4.103 Hydration number (nH) of L-proline in aqueous solution of nicotinamide (0.03 mol.kg-1) as a function of molality (m/mol.kg-1) at different temperatures. 4.105 Hydration number (nH) of L-proline in aqueous solution of nicotinamide (0.06 mol.kg-1) as a function of molality (m/mol.kg-1) at different temperatures. 4.106 Hydration number (nH) of L-proline in aqueous solution of nicotinamide (0.09 mol.kg-1) as a function of molality (m/mol.kg-1) at different temperatures.
4.107 Hydration number (nH) of L-lysine in an aqueous solution of nicotinamide (0.03 mol.kg-1) as a function of molality (m/mol.kg-1) at different temperatures.
General
Properties of solute in solvent
This confusing behavior results from the combined effects of preferential dissolution of the solute by one of the components of the mixture [7, 8] and of solvent–solvent interactions [9]. Theoretically, solvent interactions, which mean the properties of solutions, can be calculated from the properties of the individual components. The theoretical treatments must therefore assume some model (eg lattice model, cell model, etc.) for the structure of the components and their solution.
Alternatively, it is considered convenient and useful to experimentally determine the values of certain macroscopic properties of solutions for proper understanding of the structure of the solution.
Amino Acids
In aqueous solutions, amino acids are generally stable at physiological pH and exist as neutral dipolar ions, meaning that under physiological conditions both amino acid terminals are charged; positive charge (amino group) and negative charge (carboxyl group, ), so the molecules have zwitterion properties [12].
Properties of proline
It contains an α-amino group (which is in the protonated −NH3+ . form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions) and a side chain (CH2)4NH2, classifying it as a charged (at physiological pH), aliphatic amino acid. Lysine is important for proper growth and it plays an essential role in the production of carnitine, a nutrient responsible for converting fatty acids into energy and helping to lower cholesterol. Nicotinamide is subsequently formed through the conversion of nicotinic acid in the liver or through the hydrolysis of NAD+.
Once nicotinamide is taken up in the body, it functions as a precursor for the coenzyme β-nicotinamide adenine dinucleotide (NAD+) [20,21] and is also essential for the synthesis of nicotinamide adenine dinucleotide phosphate (NADP+) [22].
Structure of water
The nature of the molecular structure of water causes its molecules to have unique electrochemical properties. The expansion of the water molecule during freezing allows the ice to float on liquid water. The introduction of a solute into liquid water causes changes in the properties of the solvent similar to those caused by temperature or pressure.
The concentration dependencies of the thermodynamic properties are a measure of solute-solute interactions and in the limit of infinite dilutions these parameters serve as a measure of solute-solvent interactions.
Hydrophilic hydration
A solute that shifts the equilibrium to the left and increases the average half-life of the clusters is called a structure builder, while one that has the opposite effect is called a "structure breaker." The experimental result on various macroscopic properties provides useful information for a proper understanding of the specific interactions between the components and the structure of the solution. Thermodynamic and transport properties are sensitive to solute-solvent, solute-solute and solvent-solvent interactions.
The dissolution of any solute will disrupt the arrangement of the water molecules in the liquid state and create a hydration shell around the solute molecule.
Hydrophobic hydration and hydrophobic interaction
If the solute is an ionic species, then this hydration shell is characterized by extending from an inner layer where the water molecules next to the charge species are strongly polarized and oriented by the electrostatic field, through an intermediate region where the water molecules are polarized significantly but not strongly. oriented, in an outer solvent region of bulk water where the water molecules are only slightly polarized by the electric field of the ion [34].
Amino acids-solvent systems
Volumetric and viscometric studies of amino acids in aqueous solutions of vitamin B6 at different temperatures were performed [39]. Volumetric and viscometric studies of amino acids in aqueous solutions of L-ascorbic acid have been reported [40]. Investigations of various interactions of some vitamins in aqueous cysteine mixtures have been reported [41].
The structural properties of amino acids in aqueous glucose solution at different temperatures have been reported [44].
The object of the present work
Research on the density and speed of sound of L-serine and L-threonine in an aqueous nicotinamide solution has been reported [38]. Research on density and sound speed of L-serine and L-threonine in aqueous nicotinamide solution has been reported by a researcher [53]. To the best of our knowledge, no data have been previously reported on the density, speed of sound, apparent molar volume, partial molar volume, adiabatic compression, and isobaric expansion of L-proline and L-lysine in aqueous nicotinamide solutions at different temperatures under atmospheric pressure. .
To understand the issue of solvent-solvent interactions in aqueous solution of nicotinamide-amino acid systems, a theoretical and experimental aspect of the interactions in terms of apparent molar volume, partial molar volume, adiabatic compression, and analysis of rate properties is necessary. the voice.
