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Gerard Riess - One of the best experts on this subject based on the ideXlab platform.
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synthesis and characterization of new unsaturated esters of gellan gum
Carbohydrate Polymers, 2008Co-Authors: Mihaela Hamcerencu, Jacques Desbrieres, Abdel Khoukh, Marcel Popa, Gerard RiessAbstract:Abstract A series of Gellan Gum unsaturated esters by addition of free radical polymerizable groups, which can be polymerized under mild conditions to design biodegradable three-dimensional networks having hydrogels properties, were synthesized by esterification under various conditions. Different degrees of functionalization were obtained either homogeneously in water with acrylic acid or heterogeneously with Acryloyl Chloride and maleic anhydride in organic solvents. Acrylate and maleate groups determination was carried out by ATR-FTIR and 1 H liquid NMR techniques. The degree of substitution as determined by 1 H NMR could be controlled by varying the chemical nature of functionalization agent, reaction time and temperature. Maleic anhydride presents a higher reactivity as compared to acrylic acid and Acryloyl Chloride.
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Synthesis and characterization of new unsaturated esters of Gellan Gum
Carbohydrate Polymers, 2008Co-Authors: Mihaela Hamcerencu, Jacques Desbrieres, Abdel Khoukh, Marcel Popa, Gerard RiessAbstract:A series of Gellan Gum unsaturated esters by addition of free radical polymerizable groups, which can be polymerized under mild conditions to design biodegradable three-dimensional networks having hydrogels properties, were synthesized by esterification under various conditions. Different degrees of functionalization were obtained either homogeneously in water with acrylic acid or heterogeneously with Acryloyl Chloride and maleic anhydride in organic solvents. Acrylate and maleate groups determination was carried out by ATR-FTIR and 1H liquid NMR techniques. The degree of substitution as determined by 1H NMR could be controlled by varying the chemical nature of functionalization agent, reaction time and temperature. Maleic anhydride presents a higher reactivity as compared to acrylic acid and Acryloyl Chloride. © 2007 Elsevier Ltd. All rights reserved.
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New unsaturated derivatives of Xanthan gum: Synthesis and characterization
Polymer, 2007Co-Authors: Mihaela Hamcerencu, Jacques Desbrieres, Abdel Khoukh, Marcel Popa, Gerard RiessAbstract:Unsaturated Xanthan derivatives, which can be used for the development of biodegradable three-dimensional networks having hydrogel properties, were prepared by esterification under various conditions. Xanthan gum derivatives with different degrees of substitution were obtained by reaction with an unsaturated organic acid (acrylic acid) or with acid reactive derivatives (Acryloyl Chloride, maleic anhydride). The presence of acrylate and maleate groups in the modified structure of Xanthan gum was detected by ATR-FTIR, 1H liquid NMR and 1H HRMAS NMR spectroscopies. The degree of substitution as determined by 1H NMR could be controlled by varying the chemical nature of functionalisation agent, reaction time and temperature. The results proved that this polysaccharide can be modified by esterification with acids or unsaturated acid derivatives for further synthesis of hydrogels. Maleic anhydride presents a higher reactivity as compared to acrylic acid and Acryloyl Chloride. © 2007 Elsevier Ltd. All rights reserved.
Mihaela Hamcerencu - One of the best experts on this subject based on the ideXlab platform.
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synthesis and characterization of new unsaturated esters of gellan gum
Carbohydrate Polymers, 2008Co-Authors: Mihaela Hamcerencu, Jacques Desbrieres, Abdel Khoukh, Marcel Popa, Gerard RiessAbstract:Abstract A series of Gellan Gum unsaturated esters by addition of free radical polymerizable groups, which can be polymerized under mild conditions to design biodegradable three-dimensional networks having hydrogels properties, were synthesized by esterification under various conditions. Different degrees of functionalization were obtained either homogeneously in water with acrylic acid or heterogeneously with Acryloyl Chloride and maleic anhydride in organic solvents. Acrylate and maleate groups determination was carried out by ATR-FTIR and 1 H liquid NMR techniques. The degree of substitution as determined by 1 H NMR could be controlled by varying the chemical nature of functionalization agent, reaction time and temperature. Maleic anhydride presents a higher reactivity as compared to acrylic acid and Acryloyl Chloride.
