Dipak Sen | Kyungpook National University (original) (raw)
Papers by Dipak Sen
Fluid Phase Equilibria, 2009
The Journal of Physical Chemistry C, 2011
The extraframework gallium cations Ga 5 7þ , Ga þ , Ga 2þ , and Ga 3þ have been introduced into z... more The extraframework gallium cations Ga 5 7þ , Ga þ , Ga 2þ , and Ga 3þ have been introduced into zeolite Y. Ga,Tl-Y (Ga 42 Tl 9.3-Y or |(Ga 5 7þ) 5.8 Ga þ 6.6 Ga 2þ 4.8 Ga 3þ 1.5 Tl þ 9.3 |[Si 121 Al 71 O 384 ]-FAU) was prepared by the reaction of Tl 71-Y with Ga 0 under anhydrous conditions at 623 K. Its structure was determined by single-crystal crystallography with synchrotron X-radiation, and its composition was confirmed by energy dispersive X-ray analysis. The structure was refined in the space group Fd3m (a = 24.527(1) Å) with all 1126 unique data; the final error index, R 1 = 0.074, was calculated using only the 935 reflections with F o > 4σ(F o). Ga 0 reacted with 87% of the Tl þ ions in the zeolite, mostly to give Ga 5 7þ cations (centered tetrahedral, Ga-Ga = 2.512(3) Å). Ga 5 7þ centers 5.8 of the 8 sodalite cavities per unit cell; each terminal atom (at site I 0) bonds to three framework oxygen atoms of a double 6-ring (Ga-O = 2.050(5) Å and O-Ga-O = 99.0(2) o). The remaining Ga ions occupy five crystallographically distinct cationic sites: 2.3 Ga þ at site I 0 , 4.3 Ga þ at site II, 2.1 Ga 2þ at a second site II, 2.7 Ga 2þ at site III 0 , and 1.5 Ga 3þ at a second site I 0. The gallium ions at sites I 0 and II bond only to three 6-ring oxygen atoms; those at sites II and III 0 extend into the supercage and are easily accessible for sorption and catalysis. All Tl þ ions occupy supercage sites.
Microporous and Mesoporous Materials, 2013
Indium ions were introduced into zeolite X (FAU, Si/Al = 1.09) by anhydrous vapor-phase ion excha... more Indium ions were introduced into zeolite X (FAU, Si/Al = 1.09) by anhydrous vapor-phase ion exchange (VPIE). In 14 + (In 5 7+) 4 Na 50 + −X (approximate formula) was prepared by the reaction of fully dehydrated Na 92 + −X with 13 Torr of InCl(g) at T = 673 K. Its structure was determined using single-crystal crystallography with synchrotron Xradiation and was refined in the space group Fd3̅ (a = 24.996(1) Å) with all 1566 unique data; the final error index R 1 is 0.076. InCl(g) reacted with about 46% of the Na + ions in the zeolite, to give In 5 7+ (centered tetrahedral, In−In = 2.684(7) Å) and In + cations. In 5 7+ centers exactly half of the sodalite cavities, strongly suggesting alternating occupancy; each terminal atom (at site I′) bonds to three framework oxygen atoms of a double 6-ring (In−O = 2.248(6) Å and O−In−O = 102.2(2)°). The In + ions occupy four crystallographically distinct cationic sites: 5.8(3) per unit cell are in the sodalite cavities (site I′), 2.7(7) are near single 6-rings in the supercage (site II), 2.6(4) are near triple 4-rings in the supercage (site III′), and 3.1(5) are at second III′ site. About half of the Na + ions complete the filling of the single 6-rings; the remainder are at 12-ring sites. Most In + ions are easily approachable by guest molecules through the zeolite's 12-ring channel system.
Fluid Phase Equilibria, 2009
ABSTRACT This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and... more ABSTRACT This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and atmospheric pressure, for four binary systems composed of 1,2-dichloropropane (1,2-DCP) and four 2-alkoxyethanols. The 2-alkoxyethanols are 2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), 2-propoxyethanol (2-PE) and 2-butoxyethanol (2-BE). The VmE of the mixture has been shown positive for 2-ME, ‘s-shaped’ for all remaining systems, being negative at low and positive at high mole fraction of 1,2-DCP. The HmE values for all binary mixtures are also shown both positive at low and negative at high mole fraction of 1,2-DCP. The experimental results of HmE and VmE were fitted to Redlich–Kister equation to correlate the composition dependence of both excess properties. In this work, HmE data were also used to test the suitability of thermodynamic models (Wilson, NRTL, and UNIQUAC equations) based on local-composition theory. The results have been qualitatively discussed in terms of the polarity, self-association, and hydrogen bond among molecules.
