Dr. Sanjay Roy | Netaji Subhas Open University (original) (raw)

Papers by Dr. Sanjay Roy

Research paper thumbnail of Approaches on Carbon Free Energy Source from Water Splitting

Oriental journal of physical sciences, Jul 15, 2023

Energy from sunlight is most plentiful renewable energy resource, on condition that earth with as... more Energy from sunlight is most plentiful renewable energy resource, on condition that earth with as much as necessary power that is proficient of taking care of all desires of living being. But that energy is not always usable to us for modern society. With rising population, modern scientific requirements and other development, there must be increase in energy demand day by day. Scientifically developed procedures that may use sunlight to split water into hydrogen and oxygen may be clue to solve this concern, since water splitting generates a perfect non-hazardous fuel and must be low in cost. Thus, it is critical to research for new and economical technologies for water splitting. Since 1970 1 research has been going on making suitable device for producing H 2 and O 2. With the ongoing power of technology several economic effective strategies 2-5 have also been developed. Potency, cost value and longevity are the three major concerning factors during developing any new photochemical device. On the basis of these several approaches were made regarding this water splitting (WS) research. One of the most convenient approaches in this field is plasmonic solar approach in which surface plasmons are the basic soldier for controlling the both functions viz electronic and optical.Recent research has revealed that when exposed to photons of Sun-like intensity, plasmonic photoexcited nanostructures, as opposed to metal structures, exhibit comparatively significant photocatalytic activity. 6 In silicon based WS devices light scattering 7 controls mode of operation. Different metal based photoelectrodes (Ni, Ag, Mo etc) were developed since few years. During the solar WS reaction, semiconductor photo electrodes are involved in intricate chemical, physical, & electrical processes that operate the photogenerated electron-hole pairs for redox reactions.

Research paper thumbnail of Solubility and the solution thermodynamics of l-proline in the aqueous binary mixture of NaCl and KCl solution

Journal of Molecular Liquids

Research paper thumbnail of A 5-aminoisophthalic acid low molecular weight gelator based novel semiconducting supramolecular Zn(ii)-metallogel: unlocking an efficient Schottky barrier diode for microelectronics

Nanoscale Advances

At room temperature, an electronic device featuring a Schottky barrier diode is facilitated by a ... more At room temperature, an electronic device featuring a Schottky barrier diode is facilitated by a supramolecular Zn(ii)-metallogel derived from the low molecular weight gelator, 5-aminoisophthalic acid.

Research paper thumbnail of Effect of uni-divalent electrolyte in the interaction associated with solubility for the predominant form of L-isoleucine and L-serine in aqueous media

Journal of Molecular Liquids, Jun 1, 2023

Research paper thumbnail of Recently Reported Ru-Metal Organic Coordination Complexes and Their Application (A Review)

Russian Journal of General Chemistry, Aug 1, 2022

Research paper thumbnail of Evaluation and correlation of solubility and solvation energetics of DL-phenylalanine and DL-serine in water and aqueous ethylene glycol solutions

Journal of Molecular Liquids, 2018

Evaluation and correlation of solubility and solvation thermodynamics of glycine, dl-alanine and ... more Evaluation and correlation of solubility and solvation thermodynamics of glycine, dl-alanine and dl-valine in aqueous sodium sulphate solutions at two different temperatures. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Molliq(2017),

Research paper thumbnail of Recent developed different structural nanomaterials and their performance for supercapacitor application

Applied Materials Today, Dec 1, 2017

Developments during the past decade, electrode materials have been tuned to the nanoscale and ele... more Developments during the past decade, electrode materials have been tuned to the nanoscale and electrolytes have gained an active role enabling more efficient storage mechanism; hence increasing the performance of supercapacitors manifold. In porous carbon materials with sub-nanometer pores, the desolvation of the ions leads to surprisingly high capacitances. Oxide materials store charge by surface redox reactions which are the foremost to the pseudo capacitive effect. Understanding the physical mechanisms underlying charge storage in these materials is important for further development of supercapacitors. This brief overview focuses on the different types of recent developed (asymmetric, pseudo) supercapacitors, experimental strategies, fabrication procedure, and electrochemical properties based on nanomaterials which have been reported recently for their high-quality performance, the relevant quantitative modeling history and the future of supercapacitor research and development.

