Heat Capacities of Hydroxypropyl-α-, -β-, and -γ-Cyclodextrins in Dilute Aqueous Solution

2004 ◽  
Vol 49 (6) ◽  
pp. 1699-1702
Author(s):  
Gilberto Cardoso-Mohedano ◽  
Silvia Pérez-Casas
Keyword(s):  
Aqueous Solution ◽  
Heat Capacities ◽  
Dilute Aqueous Solution

Heat capacities of monomer models of some hydrophilic polymers in an aqueous solution from 20° to 60 °C

1982 ◽  
Vol 47 (10) ◽  
pp. 2692-2701 ◽  
Author(s):  
Ján Biroš ◽  
Antonín Sikora ◽  
Antonín Živný ◽  
Julius Pouchlý
Keyword(s):  
Aqueous Solution ◽  
Heat Capacities ◽  
Hydrophilic Polymers ◽  
The Other ◽  
Bulk Liquid ◽  
Apparent Molar Heat Capacities ◽  
Apparent Heat Capacity ◽  
Dilute Aqueous Solution ◽  
Specific Volumes ◽  
Good Agreement

The apparent molar heat capacities of propionic and isobutyric acids and of 2-hydroxyethyl pivalate and 2-(2'-hydroxyethoxy)ethyl pivalate in a dilute aqueous solution were determined with a DASM-1 m calorimeter. Moreover, the apparent specific volumes of these compounds in the aqueous solution and their molar heat capacities in the bulk liquid state were also determined. In the range 20° - 60 °C the apparent heat capacity in the aqueous solution is temperature-independent, or (in the case of propionic acid) increases slightly with temperature. The apparent heat capacities measured at 25 °C were compared with values estimated using various reported additivity schemes. Good agreement was observed for both acids; the other two compounds with more complicated molecules showed significant deviations from additivity.

scholarly journals Freeze concentration of dilute aqueous solution

1968 ◽  
Vol 17 (3) ◽  
pp. 354-355 ◽  
Author(s):  
Atsushi MIZUIKE ◽  
Shigeki KANO
Keyword(s):  
Aqueous Solution ◽  
Freeze Concentration ◽  
Dilute Aqueous Solution

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

Determination of the complexation properties of a crosslinked poly(acrylic acid) gel with copper(II), nickel(II), and lead(II) in dilute aqueous solution

2001 ◽  
Vol 79 (4) ◽  
pp. 370-376 ◽  
Author(s):  
Catherine Morlay ◽  
Yolande Mouginot ◽  
Monique Cromer ◽  
Olivier Vittori
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Acrylic Acid ◽  
Metal Ion ◽  
Conditional Stability ◽  
Binding Properties ◽  
Complex Species ◽  
Complexing Capacity ◽  
Dilute Aqueous Solution ◽  
Poly Acrylic Acid

The possible removal of copper(II), nickel(II), or lead(II) by an insoluble crosslinked poly(acrylic acid) was investigated in dilute aqueous solution. The binding properties of the polymer were examined at pH = 6.0 or 4.0 with an ionic strength of the medium µ = 0.1 or 1.0 M (NaNO3) using differential pulse polarography as an investigation means. The highest complexing capacity of the polyacid was obtained with lead(II) at pH = 6.0 with µ = 0.1 M, 4.8 mmol Pb(II)/g polymer. The conditional stability constants of the complex species formed were determined using the method proposed by Ruzic assuming that only the 1:1 complex species was formed; for lead(II) at pH = 6.0 and µ = 0.1 M, log K' = 5.3 ± 0.2. It appeared that the binding properties of the polymer increased, depending on the metal ion, in the following order: Ni(II) < Cu(II) < Pb(II). The complexing capacity and log K' values decreased with the pH or with an increase of the ionic strength. These results were in agreement with the conclusions of our previous studies of the hydrosoluble linear analogues. Finally, with the insoluble polymer, the log K' values were comparable to those previously obtained with the linear analogue whereas the complexing capacity values expressed in mmol g-1 were slightly lower.Key words: insoluble crosslinked poly(acrylic acid), copper(II), nickel(II), and lead(II) complexation.

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