![Research paper thumbnail of Introducing copper ions into zeolite Y by the thallous ion exchange method: single crystal structure of |Cu21.6Tl39.2|[Si121Al71O384]–FAU](https://attachments.academia-assets.com/89655444/thumbnails/1.jpg)
](Journal of Porous Materials, 2014
![Research paper thumbnail of Using CuCl vapor to ion exchange copper into zeolite Na–Y. Single crystal structure of |Cu30Na30Cl9|[Si121Al71O384]–FAU containing , Cu4Cl7+, Cu3Cl2+, and Cu2+](https://attachments.academia-assets.com/87668175/thumbnails/1.jpg)
](Microporous and Mesoporous Materials, 2014
A single crystal of zeolite Na-Y (FAU, Si/Al = 1.69) was treated with 1.6 Pa of anhydrous CuCl va... more A single crystal of zeolite Na-Y (FAU, Si/Al = 1.69) was treated with 1.6 Pa of anhydrous CuCl vapor at 623 K to yield Cu 30 Na 30 Cl 9-Y, in more detail jNa þ 30 Cu 2þ 2 ðCu 16 Cl 21þ 7 Þ 0:44 ðCu 4 Cl 7þ Þ 3.2 (Cu 3 Cl 2+) 2.8 |[Si 121 Al 71 O 384 ]-FAU. Its structure was determined crystallographically with synchrotron X-radiation and was refined in the space group Fd 3m (a = 24.644(1) Å) with all 1159 unique data; the final error index, R 1 = 0.064, was calculated using only the 1028 reflections with F o > 4r(F o). About 58% of the Na + ions in the zeolite were replaced by Cu 2+ , Cu 3 Cl 2+ , Cu 4 Cl 7+ , and Cu 16 Cl 21þ 7. Cu 4 Cl 7+ clusters center 41% of the sodalite cavities. Each is a centered tetrahedron with Cu-Cl = 2.931(3) Å; each terminal Cu 2+ ion bonds to three framework oxygen atoms of one ring of a double 6-ring with Cu-O = 2.222(4) Å and O-Cu-O = 110.8(5)°. Cu 16 Cl 21þ 7 clusters center 5.5% of the supercages. Four Cu + ions coordinate tetrahedrally to the chloride ion at its center (Cu-Cl = 2.66(11) Å). Each pair of these Cu + ions is bridged by a Cl À ion (Cu-Cl = 3.03(7) Å) along each tetrahedral edge. Each of these Cl À ions then coordinates to two Cu 2+ ions (Cu-Cl = 2.58(7) Å), each of which bonds to two 12-ring oxygen atoms (Cu-O = 2.35(3) and 2.41(4) Å with O-Cu-O = 67.8(8)°). About 17.5% of the 12-rings are centered by near trigonal planar Cu 3 Cl 2+ clusters (Cl À at the center, Cu-Cl-Cu = 117.2(3)°, and Cu-O = 2.52(4) Å). The single 6-rings are fully occupied by the remaining 2.0(5) Cu 2+ ions (Cu-O = 2.158(7) Å) and the 30.0(5) Na + ions (Na-O = 2.297(4) Å) per unit cell. Most of the Cu + and Cu 2+ ions in this material are accessible to guest molecules via the 12-ring channel system.
Korean Journal of Chemical Engineering, 2009
The excess molar volumes V m E and excess molar enthalpies H m E at T=298.15 K and atmospheric pr... more The excess molar volumes V m E and excess molar enthalpies H m E at T=298.15 K and atmospheric pressure for the binary systems {x1CH3CHClCH2Cl+x2CH3(CH2)n−1OH} (n=1 to 4) have been determined from density measurements by using a digital vibrating-tube densimeter and an isothermal calorimeter with flow-mixing cell, respectively. The 1-alkanols are methanol, ethanol, 1-propanol and 1-butanol. The V m E values of the binary mixtures increase with chain length of the 1-alkanols, resulting in entire negative V m E values for methanol, ‘S-shaped’ for ethanol, being nega- tive at low and positive at high mole fraction of 1,2-dichloropropane, and entire positive V m E values for both 1-propanol and 1- butanol. The H m E values for all systems show an endothermic effect (positive values), which exhibits a regular increase in magnitude when the number of -CH2- group in 1-alkanols is progressively increased and maximum values of H m E varying from 741 J·mol−1 (methanol) to 1,249 J·mol−1 (1-butanol) around x1=0.63−0.72. The experimental results of both H m E and V m E were fitted to Redlich-Kister equation to correlate the composition dependence. The experimental H m E data were also used to test the suitability of the Wilson, NRTL, and UNIQUAC models. The correlation of excess enthalpy data in these binary systems using UNIQUAC model provides the most appropriate results except for the system containing methanol.
