http://hdl.handle.net/20.500.12228/32 2026-04-07T16:01:50Z http://hdl.handle.net/20.500.12228/906 Volumetric and Sound Velocity Studies on L-Lysine and L-Arginine in Aqueous Sodium Benzoate Solution at Different Temperature Mou, Iffat Ara In this study, a general volumetric and sound velocity method was used to analyze the effects of sodium benzoate (SB) on the structure of essential amino acids (L-lysine, L-arginine). Densities and sound velocities of L-lysine and L-arginine in aqueous and in aqueous 0.05 mol.kg-1, 0.2 mol.kg-1, 0.35 mol.kg-1 and 0.5 mol.kg-1 SB solutions have been studied at 293.15K to 313.15K with an interval of 5K. The density data have been used to calculate apparent molar volume (φv), limiting apparent molar volume (φv 0), limiting apparent molar volume transfer (Δtrφv 0), apparent molar expansibilities ( 0  E ) and Helper’s constant ( E / T) p 0    . The acoustic properties such as adiabatic compressibility (βs), apparent molar adiabatic compressibility (k), limiting apparent molar adiabatic compressibility (φk 0), apparent molar adiabatic compressibility transfer (Δtrφk 0), acoustic impedance (Z) and hydration number (nH) have been calculated by densities and sound velocities data. The densities increase with the increase of concentration of amino acids. Densities of amino acids in aqueous SB solutions are higher than that of amino acids in aqueous solution. The limiting apparent molar volumes (φv 0) and the values of experimental slope (Sv) are positive. The smaller values of Sv as compared to φv 0 values suggest the dominance of solute-solvent interaction over the solute-solute interaction. The limiting apparent molar volume transfer (Δtrφv 0) values of L-lysine and L-arginine in SB solutions are negative. This indicate that ion-hydrophobic and hydrophobichydrophobic group interaction are dominating over the hydrophilic-hydrophilic interaction. The values of limiting apparent molar expansion ( 0  E ) are positive. These trends in limiting apparent molar expansions for these amino acids in each concentration of SB solutions indicating the presence of solute-solvent interaction. The Hepler’s constant p ( E / T) 0    values of binary system are entirely positive for all studied amino acids suggest the studied systems act as structure makers. In ternary system some values are small negative and some values are positive. Hepler’s constant p ( E / T) 0    in ternary solutions indicating the structure making properties of amino acids in SB solutions. The values of partial molar volumes (V̅ 2) increase with increasing of concentration of L-lysine, L-arginine for the studied systems. As the concentration of amino acids increases, the adiabatic compressibility (βs) decreases. This indicates the water molecules around the amino acids are less compressible than the water molecules in the bulk solution. The negative apparent molar adiabatic compressibility (k) values indicate the greater loss of structural compressibility of water implying a greater ordering effect by the solute on the solvent. Δtrφk 0 values of L-lysine are positive whereas Δtrφk 0 of L-arginine are negative. This indicate that hydrophilichydrophilic and ion-hydrophilic interaction are dominating for L-lysine systems whereas hydrophobic-hydrophobic and ion-hydrophobic interactions are dominating for L-arginine systems. The small Sk values also indicates the solute-solvent interactions. The increase in acoustic impedance Z, indicates the presence of effective solvent-solvent interactions with the increase in solution concentration. The positive hydration number (nH) values indicate an admirable solubility of the solutes. Water molecules around amino acids have less shrinkage than water molecules in bulk solutions. The compressive strength of the ternary solution is less than that of the binary solution. This result suggests that the proteins or peptides generated from the studied amino acids will be denatured in ternary SB solutions. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, September 2018.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 133-140). 2018-09-01T00:00:00Z http://hdl.handle.net/20.500.12228/762 Volumetric and Viscometric Properties of N-Acetylcysteine in Dimethylformamide Containing Binary and Ternary Mixtures Pal, Gopal The density and viscosity of NAC (0.10 to 1.00) mol.L−1 in H2O, DMF and DMF– H2O mixed solutions were measured and studied over the entire molarity range with in the temperature range of 298.15 to 318.15 K at 5 K interval. The apparent molar volumes, were determined from density values experimented by Density and Sound Velocity Meter (DSA 5000M) Anton Paar, Austria. In the NAC–H2O and NAC in [1:4] and [2:3] [DMFH2O] solvent systems the apparent molar volumes of NAC were found to be increased, whereas in the NAC–DMF and NAC in [4:1] and [3:2] [DMFH2O] solvent systems apparent molar volumes of NAC were found to be decreased. Apparent molar volume at infinite dilution, 0 v  and Sv values were also computed according to the experimented density values. The apparent molar volume at infinite dilution provided an idea about the presence of solutesolvent interactions of the investigated systems. Sv, the experimental slopes which provided an idea about the prevailing solutesolute interactions in the mixtures. Both 0 v  and Sv values indicated that there both solute-solute and solute-solvent interactions present in the binary as well as in ternary solutions. The investigated systems showed hasty increase of viscosity values with the increased NAC concentration but the values of viscosity decreased with the increase of temperature. In binary and ternary systems showed the similar trend viscosity changes but in different order of magnitude. The order for