Isothermal
vapor–liquid equilibrium data for the system
methanol + benzene + tetraphenylphosphonium chloride at four salt
molalities {(0.100, 0.200, 0.300, and 0.500) mol·kg–1} have been measured with the help of headspace gas chromatography
at {(308.15 and 328.15) K}. Tetraphenylphosphonium chloride can be
used as an entrainer for the separation of methanol + benzene mixture.
The experimental data were correlated using the electrolyte NRTL model.
Heparin complexation with a number of alkali, alkaline earth and transition metal ions has been the subject of studies carried out using various procedures both spectral and potentiometric [1][2][3][4][5][6][7][8][9][10]. Consider able attention was devoted to the aspects related to the stoichiometry and stability of the complexes.The interaction of metal ions with charged poly meric chains of heparin can be regarded as a rather specific process governed by not only the charge and structural parameters of the interacting species (poly mer backbone length, angles between the molecules) but also by the metal ion fractional affinity to the poly mer donor groups [6].Heparin has several types of donor groups, specifi cally, carboxyl, aminosulfone, and hydroxy groups; glycoside, ether and carbonyl oxygen atoms, and the amide nitrogen.The direct participation of the amide group in the bond formation is unlikely but cannot be ruled out completely. The heparin donor groups mainly contain oxygen atoms.It is of interest to estimate the effect of heparin on the blood plasma balance of mineral ions. The blood plasma is a very complex multicomponent system in O OH O O O HO O S O O HO O OH HN S O O HO O O S HO O O (Н 4 Hep)which hundreds reactions involving organic and inor ganic complexes take place. Note that the mathemat ical model of blood plasma designed at the Laboratory for Chemical Thermodynamics, Lomonosov Moscow State University, had more than 800 metal ion equilib ria in its data bank. Gaining information about the characteristics of metal ion equilibria (complex sto ichiometry and stability constants) existing in the plasma is first of all necessary for supplementing the existing bank of equilibria.As the investigation objects, we chose ion equilibria in the systems containing high molecular weight hep arin polyanions and cations of biometals, i.e., nickel, cobalt, manganese, and iron. Currently heparin based agents are the main anticoagulant drugs used both for prevention and therapy of thrombosis related dis eases.The purpose of this work is to estimate the effect of introduction of therapeutic doses of heparin on plasma balance of mineral ions and to characterize the effect of the (Нep 4-) polyanion on the state of equilib ria involving biometal ions. This requires solution of a number of problems, in particular, it is necessary to obtain data on the formation and stability of heparin complexes with Mn 2+ , Ni 2+ , Fe 3+ , and Co 2+ ions.
EXPERIMENTALA standard pharmacological solution of high molecular weight heparin manufactured by the Mos cow Endocrine Plant packed in 5 mL vials was used. Each milliliter of this solution contains 5000 U, each unit of activity corresponds to 0.0077 mg of heparin.Solutions of metal chlorides were prepared from exact weighed samples of analytical grade salts and standardized by complexometric titration. A support ing electrolyte solution (NaCl) was also prepared using an analytical grade weighed sample of the dry salt. The titrating agent (carbonate free solution of Abstract-The ...
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