Fluid Phase Equilibria, 2009
This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and atmosphe... more This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and atmospheric pressure, for four binary systems composed of 1,2-dichloropropane (1,2-DCP) and four 2-alkoxyethanols. The 2-alkoxyethanols are 2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), 2-propoxyethanol (2-PE) and 2-butoxyethanol (2-BE). The VmE of the mixture has been shown positive for 2-ME, ‘s-shaped’ for all remaining systems, being negative at low and positive at high mole fraction of 1,2-DCP. The HmE values for all binary mixtures are also shown both positive at low and negative at high mole fraction of 1,2-DCP. The experimental results of HmE and VmE were fitted to Redlich–Kister equation to correlate the composition dependence of both excess properties. In this work, HmE data were also used to test the suitability of thermodynamic models (Wilson, NRTL, and UNIQUAC equations) based on local-composition theory. The results have been qualitatively discussed in terms of the polarity, self-association, and hydrogen bond among molecules.
Fuel and Energy Abstracts, 2011
The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mi... more The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mixtures of {1,2-dichloropropane + methyl ethanoate, or +methyl propanoate, or +methyl butanoate} using a densimeter and an isothermal microcalorimeter, respectively, at T = 298.15 K and P = 1 atm. The HmE values of all binary mixtures are negative while VmE values are positive over the whole composition range. Both VmE and HmE values decrease with an increase of molecular weight of methyl esters. The maximum negative values of HmE for these binary systems were observed at x1 = 0.45–0.51. But, the maximum positive values of VmE lie at 0.49–0.65 mole fraction of 1,2-dichloropropane. The experimental results are discussed in terms of intermolecular interactions, particularly the self-association by dipole–dipole attraction between like and unlike molecules and formation of empty space around the molecules in the mixtures. The experimental data were correlated by three local-composition models (Wilson, NRTL, and UNIQUAC). Out of three models, NRTL equation provides the most appropriate correlating results except the binary system containing methyl butanoate.
Fluid Phase Equilibria, 2009
The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mi... more The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mixtures of {1,2-dichloropropane+methyl ethanoate, or +methyl propanoate, or +methyl butanoate} using a densimeter and an isothermal microcalorimeter, respectively, at T=298.15K and P=1atm. The HmE values of all binary mixtures are negative while VmE values are positive over the whole composition range. Both VmE and
Fluid Phase Equilibria, 2009
The Journal of Physical Chemistry C, 2011
The extraframework gallium cations Ga 5 7þ , Ga þ , Ga 2þ , and Ga 3þ have been introduced into z... more The extraframework gallium cations Ga 5 7þ , Ga þ , Ga 2þ , and Ga 3þ have been introduced into zeolite Y. Ga,Tl-Y (Ga 42 Tl 9.3-Y or |(Ga 5 7þ) 5.8 Ga þ 6.6 Ga 2þ 4.8 Ga 3þ 1.5 Tl þ 9.3 |[Si 121 Al 71 O 384 ]-FAU) was prepared by the reaction of Tl 71-Y with Ga 0 under anhydrous conditions at 623 K. Its structure was determined by single-crystal crystallography with synchrotron X-radiation, and its composition was confirmed by energy dispersive X-ray analysis. The structure was refined in the space group Fd3m (a = 24.527(1) Å) with all 1126 unique data; the final error index, R 1 = 0.074, was calculated using only the 935 reflections with F o > 4σ(F o). Ga 0 reacted with 87% of the Tl þ ions in the zeolite, mostly to give Ga 5 7þ cations (centered tetrahedral, Ga-Ga = 2.512(3) Å). Ga 5 7þ centers 5.8 of the 8 sodalite cavities per unit cell; each terminal atom (at site I 0) bonds to three framework oxygen atoms of a double 6-ring (Ga-O = 2.050(5) Å and O-Ga-O = 99.0(2) o). The remaining Ga ions occupy five crystallographically distinct cationic sites: 2.3 Ga þ at site I 0 , 4.3 Ga þ at site II, 2.1 Ga 2þ at a second site II, 2.7 Ga 2þ at site III 0 , and 1.5 Ga 3þ at a second site I 0. The gallium ions at sites I 0 and II bond only to three 6-ring oxygen atoms; those at sites II and III 0 extend into the supercage and are easily accessible for sorption and catalysis. All Tl þ ions occupy supercage sites.
