In this research, N-butyl-pyridinium tetrafluoroborate ([BPy][BF4]) ionic liquid (IL) was synthes... more In this research, N-butyl-pyridinium tetrafluoroborate ([BPy][BF4]) ionic liquid (IL) was synthesized and characterized by 1H-NMR, 13C-NMR, and FT-IR spectroscopy. The synthesized ionic liquid was employed as an extractive agent for the removal of dibenzothiophene (DBT), a typical organosulfur pollutant from the organic medium. The effect of extractive desulfurization on a model fuel with DBT was investigated. The impact of operating parameters, i.e., temperature, extraction time, IL-to-fuel ratio, and fuel to oxidizing agent ratio, on the extraction efficiency was investigated. It was observed that the IL to model fuel ratio and the H2O2 dosage have significant effects on desulfurization efficiency. An 89.49% DBT removal efficiency was obtained at a temperature of 30 °C after 35 min of extraction when the volume ratio of IL:model fuel:H2O2 was 1:1:0.04. A density functional theory (DFT) study was carried out to investigate the interactions between the IL and the sulfur-containing compounds DBT/DBTO2.
Abstract We report on a new 16 microcantilever sensor system for performing sensing experiments i... more Abstract We report on a new 16 microcantilever sensor system for performing sensing experiments in liquid or gas. The system uses two 8-microcantilever arrays that are held in a sensor cell. The microcantilever deflections are monitored by oscillating two focused optical beams over the microcantilevers such that only one microcantilever is illuminated at one time and each microcantilever is illuminated approximately once per second. The optical beams are moved using a motorized translation stage. The reflected optical beams are detected by a two-axis photo-sensitive detector (PSD) producing a series of two eight peak shaped patterns. The raw data from both the PSD and the translation stage are used to fold the peak shaped patterns from each array one on top of the other so that the deflection of the cantilevers can be obtained from the change in height of each peak. The stability of the data was found to be highly dependent on the speed of the translation stage. When the translation stage was operated between 0.5 and 1 mm/s, the deflection of each microcantilever in units of surface stress was found to be highly reproducible and consistent between arrays. As a proof-of-purpose application, the system was used to detect Ca 2+ , Sr 2+ and Cs + ions using different calix[4]arene-based sensing layers. The results obtained were found to be reproducible and completely consistent with results obtained using a typical two single microcantilever sensor set-up.
Macrocyclic [1.1.1]metacyclophanes (MCPs) containing benzene and benzofuran rings linked by methy... more Macrocyclic [1.1.1]metacyclophanes (MCPs) containing benzene and benzofuran rings linked by methylene bridges and which can be viewed as calixarene analogues, have been synthesized by demethylation of [3.3.1]MCP-diones with trimethylsilyl iodide (TMSI) in MeCN. The [3.3.1]MCP-diones are synthesized by using (p-tolylsulfonyl)methyl isocyanide (TosMIC) as the cyclization reagent in N,N-dimethylformamide (DMF) with an excess of sodium hydride. (1)H NMR spectroscopy revealed that the remaining hydroxyl group on the phenyl ring is involved in intramolecular hydrogen bonding with the oxygen of one of the benzofuran rings. O-Methylation at the lower rim of monohydroxy[1.1.1]MCP in the presence of K2CO3 in acetone afforded a novel and inherently chiral calixarene analogue, namely the macrocyclic [1.1.1]MCP, possessing C1 symmetry. The inherent chirality of the two conformers was characterized by (1)H NMR spectroscopy by addition of an excess of Pirkle's chiral shift reagent, which cause...
Three organic ionophores () based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1... more Three organic ionophores () based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3-alternate conformation, bearing two pyridyl coordinating moieties (ortho for , meta for and para for ), have been synthesized and characterized in the solid state. The solvent extraction experiments with the metal ions showed that the ability of these derivatives to complex with Ag(+) appeared to be largely dependent on the position of the nitrogen atoms of the pyridyl ring. Two different complexation modes have been confirmed by (1)H NMR titration. Ionophore armed with two pyridyl moieties, complexed with Ag(+) cation through NAg(+)S interactions; however, ionophore and ionophore complexed with Ag(+) through metal-nitrogen (NAg(+)) interactions. The DFT computational studies were consistent with the experimental findings. These findings will provide us with an important rule to design an appropriate thiacalix[4]arene ionophore in the future. Another study on the possibility for appli...
