24 documents found, page 1 of 3

Memórias da Academia das Ciências de Lisboa

Diffusion of levodopa in aqueous solutions of hydrochloric acid at 25 °C

Ternary mutual diffusion coefficients (D11, D22, D12 and D21) measured by the Taylor dispersion method are reported for aqueous solutions of {levodopa (l-dopa) + HCl} solutions at 25 °C and HCl concentrations up to 0.100 mol · dm−3. The coupled diffusion of l-dopa (1) and HCl (2) is significant, as indicated by large negative cross-diffusion coefficients. D21, for example, reaches values that are larger than D1...

Mass transport techniques as a tool for a better understanding of the structure...

Mutual diffusion coefficients, D, densities, ρ, and viscosities, η, are reported for aqueous solutions of L-3,4-dihydroxyphenylalanine (L-Dopa) at 298.15K and 310.15K at concentrations from (0.00025 to 0.0075) moldm(-3). The aim of this study is to contribute to a better understanding of the structure of these systems and the thermodynamic behaviour of L-Dopa in solution. Thus, from these experimental data it w...

Binary Mutual Diffusion Coefficients of Isoniazid Aqueous Solutions at (298.15 ...

Binary mutual diffusion coefficients measured by the Taylor dispersion method in two different laboratories (University of Naples, Federico II, Italy, and University of Coimbra, Portugal) are reported for aqueous solutions of isoniazid at concentrations from (0.000 to 0.100) mol·dm−3 and at two temperatures (298.15 and 310.15) K. The hydrodynamic radii for the isoniazid in aqueous solution are calculated from t...

Some Transport Properties of γ-Cyclodextrin Aqueous Solutions at (298.15 and 31...

Values of binary mutual diffusion (interdiffusion) coefficients, obtained by using the Taylor dispersion method, for aqueous solutions of γ-cyclodextrin in the concentration range from (0.002 to 0.010) mol·dm−3 and temperatures (298.15 and 310.15) K are reported. From these experimental results, the hydrodynamic radius values for the γ-cyclodextrin are estimated. Also, the measured diffusion coefficients are us...

Diffusion coefficients and electrical conductivities for calcium chloride aqueo...

http://www.sciencedirect.com/science/article/B6TG0-4T7XGV2-6/2/9f2789c31efbabbadc8d9358c079cafe

Mean distance of closest approach of ions: Lithium salts in aqueous solutions

Numerical values for the mean distance of closest approach of ions, "a", for lithium salts in aqueous solutions are presented and discussed. These values were obtained from both experimental activity and diffusion coefficients, and estimated by using different theoretical approaches.; http://www.sciencedirect.com/science/article/B6TGR-4RR1NKM-1/1/b8d3cdac33991c5424d567940bc0c3a6

Aggregation and micellization of sodium dodecyl sulfate in the presence of Ce(I...

Aggregation properties of sodium dodecyl sulfate (SDS) in the presence of cerium(III) chloride, at various temperatures (298.15-323.15 K) have been measured by the electrical conductance technique. The experimental data on aqueous solutions as a function of SDS concentration show the presence of two inflexion points indicating the presence of two distinct interaction mechanisms: the first, occurring at SDS conc...

Modulating the Emission Intensity of Poly-(9,9-bis(6‘-N,N,N-trimethylammonium)h...

The interaction between the cationic HTMA-PFP (Poly-(9,9-bis(6‘-N,N,N-trimethylammonium)hexyl-fluorene phenylene) bromide) and oppositely charged sodium n-alkyl sulfonate surfactants of different chain lengths has been studied in DMSO−water solutions (4% v/v) by UV−visible absorption, fluorescence spectroscopy, fluorescence lifetimes, electrical conductivity, and 1H NMR spectroscopy. Polymer−surfactant interact...

Mean distance of closest approach of ions: Sodium salts in aqueous solutions

The estimation of numerical values for the mean distance of closest approach of ions, a, of sodium salts in aqueous solutions, determined from activity and diffusion coefficients, and also from different theoretical approaches, is presented and discussed.; http://www.sciencedirect.com/science/article/B6TGR-4JCCFW7-1/1/45bf32523013b068b5040514add5505a