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Göteborgs universitets publikationer

Quantum Chemical Modeling of Propene and Butene Epoxidation with Hydrogen Peroxide

Författare och institution:
Angelica Lundin (Institutionen för kemi); Itai Panas (Institutionen för kemi- och bioteknik, Oorganisk miljökemi, Chalmers); Elisabet Ahlberg (Institutionen för kemi)
Publicerad i:
Journal of Physical Chemistry A, 113 ( 1 ) s. 282-290
Artikel, refereegranskad vetenskaplig
Sammanfattning (abstract):
The mechanism of hydrogen peroxide assisted epoxidation of propene, 1-butene, trans-2-butene, cis-2-butene, and isobutene was studied using density functional theory calculations. The results are rationalized in the context of the previously proposed direct pathway for epoxidation of ethene with hydrogen peroxide and compared to the indirect pathway involving Ti(IV) peroxide groups. The indirect Ti(IV) peroxide pathway displays a 57.8 kJ mol-1 activation enthalpy for the rate limiting step [Phys. Chem. Chem. Phys. 2007, 9, 5997]. In contrast, a lowering of the activation enthalpy is observed for the direct mechanism according to 72.3 (ethene), 53.9 (1-butene), 53.5 (propene), 46.9 (trans-2-butene), 46.6 (isobutene), and 42.6 (cis-2-butene) kJ mol-1 when the reaction takes place on a binuclear Ti(IV) dihydroxide site. These values clearly show that the direct pathway becomes the most favorable. The stability of the epoxides toward hydrolysis to the corresponding diols are also addressed. The present work clearly demonstrates the generality and efficiency of a binuclear dihydroxide site in catalyzing the epoxidation of olefins with hydrogen peroxide, thus avoiding the formation of a surface peroxide group.
Länk till sammanfattning (abstract):
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Kemi ->
Teoretisk kemi
Kemi ->
Teoretisk kemi ->
Postens nummer:
Posten skapad:
2008-12-11 20:34
Posten ändrad:
2010-03-01 15:21

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