Isopiestic studies on (methanol + sodium bromide + ammonium bromide) at the temperature 298.15 K: comparison with the partial ideal solution model

1998 ◽  
Vol 30 (6) ◽  
pp. 709-712 ◽  
Author(s):  
Zhi-Chang Wang ◽  
Xiu-Yan Li ◽  
Yi-Hui Liu
Keyword(s):  
Solution Model ◽  
Sodium Bromide ◽  
Ammonium Bromide ◽  
Ideal Solution ◽  
Partial Ideal Solution Model

Study on Flotation Separation and Determination of Mercury (II) by Sodium Bromide-Ammonium Thiocyanate-Octadecyl Trimethyl Ammonium Bromide System

2012 ◽  
Vol 554-556 ◽  
pp. 1957-1961
Author(s):  
Chang Qing Tu ◽  
Xin Rong Wen
Keyword(s):  
Metal Ions ◽  
Ammonium Thiocyanate ◽  
Sodium Bromide ◽  
New Method ◽  
Ammonium Bromide ◽  
Method Of Determination ◽  
Quantitative Separation ◽  
Solid Phases ◽  
Association Complex

The flotation separation and determination behaviours of mercury (Ⅱ) by sodium bromide -ammonium thiocyanide-octadecyl trimethyl ammonium bromide system were studied. The effects of different parameters,such as the dosages of NH4SCN and octadecyl trimethyl ammonium bromide (OTMAB),various salts and acidity etc. on the flotation yield of Hg2+have been investigated to select the experimental conditions.The results showed that in the presence of 1.0g NaBr and when the dosage of 0.1 mol/L NH4SCN was 0.50 mL and 0.01 mol/L OTMAB solution was 1.00 mL respectively, the formed water-insoluble ternary association complex of (OTMAB)2[Hg(SCN)4] floated above water phase and liquid-solid phases were formed with clear interface. In this condition, Cd2+,Mn2+,Ni2+,Co2+,Fe2+and Pb2+could not be floated and Hg2+could be floated quantitatively at pH2.0.Therefore, the quantitative separation of Hg2+from the above metal ions could be achieved. A new method of determination of trace mercury by flotation separation was established.The proposed method has been successfully applied to the determination of Hg2+in the sample of synthetic water and the flotation yield was 94.2%~97.9%.

Association between halothane and oxygenated solvents by 1H NMR spectroscopy

1995 ◽  
Vol 73 (9) ◽  
pp. 1406-1411 ◽  
Author(s):  
Marcela Tkadlecová ◽  
Jaroslav Havlíček ◽  
Vladimír Dohnal
Keyword(s):  
Nmr Spectroscopy ◽  
Complex Formation ◽  
Equilibrium Constants ◽  
Solution Model ◽  
Methyl Tert Butyl Ether ◽  
Ideal Solution ◽  
Butyl Ether ◽  
Complex Formation Equilibria ◽  
H Nmr ◽  
Halothane Concentration

Using 1H NMR spectroscopy the complex-formation equilibria between halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) and methyl tert-butyl ether or tetrahydrofuran in various inert solvents (hexane, heptane, decane, cyclohexane) were measured as a function of temperature. For two different association models (ideal solution and athermal solution), assuming only the formation of a 1:1 H-bonded complex, the equilibrium constants and the standard enthalpies of the complex-formation reaction were calculated. The ideal solution model provides values of the equilibrium constant that differ for different inert solvents. The athermal solution model makes this false solvent effect much smaller. For the low halothane concentration used, its dimerization was neglected. This assumption was verified experimentally. Keywords: 1H NMR, association, complex formation, halothane.

Stability of Al2SiO5 solid solutions

1968 ◽  
Vol 36 (282) ◽  
pp. 839-849 ◽  
Author(s):  
R. G. J. Strens
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Invariant Point ◽  
Solution Model ◽  
Stable Phase ◽  
Ideal Solution ◽  
Silicate Liquids ◽  
The Stability ◽  
Short Times ◽  
Simultaneous Growth

SummaryAn ideal solution model has been used to calculate the effect of the substitutions on the stability fields of the Al2SiO5 minerals. The results show that divariant assemblages of andalusite+sillimanite and sillimanite + kyanite solid solutions can coexist over ranges of 0·1 to 0·4 kbar at 527° C, but that kyanite+andalusite would be stable over a much narrower range. On adding (Fe, Mn)3+ to the system, the andalusite/sillimanite curve can be considered to rotate about the invariant point, first eliminating the sillimanite field, and then penetrating the kyanite field. Wide zones of viridine+sillimanite and viridine+kyanite are thus formed.In view of the ease with which epitaxial nucleation occurs in the Al2SiO5 system, it is considered that extensive metastable growth of andalusite, sillimanite, and kyanite is improbable in nature. Metastable persistence is likely to occur in dry systems, or in the presence of an ‘armour’ of the stable phase, but reaction of millimetre-sized crystals should be completed in geologically short times when aqueous or silicate liquids are present. The combination of the effects of metastable persistence and solid solution seems adequate to account for essentially all the examples of kyanite + sillimanite and kyanite + andalusite, and for many sillimanite +andalusite assemblages. In addition, if small supersaturations develop during metamorphism, simultaneous growth of andalusite + sillimanite could occur over a restricted temperature range.

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