Research paper thumbnail of Solvation thermodynamics of four amino acids in electrolytic solutions of sodium and potassium iodide salts at 298.15 K

Canadian Journal of Chemistry, Apr 1, 2023

The solubility and thermodynamics of solvation due to solute–solvent interactions of glycine, DL-... more The solubility and thermodynamics of solvation due to solute–solvent interactions of glycine, DL-alanine, DL-serine, and DL-valine were determined in this study. Mainly, the transfer of Gibbs free energies from aqueous to aqueous sodium and potassium iodide salt solutions was considered, which were calculated by direct experimental solubility data and via theoretical calculations. The equilibrium solubilities were measured at 298.15 K using simple “formol titration”. Various important physicochemical factors like enthalpy of solvation, molar volume, molar mass, molar density, etc., in aqueous electrolyte solutions were calculated at standard temperature. The thermodynamic parameters were explained to conclude about the virtual stability of the zwitterionic solutes in aqueous salt mixtures. The factors that are associated with solubility were also explained and correlated with physical and thermodynamic point of view.

Research paper thumbnail of Exploring the Solubility and Solvation Thermodynamics of Coumarin in a Range of Aqua-Organic Solvents

New Journal of Chemistry, 2023

This study presents the solubility and solvation thermodynamics of coumarin in a range of aqua-or... more This study presents the solubility and solvation thermodynamics of coumarin in a range of aqua-organic solvent mixtures at various temperatures. The solubility order of coumarin was determined as follows: DMF > DMSO > ACN > H2O.

Research paper thumbnail of Thermodynamics and mechanisms of glycine solvation in aqueous NaCl and KCl solutions at 298.15 K

Russian Journal of Physical Chemistry A, Oct 13, 2015

In the present study the solubility of glycine in aqueous sodium chloride and potassium chloride ... more In the present study the solubility of glycine in aqueous sodium chloride and potassium chloride solution was determined under different experimental conditions using ‘formol titrimetry’ method. The thermodynamic parameters like standard transfer Gibbs energies and entropies have been evaluated at 298.15 K. Other important parameters like molar volume, densities, solvent diameter, etc., of the experimental solutions have also been determined in this study. The above mentioned parameters have been used to determine ∆t,ch0(i)i.e., chemical effects of the transfer Gibbs energies and T∆t,ch0(i)i.e., chemical effects of the transfer entropy. The solvation of glycine is influenced by different factors such as nature of the solute, interactions between solute and solvents, etc., which has been explained by different physical and analytical approach.

Research paper thumbnail of Transfer entropies of solvation of a series of homologous ï¡-amino acids in aqueous mixtures of protic ethylene glycol

BioChemistry: An Indian Journal, 2010

Standard transfer entropies, S0 (i) t i„ of a series of homologous ii-amino acids (i) like g... more Standard transfer entropies, S0 (i) t i„ of a series of homologous ii-amino acids (i) like glycine (gly), dl-alanine (ala), dl-ii-amino butyric acid (aba) and dl-nor-valine (nor-val) from water to aqueous mixture of protic ethylene glycol (EG) with 0, 20, 40, 60, 80 and 100wt%EG compositions have been evaluated at 25i‚°C. For this purpose the solubility of the amino acids measured using ‘formol titrimetryÂ’ at 15i‚°, 20i‚°, 30i‚°, and 35i‚°C and that of 25i‚°C reported earlier. S0 (i) t i„ of the acids as well as their chemical effects, S0 (i) t ,ch i„ obtained after correcting for the cavity effects, S0 (i) t ,cav i„ and dipole-dipole interaction effect, S0 (i) t ,di€­d i„ . The chemical contributions of transfer entropies, T S0 (i) t ,ch i„ of amino acids are guided by the superimposed effects of increased acidity affecting the RCOO- part, decreased basicity affecting the NH3 + part and decreased HbH affecting Ri‚¢ group of Zwitterionic amino acids Ri‚¢CH(NH3 +)COO-, and the complex structural interactions of EG-H2Omixtures.

