The halide ion activity of dyes and organic salts in aqueous solution

1967 ◽  
Vol 71 (11) ◽  
pp. 3488-3493 ◽  
Author(s):  
John F. Padday
Keyword(s):  
Aqueous Solution ◽  
Organic Salts ◽  
Ion Activity

Block copolymer and organic salts in forming aqueous biphases: a platform to identify molecular interactions in aqueous medium

RSC Advances ◽  
2016 ◽  
Vol 6 (81) ◽  
pp. 77673-77681 ◽  
Author(s):  
Arabinda Chakraborty ◽  
Chhanda Mukhopadhyay ◽  
Kamalika Sen
Keyword(s):  
Aqueous Solution ◽  
Block Copolymer ◽  
Aqueous Medium ◽  
Molecular Interactions ◽  
Sodium Acetate ◽  
Sodium Citrate ◽  
Organic Salts ◽  
Aqueous Biphasic Systems ◽  
Aqueous Biphasic ◽  
Biphasic Systems

An aqueous solution of a tri-block copolymer PPG–PEG–PPG has been used with two organic salts, sodium acetate and sodium citrate, to create new aqueous biphasic systems (ABS).

scholarly journals THE KINETICS OF PENETRATION

1934 ◽  
Vol 17 (3) ◽  
pp. 445-467 ◽  
Author(s):  
W. J. V. Osterhout ◽  
S. E. Kamerling ◽  
W. M. Stanley
Keyword(s):  
Aqueous Solution ◽  
Aqueous Phase ◽  
Partition Coefficients ◽  
Living Cells ◽  
Organic Salts ◽  
Outward Diffusion ◽  
Factors Affecting ◽  
Unstirred Layers ◽  
Diffusion Constants ◽  
Aqueous Layer

Some of the factors affecting penetration in living cells may be advantageously studied in models in which the organic salts KG and NaG diffuse from an aqueous solution A, through a non-aqueous layer B (representing the protoplasmic surface) into an aqueous solution C (representing the sap and hence called artificial sap) where they react with CO2 to form KHCO3 and NaHCO3. Their relative proportions in C depend chiefly on the partition coefficients and on the diffusion constants in the non-aqueous layer. But the ratio is also affected by other variables, among which are the following: 1. Temperature, affecting diffusion constants and partition coefficients and altering the thickness of the unstirred layers by changing viscosity. 2. Viscosity (especially in the non-aqueous layers) which depends on temperature and the presence of solutes. 3. Rate of stirring, which affects the thickness of the unstirred layers and the transport of electrolyte in those that are stirred. 4. Shape and surface area of the non-aqueous layer. 5. Surface forces. 6. Reactions occurring at the outer surface such as loss of water by the electrolyte or its molecular association in the non-aqueous phase. The reverse processes will occur at the inner surface and here also combinations with acids or other substances in the "artificial sap" may occur. 7. Outward diffusion from the artificial sap. The outward movement of KHCO3 and NaHCO3 is small compared with the inward movement of KG and NaG when the concentrations are equal. This is because the partition coefficients3 of the bicarbonates are very low as compared with those of NaG and KG. Since CO2 and HCO3- diffuse into A and combine with KG and NaG the inward movement of potassium and sodium falls off in proportion as the concentration of KG and NaG is lessened. 8. Movement of water into the non-aqueous phase and into the artificial sap. This may have a higher temperature coefficient than the penetration of electrolytes. 9. Variation of the partition coefficients with concentration and pH. Many of these variables may occur in living cells. (It happens that the range of variation in the ratio of potassium to sodium in the models resembles that found in Valonia.)

Osmotic coefficient and mean ion activity coefficient of NiCl2 aqueous solution at several temperatures

2016 ◽  
Vol 100 ◽  
pp. 72-78 ◽  
Author(s):  
Peikang Dai ◽  
Huaqiang Huang ◽  
Zhiying Ding ◽  
Yaning He ◽  
Shijun Liu
Keyword(s):  
Aqueous Solution ◽  
Activity Coefficient ◽  
Osmotic Coefficient ◽  
Ion Activity

Structures Formed by Cryoprotective Agents Used in Freezc-Etching

1971 ◽  
Vol 29 ◽  
pp. 448-449
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe
Keyword(s):  
Aqueous Solution ◽  
Polyethylene Oxide ◽  
Liquid Nitrogen Temperature ◽  
Ice Crystals ◽  
Etching Technique ◽  
Structural Constituent ◽  
Cryoprotective Agents ◽  
Quick Freezing ◽  
Freeze Etching ◽  
Fractured Surface

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

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