Реакции фталимид-N-оксильного радикала с производными фурана
Електронний архів E-archive DonNTU – (Electronic archive Donetsk National Technical University)
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| Title |
Реакции фталимид-N-оксильного радикала с производными фурана
PHTHALIMIDE-N-OXYL RADICAL REACTION WITH FURAN DERIVATIVES |
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| Creator |
Литвинов, Ю.Е.
Кущ, О.В. Компанец, М.А. Новохатько, А.A. |
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| Subject |
окисление
N-гидроксифталимид фталимид-N-оксильный радикал фурановые производные oxidation N-hydroxyphthalimide phthalimide-N-oxyl radical uran derivatives |
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| Description |
Recently furan compounds derived from renewable raw materials are of considerable interest as platform chemicals of bulk organic synthesis. Among them is 5-hydroxymethylfurfural (HMF) which is an organic compound derived from dehydration of hexoses. Oxidation of HMF gives 2,5-furandicarboxylic acid, which has been proposed as a replacement for terephthalic acid in the production of polyesters, and 2,5-diformylfuran - starting material for the synthesis of pharmaceuticals and luminescent polymers. Oxidation of HMF usually proceeds with the addition of stoichiometric amounts of inorganic oxidants such as Pb(OAc)4, CrO3, HNO3, N2O4, BaMnO4. These oxidation processes are expensive, produce large amount of hazardous waste, and proceed in harsh conditions.Another approach to the different furanics production is to use molecular oxygen as oxidant under catalysis of N-hydroxyphthalimide (NHPI). In oxidation processes, NHPI acts as a precursor of the phthalimide-N-oxyl (PINO) radical, the effective species in the reaction of H-atom abstraction from the molecule of substrate. Key reaction in furanics oxidation is H-abstraction from the molecules of HMF, 2,5-difurfuryl alcohol (DHF) and DFF. PINO radical has been generated in situ from parent hydroxyimide, NHPI, by oxidation with iodobenzenediacetate. The rate constant of H-abstraction (kH) from disubstituted furans by PINO has been determined spectroscopically in acetonitrile. Obtained data shows that the bimolecular rate constant of hydrogen abstraction from the aldehyde group of DFF is lower than the rate constant for hydroxymethyl group of 2,5-difurfurylalcohol. It means that in the oxidation process hydroxymethyl group oxidized primarely in the presence of a PINO. A feature of oxidative transformations HMF is that the direction of the reaction and oxidation products, respectively, depend on the reaction conditions. The process can proceed by simultaneous or sequential oxidation of the hydroxymethyl group and aldehyde groups, but it is also possible the selective oxidation of one functional group. Wherein the hydroxymethyl group can be oxidized to an aldehyde group as well as to a carboxyl group without affecting the second functional group and the furan ring. Using a mild oxidant such as molecular oxygen and catalysts based on NHPI allows directionally oxidizing alcohol groups, including 2-hydroxymethyl group to a formyl group, and the highly reactive aldehyde group is not oxidized. Измерены константы скорости реакций отрыва атома водорода фталимид-N-оксильным радикалом от С-Н связей гидроксиметильной и альдегидной групп фурановых соединений – 2,5-дифурфурилового спирта, 5-гидроксиметилфурфурола и 2,5-диформилфурана. Показано, что в условиях каталитического радикального окисления гидроксиметильная группа в фурановом кольце является значительно более реакционноспособной по сравнению с альдегидной. |
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| Date |
2014-04-15T14:32:20Z
2014-04-15T14:32:20Z 2014 |
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| Type |
Article
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| Identifier |
УДК 542.9437+544.431.15
http://ea.donntu.edu.ua/handle/123456789/25978 |
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| Language |
other
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| Publisher |
Наукові праці ДонНТУ. Серія: Хімія і хімічна технологія. - 2014. - Вип. 1(22). - С. 112-119
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