Research paper thumbnail of Solvation Thermodynamics of DL-α-Amino Butyric Acid in Aqueous Sodium Sulfate Solvent System

Russian Journal of Physical Chemistry A

Research paper thumbnail of Effect of NH4+ and SO42− ions on the solubility and solvation thermodynamics of l-proline at different temperatures

Research paper thumbnail of Solubility and solvation thermodynamics of l-tryptophan in aqueous methanol solvent mixtures

Canadian Journal of Chemistry

This article presents mole fraction solubilities of l-tryptophan in binary aqueous methanol solve... more This article presents mole fraction solubilities of l-tryptophan in binary aqueous methanol solvent systems and applied them to estimate thermodynamical parameters like transfer Gibbs free energetics and entropies of solutions. The estimated thermodynamic energies were linked with interaction parameters like dipole–dipole interactions, enthalpy due to transfer of l-tryptophan from water to binary water–methanol solvent mixtures. The transfer Gibbs free energetics for chemical interactions and entropies for solvent–solvent interaction were calculated by mathematical relations. The chemical transfer energetics was applied to explain the probable stability of l-tryptophan in the mixed solvents. Many associated thermophysical parameters were also calculated at standard temperature (298.15 K).

Research paper thumbnail of Solubility and thermodynamical phenomenafor l-serine and l-isoleucine in chloride Salts of Na+ and K+ electrolytic media

Journal of Molecular Liquids

Research paper thumbnail of Solubility of á-amino butyric acid in water-NaNO3 mixture and analysis of related thermodynamic parameters

Analytical chemistry, an Indian journal, 2015

Solubility data of DL-a-amino butyric acid are obtained, using the ‘formal titrimetryÂ’ method... more Solubility data of DL-a-amino butyric acid are obtained, using the ‘formal titrimetryÂ’ method in water and aqueous solution with various sodium nitrate (NaNO3) concentrations in the temperatures 288.15, 293.15, 298.15, 303.15 and 308.15 K. The standard transfers Gibbs energies and entropies have been evaluated for this amino acid from water to aqueous mixture of sodium nitrate solution at 298.15 K. The chemical effects of the transfer Gibbs energies ( 0 ( ) , G i t ch i„ ), obtained by subtracting theoretically computed G0 (i) t i„ due to cavity and dipole-dipole interactions effects from the total transfer free energies, G (i) 0 t i„ .Again S (i) 0 t ,ch i”i„ have been evaluated after elimination of cavity effect and dipole-dipole interaction effects from total transfer ( T S (i) 0 t i„ ) entropies. The various solvent parameters as well as thermodynamic parameters likemolar volume, densities, dipole moment and solvent diameter of aqueous solution of sodium ni...

Research paper thumbnail of Solvation Chemistry of DL‐Nor‐Valine in Aqueous Mixture of Dipolar Aprotic N,N‐Dimethyl Formamide

Journal of the Chinese Chemical Society, 2014

In this article, we reported the solubilities of the amino acid DL‐nor‐valine (VAL) at five equid... more In this article, we reported the solubilities of the amino acid DL‐nor‐valine (VAL) at five equidistant temeratures i.e. from 15 to 35 °C in aqueous mixtures of N,N‐dimethyl formamide (DMF). The Standard free energies (ΔG (i)) and entropies (ΔS (i)) of transfer of VAL from water to aqueous mixture of cationophilic dipolar aprotic DMF have been evaluated at 25 °C. The transfer of Gibbs energies (ΔG (i)) and entropies (TΔS (i)) due to the chemical effects have been obtained after elimination of cavity effect, estimated by the scaled particle theory and dipole‐dipole interaction effects, computed by the used of Keesom‐orientation expression. The chemical contribution of transfer energetics of DL‐nor‐valine (VAL) are mainly guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMF mixtures as compared to that of reference solvent, water.