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Synthesis and characterization of new unsaturated esters of Gellan Gum
Carbohydrate Polymers, 2008Co-Authors: Mihaela Hamcerencu, Jacques Desbrieres, Abdel Khoukh, Marcel Popa, Gerard RiessAbstract:A series of Gellan Gum unsaturated esters by addition of free radical polymerizable groups, which can be polymerized under mild conditions to design biodegradable three-dimensional networks having hydrogels properties, were synthesized by esterification under various conditions. Different degrees of functionalization were obtained either homogeneously in water with acrylic acid or heterogeneously with Acryloyl Chloride and maleic anhydride in organic solvents. Acrylate and maleate groups determination was carried out by ATR-FTIR and 1H liquid NMR techniques. The degree of substitution as determined by 1H NMR could be controlled by varying the chemical nature of functionalization agent, reaction time and temperature. Maleic anhydride presents a higher reactivity as compared to acrylic acid and Acryloyl Chloride. © 2007 Elsevier Ltd. All rights reserved.
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New unsaturated derivatives of Xanthan gum: Synthesis and characterization
Polymer, 2007Co-Authors: Mihaela Hamcerencu, Jacques Desbrieres, Abdel Khoukh, Marcel Popa, Gerard RiessAbstract:Unsaturated Xanthan derivatives, which can be used for the development of biodegradable three-dimensional networks having hydrogel properties, were prepared by esterification under various conditions. Xanthan gum derivatives with different degrees of substitution were obtained by reaction with an unsaturated organic acid (acrylic acid) or with acid reactive derivatives (Acryloyl Chloride, maleic anhydride). The presence of acrylate and maleate groups in the modified structure of Xanthan gum was detected by ATR-FTIR, 1H liquid NMR and 1H HRMAS NMR spectroscopies. The degree of substitution as determined by 1H NMR could be controlled by varying the chemical nature of functionalisation agent, reaction time and temperature. The results proved that this polysaccharide can be modified by esterification with acids or unsaturated acid derivatives for further synthesis of hydrogels. Maleic anhydride presents a higher reactivity as compared to acrylic acid and Acryloyl Chloride. © 2007 Elsevier Ltd. All rights reserved.
Laurie J. Butler - One of the best experts on this subject based on the ideXlab platform.
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Two HCl-Elimination Channels and Two CO-Formation Channels Detected with Time-Resolved Infrared Emission upon Photolysis of Acryloyl Chloride [CH2CHC(O)Cl] at 193 nm.
The journal of physical chemistry. A, 2015Co-Authors: Pei Wen Lee, Laurie J. Butler, Preston G. Scrape, Yuan-pern LeeAbstract:Following photodissociation of gaseous Acryloyl Chloride, CH2CHC(O)Cl, at 193 nm, temporally resolved vibration–rotational emission spectra of HCl (v ≤ 7, J ≤ 35) in region 2350–3250 cm–1 and of CO (v ≤ 4, J ≤ 67) in region 1865–2300 cm–1 were recorded with a step-scan Fourier-transform spectrometer. The HCl emission shows a minor low-J component for v ≤ 4 with average rotational energy Erot = 9 ± 3 kJ mol–1 and vibrational energy Evib = 28 ± 7 kJ mol–1 and a major high-J component for v ≤ 7 with average rotational energy Erot = 36 ± 6 kJ mol–1 and vibrational energy Evib = 49 ± 9 kJ mol–1; the branching ratio of these two channels is ∼0.2:0.8. Using electronic structure calculations to characterize the transition states and each intrinsic reaction coordinate, we find that the minor pathway corresponds to the four-center HCl-elimination of CH2ClCHCO following a 1,3-Cl-shift of CH2CHC(O)Cl, whereas the major pathway corresponds to the direct four-center HCl-elimination of CH2CHC(O)Cl. Although several chan...