In this research, N-butyl-pyridinium tetrafluoroborate ([BPy][BF4]) ionic liquid (IL) was synthes... more In this research, N-butyl-pyridinium tetrafluoroborate ([BPy][BF4]) ionic liquid (IL) was synthesized and characterized by 1H-NMR, 13C-NMR, and FT-IR spectroscopy. The synthesized ionic liquid was employed as an extractive agent for the removal of dibenzothiophene (DBT), a typical organosulfur pollutant from the organic medium. The effect of extractive desulfurization on a model fuel with DBT was investigated. The impact of operating parameters, i.e., temperature, extraction time, IL-to-fuel ratio, and fuel to oxidizing agent ratio, on the extraction efficiency was investigated. It was observed that the IL to model fuel ratio and the H2O2 dosage have significant effects on desulfurization efficiency. An 89.49% DBT removal efficiency was obtained at a temperature of 30 °C after 35 min of extraction when the volume ratio of IL:model fuel:H2O2 was 1:1:0.04. A density functional theory (DFT) study was carried out to investigate the interactions between the IL and the sulfur-containing compounds DBT/DBTO2.
Abstract We report on a new 16 microcantilever sensor system for performing sensing experiments i... more Abstract We report on a new 16 microcantilever sensor system for performing sensing experiments in liquid or gas. The system uses two 8-microcantilever arrays that are held in a sensor cell. The microcantilever deflections are monitored by oscillating two focused optical beams over the microcantilevers such that only one microcantilever is illuminated at one time and each microcantilever is illuminated approximately once per second. The optical beams are moved using a motorized translation stage. The reflected optical beams are detected by a two-axis photo-sensitive detector (PSD) producing a series of two eight peak shaped patterns. The raw data from both the PSD and the translation stage are used to fold the peak shaped patterns from each array one on top of the other so that the deflection of the cantilevers can be obtained from the change in height of each peak. The stability of the data was found to be highly dependent on the speed of the translation stage. When the translation stage was operated between 0.5 and 1 mm/s, the deflection of each microcantilever in units of surface stress was found to be highly reproducible and consistent between arrays. As a proof-of-purpose application, the system was used to detect Ca 2+ , Sr 2+ and Cs + ions using different calix[4]arene-based sensing layers. The results obtained were found to be reproducible and completely consistent with results obtained using a typical two single microcantilever sensor set-up.
Macrocyclic [1.1.1]metacyclophanes (MCPs) containing benzene and benzofuran rings linked by methy... more Macrocyclic [1.1.1]metacyclophanes (MCPs) containing benzene and benzofuran rings linked by methylene bridges and which can be viewed as calixarene analogues, have been synthesized by demethylation of [3.3.1]MCP-diones with trimethylsilyl iodide (TMSI) in MeCN. The [3.3.1]MCP-diones are synthesized by using (p-tolylsulfonyl)methyl isocyanide (TosMIC) as the cyclization reagent in N,N-dimethylformamide (DMF) with an excess of sodium hydride. (1)H NMR spectroscopy revealed that the remaining hydroxyl group on the phenyl ring is involved in intramolecular hydrogen bonding with the oxygen of one of the benzofuran rings. O-Methylation at the lower rim of monohydroxy[1.1.1]MCP in the presence of K2CO3 in acetone afforded a novel and inherently chiral calixarene analogue, namely the macrocyclic [1.1.1]MCP, possessing C1 symmetry. The inherent chirality of the two conformers was characterized by (1)H NMR spectroscopy by addition of an excess of Pirkle's chiral shift reagent, which cause...
Three organic ionophores () based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1... more Three organic ionophores () based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3-alternate conformation, bearing two pyridyl coordinating moieties (ortho for , meta for and para for ), have been synthesized and characterized in the solid state. The solvent extraction experiments with the metal ions showed that the ability of these derivatives to complex with Ag(+) appeared to be largely dependent on the position of the nitrogen atoms of the pyridyl ring. Two different complexation modes have been confirmed by (1)H NMR titration. Ionophore armed with two pyridyl moieties, complexed with Ag(+) cation through NAg(+)S interactions; however, ionophore and ionophore complexed with Ag(+) through metal-nitrogen (NAg(+)) interactions. The DFT computational studies were consistent with the experimental findings. These findings will provide us with an important rule to design an appropriate thiacalix[4]arene ionophore in the future. Another study on the possibility for appli...
Uploads
Papers by Shofiur Rahman