Research paper thumbnail of Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Non-aqueous Binary Mixtures of Protic Ethylene Glycol and Dipolar Aprotic Acetonitrile

Journal of Solution Chemistry, 2013

Standard transfer Gibbs energies left(UpdeltaGt0(i)right)\left( {\Updelta G_{t}^{0} (i)} \right)left(UpdeltaGt0(i)right)(ΔGt0(i)) and entro... more Standard transfer Gibbs energies left(UpdeltaGt0(i)right)\left( {\Updelta G_{t}^{0} (i)} \right)left(UpdeltaGt0(i)right)(ΔGt0(i)) and entropies left(UpdeltaSt0(i)right)\left( {\Updelta S_{t}^{0} (i)} \right)left(UpdeltaSt0(i)right)(ΔSt0(i)) of transfer of the homologous α-amino acids: glycine, dl-alanine, dl-α-amino butyric acid and dl-nor-valine (nor-val) from protic ethylene glycol (EG) to proton/cation-phobic dipolar aprotic acetonitrile (ACN) mixed solvents with 0, 20, 40, 60, 80 and 100 wt% ACN compositions have been determined at 25 °C. For this purpose solubilities of the α-amino acids were measured by “formol titrimetry” at 15, 20, 25, 30 and 35 °C. The chemical components of these Gibbs energies left(UpdeltaGt,rmch0(i)right)\left( {\Updelta G_{t,\rm{ch}}^{0} (i)} \right)left(UpdeltaGt,rmch0(i)right)(ΔGt,ch0(i)) and entropies left(rmTUpdeltaSt,rmch0(i)right)\left( {{\rm T}\Updelta S_{t,\rm{ch}}^{0} (i)} \right)left(rmTUpdeltaSt,rmch0(i)right)(TΔSt,ch0(i)) of the homologous α-amino acids have been computed by subtracting the cavity effects and dipole–dipole interaction effects. The chemical contributions of transfer energetics of these homologous α-amino acids are determined by different types of interactions. The decreased acidity, basicity, H-bonding capacity, solvophilic solvation and solvophobic solvation and increased dispersion and soft–soft interaction of ethylene glycol and acetonitrile mixtures, as compared to EG, are the guiding factors. The characteristics of the solvation thermodynamics of α-amino acids in protic EG and proton/cation-philic dipolar aprotic DMF mixed solvent systems studied earlier are also discussed here for comparison.

Research paper thumbnail of Thermodynamic Solvation of a-Amino Butyric Acid in Aqueous Mixture of Dipolar Aprotic N,N-Dimethyl formamide

Asian Journal of Chemistry, 2013

Standard transfer free energies (∆Gt 0 (i)) and entropies (∆St 0 (i)) of α-amino butyric acid fro... more Standard transfer free energies (∆Gt 0 (i)) and entropies (∆St 0 (i)) of α-amino butyric acid from water to aqueous mixture of cationophilic dipolar aprotic N,N-dimethyl formamide have been evaluated at 25 ºC from solubility measurements of the amino acid at five equidistant temperatures i.e., from 15 to 35 ºC. The chemical effects of the transfer Gibbs energies [∆G 0 t,ch(i)] and entropies of transfer [T∆S 0 t,ch(i)] have been obtained after elimination of cavity effect, estimated by the scaled particle theory and dipole-dipole interaction effects, computed by the use of Keesom-orientation expression. The chemical contribution of transfer energetics of α-amino butyric acid are guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMF mixtures as compared to that of reference solvent, water.

Research paper thumbnail of Solubility and transfer Gibbs free energetics of glycine, DL-alanine, DL-nor-valine and DL-serine in aqueous sodium fluoride and potassium fluoride solutions at 298.15 K

The experimental saturated solubilities of glycine, DL-alanine, DL-nor-valine and DL-serine in aq... more The experimental saturated solubilities of glycine, DL-alanine, DL-nor-valine and DL-serine in aqueous mixtures of NaF and KF solutions at 298.15 K are measured by using an analytical ‘formol titrimetry’ method. Subsequently, the standard transfer Gibbs free energy, enthalpy for cavity formation, Gibbs free energy for cavity formation and Gibbs free energy for dipole-dipole interaction have been computed. The chemical contribution for the standard transfer Gibbs free energies for the experimental amino acids have been obtained by subtracting the cavity effects and dipole-dipole interaction effects from the total standard transfer Gibbs free energy (∆ (i)). The stability of the studied amino acids in aqueous NaF and KF in terms of thermodynamic parameters are discussed and compared.