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Two HCl-Elimination Channels and Two CO-Formation Channels Detected with Time-Resolved Infrared Emission upon Photolysis of Acryloyl Chloride [CH2CHC(O)Cl] at 193 nm
2015Co-Authors: Pei Wen Lee, Laurie J. Butler, Preston G. Scrape, Yuan-pern LeeAbstract:Following photodissociation of gaseous Acryloyl Chloride, CH2CHC(O)Cl, at 193 nm, temporally resolved vibration–rotational emission spectra of HCl (v ≤ 7, J ≤ 35) in region 2350–3250 cm–1 and of CO (v ≤ 4, J ≤ 67) in region 1865–2300 cm–1 were recorded with a step-scan Fourier-transform spectrometer. The HCl emission shows a minor low-J component for v ≤ 4 with average rotational energy Erot = 9 ± 3 kJ mol–1 and vibrational energy Evib = 28 ± 7 kJ mol–1 and a major high-J component for v ≤ 7 with average rotational energy Erot = 36 ± 6 kJ mol–1 and vibrational energy Evib = 49 ± 9 kJ mol–1; the branching ratio of these two channels is ∼0.2:0.8. Using electronic structure calculations to characterize the transition states and each intrinsic reaction coordinate, we find that the minor pathway corresponds to the four-center HCl-elimination of CH2ClCHCO following a 1,3-Cl-shift of CH2CHC(O)Cl, whereas the major pathway corresponds to the direct four-center HCl-elimination of CH2CHC(O)Cl. Although several channels are expected for CO produced from the secondary dissociation of C2H3CO and H2CCCO, each produced from two possible dissociation channels of CH2CHC(O)Cl, the CO emission shows a near-Boltzmann rotational distribution with average rotational energy Erot = 21 ± 4 kJ mol–1 and average vibrational energy Evib = 10 ± 4 kJ mol–1. Consideration of the branching fractions suggests that the CO observed with greater vibrational excitation might result from secondary decomposition of H2CCCO that was produced via the minor low-J HCl-elimination channel, while the internal state distributions of CO produced from the other three channels are indistinguishable. We also introduce a method for choosing the correct point along the intrinsic reaction coordinate for a roaming HCl elimination channel to generate a Franck–Condon prediction for the HCl vibrational energy
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193-nm photodissociation of Acryloyl Chloride to probe the unimolecular dissociation of CH2CHCO radicals and CH2CCO
The Journal of chemical physics, 2004Co-Authors: D. E. Szpunar, J. L. Miller, Laurie J. ButlerAbstract:The work presented here uses photofragment translational spectroscopy to investigate the primary and secondary dissociation channels of Acryloyl Chloride (CH2=CHCOCl) excited at 193 nm. Three primary channels were observed. Two C–Cl fission channels occur, one producing fragments with high kinetic recoil energies and the other producing fragments with low translational energies. These channels produced nascent CH2CHCO radicals with internal energies ranging from 23 to 66 kcal/mol for the high-translational-energy channel and from 50 to 68 kcal/mol for the low-translational-energy channel. We found that all nascent CH2CHCO radicals were unstable to CH2CH+CO formation, in agreement with the G3//B3LYP barrier height of 22.4 kcal/mol to within experimental and computational uncertainties. The third primary channel is HCl elimination. All of the nascent CH2CCO coproducts were found to have enough internal energy to dissociate, producing CH2C:+CO, in qualitative agreement with the G3//B3LYP barrier of 39.5 kcal...
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Emission spectroscopy of the predissociative excited state dynamics of acrolein, acrylic acid, and Acryloyl Chloride at 199 nm
The Journal of Chemical Physics, 1995Co-Authors: Michael F. Arendt, Paul W. Browning, Laurie J. ButlerAbstract:The emission spectroscopy of acrolein (C3H4O), acrylic acid (C2H3COOH), and Acryloyl Chloride (C2H3COCl) excited at 199 nm elucidates the dominant electronic character of the excited state reached by the optical transition at this wavelength. Progressions in the C=C and C=O stretching overtones and various combination bands suggest the antibonding orbital has mixed π*(C=C)/π*(C=O) character. We interpret the results in conjunction with ab initio calculations at the configuration interaction singles level to identify the influence of resonance in the excited state of these conjugated molecules. The results on acrylic acid are of particular interest as excitation in this absorption band produces the HOCO intermediate of the OH+CO→H+CO2 reaction that is important in combustion.
Yuan-pern Lee - One of the best experts on this subject based on the ideXlab platform.
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Two HCl-Elimination Channels and Two CO-Formation Channels Detected with Time-Resolved Infrared Emission upon Photolysis of Acryloyl Chloride [CH2CHC(O)Cl] at 193 nm.
The journal of physical chemistry. A, 2015Co-Authors: Pei Wen Lee, Laurie J. Butler, Preston G. Scrape, Yuan-pern LeeAbstract:Following photodissociation of gaseous Acryloyl Chloride, CH2CHC(O)Cl, at 193 nm, temporally resolved vibration–rotational emission spectra of HCl (v ≤ 7, J ≤ 35) in region 2350–3250 cm–1 and of CO (v ≤ 4, J ≤ 67) in region 1865–2300 cm–1 were recorded with a step-scan Fourier-transform spectrometer. The HCl emission shows a minor low-J component for v ≤ 4 with average rotational energy Erot = 9 ± 3 kJ mol–1 and vibrational energy Evib = 28 ± 7 kJ mol–1 and a major high-J component for v ≤ 7 with average rotational energy Erot = 36 ± 6 kJ mol–1 and vibrational energy Evib = 49 ± 9 kJ mol–1; the branching ratio of these two channels is ∼0.2:0.8. Using electronic structure calculations to characterize the transition states and each intrinsic reaction coordinate, we find that the minor pathway corresponds to the four-center HCl-elimination of CH2ClCHCO following a 1,3-Cl-shift of CH2CHC(O)Cl, whereas the major pathway corresponds to the direct four-center HCl-elimination of CH2CHC(O)Cl. Although several chan...