Microporous and Mesoporous Materials, 2013
Indium ions were introduced into zeolite X (FAU, Si/Al = 1.09) by anhydrous vapor-phase ion excha... more Indium ions were introduced into zeolite X (FAU, Si/Al = 1.09) by anhydrous vapor-phase ion exchange (VPIE). In 14 + (In 5 7+) 4 Na 50 + −X (approximate formula) was prepared by the reaction of fully dehydrated Na 92 + −X with 13 Torr of InCl(g) at T = 673 K. Its structure was determined using single-crystal crystallography with synchrotron Xradiation and was refined in the space group Fd3̅ (a = 24.996(1) Å) with all 1566 unique data; the final error index R 1 is 0.076. InCl(g) reacted with about 46% of the Na + ions in the zeolite, to give In 5 7+ (centered tetrahedral, In−In = 2.684(7) Å) and In + cations. In 5 7+ centers exactly half of the sodalite cavities, strongly suggesting alternating occupancy; each terminal atom (at site I′) bonds to three framework oxygen atoms of a double 6-ring (In−O = 2.248(6) Å and O−In−O = 102.2(2)°). The In + ions occupy four crystallographically distinct cationic sites: 5.8(3) per unit cell are in the sodalite cavities (site I′), 2.7(7) are near single 6-rings in the supercage (site II), 2.6(4) are near triple 4-rings in the supercage (site III′), and 3.1(5) are at second III′ site. About half of the Na + ions complete the filling of the single 6-rings; the remainder are at 12-ring sites. Most In + ions are easily approachable by guest molecules through the zeolite's 12-ring channel system.
Fluid Phase Equilibria, 2009
ABSTRACT This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and... more ABSTRACT This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and atmospheric pressure, for four binary systems composed of 1,2-dichloropropane (1,2-DCP) and four 2-alkoxyethanols. The 2-alkoxyethanols are 2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), 2-propoxyethanol (2-PE) and 2-butoxyethanol (2-BE). The VmE of the mixture has been shown positive for 2-ME, ‘s-shaped’ for all remaining systems, being negative at low and positive at high mole fraction of 1,2-DCP. The HmE values for all binary mixtures are also shown both positive at low and negative at high mole fraction of 1,2-DCP. The experimental results of HmE and VmE were fitted to Redlich–Kister equation to correlate the composition dependence of both excess properties. In this work, HmE data were also used to test the suitability of thermodynamic models (Wilson, NRTL, and UNIQUAC equations) based on local-composition theory. The results have been qualitatively discussed in terms of the polarity, self-association, and hydrogen bond among molecules.
Journal of Porous Materials, 2014
Microporous and Mesoporous Materials, 2014
A single crystal of zeolite Na-Y (FAU, Si/Al = 1.69) was treated with 1.6 Pa of anhydrous CuCl va... more A single crystal of zeolite Na-Y (FAU, Si/Al = 1.69) was treated with 1.6 Pa of anhydrous CuCl vapor at 623 K to yield Cu 30 Na 30 Cl 9-Y, in more detail jNa þ 30 Cu 2þ 2 ðCu 16 Cl 21þ 7 Þ 0:44 ðCu 4 Cl 7þ Þ 3.2 (Cu 3 Cl 2+) 2.8 |[Si 121 Al 71 O 384 ]-FAU. Its structure was determined crystallographically with synchrotron X-radiation and was refined in the space group Fd 3m (a = 24.644(1) Å) with all 1159 unique data; the final error index, R 1 = 0.064, was calculated using only the 1028 reflections with F o > 4r(F o). About 58% of the Na + ions in the zeolite were replaced by Cu 2+ , Cu 3 Cl 2+ , Cu 4 Cl 7+ , and Cu 16 Cl 21þ 7. Cu 4 Cl 7+ clusters center 41% of the sodalite cavities. Each is a centered tetrahedron with Cu-Cl = 2.931(3) Å; each terminal Cu 2+ ion bonds to three framework oxygen atoms of one ring of a double 6-ring with Cu-O = 2.222(4) Å and O-Cu-O = 110.8(5)°. Cu 16 Cl 21þ 7 clusters center 5.5% of the supercages. Four Cu + ions coordinate tetrahedrally to the chloride ion at its center (Cu-Cl = 2.66(11) Å). Each pair of these Cu + ions is bridged by a Cl À ion (Cu-Cl = 3.03(7) Å) along each tetrahedral edge. Each of these Cl À ions then coordinates to two Cu 2+ ions (Cu-Cl = 2.58(7) Å), each of which bonds to two 12-ring oxygen atoms (Cu-O = 2.35(3) and 2.41(4) Å with O-Cu-O = 67.8(8)°). About 17.5% of the 12-rings are centered by near trigonal planar Cu 3 Cl 2+ clusters (Cl À at the center, Cu-Cl-Cu = 117.2(3)°, and Cu-O = 2.52(4) Å). The single 6-rings are fully occupied by the remaining 2.0(5) Cu 2+ ions (Cu-O = 2.158(7) Å) and the 30.0(5) Na + ions (Na-O = 2.297(4) Å) per unit cell. Most of the Cu + and Cu 2+ ions in this material are accessible to guest molecules via the 12-ring channel system.
