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Acid Dissociation Constant

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Yasuro Yamanaka – One of the best experts on this subject based on the ideXlab platform.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous alkanolpiperidine
    Energy Procedia, 2017
    Co-Authors: Yukio Furukawa, Hiroshi Sato, Hirotaka Koriki, Daiki Shuto, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of HCO 3 – /CO 3 2– , amine/protonated amine, carbamate/protonated carbamate, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature, and composition changes and CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 9 kinds of alkanolpiperidines using 13 C-NMR spectroscopy. The p K a values of these alkanolpiperidines were measured. The initial CO 2 capture rates of alkanolpiperidines do not depend on their p K a values, which is quite different from general trends of aqueous amine absorbents. The CO 2 release amount of each alkanolpiperidine increased with decreasing p K a, as a general trend. The CO 2 release amounts of 1-HE-PD, 2-HM-1-M-PD, 3-HM-1-M-PD, and 4-HM-1-M-PD increased with increasing concentrations.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamines
    Energy Procedia, 2014
    Co-Authors: Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of chemical species such as CO3/HCO3, amine/protonated amine, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature and concentration changes after CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 12 kinds of tertiary alkanolamines using 13C-NMR spectroscopy. A positive linear correlation was found between the CO 2 capture rates of alkanolamines having a normal hydroxyalkyl group and their p K a values. The CO 2 capture rates of alkanolamines having a branched hydroxyalkyl group were lower than those in this relationship. The CO 2 release amount of each tertiary aminamine increased with decreasing p K a, as a general trend. N – ethyldiethanolamine (EDEA) showed the largest CO 2 release amount and a moderately high rate of CO 2 absorption.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamine piperazine blends
    Energy Procedia, 2014
    Co-Authors: Miho Nitta, Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the concentration changes of chemical species such as CO32-/HCO3 , amine/protonated species, carbonate/protonated species, carbamates/protonated species, etc. in the course of CO2 absorption and those after CO2 release upon heating at 93 °C for 30 min for aqueous blends of piperazine (PZ) and each of 11 tertiary alkanolamines using 13C-NMR spectroscopy. The initial rates of CO2 capture of the blends ranged between 0.125 and 0.167 mol/L min, which were contributed by the rapid formation of PZ monocarbamate. A positive linear correlation was found between the CO2 release amounts of the blends upon heating and the pKa values of the tertiary alkanolamines. The CO2 content captured as PZ mono- and bis-carbamates decreased upon heating in the pKa range smaller than 9.34, whereas it increased upon heating in the pKa range higher than 9.55. A tertiary alkanolamine having the pKa smaller than 9.34 is promising as a blend amine with PZ.

Yukio Furukawa – One of the best experts on this subject based on the ideXlab platform.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous alkanolpiperidine
    Energy Procedia, 2017
    Co-Authors: Yukio Furukawa, Hiroshi Sato, Hirotaka Koriki, Daiki Shuto, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of HCO 3 – /CO 3 2– , amine/protonated amine, carbamate/protonated carbamate, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature, and composition changes and CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 9 kinds of alkanolpiperidines using 13 C-NMR spectroscopy. The p K a values of these alkanolpiperidines were measured. The initial CO 2 capture rates of alkanolpiperidines do not depend on their p K a values, which is quite different from general trends of aqueous amine absorbents. The CO 2 release amount of each alkanolpiperidine increased with decreasing p K a, as a general trend. The CO 2 release amounts of 1-HE-PD, 2-HM-1-M-PD, 3-HM-1-M-PD, and 4-HM-1-M-PD increased with increasing concentrations.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamines
    Energy Procedia, 2014
    Co-Authors: Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of chemical species such as CO3/HCO3, amine/protonated amine, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature and concentration changes after CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 12 kinds of tertiary alkanolamines using 13C-NMR spectroscopy. A positive linear correlation was found between the CO 2 capture rates of alkanolamines having a normal hydroxyalkyl group and their p K a values. The CO 2 capture rates of alkanolamines having a branched hydroxyalkyl group were lower than those in this relationship. The CO 2 release amount of each tertiary amine increased with decreasing p K a, as a general trend. N – ethyldiethanolamine (EDEA) showed the largest CO 2 release amount and a moderately high rate of CO 2 absorption.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamine piperazine blends
    Energy Procedia, 2014
    Co-Authors: Miho Nitta, Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the concentration changes of chemical species such as CO32-/HCO3 , amine/protonated species, carbonate/protonated species, carbamates/protonated species, etc. in the course of CO2 absorption and those after CO2 release upon heating at 93 °C for 30 min for aqueous blends of piperazine (PZ) and each of 11 tertiary alkanolamines using 13C-NMR spectroscopy. The initial rates of CO2 capture of the blends ranged between 0.125 and 0.167 mol/L min, which were contributed by the rapid formation of PZ monocarbamate. A positive linear correlation was found between the CO2 release amounts of the blends upon heating and the pKa values of the tertiary alkanolamines. The CO2 content captured as PZ mono- and bis-carbamates decreased upon heating in the pKa range smaller than 9.34, whereas it increased upon heating in the pKa range higher than 9.55. A tertiary alkanolamine having the pKa smaller than 9.34 is promising as a blend amine with PZ.