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Two HCl-Elimination Channels and Two CO-Formation Channels Detected with Time-Resolved Infrared Emission upon Photolysis of Acryloyl Chloride [CH2CHC(O)Cl] at 193 nm
2015Co-Authors: Pei Wen Lee, Laurie J. Butler, Preston G. Scrape, Yuan-pern LeeAbstract:Following photodissociation of gaseous Acryloyl Chloride, CH2CHC(O)Cl, at 193 nm, temporally resolved vibration–rotational emission spectra of HCl (v ≤ 7, J ≤ 35) in region 2350–3250 cm–1 and of CO (v ≤ 4, J ≤ 67) in region 1865–2300 cm–1 were recorded with a step-scan Fourier-transform spectrometer. The HCl emission shows a minor low-J component for v ≤ 4 with average rotational energy Erot = 9 ± 3 kJ mol–1 and vibrational energy Evib = 28 ± 7 kJ mol–1 and a major high-J component for v ≤ 7 with average rotational energy Erot = 36 ± 6 kJ mol–1 and vibrational energy Evib = 49 ± 9 kJ mol–1; the branching ratio of these two channels is ∼0.2:0.8. Using electronic structure calculations to characterize the transition states and each intrinsic reaction coordinate, we find that the minor pathway corresponds to the four-center HCl-elimination of CH2ClCHCO following a 1,3-Cl-shift of CH2CHC(O)Cl, whereas the major pathway corresponds to the direct four-center HCl-elimination of CH2CHC(O)Cl. Although several channels are expected for CO produced from the secondary dissociation of C2H3CO and H2CCCO, each produced from two possible dissociation channels of CH2CHC(O)Cl, the CO emission shows a near-Boltzmann rotational distribution with average rotational energy Erot = 21 ± 4 kJ mol–1 and average vibrational energy Evib = 10 ± 4 kJ mol–1. Consideration of the branching fractions suggests that the CO observed with greater vibrational excitation might result from secondary decomposition of H2CCCO that was produced via the minor low-J HCl-elimination channel, while the internal state distributions of CO produced from the other three channels are indistinguishable. We also introduce a method for choosing the correct point along the intrinsic reaction coordinate for a roaming HCl elimination channel to generate a Franck–Condon prediction for the HCl vibrational energy
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Infrared absorption of 3-propenonyl (⋅CH2CHCO) radical generated upon photolysis of Acryloyl Chloride [CH2CHC(O)Cl] in solid para-H2
The Journal of chemical physics, 2013Co-Authors: Prasanta Kumar Das, Yuan-pern LeeAbstract:Irradiation at 193 nm of a p-H2 matrix containing Acryloyl Chloride CH2CHC(O)Cl at 3.2 K yielded infrared absorption lines at 3143.6 (ν1), 3057.0 (ν2), 3048.0 (ν3), 2103.1 (ν4), 1461.0 (ν5), 1349.8 (ν6), 1223.7 (ν11+ν12 or 2ν12), 1092.8 (ν8), 918.1 (ν9), 691.0 (ν10), 624.3 (ν11), and 597.1 (ν12) cm−1 that are assigned to the 3-propenonyl (⋅CH2CHCO) radical. The assignments are based on the photolytic behavior and a comparison of observed vibrational wavenumbers and infrared intensities with those predicted with the B3PW91/aug-cc-pVDZ method. The observation is consistent with a major radical formation channel CH2CHCO + Cl followed by escape of the Cl atom from the original p-H2 cage. The observation of 3-propenonyl (⋅CH2CHCO) radical but not 3-propenalyl (s-cis- or s-trans-CH2CHĊO) radical indicates that the former is the most stable isomer and that the barrier heights for conversion from s-cis- or s-trans-CH2CHĊO to ⋅CH2CHCO are small.
M. A. Diab - One of the best experts on this subject based on the ideXlab platform.
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Thermal degradation of poly(Acryloyl Chloride) and copolymers of Acryloyl Chloride with methyl acrylate
Polymer Degradation and Stability, 1994Co-Authors: K.s. Khairou, M. A. DiabAbstract:Abstract The products of thermal degradation of poly(Acryloyl Chloride) (PAC) homopolymer and copolymers of Acryloyl Chloride with methyl acrylate (AC-MA), covering the entire composition range, have been analysed quantitatively using thermal analysis, IR spectroscopy and gas-liquid chromatography. The major products of degradation of PAC homopolymer are HCl, CO and chain fragments. Methyl Chloride, CO 2 , CO, methanol and chain fragments are the principal products of degradation of AC-MA copolymers. Possible mechanisms for the formation of these products are described and discussed.
