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George Marston - One of the best experts on this subject based on the ideXlab platform.
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the effect of criegee intermediate scavengers on the oh yield from the reaction of ozone with 2 methylbut 2 ene
Journal of Physical Chemistry A, 2001Co-Authors: David Johnson, And Alison G Lewin, George MarstonAbstract:The yield of OH from the gas-phase reaction of ozone with 2-Methylbut-2-Ene has been measured in the presence of various molecules (H2O, SO2, butanone, and acetic acid) that can act as scavengers for the Criegee intermediates (CIs) formed in the reaction. No discernible difference is observed between experiments carried out in the presence and absence of these scavengers. The results indicate that the thermal decomposition of CIs that give OH radicals is fast compared with their bimolecular reaction with the scavengers under the conditions of the experiments. Combined with the results of a recent time-resolved study, upper limits (in units of cm3 molecule-1 s-1) were determined for the bimolecular reactions of the CI with H2O (1 × 10-16), SO2 (4 × 10-15), butanone (2 × 10-14), and acetic acid (1 × 10-14). The results imply that these reactions are too slow to inhibit OH formation in the ozonolysis of alkenes and that the currently recommended OH yields can be used in models of atmospheric chemistry.
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Product yields in the reactions of ozone with Z-but-2-ene, E-but-2-ene and 2-Methylbut-2-Ene
Chemosphere, 1999Co-Authors: C.d. Mcgill, Andrew R. Rickard, David Johnson, George MarstonAbstract:Abstract Preliminary results on some aspects of the mechanisms of the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene are presented. Primary carbonyl product yields were measured under ‘OH-free’ conditions and OH yields were determined by monitoring the disappearance of 1,3,5-trimethylbenzene. Ethanal yields relative to alkene consumed were measured as 0.86±0.03, 0.85±0.07 and 0.66±0.02 for the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene, respectively. For 2-Methylbut-2-Ene, the propanone yield was 0.35±0.03. Hydroxyl radical yields relative to alkene consumed were measured as 0.33±0.07, 0.54±0.11 and 0.81±0.16 for the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene, respectively.
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Hydroxyl‐radical formation in the gas‐phase ozonolysis of 2‐methylbut‐2‐ene
Geophysical Research Letters, 1998Co-Authors: George Marston, C.d. Mcgill, Andrew R. RickardAbstract:Relative rate constants have been measured for the reactions of eight pairs of organic compounds with the reactive species formed in the reaction of ozone with 2-Methylbut-2-Ene. A total of eight compounds were studied, including three alkanes, two alkenes, two conjugated alkenes and one aromatic hydrocarbon. With the exception of one pair of compounds (cyclohexane/2-methylpropane), the relative rate constants obtained are consistent with the assumption that the reactive intermediate is the hydroxyl radical, OH. The origin of the anomalous result for the cyclohexane/2-methylpropane pair is not clear.
C.d. Mcgill - One of the best experts on this subject based on the ideXlab platform.
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Product yields in the reactions of ozone with Z-but-2-ene, E-but-2-ene and 2-Methylbut-2-Ene
Chemosphere, 1999Co-Authors: C.d. Mcgill, Andrew R. Rickard, David Johnson, George MarstonAbstract:Abstract Preliminary results on some aspects of the mechanisms of the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene are presented. Primary carbonyl product yields were measured under ‘OH-free’ conditions and OH yields were determined by monitoring the disappearance of 1,3,5-trimethylbenzene. Ethanal yields relative to alkene consumed were measured as 0.86±0.03, 0.85±0.07 and 0.66±0.02 for the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene, respectively. For 2-Methylbut-2-Ene, the propanone yield was 0.35±0.03. Hydroxyl radical yields relative to alkene consumed were measured as 0.33±0.07, 0.54±0.11 and 0.81±0.16 for the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene, respectively.
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Hydroxyl‐radical formation in the gas‐phase ozonolysis of 2‐methylbut‐2‐ene
Geophysical Research Letters, 1998Co-Authors: George Marston, C.d. Mcgill, Andrew R. RickardAbstract:Relative rate constants have been measured for the reactions of eight pairs of organic compounds with the reactive species formed in the reaction of ozone with 2-Methylbut-2-Ene. A total of eight compounds were studied, including three alkanes, two alkenes, two conjugated alkenes and one aromatic hydrocarbon. With the exception of one pair of compounds (cyclohexane/2-methylpropane), the relative rate constants obtained are consistent with the assumption that the reactive intermediate is the hydroxyl radical, OH. The origin of the anomalous result for the cyclohexane/2-methylpropane pair is not clear.
