstic acid solution. Lipoprotein X is then precipitated from the supernatant fluid with an alkaline solution of magnesium ion, and phospholipid is determined in this precipitate. Results are linearly related to concentration of lipoprotein X. The CV is less than 3%. Results correlated well with those for agar gel electrophoresis.

The preparation of some 2-nitroacridines and related compounds

1981 ◽  
Vol 34 (4) ◽  
pp. 839 ◽  
Author(s):  
J Rosewear ◽  
JFK Wilshire
Keyword(s):  
Acid Solution ◽  
Trifluoroacetic Acid ◽  
Ion Treatment ◽  
Related Compounds

The reaction of 2-fluoro-5-trobenzaldehyde with a wide variety of arylamines gives, in general, mixtures of the corresponding 2-arylamino-5-nitrobenzaldehydes and their related anils. Both aldehydes and anils readily underwent acid-catalysed cyclization to give the corresponding 2-nitro-acridines. The effect of substituent on the rate of cyclization of these aldehydes and of some related anilino-benzaldehydes and -acetophenones has been studied in trifluoroacetic acid solution by means of 1H n.m.r. spectroscopy. A solution of 2-(N-methylanilino)-5-nitrobenzaldehyde in trifluoroacetic acid appears to contain a substituted acridinium ion; treatment of this solution with alkali gave 10-methyl-2-nitroacridone. 1H n.m.r. data for a wide variety of substituted 2-nitro-acridines are discussed.

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