The thermodynamic characteristics of step dissociation of trimethylenediamino-N,N,N′,N′-tetraacetic acid

2008 ◽  
Vol 82 (1) ◽  
pp. 41-44 ◽  
Author(s):  
S. N. Gridchin
Keyword(s):  
Thermodynamic Characteristics ◽  
Tetraacetic Acid ◽  
Step Dissociation

scholarly journals THERMODYNAMIC CHARACTERISTICS OF ACID-CORE REACTIONS INTERACTIONS IN THE WATER SOLUTION PIRIDOXAL-5'-PHOSPHATE

2020 ◽  
Vol 63 (7) ◽  
pp. 10-14
Author(s):  
Alexander I. Lytkin ◽  
Olga N. Krutova ◽  
Ekaterina D. Krutova ◽  
Yuliya V. Mokhova ◽  
Elena Yu. Tyunina
Keyword(s):  
Confidence Interval ◽  
Thermal Effects ◽  
Water Solution ◽  
Thermodynamic Characteristics ◽  
Equilibrium Composition ◽  
Potassium Nitrate ◽  
Biologically Active ◽  
Water Dissociation ◽  
Time Curve ◽  
Step Dissociation

As the object of the study, we selected 3-hydroxy-2-methyl-5-(phosphonic) methyl-4-pyridincarboxaldehyde (pyridoxal-5'-phosphate) which is one of the most important biologically active compounds. Direct calorimetric method was used to measure the thermal effects of interaction of the solution of pyridoxal-5'-phosphate with solutions of nitric acid and potassium hydroxide at 298.15K and ionic strength values of 0.5; 1.0 and 1.5 against the background of electrolyte-supporting potassium nitrate. The measurements were carried out in a calorimeter with an isothermal shell equipped with a 60 cm3 reaction vessel and electric calibration at T = 298.15K ± 0.01 К and P = 100.5± 0.7 kPa and automatic recording of the temperature-time curve. Relative measurement error for heats of dissolution of a standard substance was -0.1-0.3%. Close values of constant sequencing of pyridosal-5'-phosphate do not allow to distinguish such an area of pH where only one of the processes of step dissociation would occur. In this regard the total thermal effect of protonation of pyridoxal-5'-phosphate would be measured. Calculation of the equilibrium composition of the system took into account processes step dissociation and water dissociation was carried out according to the KEV program. The thermal effects of stepwise dissociation of pyridoxal-5'-phosphate are calculated using the universal HEAT program. Because, the thermal effects of dilution were measured in three concentration ranges of KNO3: 0.4-0.5;0.9-1.0; 1.4-1.5 mol /l, the number of experiments in each series was at least four. To calculate the confidence interval of the average value of DН Student's criterion was taken at a confidence interval of 0.95 The standard thermal effects of stepwise ionization of pyridoxal-5'-phosphate were found by extrapolation of experimentally obtained amounts of piridoxyxal-5'-phosphate to zero ion force of the solution.

Heterozygous Abnormal Fibrinogen Osaka III with the Replacement of γ Arginine-275 by Histidine Has an Apparently Higher Molecular Weight γ-Chain Variant

1992 ◽  
Vol 68 (05) ◽  
pp. 534-538 ◽  
Author(s):  
Nobuhiko Yoshida ◽  
Shingi Imaoka ◽  
Hajime Hirata ◽  
Michio Matsuda ◽  
Shinji Asakura
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulfate ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Tetraacetic Acid ◽  
Fibrin Monomer ◽  
Sds Page ◽  
Thrombotic Tendency ◽  
Chain Variant

SummaryCongenitally abnormal fibrinogen Osaka III with the replacement of γ Arg-275 by His was found in a 38-year-old female with no bleeding or thrombotic tendency. Release of fibrinopeptide(s) by thrombin or reptilase was normal, but her thrombin or reptilase time in the absence of calcium was markedly prolonged and the polymerization of preformed fibrin monomer which was prepared by the treatment of fibrinogen with thrombin or reptilase was also markedly defective. Propositus' fibrinogen had normal crosslinking abilities of α- and γ-chains. Analysis of fibrinogen chains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system of Laemmli only revealed the presence of abnormal γ-chain with an apparently higher molecular weight, the presence of which was more clearly detected with SDS-PAGE of fibrin monomer obtained by thrombin treatment. Purified fragment D1 of fibrinogen Osaka III also seemed to contain an apparently higher molecular weight fragment D1 γ remnant on Laemmli gels, which was digested faster than the normal control by plasmin in the presence of [ethy-lenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA).

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

Oxidation of ethylenediphosphinetetraacetate anions

1983 ◽  
Vol 48 (9) ◽  
pp. 2604-2608
Author(s):  
Jana Podlahová ◽  
Jaroslav Podlaha
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Electronic Structure ◽  
Acid Solutions ◽  
Tetraacetic Acid ◽  
Single Product ◽  
Weakly Acid ◽  
Inhibiting Effect ◽  
Oxidation By Molecular Oxygen ◽  
Protonated Forms

The oxidation of the ethylenediphosphinetetraacetate anion and its protonated forms by iodine, periodate, hydrogen peroxide, and oxygen has been studied in aqueous solution. The oxidation by the first three reagents is fast and yields a single product, bis(phosphine oxide), which has been isolated and characterized as ethylenebis(phosphinyl)tetraacetic acid. The oxidation by molecular oxygen proceeds considerably more slowly; in weakly acid solutions its rate is determined by the properties of the oxygen rather than by the electronic structure of the various protonated substrate species. The inhibiting effect of the phosphonium structures takes place only in strongly acid solutions.

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