binary and ternary systems are: NAC– DMF > NACH2O and NAC in [3:2] [DMF–H2O] > NAC in [4:1] [DMF–H2O] > NAC in [2:3] [DMF–H2O] > NAC in [1:4] [DMF–H2O] > NAC–DMF > NACH2O, respectively. The viscosity values were employed to determine the viscosity coefficients i.e., A and B-coefficients; change of free energy, G*; change of enthalpy, H* as well as change of entropy, S*. Negative values of A and positive values of B co-efficients suggesting that weak solute-solute but strong solute-solvent interaction present in the binary and ternary solution, respectively. From these thermodynamic parameters state of the spontaneity of the investigated systems were known. On the basis of this data, the predominant molecular interactions occurring between NAC–H2O and NAC in [1:4] and [2:3] [DMFH2O] solvent systems were found to be solute-solute interaction, where as in NAC–DMF and NAC in [4:1] and [3:2] [DMFH2O] solvent systems solute-solvent interaction were predominant. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, 29 June, 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 74-80). 2019-06-29T00:00:00Z http://hdl.handle.net/20.500.12228/551 Effect of Surfactant on Formation of Hydroxyapatite under Reverse Micelle Condition Yeasmin, Fargana Hydroxyapatite, (HAp), Ca10(PO4)6(OH)2, is a naturally occurring material found in the inorganic component of human bone and enamel. The constituent elements of HAp are primarily calcium and phosphorous, with a stoichiometric calcium to phosphorous ratio is 1.667 capable of promoting intimate bone growth onto femoral implants. The performance, lifespan and quality of the resultant biological coating in vivo is largely dependent on the coating morphology, phase composition, particle size and crystallinity of the powders pre-coating application. The present study focused on preparing Hydroxyapatite nanoparticles (HAp-NPs) through chemical precipitation technique using mixed micelle core as a nanoreactor. Mixed micelle core was used to control morphology such as crystallinity, particle size, particle shape, particle size. Anionic (sodium dodecyl sulphate (SOS)) and cationic (Cetyl trimethyl ammonium bromide (CTAB)) surfactants were used to prepare the mixed micellar core. 18 : 2 ratio of propanol-1 : water system experimentally selected for the formation of reverse micelle for the afore mentioned surfactants. Compositions of both surfactants were varied to control the morphology of HAp-NPs under the same experimental condition. Several techniques such as FTIR, XRD, TOA and SEM were used to characterize the prepared HAp-NPs. Appearance of peaks at various position of the FTIR spectrum shows the PO vibrations of PO;- which are characteristics of hydroxyapatite. In addition, the diffraction pattern of the prepared HAp-NPs are in well agreement with the standard published by the International Centre for Diffraction Data. However, the diffractogram indicates the presence of crystalline as well as amorphous phase. No significant weight loss was observed for the prepared HAp-NPs. SEM result reveals significant morphological variation of the prepared HAp-NPs by changing the amount of two surfactants. Variation of the ratio of surfactants SOS and CT AB allow the variation in the morphology of the prepared particles. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Masters of Philosophy in Chemistry, December 2018.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 57-61). 2018-12-23T00:00:00Z http://hdl.handle.net/20.500.12228/542 Studies on Volumetric and Viscometric Properties on N-Acetylcysteine in Acetic Acid-Water Binary and Ternary Mixtures Vattya, Banamali The density and viscosity of NAC (0.10 to 1.00) mol.L−1 in H2O, CH3COOH and H2O–CH3COOH mixed solutions were measured and analyzed over the whole concentration range at (298.15, 303.15, 308.15, 313.15 and 318.15) K temperatures. The apparent molar volumes were obtained from the experimental density data. In the NAC– H2O and NAC in [9:1] [H2O–CH3COOH] solvent systems the apparent molar volume of NAC increases, whereas in the NAC–CH3COOH and NAC in [4:1], [7:3] and [3:2] [H2O–CH3COOH] solvent systems it decreases. With the help of experimental density data apparent molar volume at infinite dilution, and Sv values were also calculated. The apparent molar volume at infinite dilution gives an idea about the presence of solutesolvent interactions while Sv is the experimental slopes which give an idea about the prevailing solutesolute interactions in the mixtures. The calculated data indicate that there may be solute-solute and solute-solvent interactions present in the binary and ternary solutions. Binary and ternary systems showed rapid increase of viscosity values with the increase in NAC concentration but the values of viscosity decreased with the increase of temperature for all the experimented system. The viscosity data were employed to find out the viscosity (A, B) coefficients, change of free energy, G*, change of enthalpy, H* as well as change of entropy, S*. From these thermodynamic parameters state of the spontaneity of the investigated systems were identified. Moreover, negative A and positive B co-efficient values suggesting that weak solutesolute but strong solute-solvent interaction present in the binary and ternary solution. On the basis of this data, the predominant molecular interactions occurring between NAC– H2O and NAC in [9:1] [H2O–CH3COOH] solvent systems were found to be solute-solute interaction, whereas in NAC–CH3COOH and NAC in [4:1], [7:3] and [3:2] [H2O– CH3COOH] solvent systems solute-solvent interaction were predominant. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, June 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 68-72). 2019-06-29T00:00:00Z