Research paper thumbnail of Approaches on Carbon Free Energy Source from Water Splitting

Oriental journal of physical sciences, Jul 15, 2023

Energy from sunlight is most plentiful renewable energy resource, on condition that earth with as... more Energy from sunlight is most plentiful renewable energy resource, on condition that earth with as much as necessary power that is proficient of taking care of all desires of living being. But that energy is not always usable to us for modern society. With rising population, modern scientific requirements and other development, there must be increase in energy demand day by day. Scientifically developed procedures that may use sunlight to split water into hydrogen and oxygen may be clue to solve this concern, since water splitting generates a perfect non-hazardous fuel and must be low in cost. Thus, it is critical to research for new and economical technologies for water splitting. Since 1970 1 research has been going on making suitable device for producing H 2 and O 2. With the ongoing power of technology several economic effective strategies 2-5 have also been developed. Potency, cost value and longevity are the three major concerning factors during developing any new photochemical device. On the basis of these several approaches were made regarding this water splitting (WS) research. One of the most convenient approaches in this field is plasmonic solar approach in which surface plasmons are the basic soldier for controlling the both functions viz electronic and optical.Recent research has revealed that when exposed to photons of Sun-like intensity, plasmonic photoexcited nanostructures, as opposed to metal structures, exhibit comparatively significant photocatalytic activity. 6 In silicon based WS devices light scattering 7 controls mode of operation. Different metal based photoelectrodes (Ni, Ag, Mo etc) were developed since few years. During the solar WS reaction, semiconductor photo electrodes are involved in intricate chemical, physical, & electrical processes that operate the photogenerated electron-hole pairs for redox reactions.

Research paper thumbnail of Solubility and the solution thermodynamics of l-proline in the aqueous binary mixture of NaCl and KCl solution

Journal of Molecular Liquids

Research paper thumbnail of A 5-aminoisophthalic acid low molecular weight gelator based novel semiconducting supramolecular Zn(ii)-metallogel: unlocking an efficient Schottky barrier diode for microelectronics

Nanoscale Advances

At room temperature, an electronic device featuring a Schottky barrier diode is facilitated by a ... more At room temperature, an electronic device featuring a Schottky barrier diode is facilitated by a supramolecular Zn(ii)-metallogel derived from the low molecular weight gelator, 5-aminoisophthalic acid.

Research paper thumbnail of Effect of uni-divalent electrolyte in the interaction associated with solubility for the predominant form of L-isoleucine and L-serine in aqueous media

Journal of Molecular Liquids, Jun 1, 2023

Research paper thumbnail of Recently Reported Ru-Metal Organic Coordination Complexes and Their Application (A Review)

Russian Journal of General Chemistry, Aug 1, 2022

Research paper thumbnail of Evaluation and correlation of solubility and solvation energetics of DL-phenylalanine and DL-serine in water and aqueous ethylene glycol solutions

Journal of Molecular Liquids, 2018

Evaluation and correlation of solubility and solvation thermodynamics of glycine, dl-alanine and ... more Evaluation and correlation of solubility and solvation thermodynamics of glycine, dl-alanine and dl-valine in aqueous sodium sulphate solutions at two different temperatures. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Molliq(2017),

Research paper thumbnail of Recent developed different structural nanomaterials and their performance for supercapacitor application

Applied Materials Today, Dec 1, 2017

Developments during the past decade, electrode materials have been tuned to the nanoscale and ele... more Developments during the past decade, electrode materials have been tuned to the nanoscale and electrolytes have gained an active role enabling more efficient storage mechanism; hence increasing the performance of supercapacitors manifold. In porous carbon materials with sub-nanometer pores, the desolvation of the ions leads to surprisingly high capacitances. Oxide materials store charge by surface redox reactions which are the foremost to the pseudo capacitive effect. Understanding the physical mechanisms underlying charge storage in these materials is important for further development of supercapacitors. This brief overview focuses on the different types of recent developed (asymmetric, pseudo) supercapacitors, experimental strategies, fabrication procedure, and electrochemical properties based on nanomaterials which have been reported recently for their high-quality performance, the relevant quantitative modeling history and the future of supercapacitor research and development.