Kogoro Hayashi – One of the best experts on this subject based on the ideXlab platform.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamines
    Energy Procedia, 2014
    Co-Authors: Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of chemical species such as CO3/HCO3, amine/protonated amine, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature and concentration changes after CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 12 kinds of tertiary alkanolamines using 13C-NMR spectroscopy. A positive linear correlation was found between the CO 2 capture rates of alkanolamines having a normal hydroxyalkyl group and their p K a values. The CO 2 capture rates of alkanolamines having a branched hydroxyalkyl group were lower than those in this relationship. The CO 2 release amount of each tertiary amine increased with decreasing p K a, as a general trend. N – ethyldiethanolamine (EDEA) showed the largest CO 2 release amount and a moderately high rate of CO 2 absorption.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamine piperazine blends
    Energy Procedia, 2014
    Co-Authors: Miho Nitta, Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the concentration changes of chemical species such as CO32-/HCO3 , amine/protonated species, carbonate/protonated species, carbamates/protonated species, etc. in the course of CO2 absorption and those after CO2 release upon heating at 93 °C for 30 min for aqueous blends of piperazine (PZ) and each of 11 tertiary alkanolamines using 13C-NMR spectroscopy. The initial rates of CO2 capture of the blends ranged between 0.125 and 0.167 mol/L min, which were contributed by the rapid formation of PZ monocarbamate. A positive linear correlation was found between the CO2 release amounts of the blends upon heating and the pKa values of the tertiary alkanolamines. The CO2 content captured as PZ mono- and bis-carbamates decreased upon heating in the pKa range smaller than 9.34, whereas it increased upon heating in the pKa range higher than 9.55. A tertiary alkanolamine having the pKa smaller than 9.34 is promising as a blend amine with PZ.

Hiroshi Sato – One of the best experts on this subject based on the ideXlab platform.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous alkanolpiperidine
    Energy Procedia, 2017
    Co-Authors: Yukio Furukawa, Hiroshi Sato, Hirotaka Koriki, Daiki Shuto, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of HCO 3 – /CO 3 2– , amine/protonated amine, carbamate/protonated carbamate, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature, and composition changes and CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 9 kinds of alkanolpiperidines using 13 C-NMR spectroscopy. The p K a values of these alkanolpiperidines were measured. The initial CO 2 capture rates of alkanolpiperidines do not depend on their p K a values, which is quite different from general trends of aqueous amine absorbents. The CO 2 release amount of each alkanolpiperidine increased with decreasing p K a, as a general trend. The CO 2 release amounts of 1-HE-PD, 2-HM-1-M-PD, 3-HM-1-M-PD, and 4-HM-1-M-PD increased with increasing concentrations.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamines
    Energy Procedia, 2014
    Co-Authors: Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the formation rates of chemical species such as CO3/HCO3, amine/protonated amine, and carbonate/protonated carbonate in the course of CO 2 absorption at room temperature and concentration changes after CO 2 release upon heating at 93 °C for 30 min for aqueous solutions of 12 kinds of tertiary alkanolamines using 13C-NMR spectroscopy. A positive linear correlation was found between the CO 2 capture rates of alkanolamines having a normal hydroxyalkyl group and their p K a values. The CO 2 capture rates of alkanolamines having a branched hydroxyalkyl group were lower than those in this relationship. The CO 2 release amount of each tertiary amine increased with decreasing p K a, as a general trend. N – ethyldiethanolamine (EDEA) showed the largest CO 2 release amount and a moderately high rate of CO 2 absorption.

