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Catalytic effect of metal oxides on CO<sub>2</sub> absorption in an aqueous potassium salt of lysine
Dharmalingam, Sivanesan,Park, Ki Tae,Lee, Ju-Yeol,Park, Il-Gun,Jeong, Soon Kwan THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.68 No.-
<P><B>Abstract</B></P> <P>We report the catalytic effects of metal oxides on the CO<SUB>2</SUB> absorption rate in an aqueous potassium salt of <SMALL>L</SMALL>-lysine-HCl using the vapor liquid equilibrium method. The best CO<SUB>2</SUB> absorption rate obtained through testing metal oxides in a highly concentrated potassium salt of amino acids (2.0M) was identified using CuO. The recyclability of the metal oxides was tested over three cycles. The catalyst CuO was found to enhance the absorption rate of CO<SUB>2</SUB> by 61%. A possible mechanism was proposed based on NMR spectroscopy studies. Further, the effect of change in liquid absorbent viscosity on CO<SUB>2</SUB> absorption is discussed.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Catalytic effect of metal oxides on CO2 absorption in an aqueous potassium salt of lysine
Sivanesan Dharmalingam,박기태,이주열,박일건,정순관 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-
We report the catalytic effects of metal oxides on the CO2 absorption rate in an aqueous potassium salt of l-lysine-HCl using the vapor liquid equilibrium method. The best CO2 absorption rate obtained through testing metal oxides in a highly concentrated potassium salt of amino acids (2.0 M) was identified using CuO. The recyclability of the metal oxides was tested over three cycles. The catalyst CuO was found to enhance the absorption rate of CO2 by 61%. A possible mechanism was proposed based on NMR spectroscopy studies. Further, the effect of change in liquid absorbent viscosity on CO2 absorption is discussed.
Synthesis of Asymmetric Pyrazoline Derivatives from Phenylthiophenechalcones; DFT Mechanistic Study
Aboelnaga, Asmaa,Mansour, Eman,Ahmed, Hoda. A.,Hagar, Mohamed Korean Chemical Society 2021 대한화학회지 Vol.65 No.2
New phenylthiophenechalcones,1-(biphenyl-4-yl)-3-(5-phenylthiophen-2-yl)prop-2-en-1-one (3a) and 3-(5-phenylthiophen-2-yl)-1-(4-(piperidin-1-yl) phenyl) prop-2-en-1-one (3b) were synthesized, next, their treatment with thiosemicarbazide in ethanol afforded their pyrazoline derivatives (4a) and (4b), respectively. The molecular structures of the synthesized compounds were confirmed via elemental analysis, FT-IR, 1H, 13C NMR and mass spectroscopy. The geometrical elucidation of four suggested conformers has been studied for these compounds. DFT calculations have been performed to study the stability and the structural parameters of the predicted conformers and revealed that orientation of the biphenyl and the phenylthiophene moieties affect the stability of the estimated conformers of the synthesized chalcones and pyrazoline. Moreover, two reaction mechanisms have been proposed to illustrate the reaction products and the DFT calculations have been used to confirm the reaction mechanism of the pyrazoline compounds.
Mohsin Kazmi,Nadeem Feroze,Shahid Naveed,Syed Hassan Javed 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.10
Deletion of Cu(II) from synthetic solution was investigated using ground Prunus Amygdalus shell (GPAS). FTIR revealed the probable functional groups for the binding of Cu(II). XRD revealed amorphous nature of the GPAS. SEM analysis furnished microscopic details of GPAS. GPAS size analysis was done using seven ASTM screens and three mean diameters, namely mass mean, volume mean and volume surface mean diameters. Kinetic study consisted of pseudo-first and pseudo-second order kinetics. Langmuir and Freundlich isotherms were used to elucidate the isotherm study of uptake of Cu(II) onto GPAS. Trend of Scatchard was used to verify the applicability of the Freundlich model, while D-R model helped to determine the nature of biosorption. A detailed analysis for rate controlling step was made. Various mean diameters were used to estimate the diffusion coefficient for the biosorption of Cu(II) onto GPAS.
Reaction Mechanism of Partial Oxidation of Methane to Synthesis Gas over Supported Ni Catalysts
Kim, Sang-Bum,Kim, Young-Kook,Lim, Yun-Su,Kim, Myung-Soo,Hahm, Hyun-Sik 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.6
A mechanistic study on the partial oxidation of methane to synthesis gas (H₂ and CO) was conducted with supported nickel catalysts. To investigate the reaction mechanism, pulse experiments, O₂-TPD, and a comparison of the moles of reactants and products were carried out. From the O₂-TPD experiment, it was observed that the active catalyst in the synthesis gas production desorbed oxygen at a lower temperature. In the pulse experiment, the temperature of the top of the catalyst bed increased with the pulses, whereas the temperature of the bottom decreased. This suggests that there are two kinds of reactions, that is, the total oxidation of methane (exothermic) at the top and reforming reactions (endothermic) at the bottom. From the comparison of the moles of reactants and products, it was found that the moles of CO₂, CH₄, H₂O decreased as the moles of H₂ and CO increased. The results support the mechanism that synthesis gas is produced through a two-step reaction mechanism: the total oxidation of methane to CO₂ and H₂O takes place first, followed by the reforming reaction of the produced CO₂ and H₂O with residual CH₄ to form synthesis gas.
Influence of Solution pH on Drug Release from Ionic Hydrogel Lens
김근희,김혁정,노혜란 한국고분자학회 2019 Macromolecular Research Vol.27 No.2
Hydrogel contact lenses have shown the possibility for uses in ophthalmological treatment for the last decades. Moreover, structural changes responsive to solution pH have given further applications toward more complicated drug delivery for physiological and pathological states of a wearer. However, unpredicted variables, swelling degree, and polymer degeneration, have been hurdles for the evaluation and quantification of a designed pharmaceutic system. Many scientists believe understanding empirical/semi-empirical mechanisms behind the drug release can offer simple solutions to quantify and furthermore control the drug release. In this study, we developed silicon-copolymerized hydrogel contact lenses with various functional monomers for delivery of hydroxypropyl methylcellulose, one of the commonly used dry eye drugs. Under the physiological pH, the prepared hydrogels showed different swelling reactions in response to ionic interaction. In addition, analysis of the pH sensitivity and maximum release amounts against the artificial tear pH suggested possible molecular changes in the functional groups and swelling behaviors. Accordingly, the mathematical parameters were calculated to better understand the drug release mechanism from hydrogels. By evaluating these parameters, the primary rate-limiting factors of the silicone hydrogel contact lenses were determined at the investigated pH. These results, with the simple mechanistic study, imply the potentials of silicone hydrogel contact lens in controlled drug delivery under the physiological conditions.