José-luis Giner - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and immunological evaluation of the 4-β-glucoside of HMBPP
Bioorganic & medicinal chemistry letters, 2011Co-Authors: José-luis Giner, Hong Wang, Craig T. MoritaAbstract:HMBPP ((E)-4-hydroxy-3-methyl-2-butenyl pyrophosphate) is a highly potent innate immunogen that stimulates human γδ T cells expressing the Vγ2Vδ2 T cell antigen receptor. To determine if glycoside conjugates of HMBPP retain activity, the 4-β-glucoside and its acetylated homolog were synthesized and tested for their ability to stimulate γδ T cells. The glycoside HMBPP conjugate stimulated human γδ T cells with an EC50 of 78 nM. The tetraacetyl glycoside HMBPP conjugate was also active (EC50 = 360 nM). The two isomeric mono-β-glucosides of the parent (E)-2-Methylbut-2-Ene-1,4-diol, however, were not active. Thus, HMBPP glycosylated at the 4-OH position stimulates γδ T cells as long as the pyrophosphate moiety is present.
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Enantiomerically enriched [2-2H]-isopentenyl alcohol from (E)-2-Methylbut-2-Ene-1,4-diol by an asymmetric retro-ene reaction
Chemical Communications, 2002Co-Authors: José-luis Giner, Duilio ArigoniAbstract:A sample of [2-2H]-isopentenyl alcohol containing 72% of the (S)-enantiomer has been prepared via pyrolysis of a C-1′ deuterated form of the 1-tetra-O-acetyl-β-D-glucoside of (E)-2-Methylbut-2-Ene-1,4-diol.
Andrew R. Rickard - One of the best experts on this subject based on the ideXlab platform.
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Product yields in the reactions of ozone with Z-but-2-ene, E-but-2-ene and 2-Methylbut-2-Ene
Chemosphere, 1999Co-Authors: C.d. Mcgill, Andrew R. Rickard, David Johnson, George MarstonAbstract:Abstract Preliminary results on some aspects of the mechanisms of the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene are presented. Primary carbonyl product yields were measured under ‘OH-free’ conditions and OH yields were determined by monitoring the disappearance of 1,3,5-trimethylbenzene. Ethanal yields relative to alkene consumed were measured as 0.86±0.03, 0.85±0.07 and 0.66±0.02 for the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene, respectively. For 2-Methylbut-2-Ene, the propanone yield was 0.35±0.03. Hydroxyl radical yields relative to alkene consumed were measured as 0.33±0.07, 0.54±0.11 and 0.81±0.16 for the reactions of ozone with Z -but-2-ene, E -but-2-ene and 2-Methylbut-2-Ene, respectively.
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Hydroxyl‐radical formation in the gas‐phase ozonolysis of 2‐methylbut‐2‐ene
Geophysical Research Letters, 1998Co-Authors: George Marston, C.d. Mcgill, Andrew R. RickardAbstract:Relative rate constants have been measured for the reactions of eight pairs of organic compounds with the reactive species formed in the reaction of ozone with 2-Methylbut-2-Ene. A total of eight compounds were studied, including three alkanes, two alkenes, two conjugated alkenes and one aromatic hydrocarbon. With the exception of one pair of compounds (cyclohexane/2-methylpropane), the relative rate constants obtained are consistent with the assumption that the reactive intermediate is the hydroxyl radical, OH. The origin of the anomalous result for the cyclohexane/2-methylpropane pair is not clear.
Duilio Arigoni - One of the best experts on this subject based on the ideXlab platform.
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Enantiomerically enriched [2-2H]-isopentenyl alcohol from (E)-2-Methylbut-2-Ene-1,4-diol by an asymmetric retro-ene reaction
Chemical Communications, 2002Co-Authors: José-luis Giner, Duilio ArigoniAbstract:A sample of [2-2H]-isopentenyl alcohol containing 72% of the (S)-enantiomer has been prepared via pyrolysis of a C-1′ deuterated form of the 1-tetra-O-acetyl-β-D-glucoside of (E)-2-Methylbut-2-Ene-1,4-diol.