  • 13c nmr study of Acid Dissociation Constant pka effects on the co2 absorption and regeneration of aqueous tertiary alkanolamine piperazine blends
    Energy Procedia, 2014
    Co-Authors: Miho Nitta, Kogoro Hayashi, Yukio Furukawa, Hiroshi Sato, Yasuro Yamanaka
    Abstract:

    Abstract We have studied the concentration changes of chemical species such as CO32-/HCO3 , amine/protonated species, carbonate/protonated species, carbamates/protonated species, etc. in the course of CO2 absorption and those after CO2 release upon heating at 93 °C for 30 min for aqueous blends of piperazine (PZ) and each of 11 tertiary alkanolamines using 13C-NMR spectroscopy. The initial rates of CO2 capture of the blends ranged between 0.125 and 0.167 mol/L min, which were contributed by the rapid formation of PZ monocarbamate. A positive linear correlation was found between the CO2 release amounts of the blends upon heating and the pKa values of the tertiary alkanolamines. The CO2 content captured as PZ mono- and bis-carbamates decreased upon heating in the pKa range smaller than 9.34, whereas it increased upon heating in the pKa range higher than 9.55. A tertiary alkanolamine having the pKa smaller than 9.34 is promising as a blend amine with PZ.

Yahya Nural – One of the best experts on this subject based on the ideXlab platform.

  • synthesis biological properties and Acid Dissociation Constant of novel naphthoquinone triazole hybrids
    Bioorganic Chemistry, 2020
    Co-Authors: Yahya Nural, Sadin Ozdemir, Osman Doluca, Bunyamin Demir, Mustafa Serkan Yalcin, Hasan Atabey, Beyza Kanat, Selma Erat, Hayati Sari, Zeynel Seferoglu
    Abstract:

    Abstract A series of novel 1,4-naphthoquinone–triazole hybrids, N-(3-amino-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-2-(4-R-1H-1,2,3-triazol-1-yl)acetamide, was synthesized by click chemistry in the presence of sodium ascorbate and copper(II) sulfate pentahydrate in 81–94% yield. Various biological properties of the synthesized compounds including DNA binding/cleavage, antioxidant, antibacterial and antifungal properties were evaluated. The DNA binding study was performed using dsDNA and G-quadruplex DNA. All of the compounds showed fluorescence increase in the presence of DNA, regardless of the structure. Up to 2.9 and 2.5 times fluorescence increase upon incubation with double stranded or G-quadruplex DNA was detected for 5f and 5g, respectively. The docking studies performed on dsDNA and G-quadruplex structures suggested compounds’ mode of interactions were populated around the grooves. All of the compounds showed excellent DNA cleavage activity and 5e was almost degraded the plasmid DNA. The highest radical scavenging activity was obtained as 89.9% at 200 mg/L with 5d. However, the highest ferrous chelating activity was obtained as 68.1% at 200 mg/L with 5g. The compounds exhibited antimicrobial activity against Bacillus cereus, Legionella pneumophila subsp. pneumophila, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus hirae as bacteria strains and Candida albicans and Candida tropicalis as microfungus strains. The compounds exhibited antibacterial and antifungal activity in the range of 4–128 μg/mL and 16–128 μg/mL, respectively. The best antimicrobial activity was obtained with 5d and 5e with a MIC value of 4 μg/mL against Enterococcus hirae. The Acid Dissociation Constants (pKa) were determined potentiometrically in 20% (v/v) dimethyl sulfsulfoxide-water hydro-organic solvent at an ionic background of 0.1 mol/L of NaCl, at 25 ± 0.1 °C. Five pKa values were obtained for each ligand.