Physical Properties and chemical constitutions
An additional property is one that, for a given system, is the sum of the corresponding properties of the constituents. The only strictly additive property is mass, since the mass of a molecule is exactly equal to the sum of the masses of its constituent atoms, and similarly the mass of a mixture is the sum of the separate masses of the constituent parts. There are other molecular properties such as molar volume, radioactivity, etc. that are highly additive in nature. ii) Purely constitutive properties: A property which depends entirely on the arrangement of atoms in a molecule and not on their number is called a purely constitutive property.
For example, the optical activity is the property of the asymmetry of the molecule and occurs in all compounds with an overall asymmetry. iii) Constitutive and additive properties: These are additive properties, but the additive character is modified by the way in which the atom or constituent parts of a system are linked together.
Density
The relative density of a substance is the ratio between the weight of a certain volume of the substance and the weight of the same volume of water at the same temperature (d104). The absolute density of a given substance at a temperature t0C is equal to the relative density multiplied by the density of water at the temperature. The density of a liquid can be determined by weighing a known volume of liquid in a gauge or pycnometer, or by a buoyancy method based on the "Archimedes principle".
In our current investigation, the density of the pure components and the mixture was determined by weighing a specific volume of the liquid in question in a density bottle.
Density and temperature
17. at 40 C), the density of water at this temperature in gmL-1 is equal to unity, and the density of water at any other temperature is expressed in terms of the density of water at 40 C and expressed by (d104).
Molarity
Molar volume of Mixtures
For one mole of solute dissolved in one liter of solution, C=l, i.e. Such a solution is called 1 molar. When two components are mixed together, there can be either a positive or a negative deviation in volume. The positive deviation in volume ie. volume expansion was explained by the breakdown of the association method by H-bonding of the associated liqs.
The negative deviation in molar volume ie. Volume contraction has been thought by many observers to result from i) compound formation by association, ii) decrease in the intermolecular distance between the interacting molecules, iii) interstitial accommodation of smaller species in the structural network of the larger species and (iv) change in the mass structure of any of the substances that make up the mixture.
Apparent/ partial molar volume
The usefulness of the concept of partial molarity is that it can be represented mathematically as,. The concentration dependence of the apparent molar volume of electrolytes was described by the Masson equation [60], the Redlich-Mayer equation [62] and the Owen-Brinkley equation [61]. Masson [60] found that the apparent molar volume of electrolytes varies with the square root of the molar concentration as,.
For dilute solutions, the limiting law for the concentration dependence on the apparent molar volume of electrolytes is given by the equation.
Theory of ultrasonic velocity
Where is the compressibility of the solvent, i is the number of ions of species i of valence Zi formed by one molecule of the electrolyte and the other symbols have their usual meaning [62]. The density of the fluid in front of the wave front is the undisturbed bulk density (ρ), which lies between the local densities of the medium C and R. An important aspect of sound propagation is the fact that if the frequency of the sound is generated by sufficiently high audio frequencies that are between 103 and 104 Hz. oscillations per second), the compressions and refractions are achieved very quickly as the sound path moves through the medium.
This condition means that heat transport between the compressed and dehydrated regions of the medium and the environment is slow relative to the creations of the compression and refractions.
Acoustic Impedance
Relative association
The adiabatic compressibility, βs of the solution for binary and ternary systems was determined from density and sound speed data using the following equation, The apparent molar adiabatic compressibility, βs of the solution for binary and ternary systems was determined from density and sound speed data by the following equation, Where, is the density of the experimental solution and u is the adiabatic compressibility of the solution.
The hydration number, nH of solutions for binary and ternary systems, was determined from density and sound speed data using the following equation.
Volumetric Properties
The values of the apparent molar volume (φv) of aqueous amino acids are positive and increase linearly with the increase in the concentration of amino acids. The apparent molar volume (φv) values of aqueous L-lysine are higher than L-proline, which due to the number of carbons in the alkyl group present in amino acids viz. at a fixed nicotinamide concentration and temperature, the increase of φv with the concentration of added amino acids in the investigated molality range may be due to the cluster formation or aggregation.
Also, the apparent molar volume increases with the increase in the number of carbons in the alkyl group present in amino acids, viz. the limiting apparent molar volume (φv0.) of amino acids reflects the true volume of the solute. Experimental slope (SV) values are positive for all amino acid concentrations.
The non-zero values of SV indicate the presence of solute interactions in solutions of amino acids. The limiting values of apparent molar volume transfer of amino acids from water to aqueous nicotinamide solutions at infinite dilution were calculated using the equation. The observed positive values of Δtrφv0 suggest strong ion-ion interactions of amino acids with nicotinamide.
Because the structural part of amino acids and aqueous nicotinamide contains polar groups, interactions between them promote the structure-forming ability of the solute in the solvent. This suggests that solute-solvent interactions increase with the increase in amino acid concentration.
Ultrasonic properties
