scholarly journals Effect of MgCI2 and CaCI2 on the Bubble Point of Mixed- Solvents (Toluene-Isopropyl Alcohol-H20 System)

2006 ◽  
Vol 6 (2) ◽  
pp. 98
Author(s):  
Nathaniel P. Dugos ◽  
Noel P. Cabigon ◽  
Yolanda P. Brondial

This study investigated the effect of CaCl2 and MgCI2,both alkaline earth metal salts on the boiling points of a mixed-solvent system composed of toluene, isopropyl alcohol and water. The effect of the concentration of the salt on the boiling point of this ternary system was also examined. Results showed that mixed- solvents added with CaCl2 boil at higher temperatures than those with MgCl2even though the latter salt is higher in molal concentration. This proves that MgCI2, which has a smaller ionic radius than CaCl2 is more effective in reducing the molecular affinity to polar and associating solvents (water and isopropyl alcohol) than to the non-polar solvent (toluene). The mixed- solvent system added with MgCl2 registered higher boiling point deviation than those with CaCI2, though both showed positive deviations. Based on the results, either of the two salts can be an effective mass separating agent. However it is shown that MgCl2is better than CaCl2 because the solutions with MgCI2 generally exhibited lower boiling points. Though the difference in temperature deviations of the two salts is statistically not significant, a difference in temperature of one degree is economically significant considering the cost of energy.

1998 ◽  
Vol 39 (4) ◽  
pp. 291-312 ◽  
Author(s):  
J.S. Church ◽  
A.S. Davie ◽  
P.J. Scammells ◽  
D.J. Tucker

2021 ◽  
Vol 60 (39) ◽  
pp. 14026-14037
Author(s):  
Nurul Nadiah Abd Razak ◽  
Lai Ti Gew ◽  
Yolande Pérès ◽  
Patrick Cognet ◽  
Mohamed Kheireddine Aroua

It is well known that the molecular refractivity of most salts, as calculated by the Lorentz-Lorenz formula, is nearly independent of the concentration in moderately dilute aqueous solutions. Walden determined the refractivities of tetra-ethyl-ammonium iodide and other similar salts in a variety of solvents and found that, while the molecular refractivity was approximately independent of the concentration in each solvent, it varied from one solvent to another, the greatest variation from the value in water, amounting to about 2 per cent., being obtained in nitro-methane, Schreiner has recently determined the molecular refractivity of hydrogen chloride and lithium chloride in methyl and ethyl alcohols, and found that in the case of lithium chloride the value is independent of the concentration up to a concentration of about 3 M. His values for R 18 D for lithium chloride are: 8.73 in water, 8.55 in methyl alcohol and 8.38 in ethyl alcohol. The difference between the values in water and ethyl alcohol appeared to make it just possible to determine the variation of the refractivity with the composition of the solvent in mixtures of water and the alcohol. It is possible that a solvent might he found, miscible in water in all proportions, in which the value of It is further removed from that in water. Such a substance would he more suitable than alcohol for the investigation of this effect, but in order to correlate the results with the measurements recorded in Part II of the activities of alcohol and water in water-alcohol-lithium chloride solutions, it seemed desirable to investigate this case in the first instance. The variation of the refractivity of a salt with the composition of a mixed solvent may be expected to give some indication of the composition of the solvent in the immediate vicinity of the ions. For the refractivity of a salt is determined by (1) the polarisability of the ions themselves and (2) the change in the polarisability of the solvent produced by their presence. The molecular refractivity of a salt in a solution containing m grams of a salt in w grams of the solvent is taken as R = M/ m ( n 2 -1/ n 2 + 2 . w + m / d - n 2 0 -1/ n 2 0 + 2 . w / d 0 (1) where n , and d and n 0 , d 0 are the refractive index and density of the solution and of the solvent, respectively, and M the molecular weight of the salt.


2003 ◽  
Vol 56 (5) ◽  
pp. 423 ◽  
Author(s):  
José A. C. Alves ◽  
Amadeu F. Brigas ◽  
Robert A. W. Johnstone

Adsorption isotherms in the liquid phase can be used to determine the relative strengths of adsorption of reactants and solvent at a catalyst surface. Such isotherms can then be used to indicate which type of solvent would be most suitable for a heterogeneously catalyzed reaction in the liquid-phase. Solubility in any chosen solvent is also important. As examples, rates of heterogeneously catalyzed liquid-phase transfer hydrogenolyzes of aryl tetrazolyl ethers (1) have been shown to be highly dependent on both the nature of the solvent and on the solution concentrations of the reactants. The rate of reaction can be varied from zero to a maximum and then back to zero simply by adjusting the solubility of the reductant through changes in the proportion of water in a mixed-solvent system.


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