Encontrados 7 documentos, a visualizar página 1 de 1
Functionalization of dipyrromethanes via hetero-Diels–Alder reaction with azo- ...
Pereira, Nelson A. M.; Lemos, Américo; Serra, Arménio C.; Melo, Teresa M.V.D. Pinho e5,5′-Diethyl- and 5-phenyldipyrromethanes participate in cycloadditions with azo- and nitrosoalkenes giving dipyrromethanes with side chains containing open chain oximes and hydrazones. By controlling reaction stoichiometry it is possible to get mono or 1,9-disubstituted derivatives. The reported methodology gave access to a range of dipyrromethanes with good structural features for various applications. It was...
Silica grafted polyethylenimine as heterogeneous catalyst for condensation reac...
Ribeiro, Sonia M.; Serra, Arménio. C.; Gonsalves, A. M. d’A. RochaPrimary amine groups were attached to a silica surface by using α,ω-diamines derivatives and (3-glycidyloxypropyl)-trimethoxysilane activation. The same activation was used to graft polyethylenimine, which also contains secondary and tertiary amine groups. These silica aminated structures were tested as heterogeneous catalysts in nitroaldol condensation with nitromethane, the derivative with the polyethylenimin...
Immobilised porphyrins in monoterpene photooxidations
Ribeiro, Sónia M.; Serra, Arménio C.; Gonsalves, A. M. D'A. RochaPorphyrins were covalently linked to modified Merrifield polymers by chlorosulphonation activation of the porphyrin nucleus. These supported porphyrins were used as photosensitizers to promote singlet oxygen oxidation of monoterpenes with an efficiency that depends on porphyrin structure and the spacer used to link it to the polymer structure. The performance of these photosensitizers was studied. Citronellol a...
Covalently immobilized porphyrins as photooxidation catalysts
Ribeiro, Sónia M.; Serra, Arménio C.; Rocha Gonsalves, A. M. D'A.Porphyrins covalently linked to aminomethylated Merrifield polymers, by chlorosulfonation activation of the porphyrin nucleus, are able to generate singlet oxygen with an efficiency which is related to the spacer between porphyrin and the polymer backbone. Juglone and ascaridole are efficiently produced in the presence of these supported catalysts. ; http://www.sciencedirect.com/science/article/B6THR-4NTRT0M...
Heavy-atom effects on metalloporphyrins and polyhalogenated porphyrins
Azenha, Emília G.; Serra, Arménio C.; Pineiro, Marta; Pereira, Mariette M.; Seixas de Melo, J.; Arnaut, Luis G.; Formosinho, Sebastião J.http://www.sciencedirect.com/science/article/B6TFM-45PTWJX-J/1/69780b458d5289db997df5735c97350c
Oxidation of azo dyes in oil-in-water microemulsions catalyzed by metalloporphy...
Häger, Maria; Holmberg, Krister; Rocha Gonsalves, António M. d'A.; Serra, Arménio C.Hydrogen peroxide oxidation of two aqueous azo dyes, methyl orange and amaranth, catalyzed by manganese porphyrins, have been performed in an oil-in-water microemulsion based on a nonionic surfactant, C12E8. A lipophilic acid was used as cocatalyst in a variable amount. The oxidation was followed by UV spectroscopy. It was shown that the reactions performed in the microemulsion were rapid for both dyes and the ...
On the mechanism of carboxylic acid co-catalyst assisted metalloporphyrin oxida...
d'A. Rocha Gonsalves, António M.; Serra, Arménio C.The role of the carboxylic acid as co-catalyst in metalloporphyrin catalytic hydrogen peroxide oxidations is discussed, taking into account its dependence on the ratio relatively to the catalyst. The catalytic efficiency and stability of the catalyst in the presence of an excess of carboxylic acid suggests that a metallo-acylperoxo complex can be the effective oxidation intermediate. ; http://www.sciencedire...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||