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M Paluch - One of the best experts on this subject based on the ideXlab platform.
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unexpected crossover in the kinetics of Mutarotation in the supercooled region the role of h bonds
Scientific Reports, 2018Co-Authors: Kamila Wolnica, K Kaminski, Mateusz Dulski, Ewa Kaminska, Magdalena Tarnacka, Roman Wrzalik, Wioleta śmiszeklindert, M PaluchAbstract:Intra- and intermolecular studies on the molten L-sorbose have been carried out at variable temperature conditions to determine the crosover temperature (T c ). In addition, isothermal time-dependent FTIR and Raman measurements were performed to probe the pace of Mutarotation and activation energy of this reaction in the studied saccharide, which varied from 53–62 kJ/mol up to 177–192 kJ/mol below and above T c , respectively. To explain the change in activation barrier for the Mutarotation a complementary analysis using difference FTIR spectra collected around T c = 365 K in the hydroxyl region has been done. It was found that the alteration of kinetic parameters and molecular dynamics around T c are strictly related to the variation in the strength of H-bonds which above T c are significantly weaken, increasing the freedom of rotation of functional groups and movement of individual molecules. That phenomenon most likely affects the proton transfer, underlying molecular mechanism of Mutarotation, which may lead to the significant increase in activation barrier. The new insight into a molecular aspect of the Mutarotation around T c has created an opportunity to better understanding the relationship between physics of condensed matter and the potential role of H-bonds dynamics on the progress of the chemical reaction in highly viscous systems.
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a study on the progress of Mutarotation above and below the tg and the relationship between constant rates and structural relaxation times
Physical Chemistry Chemical Physics, 2017Co-Authors: Kamila Wolnica, K Kaminski, Mateusz Dulski, A Cecotka, Ewa Kaminska, Magdalena Tarnacka, Roman Wrzalik, M PaluchAbstract:Comprehensive FTIR studies on the progress of Mutarotation in D-fructose mixed with maltitol have been carried out over a wide range of temperatures, both above and below the glass transition temperature Tg. In addition to the analysis of single bands, we have developed a completely new approach considering the full spectral range to follow the overall progress of the reaction. We have found that at the calorimetric Tg, there is a clear change in the temperature dependence of constant rates. The activation barrier for Mutarotation changes from around 59 kJ mol−1 (the supercooled state) to around 249 kJ mol−1 (the glassy state). This dramatic variation in the activation barrier is consistent with the change in the mechanism of this specific chemical conversion, as theoretically considered by Wlodarczyk et al. [Phys. Chem. Chem. Phys., 2014, 16, 4694–4698]. Alternatively, it can also be connected to the change in the viscosity of the sample. Additionally, we investigated the relationship between constant rates (k) of Mutarotation, structural relaxation times (τα), and dc conductivity (σdc) above and below the glass transition temperature. It was found that there was a linear correlation between all these quantities; they scale with various exponents changing at Tg. Our results also indicate that a single activation barrier might not be sufficient to describe the Mutarotation process.
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experimental ftir bds and theoretical analysis of Mutarotation kinetics of d fructose mixed with different alcohols in the supercooled region
RSC Advances, 2016Co-Authors: Mateusz Dulski, K Kaminski, Satya Narayan Tripathy, A Cecotka, Kamila Wolnica, Magdalena Tarnacka, Roman Wrzalik, A Sakalouski, M PaluchAbstract:The Mutarotation kinetics of pure molten D-fructose and its binary mixture with alcohols (i.e., sorbitol and maltitol) have been reported using Fourier Transform Infrared (FTIR), Broadband Dielectric Spectroscopy (BDS) and Density Functional Theory (DFT) calculations. The time evolution of the integrated intensity and structural relaxation time acts as a suitable dynamical observable to monitor the progress of the reaction in FTIR and BDS, respectively, leading to the construction of kinetic curves for the process. The bands at 776 cm−1 (νβ) and 990 cm−1 (να) indicate the respective vibrations originating from the β and α-isomers of D-fructose. The rate constants estimated from FTIR, (kIR) are shorter than those obtained from BDS, (kBDS) studies and the activation energies determined from both spectroscopies differ by more than 30 kJ mol−1. This is interpreted in the context of specific reaction pathways that contribute to the rate constants and drive Mutarotation. Additionally, it is found that the rate of Mutarotation depends on the system studied i.e., in binary mixtures consisting of sorbitol and D-fructose it becomes faster, while in solid dispersion with maltitol it gets slower. This fact can be explained by taking into account the viscosity of the system. In addition, natural bond orbital (NBO) calculations and an electrostatic potential surface (EPS) analysis were carried out to gain insight into the atomic charge distribution and description of the possible interactions between D-fructose and alcohol molecules. We note that there are some differences between both systems under examination in the strength of H-bonds. However, the impact of these interactions on the progress on Mutarotation is not as significant as viscosity.