Research paper thumbnail of Solvation thermodynamics of four amino acids in electrolytic solutions of sodium and potassium iodide salts at 298.15 K

Canadian Journal of Chemistry, Apr 1, 2023

The solubility and thermodynamics of solvation due to solute–solvent interactions of glycine, DL-... more The solubility and thermodynamics of solvation due to solute–solvent interactions of glycine, DL-alanine, DL-serine, and DL-valine were determined in this study. Mainly, the transfer of Gibbs free energies from aqueous to aqueous sodium and potassium iodide salt solutions was considered, which were calculated by direct experimental solubility data and via theoretical calculations. The equilibrium solubilities were measured at 298.15 K using simple “formol titration”. Various important physicochemical factors like enthalpy of solvation, molar volume, molar mass, molar density, etc., in aqueous electrolyte solutions were calculated at standard temperature. The thermodynamic parameters were explained to conclude about the virtual stability of the zwitterionic solutes in aqueous salt mixtures. The factors that are associated with solubility were also explained and correlated with physical and thermodynamic point of view.

Research paper thumbnail of Exploring the Solubility and Solvation Thermodynamics of Coumarin in a Range of Aqua-Organic Solvents

New Journal of Chemistry, 2023

This study presents the solubility and solvation thermodynamics of coumarin in a range of aqua-or... more This study presents the solubility and solvation thermodynamics of coumarin in a range of aqua-organic solvent mixtures at various temperatures. The solubility order of coumarin was determined as follows: DMF > DMSO > ACN > H2O.

Research paper thumbnail of Thermodynamics and mechanisms of glycine solvation in aqueous NaCl and KCl solutions at 298.15 K

Russian Journal of Physical Chemistry A, Oct 13, 2015

In the present study the solubility of glycine in aqueous sodium chloride and potassium chloride ... more In the present study the solubility of glycine in aqueous sodium chloride and potassium chloride solution was determined under different experimental conditions using ‘formol titrimetry’ method. The thermodynamic parameters like standard transfer Gibbs energies and entropies have been evaluated at 298.15 K. Other important parameters like molar volume, densities, solvent diameter, etc., of the experimental solutions have also been determined in this study. The above mentioned parameters have been used to determine ∆t,ch0(i)i.e., chemical effects of the transfer Gibbs energies and T∆t,ch0(i)i.e., chemical effects of the transfer entropy. The solvation of glycine is influenced by different factors such as nature of the solute, interactions between solute and solvents, etc., which has been explained by different physical and analytical approach.

Research paper thumbnail of Transfer entropies of solvation of a series of homologous ï¡-amino acids in aqueous mixtures of protic ethylene glycol

BioChemistry: An Indian Journal, 2010

Standard transfer entropies, S0 (i) t i„ of a series of homologous ii-amino acids (i) like g... more Standard transfer entropies, S0 (i) t i„ of a series of homologous ii-amino acids (i) like glycine (gly), dl-alanine (ala), dl-ii-amino butyric acid (aba) and dl-nor-valine (nor-val) from water to aqueous mixture of protic ethylene glycol (EG) with 0, 20, 40, 60, 80 and 100wt%EG compositions have been evaluated at 25i‚°C. For this purpose the solubility of the amino acids measured using ‘formol titrimetryÂ’ at 15i‚°, 20i‚°, 30i‚°, and 35i‚°C and that of 25i‚°C reported earlier. S0 (i) t i„ of the acids as well as their chemical effects, S0 (i) t ,ch i„ obtained after correcting for the cavity effects, S0 (i) t ,cav i„ and dipole-dipole interaction effect, S0 (i) t ,di€­d i„ . The chemical contributions of transfer entropies, T S0 (i) t ,ch i„ of amino acids are guided by the superimposed effects of increased acidity affecting the RCOO- part, decreased basicity affecting the NH3 + part and decreased HbH affecting Ri‚¢ group of Zwitterionic amino acids Ri‚¢CH(NH3 +)COO-, and the complex structural interactions of EG-H2Omixtures.