Korean Journal of Chemical Engineering, 2009
The excess molar volumes V m E and excess molar enthalpies H m E at T=298.15 K and atmospheric pr... more The excess molar volumes V m E and excess molar enthalpies H m E at T=298.15 K and atmospheric pressure for the binary systems {x1CH3CHClCH2Cl+x2CH3(CH2)n−1OH} (n=1 to 4) have been determined from density measurements by using a digital vibrating-tube densimeter and an isothermal calorimeter with flow-mixing cell, respectively. The 1-alkanols are methanol, ethanol, 1-propanol and 1-butanol. The V m E values of the binary mixtures increase with chain length of the 1-alkanols, resulting in entire negative V m E values for methanol, ‘S-shaped’ for ethanol, being nega- tive at low and positive at high mole fraction of 1,2-dichloropropane, and entire positive V m E values for both 1-propanol and 1- butanol. The H m E values for all systems show an endothermic effect (positive values), which exhibits a regular increase in magnitude when the number of -CH2- group in 1-alkanols is progressively increased and maximum values of H m E varying from 741 J·mol−1 (methanol) to 1,249 J·mol−1 (1-butanol) around x1=0.63−0.72. The experimental results of both H m E and V m E were fitted to Redlich-Kister equation to correlate the composition dependence. The experimental H m E data were also used to test the suitability of the Wilson, NRTL, and UNIQUAC models. The correlation of excess enthalpy data in these binary systems using UNIQUAC model provides the most appropriate results except for the system containing methanol.
Fluid Phase Equilibria, 2009
This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and atmosphe... more This article presents the experimental data of VmE and HmE, obtained at T = 298.15 K and atmospheric pressure, for four binary systems composed of 1,2-dichloropropane (1,2-DCP) and four 2-alkoxyethanols. The 2-alkoxyethanols are 2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), 2-propoxyethanol (2-PE) and 2-butoxyethanol (2-BE). The VmE of the mixture has been shown positive for 2-ME, ‘s-shaped’ for all remaining systems, being negative at low and positive at high mole fraction of 1,2-DCP. The HmE values for all binary mixtures are also shown both positive at low and negative at high mole fraction of 1,2-DCP. The experimental results of HmE and VmE were fitted to Redlich–Kister equation to correlate the composition dependence of both excess properties. In this work, HmE data were also used to test the suitability of thermodynamic models (Wilson, NRTL, and UNIQUAC equations) based on local-composition theory. The results have been qualitatively discussed in terms of the polarity, self-association, and hydrogen bond among molecules.
Fuel and Energy Abstracts, 2011
The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mi... more The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mixtures of {1,2-dichloropropane + methyl ethanoate, or +methyl propanoate, or +methyl butanoate} using a densimeter and an isothermal microcalorimeter, respectively, at T = 298.15 K and P = 1 atm. The HmE values of all binary mixtures are negative while VmE values are positive over the whole composition range. Both VmE and HmE values decrease with an increase of molecular weight of methyl esters. The maximum negative values of HmE for these binary systems were observed at x1 = 0.45–0.51. But, the maximum positive values of VmE lie at 0.49–0.65 mole fraction of 1,2-dichloropropane. The experimental results are discussed in terms of intermolecular interactions, particularly the self-association by dipole–dipole attraction between like and unlike molecules and formation of empty space around the molecules in the mixtures. The experimental data were correlated by three local-composition models (Wilson, NRTL, and UNIQUAC). Out of three models, NRTL equation provides the most appropriate correlating results except the binary system containing methyl butanoate.
Fluid Phase Equilibria, 2009
The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mi... more The excess molar volumes VmE and excess molar enthalpies HmE have been measured for the binary mixtures of {1,2-dichloropropane+methyl ethanoate, or +methyl propanoate, or +methyl butanoate} using a densimeter and an isothermal microcalorimeter, respectively, at T=298.15K and P=1atm. The HmE values of all binary mixtures are negative while VmE values are positive over the whole composition range. Both VmE and