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evidence of pressure induced intermolecular proton transfer via Mutarotation the case of supercooled d fructose
Physical Chemistry Chemical Physics, 2015Co-Authors: Adam Cecotka, Satya Narayan Tripathy, M PaluchAbstract:This paper describes a systematic investigation on the role of pressure in Mutarotation kinetics of supercooled D-fructose using dielectric spectroscopy. The structural relaxation time acts as a suitable dynamical observable to monitor the Mutarotation process that enables the construction of the kinetic curves. The reaction kinetic shapes have been analyzed using the Avrami model. At low temperature, sigmoidal kinetic curves are noted, which correspond to the high concentration of furanosidic forms. The magnitude of activation energy of the process significantly decreases with increasing pressure and is comparable to the solvated systems at 100 MPa. A potential connection between cooperative motion and the origin of intermolecular proton transfer via Mutarotation at elevated pressure is also discussed. These experimental observations have fundamental significance on theoretical explanation of the mechanism involving Mutarotation in sugars.
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a Mutarotation mechanism based on dual proton exchange in the amorphous d glucose
Physical Chemistry Chemical Physics, 2014Co-Authors: P Wlodarczyk, M Paluch, A Wlodarczyk, M HyraAbstract:It is a well known fact that carbohydrates have unusual chemical and physical properties when they approach the glassy state during the cooling process. Differences between sugar aqueous solutions and their pure anhydrous states are caused mainly by the different intermolecular interactions related to the different hydrogen bond patterns. The Mutarotation, a specific reaction in the saccharides, was recently investigated in the supercooled liquid and the glassy state of D-glucose. It was shown that the activation energy of this process in the supercooled liquid state is twice as low as for the same process in aqueous solution. In contrast, the activation energy in the glassy state is twice as high as in the aqueous solution. Herein, we present possible explanations for this phenomenon and propose a universal mechanism for the Mutarotation process in the amorphous state of matter. In this work, for the first time, a double proton exchange mechanism in carbohydrates is proposed.
P Wlodarczyk - One of the best experts on this subject based on the ideXlab platform.
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a Mutarotation mechanism based on dual proton exchange in the amorphous d glucose
Physical Chemistry Chemical Physics, 2014Co-Authors: P Wlodarczyk, M Paluch, A Wlodarczyk, M HyraAbstract:It is a well known fact that carbohydrates have unusual chemical and physical properties when they approach the glassy state during the cooling process. Differences between sugar aqueous solutions and their pure anhydrous states are caused mainly by the different intermolecular interactions related to the different hydrogen bond patterns. The Mutarotation, a specific reaction in the saccharides, was recently investigated in the supercooled liquid and the glassy state of D-glucose. It was shown that the activation energy of this process in the supercooled liquid state is twice as low as for the same process in aqueous solution. In contrast, the activation energy in the glassy state is twice as high as in the aqueous solution. Herein, we present possible explanations for this phenomenon and propose a universal mechanism for the Mutarotation process in the amorphous state of matter. In this work, for the first time, a double proton exchange mechanism in carbohydrates is proposed.
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Mutarotation in biologically important pure l fucose and its enantiomer
Journal of Physics: Condensed Matter, 2013Co-Authors: P Wlodarczyk, K Kaminski, A Cecotka, Karolina Adrjanowicz, M PaluchAbstract:The sugar specific Mutarotation reaction in biologically important L-fucose and its enantiomer in the pure, anhydrous, supercooled liquid state has been studied. Kinetics measurements in the temperature range 313?328?K at ambient pressure have been performed by means of dielectric spectroscopy, a method widely used for studying the molecular dynamics of glass-forming liquids. The kinetic curves have been obtained by tracking the equilibration process in sugar melted and quenched to the desired temperature. Thereafter, an activation energy equal to Ea?=?140?kJ?mol?1 for D-fucose and Ea?=?123?kJ?mol?1 for L-fucose has been derived from the Arrhenius fit of temperature dependent rate constants. It was also shown that the kinetics curves at the lowest temperatures studied have sigmoidal shape, which was connected to the high concentration of furanosidic forms.