Research paper thumbnail of Solvation Thermodynamics of DL-α-Amino Butyric Acid in Aqueous Sodium Sulfate Solvent System

Russian Journal of Physical Chemistry A

Research paper thumbnail of Effect of NH4+ and SO42− ions on the solubility and solvation thermodynamics of l-proline at different temperatures

Research paper thumbnail of Solubility and solvation thermodynamics of l-tryptophan in aqueous methanol solvent mixtures

Canadian Journal of Chemistry

This article presents mole fraction solubilities of l-tryptophan in binary aqueous methanol solve... more This article presents mole fraction solubilities of l-tryptophan in binary aqueous methanol solvent systems and applied them to estimate thermodynamical parameters like transfer Gibbs free energetics and entropies of solutions. The estimated thermodynamic energies were linked with interaction parameters like dipole–dipole interactions, enthalpy due to transfer of l-tryptophan from water to binary water–methanol solvent mixtures. The transfer Gibbs free energetics for chemical interactions and entropies for solvent–solvent interaction were calculated by mathematical relations. The chemical transfer energetics was applied to explain the probable stability of l-tryptophan in the mixed solvents. Many associated thermophysical parameters were also calculated at standard temperature (298.15 K).

Research paper thumbnail of Solubility and thermodynamical phenomenafor l-serine and l-isoleucine in chloride Salts of Na+ and K+ electrolytic media

Journal of Molecular Liquids

Research paper thumbnail of Solubility of á-amino butyric acid in water-NaNO3 mixture and analysis of related thermodynamic parameters

Analytical chemistry, an Indian journal, 2015

Solubility data of DL-a-amino butyric acid are obtained, using the ‘formal titrimetryÂ’ method... more Solubility data of DL-a-amino butyric acid are obtained, using the ‘formal titrimetryÂ’ method in water and aqueous solution with various sodium nitrate (NaNO3) concentrations in the temperatures 288.15, 293.15, 298.15, 303.15 and 308.15 K. The standard transfers Gibbs energies and entropies have been evaluated for this amino acid from water to aqueous mixture of sodium nitrate solution at 298.15 K. The chemical effects of the transfer Gibbs energies ( 0 ( ) , G i t ch i„ ), obtained by subtracting theoretically computed G0 (i) t i„ due to cavity and dipole-dipole interactions effects from the total transfer free energies, G (i) 0 t i„ .Again S (i) 0 t ,ch i”i„ have been evaluated after elimination of cavity effect and dipole-dipole interaction effects from total transfer ( T S (i) 0 t i„ ) entropies. The various solvent parameters as well as thermodynamic parameters likemolar volume, densities, dipole moment and solvent diameter of aqueous solution of sodium ni...

Research paper thumbnail of Solvation Chemistry of DL‐Nor‐Valine in Aqueous Mixture of Dipolar Aprotic N,N‐Dimethyl Formamide

Journal of the Chinese Chemical Society, 2014

In this article, we reported the solubilities of the amino acid DL‐nor‐valine (VAL) at five equid... more In this article, we reported the solubilities of the amino acid DL‐nor‐valine (VAL) at five equidistant temeratures i.e. from 15 to 35 °C in aqueous mixtures of N,N‐dimethyl formamide (DMF). The Standard free energies (ΔG (i)) and entropies (ΔS (i)) of transfer of VAL from water to aqueous mixture of cationophilic dipolar aprotic DMF have been evaluated at 25 °C. The transfer of Gibbs energies (ΔG (i)) and entropies (TΔS (i)) due to the chemical effects have been obtained after elimination of cavity effect, estimated by the scaled particle theory and dipole‐dipole interaction effects, computed by the used of Keesom‐orientation expression. The chemical contribution of transfer energetics of DL‐nor‐valine (VAL) are mainly guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMF mixtures as compared to that of reference solvent, water.

Research paper thumbnail of Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Non-aqueous Binary Mixtures of Protic Ethylene Glycol and Dipolar Aprotic Acetonitrile

