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Description
| - Byla studována kinetika, mechanismus a produkty následných reakcí hydrolýzy substituovaných aryl-N-hydroxykarbamátů, jejich N-methyl a N-fenylanalog ve vodných roztocích pufrů a hydroxidu sodného při 20 a 60 °C. Hydrolýza substituovaných fenyl-N-hydroxykarbamátů probíhá mechanismem E1cB za vzniku fenolů resp. fenolátů a N-hydroxykarbamátu, který se dále v reakčním prostředí rozkládá na alkalický uhličitan, amoniak a dusík. Reakce N-methyl a N-fenylanalog ve stejném prostředí probíhá concerted mechanismem a konečnými produkty hydrolýzy těchto látek jsou fenoly resp. fenoláty, alkalický uhličitan, methylamin resp. anilin a azoxybenzen.. Pro posouzení mechanismů bylo užito Brønstedova kriteria. 4-Nitrophenyl-N-methylkarbamát podléhá za podmínek hydrolýzy v rozsahu při pH 7-14 převážně Smilesovu přesmyku na natrium-N-methyl-(4-nitrofenoxy)karbamát (cs)
- The kinetics and mechanism of the degradation reactions of substituted phenyl N-hydroxycarbamates and their N-methyl and N-phenyl analogues have been studied at pseudo-first-order reaction conditions in aqueous buffers and sodium hydroxide solutions at 20 XC and 60 XC and at I = 1 molPlV1. The dependence of log kobs on pH for phenyl N-hydroxycarbamates at pH < 9 and pH > 13 is linear with the unit slope; at pH 10-12 log kobs is pH independent. The Bronsted coefficient betalg is about ˇV1 (pH 7-13) and V1.53 (pH > 13) indicating that the degradation reaction of phenyl N-hydroxycarbamates follows an E1cB mechanism giving the corresponding phenol/phenolate and HOVN=C=O. The latter species undergoes further decomposition to give carbonate, nitrogen and ammonia as final products. In contrast to the phenyl N-hydroxycarbamates the N-methyl derivatives at pH 7-9 undergo degradation to the corresponding phenol/phenolate, carbonate and methylamine via a concerted mechanism (?Ňlg is about V0.75).
- The kinetics and mechanism of the degradation reactions of substituted phenyl N-hydroxycarbamates and their N-methyl and N-phenyl analogues have been studied at pseudo-first-order reaction conditions in aqueous buffers and sodium hydroxide solutions at 20 XC and 60 XC and at I = 1 molPlV1. The dependence of log kobs on pH for phenyl N-hydroxycarbamates at pH < 9 and pH > 13 is linear with the unit slope; at pH 10-12 log kobs is pH independent. The Bronsted coefficient betalg is about ˇV1 (pH 7-13) and V1.53 (pH > 13) indicating that the degradation reaction of phenyl N-hydroxycarbamates follows an E1cB mechanism giving the corresponding phenol/phenolate and HOVN=C=O. The latter species undergoes further decomposition to give carbonate, nitrogen and ammonia as final products. In contrast to the phenyl N-hydroxycarbamates the N-methyl derivatives at pH 7-9 undergo degradation to the corresponding phenol/phenolate, carbonate and methylamine via a concerted mechanism (?Ňlg is about V0.75). (en)
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Title
| - Kinetika a mechanismus bazicky katalyzované degradace substituovaných aryl-N-hydroxykarbamátů, jejich N-methyl a N-fenyl analog (cs)
- Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues
- Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues (en)
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skos:prefLabel
| - Kinetika a mechanismus bazicky katalyzované degradace substituovaných aryl-N-hydroxykarbamátů, jejich N-methyl a N-fenyl analog (cs)
- Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues
- Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues (en)
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skos:notation
| - RIV/00216275:25310/04:00001316!RIV08-MSM-25310___
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http://linked.open.../vavai/riv/strany
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http://linked.open...avai/riv/aktivita
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http://linked.open...avai/riv/aktivity
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http://linked.open...iv/cisloPeriodika
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http://linked.open...vai/riv/dodaniDat
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http://linked.open...aciTvurceVysledku
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http://linked.open.../riv/druhVysledku
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http://linked.open...iv/duvernostUdaju
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http://linked.open...titaPredkladatele
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http://linked.open...dnocenehoVysledku
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http://linked.open...ai/riv/idVysledku
| - RIV/00216275:25310/04:00001316
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http://linked.open...riv/jazykVysledku
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http://linked.open.../riv/klicovaSlova
| - Kinetics; mechanism; substituted aryl-N-hydroxycarbamates (en)
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http://linked.open.../riv/klicoveSlovo
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http://linked.open...odStatuVydavatele
| - GB - Spojené království Velké Británie a Severního Irska
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http://linked.open...ontrolniKodProRIV
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http://linked.open...i/riv/nazevZdroje
| - Organic&Biomolecular Chemistry
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http://linked.open...in/vavai/riv/obor
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http://linked.open...ichTvurcuVysledku
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http://linked.open...cetTvurcuVysledku
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http://linked.open...UplatneniVysledku
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http://linked.open...v/svazekPeriodika
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http://linked.open...iv/tvurceVysledku
| - Beier, Petr
- Hanusek, Jiří
- Mindl, Jaromír
- Štěrba, Vojeslav
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http://linked.open...n/vavai/riv/zamer
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http://localhost/t...ganizacniJednotka
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