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rheological study of Mutarotation of fructose in anhydrous state
Journal of Physical Chemistry B, 2013Co-Authors: Yangyang Wang, P Wlodarczyk, Alexei P Sokolov, M PaluchAbstract:Rheological measurement was employed to study the Mutarotation of D-fructose in anhydrous state. By monitoring the evolution of shear viscosity with time, rate constants for Mutarotation were estimated, and two different stages of this reaction were identified. One of the Mutarotation stages is rapid and has a low activation energy, whereas the other is much slower and has a much higher activation energy. Possible conversions corresponding to these two phases are discussed. This work demonstrates that, in addition to the routine techniques such polarimetry and gas-liquid chromatography, rheological measurement can be used as an alternative method to continuously monitor the Mutarotation of sugars.
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mechanism of Mutarotation in supercooled liquid phase studies on l sorbose
Journal of Chemical Physics, 2012Co-Authors: P Wlodarczyk, M Paluch, K Kaminski, J Ziolo, Andrzej Grzybowski, A Cecotka, Jaroslaw MarkowskiAbstract:We have studied Mutarotation in anhydrous supercooled L-sorbose by means of dielectric spectroscopy. The phenomenon observed in L-sorbose is much faster than in the structurally similar D-fructose. The kinetics of this process has been determined by applying 1st order kinetics model. Activation energy equal to 68 kJ/mol was obtained from temperature dependence of rate constants. To understand differences in Mutarotation rate between D-fructose and L-sorbose, quantum mechanical calculations were performed to study mechanism of this phenomenon. The possible impact of water absorbed from air on the Mutarotation in supercooled liquid state has been checked. It turned out that the process is probably intermolecular and the water molecules or other carbohydrate molecules assist in the proton transfer process. Finally we have shown that the rate constant can be alternatively determined from frequency of the maximum of peak, obtained by performing Fourier transform of kinetic curve.
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studies on mechanism of reaction and density behavior during anhydrous d fructose Mutarotation in the supercooled liquid state
Journal of Chemical Physics, 2011Co-Authors: P Wlodarczyk, M Paluch, K Kaminski, L Hawelek, J PionteckAbstract:Recently, we have studied the Mutarotation kinetics in D-fructose by means of dielectric spectroscopy. In the present work we investigate density behavior of D-fructose during Mutarotation process. By performing volume measurements at temperature T = 303 K and pressure p = 10 MPa we are able to monitor kinetics of this process. As a result we found nearly the same value of the rate constant as previously determined from dielectric measurements. However, these two experimental methods monitor different molecular aspects of Mutarotation phenomenon in D-fructose. Dielectric spectroscopy is sensitive to the decay of former ring as well as to the forming of another, while specific volume measurements are sensitive to the forming of new tautomers only. Calculations of activation energy of Mutarotation in D-fructose led us to the conclusion, that mechanism of this reaction in amorphous phase could be based on internal proton transfer. Moreover it was found that the main Mutarotation path in quenched D-fructose melt is transformation of α,β-furanose to β-pyranose.
K Kaminski - One of the best experts on this subject based on the ideXlab platform.
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unexpected crossover in the kinetics of Mutarotation in the supercooled region the role of h bonds
Scientific Reports, 2018Co-Authors: Kamila Wolnica, K Kaminski, Mateusz Dulski, Ewa Kaminska, Magdalena Tarnacka, Roman Wrzalik, Wioleta śmiszeklindert, M PaluchAbstract:Intra- and intermolecular studies on the molten L-sorbose have been carried out at variable temperature conditions to determine the crosover temperature (T c ). In addition, isothermal time-dependent FTIR and Raman measurements were performed to probe the pace of Mutarotation and activation energy of this reaction in the studied saccharide, which varied from 53–62 kJ/mol up to 177–192 kJ/mol below and above T c , respectively. To explain the change in activation barrier for the Mutarotation a complementary analysis using difference FTIR spectra collected around T c = 365 K in the hydroxyl region has been done. It was found that the alteration of kinetic parameters and molecular dynamics around T c are strictly related to the variation in the strength of H-bonds which above T c are significantly weaken, increasing the freedom of rotation of functional groups and movement of individual molecules. That phenomenon most likely affects the proton transfer, underlying molecular mechanism of Mutarotation, which may lead to the significant increase in activation barrier. The new insight into a molecular aspect of the Mutarotation around T c has created an opportunity to better understanding the relationship between physics of condensed matter and the potential role of H-bonds dynamics on the progress of the chemical reaction in highly viscous systems.