Journal of Solution Chemistry, 2013

Standard transfer Gibbs energies left(UpdeltaGt0(i)right)\left( {\Updelta G_{t}^{0} (i)} \right)left(UpdeltaGt0(i)right)(ΔGt0(i)) and entro... more Standard transfer Gibbs energies left(UpdeltaGt0(i)right)\left( {\Updelta G_{t}^{0} (i)} \right)left(UpdeltaGt0(i)right)(ΔGt0(i)) and entropies left(UpdeltaSt0(i)right)\left( {\Updelta S_{t}^{0} (i)} \right)left(UpdeltaSt0(i)right)(ΔSt0(i)) of transfer of the homologous α-amino acids: glycine, dl-alanine, dl-α-amino butyric acid and dl-nor-valine (nor-val) from protic ethylene glycol (EG) to proton/cation-phobic dipolar aprotic acetonitrile (ACN) mixed solvents with 0, 20, 40, 60, 80 and 100 wt% ACN compositions have been determined at 25 °C. For this purpose solubilities of the α-amino acids were measured by “formol titrimetry” at 15, 20, 25, 30 and 35 °C. The chemical components of these Gibbs energies left(UpdeltaGt,rmch0(i)right)\left( {\Updelta G_{t,\rm{ch}}^{0} (i)} \right)left(UpdeltaGt,rmch0(i)right)(ΔGt,ch0(i)) and entropies left(rmTUpdeltaSt,rmch0(i)right)\left( {{\rm T}\Updelta S_{t,\rm{ch}}^{0} (i)} \right)left(rmTUpdeltaSt,rmch0(i)right)(TΔSt,ch0(i)) of the homologous α-amino acids have been computed by subtracting the cavity effects and dipole–dipole interaction effects. The chemical contributions of transfer energetics of these homologous α-amino acids are determined by different types of interactions. The decreased acidity, basicity, H-bonding capacity, solvophilic solvation and solvophobic solvation and increased dispersion and soft–soft interaction of ethylene glycol and acetonitrile mixtures, as compared to EG, are the guiding factors. The characteristics of the solvation thermodynamics of α-amino acids in protic EG and proton/cation-philic dipolar aprotic DMF mixed solvent systems studied earlier are also discussed here for comparison.

Research paper thumbnail of Thermodynamic Solvation of a-Amino Butyric Acid in Aqueous Mixture of Dipolar Aprotic N,N-Dimethyl formamide

Asian Journal of Chemistry, 2013

Standard transfer free energies (∆Gt 0 (i)) and entropies (∆St 0 (i)) of α-amino butyric acid fro... more Standard transfer free energies (∆Gt 0 (i)) and entropies (∆St 0 (i)) of α-amino butyric acid from water to aqueous mixture of cationophilic dipolar aprotic N,N-dimethyl formamide have been evaluated at 25 ºC from solubility measurements of the amino acid at five equidistant temperatures i.e., from 15 to 35 ºC. The chemical effects of the transfer Gibbs energies [∆G 0 t,ch(i)] and entropies of transfer [T∆S 0 t,ch(i)] have been obtained after elimination of cavity effect, estimated by the scaled particle theory and dipole-dipole interaction effects, computed by the use of Keesom-orientation expression. The chemical contribution of transfer energetics of α-amino butyric acid are guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMF mixtures as compared to that of reference solvent, water.

Research paper thumbnail of Solubility and transfer Gibbs free energetics of glycine, DL-alanine, DL-nor-valine and DL-serine in aqueous sodium fluoride and potassium fluoride solutions at 298.15 K

The experimental saturated solubilities of glycine, DL-alanine, DL-nor-valine and DL-serine in aq... more The experimental saturated solubilities of glycine, DL-alanine, DL-nor-valine and DL-serine in aqueous mixtures of NaF and KF solutions at 298.15 K are measured by using an analytical ‘formol titrimetry’ method. Subsequently, the standard transfer Gibbs free energy, enthalpy for cavity formation, Gibbs free energy for cavity formation and Gibbs free energy for dipole-dipole interaction have been computed. The chemical contribution for the standard transfer Gibbs free energies for the experimental amino acids have been obtained by subtracting the cavity effects and dipole-dipole interaction effects from the total standard transfer Gibbs free energy (∆ (i)). The stability of the studied amino acids in aqueous NaF and KF in terms of thermodynamic parameters are discussed and compared.

Research paper thumbnail of Book 3: Chemistry in Everyday's Life

Research paper thumbnail of BOOK2: Solvation of Some Αamino Acids in Aquo-organic Binary Solvents

Research paper thumbnail of Chemistry of Water: Cradle of Life

The present book entitled " Chemistry of Water: Cradle of Life " deals with various aspects of wa... more The present book entitled " Chemistry of Water: Cradle of Life " deals with various aspects of water including its chemical and physical properties, chemistry of water, water quality parameters, water pollution and its prevention, its impact in the environment as well as in our everyday's life and many others new informations about water structure. This summaries why water is a cradle of life. The book must be an imperative and valuable to the school level students, college level students, especially