  • polysubstituted pyrrolidines linked to 1 2 3 triazoles synthesis crystal structure dft studies Acid Dissociation Constant drug likeness and anti proliferative activity
    Journal of Molecular Structure, 2020
    Co-Authors: Tuncay Ince, Bunyamin Demir, Hasan Atabey, Selma Erat, Riza Serttas, Nurgul Seferoglu, Suat Erdogan, Ertan Sahin, Yahya Nural
    Abstract:

    Abstract Novel pyrrolidines linked to 1,2,3-triazole derivatives, dimethyl 1-(2-(4-R-1H-1,2,3-triazol-1-yl)acetyl)-5,5-diphenylpyrrolidine-2,4-dicarboxylate, were synthesized in the presence of sodium ascorbate and copper (II) sulfate pentahydrate by click chemistry in excellent 89–95% yield. The 1H NMR, 13C NMR, DEPT, COSY, HMQC, FT-IR, HRMS and elemental analysis techniques were used for structural characterization. A single crystal X-ray diffraction study was performed in order to determine the stereochemistry of the compounds. The optimization geometry of the compounds was obtained by performing density functional theory. However, the global reactivity parameters were estimated from frontier molecular orbitals. The calculated global reactivity parameters showed that the most reactive compound was 4e and the least reactive compounds were 4a, 4c and 4d. The Acid Dissociation Constants were determined using potentiometric titrtitration in 20% (v/v) dimethyl sulfsulfoxide-water hydro-organic solvent at 25 ± 0.1 °C, and four Dissociation Constants relating nitrogen atoms were obtained for each ligand. Six synthesized compounds were screened for their in vitro anti-proliferative activities against human prostate cancer cells, all of which significantly reduced cell proliferation. One of the compounds 4d showed much more anti-proliferative potential relative to the others, delaying the cells at the DNA synthesis phase. The drug-likeness model score (DLS) calculations for all the synthesized compounds using MolSoft websites supported the experimental results of anti-proliferative bioactivity study, and 4d was found to be maximum DLS value of 1.01.

  • synthesis crystal structure dft studies Acid Dissociation Constant and antimicrobial activity of methyl 2 4 chlorophenyl 7a 4 chlorophenyl carbamothioyl 1 oxo 5 5 diphenyl 3 thioxo hexahydro 1h pyrrolo 1 2 e imidazole 6 carboxylate
    Journal of Molecular Structure, 2018
    Co-Authors: Yahya Nural, Nurgul Seferoglu, Ertan Sahin, Muge Gemili, Mahmut Ulger, Hayati Sari
    Abstract:

    Abstract A novel bicyclic thiohydantoin fused to pyrrolidine compound, methyl 2-(4-chlorophenyl)-7a-((4-chlorophenyl)carbamothioyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate, was synthesized by the cyclization reaction of dimethyl 5,5-diphenylpyrrolidine-2,4-dicarboxylate and 4-chlorophenyl isothiocyanate in the presence of 4-(dimethylamino)pyridine to form methyl 2-(4-chlorophenyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate with concomitant addition reaction of the 4-chlorophenyl isothiocyanate in 79% yield. The structural characterization was performed by NMR, FT-IR, MS and HRMS techniques, and the stereochemistry of the compound was determined by single crystal X-ray diffraction study. In addition, the molecular structure and 1H and 13C NMR chemical shifts of the compound were obtained with the density functional theory and Hartree-Fock calculations. Acid Dissociation Constants of the compound were determined using potentiometric titrtitration method in 25% (v/v) dimethyl sulfsulfoxide-water hydroorganic solvent at 25 ± 0.1 °C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Four Acid Dissociation Constants were obtained for the compound, and we suggest that these Acid Dissociation Constants are related to the NH, for two groups of enthiols and enol groups. Antimicrobial activity study was performed against S. aureus, B. subtilis, A. hydrophila, E. coli and A. baumannii as bacterial standard strains, and against M. tuberculosis H37Rv as mycobacterial strain. The compound exhibited antibacterial activity in the range of 31.25–62.5 μg/mL, and antimycobacterial activity with a MIC value of 40 μg/mL against the indicated strains.