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a study on the progress of Mutarotation above and below the tg and the relationship between constant rates and structural relaxation times
Physical Chemistry Chemical Physics, 2017Co-Authors: Kamila Wolnica, K Kaminski, Mateusz Dulski, A Cecotka, Ewa Kaminska, Magdalena Tarnacka, Roman Wrzalik, M PaluchAbstract:Comprehensive FTIR studies on the progress of Mutarotation in D-fructose mixed with maltitol have been carried out over a wide range of temperatures, both above and below the glass transition temperature Tg. In addition to the analysis of single bands, we have developed a completely new approach considering the full spectral range to follow the overall progress of the reaction. We have found that at the calorimetric Tg, there is a clear change in the temperature dependence of constant rates. The activation barrier for Mutarotation changes from around 59 kJ mol−1 (the supercooled state) to around 249 kJ mol−1 (the glassy state). This dramatic variation in the activation barrier is consistent with the change in the mechanism of this specific chemical conversion, as theoretically considered by Wlodarczyk et al. [Phys. Chem. Chem. Phys., 2014, 16, 4694–4698]. Alternatively, it can also be connected to the change in the viscosity of the sample. Additionally, we investigated the relationship between constant rates (k) of Mutarotation, structural relaxation times (τα), and dc conductivity (σdc) above and below the glass transition temperature. It was found that there was a linear correlation between all these quantities; they scale with various exponents changing at Tg. Our results also indicate that a single activation barrier might not be sufficient to describe the Mutarotation process.
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experimental ftir bds and theoretical analysis of Mutarotation kinetics of d fructose mixed with different alcohols in the supercooled region
RSC Advances, 2016Co-Authors: Mateusz Dulski, K Kaminski, Satya Narayan Tripathy, A Cecotka, Kamila Wolnica, Magdalena Tarnacka, Roman Wrzalik, A Sakalouski, M PaluchAbstract:The Mutarotation kinetics of pure molten D-fructose and its binary mixture with alcohols (i.e., sorbitol and maltitol) have been reported using Fourier Transform Infrared (FTIR), Broadband Dielectric Spectroscopy (BDS) and Density Functional Theory (DFT) calculations. The time evolution of the integrated intensity and structural relaxation time acts as a suitable dynamical observable to monitor the progress of the reaction in FTIR and BDS, respectively, leading to the construction of kinetic curves for the process. The bands at 776 cm−1 (νβ) and 990 cm−1 (να) indicate the respective vibrations originating from the β and α-isomers of D-fructose. The rate constants estimated from FTIR, (kIR) are shorter than those obtained from BDS, (kBDS) studies and the activation energies determined from both spectroscopies differ by more than 30 kJ mol−1. This is interpreted in the context of specific reaction pathways that contribute to the rate constants and drive Mutarotation. Additionally, it is found that the rate of Mutarotation depends on the system studied i.e., in binary mixtures consisting of sorbitol and D-fructose it becomes faster, while in solid dispersion with maltitol it gets slower. This fact can be explained by taking into account the viscosity of the system. In addition, natural bond orbital (NBO) calculations and an electrostatic potential surface (EPS) analysis were carried out to gain insight into the atomic charge distribution and description of the possible interactions between D-fructose and alcohol molecules. We note that there are some differences between both systems under examination in the strength of H-bonds. However, the impact of these interactions on the progress on Mutarotation is not as significant as viscosity.
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Mutarotation in biologically important pure l fucose and its enantiomer
Journal of Physics: Condensed Matter, 2013Co-Authors: P Wlodarczyk, K Kaminski, A Cecotka, Karolina Adrjanowicz, M PaluchAbstract:The sugar specific Mutarotation reaction in biologically important L-fucose and its enantiomer in the pure, anhydrous, supercooled liquid state has been studied. Kinetics measurements in the temperature range 313?328?K at ambient pressure have been performed by means of dielectric spectroscopy, a method widely used for studying the molecular dynamics of glass-forming liquids. The kinetic curves have been obtained by tracking the equilibration process in sugar melted and quenched to the desired temperature. Thereafter, an activation energy equal to Ea?=?140?kJ?mol?1 for D-fucose and Ea?=?123?kJ?mol?1 for L-fucose has been derived from the Arrhenius fit of temperature dependent rate constants. It was also shown that the kinetics curves at the lowest temperatures studied have sigmoidal shape, which was connected to the high concentration of furanosidic forms.
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mechanism of Mutarotation in supercooled liquid phase studies on l sorbose
Journal of Chemical Physics, 2012Co-Authors: P Wlodarczyk, M Paluch, K Kaminski, J Ziolo, Andrzej Grzybowski, A Cecotka, Jaroslaw MarkowskiAbstract:We have studied Mutarotation in anhydrous supercooled L-sorbose by means of dielectric spectroscopy. The phenomenon observed in L-sorbose is much faster than in the structurally similar D-fructose. The kinetics of this process has been determined by applying 1st order kinetics model. Activation energy equal to 68 kJ/mol was obtained from temperature dependence of rate constants. To understand differences in Mutarotation rate between D-fructose and L-sorbose, quantum mechanical calculations were performed to study mechanism of this phenomenon. The possible impact of water absorbed from air on the Mutarotation in supercooled liquid state has been checked. It turned out that the process is probably intermolecular and the water molecules or other carbohydrate molecules assist in the proton transfer process. Finally we have shown that the rate constant can be alternatively determined from frequency of the maximum of peak, obtained by performing Fourier transform of kinetic curve.
Alberto Marra - One of the best experts on this subject based on the ideXlab platform.
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synthesis of sugar based silica gels by copper catalysed azide alkyne cycloaddition via a single step azido activated silica intermediate and the use of the gels in hydrophilic interaction chromatography
Chemistry: A European Journal, 2010Co-Authors: Lisa Moni, Alessia Ciogli, Ilaria Dacquarica, Alessandro Dondoni, Francesco Gasparrini, Alberto MarraAbstract:: Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide-alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C-galactoside 1 and propargyl O-lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of Mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoids.
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Synthesis of Sugar-Based Silica Gels by Copper-Catalysed Azide–Alkyne Cycloaddition via a Single-Step Azido-Activated Silica Intermediate and the Use of the Gels in Hydrophilic Interaction Chromatography
'Wiley', 2010Co-Authors: Lisa Moni, Alessia Ciogli, Ilaria Dacquarica, Alessandro Dondoni, Francesco Gasparrini, Alberto MarraAbstract:Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide–alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C-galactoside 1 and propargyl O-lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of Mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoid
J Ziolo - One of the best experts on this subject based on the ideXlab platform.
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mechanism of Mutarotation in supercooled liquid phase studies on l sorbose
Journal of Chemical Physics, 2012Co-Authors: P Wlodarczyk, M Paluch, K Kaminski, J Ziolo, Andrzej Grzybowski, A Cecotka, Jaroslaw MarkowskiAbstract:We have studied Mutarotation in anhydrous supercooled L-sorbose by means of dielectric spectroscopy. The phenomenon observed in L-sorbose is much faster than in the structurally similar D-fructose. The kinetics of this process has been determined by applying 1st order kinetics model. Activation energy equal to 68 kJ/mol was obtained from temperature dependence of rate constants. To understand differences in Mutarotation rate between D-fructose and L-sorbose, quantum mechanical calculations were performed to study mechanism of this phenomenon. The possible impact of water absorbed from air on the Mutarotation in supercooled liquid state has been checked. It turned out that the process is probably intermolecular and the water molecules or other carbohydrate molecules assist in the proton transfer process. Finally we have shown that the rate constant can be alternatively determined from frequency of the maximum of peak, obtained by performing Fourier transform of kinetic curve.
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kinetic processes in supercooled monosaccharides upon melting application of dielectric spectroscopy in the Mutarotation studies of d ribose
Journal of Chemical Physics, 2010Co-Authors: P Wlodarczyk, M Paluch, K Kaminski, S Haracz, Mateusz Dulski, J Ziolo, M WygledowskakaniaAbstract:Dielectric spectroscopy has been recently used to monitor Mutarotation in undercooled D-fructose. This method can be viewed as a universal method to study Mutarotation phenomenon in the whole family of monosaccharides. In this paper, we studied kinetics of mutaration of anhydrous D-ribose at ambient pressure as well as pressure effect on the rate constant of this process. Ribose Mutarotation behavior is compared to the one obtained for D-fructose. In addition, we attempted to determine the "direction" of Mutarotation in undercooled monosaccharides after quenching the melted sample. To this end, analysis of dipole moments of different tautomers of D-fructose and D-ribose have been performed. Conformational analysis of studied carbohydrates was done with use of density functional theory. Geometry optimizations as well as calculations of dipole moments were done on the 6-311++G(d,p)/B3LYP level. Finally, it turned out that data obtained from the Mutarotation experiment might be helpful in understanding the origin of gamma-process occurring in the whole family of carbohydrates.
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Mutarotation in d fructose melt monitored by dielectric spectroscopy
Journal of Physical Chemistry B, 2009Co-Authors: P Wlodarczyk, M Paluch, K Kaminski, J ZioloAbstract:Broadband dielectric spectroscopy was employed to investigate the kinetics of the Mutarotation of d-fructose. In this article, d-fructose tautomerization behavior in pure melt is revealed. By monit...
