Anchored ironporphyrins?the role of talc-aminofunctionalyzed phyllosilicates in the catalysis of oxidation of alkanes and alkenes

Faria, André Luiz de; Airoldi, Cláudio; Doro, Fábio Gorzoni; Fonseca, Maria G. da; Assis, Marilda das Dores

doi:10.1016/j.apcata.2004.03.035

Cited by 26 publications

(6 citation statements)

References 37 publications

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“…In the reaction with m-CPBA, benzaldehyde production is also achieved, but phenylacetaldehyde is formed as minor product. The fact that benzaldehyde levels are relatively high in our case suggests greater contribution from the radicalar route [23]. As for styrene oxidation, styrene epoxide is the major product (epoxide yield = 26%), but benzaldehyde formation (yield = 2%) also occurs when H 2 O 2 is used as the oxygen transfer agent.…”

Section: Discussionmentioning

confidence: 95%

Synthesis, characterization, and catalytic properties of a mesostructured lamellar xerogel tungsten oxide phase

Bolsoni

Santos

Assis

et al. 2011

Journal of Non-Crystalline Solids

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a b s t r a c tCetyltrimethylammonium bromide (CTAB) and n-hexadecylamine (HDA) have been used as template in the synthesis of a mesolamellar xerogel tungsten oxide phase (WO 3 /CTAB/HDA). The catalytic properties of the resulting material were investigated in the oxidation of cis-cyclooctene, styrene, and cyclohexane, using hydrogen peroxide (H 2 O 2 ), terc-butyl hydroperoxide (t-BOOH), or m-chlorperbenzoic acid (m-CPBA) as oxygen transfer agent. In general, the catalytic results were comparable to those obtained with related systems, thus suggesting the potential application of this material as catalyst for epoxidation reactions.

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Section: Discussionmentioning

confidence: 95%

Synthesis, characterization, and catalytic properties of a mesostructured lamellar xerogel tungsten oxide phase

Bolsoni

Santos

Assis

et al. 2011

Journal of Non-Crystalline Solids

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“…Furthermore, the analysis of the DRS-UV/ vis spectrum of the Sil-Cl@MnP (Figure 4) revealed that there were no significant changes in the porphyrin macrocycle or the metal center ion, as it was possible to observe the charge transfer bands around 380 nm, the Soret band (∼478 nm) and the two Q bands (between 500 and 650 nm), denoting the presence of MnP with the metal ion with oxidation state 3+ on the silica surface. 38 Immobilization by covalent bonding via the periphery of the porphyrin macrocycle keeps the Mn-porphyrin away from the support due to the organic spacer chain, therefore minimizing the steric and polarizing effects of the surface, 39 differently from what would occur if the immobilization was via the porphyrin metal center.…”

Section: Catalyst Preparationmentioning

confidence: 99%

Degradation of Dyes Catalyzed by Aminophenyl-Substituted Mn-Porphyrin Immobilized on Chloropropyl Silica Gel and Evaluation of Phytotoxicity

de Oliveira,

Docílio Pereira,

da Silva Pereira

et al. 2024

ACS Omega

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A heterogenized Mn(III) porphyrin-based catalyst was prepared for dye degradation. The new Mn(III) complex of 5,15-bis(4-aminophenyl)-10,20-diphenylporphyrin was immobilized, via covalent bond, in chloropropyl silica gel, generating the material (Sil-Cl@MnP) with a loading of 23 μmol manganese porphyrin (MnP) per gram of Sil-Cl. This material was used as a catalyst in degradation reactions of model dyes, a cationic dye [methylene blue (MB)] and an anionic dye (reactive red 120, RR120), using PhI(OAc) 2 and H 2 O 2 as oxidants. The oxidation reactions were carried out after the dye reached adsorption/ desorption equilibrium with the catalytic material, with a much higher percentage of adsorption being observed for the cationic MB dye (20%) than for the anionic RR120 dye (3%), which may be associated with electrostatic attraction or repulsion effects, respectively, with the negatively charged surface of the silica (zeta potential measurement for Sil-Cl@MnP, ζ = −19.2 mV). In general, there was a higher degradation percentage for MB than for RR120, probably because the size and charge of RR120 would hinder its approach to the MnP active species on the silica surface. With respect to the oxidant, the PhI(OAc) 2 -based systems showed a higher degradation percentage than those of H 2 O 2 . It was observed that the increase in the oxidant concentration promoted a significant increase in the degradation of MB, with a degradation of approximately 65%. The efficiency of the catalyst was also evaluated after successive additions of the oxidant every 2 h, and it can be seen that the catalyst had no loss of efficiency, with a degradation percentage greater than 80% being observed after 8 h of reaction. The phytotoxicity of the products formed in the system was evaluated in a 1:23.5:188 molar ratio Sil-Cl@MnP: MB:PhI(OAc) 2 was used. In these studies, phytotoxicity was found for the germination of lettuce seeds when the original solution was used without dilution; however, when diluted (10% V/V), the results were close to the positive and negative controls. Thus, the material obtained proved to be a potential candidate for application in the degradation reactions of environmental pollutants.

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“…Como é de se esperar, a formação de complexos dentro da cavidade lamelar causa um aumento da distância interlamelar e em alguns casos, um tratamento com ácido após a formação do composto de coordenação facilita a recuperação do material de partida, sem quaisquer danos às propriedades de adsorção 77 e, dessa maneira, essa classe de compostos cristalinos, de fácil obtenção em condições amenas, desponta como uma promissora fonte no emprego em extração de metais do meio ambiente. Uma outra aplicação dessa classe de filossilicato está associada à catálise de oxidação de alcanos e alquenos, quando um derivado da porfirina é adicionado covalentemente ao suporte inorgânico previamente imobilizado com o grupo amino 83 .…”

Section: Compostos Lamelaresunclassified

A relevante potencialidade dos centros básicos nitrogenados disponíveis em polímeros inorgânicos e biopolímeros na remoção catiônica

Airoldi¹

2008

Quím. Nova

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cation removal by using nitrogenated basic centers. The data demonstrate the importance of the desired groups when free or immobilized on natural or synthesized inorganic polymers through silanol groups. Thus, the most studied silica gel is followed by natural crysotile and talc polymers, and the synthesized mesopore silicas, talc-like, silicic acids, phosphates and phyllosilicates. The organic natural biopolymeric chitin and cellulose were chemically modified to improve the availability of the amine groups or the reactivity with desirable molecules to enlarge the content of basic centers. The cation removal takes place at the solid/liquid interface and some interactive effects have their thermodynamic data determined.Keywords: inorganic polymer; biopolymer; cation removal. INTRODUÇÃONos dias de hoje, quando se veicula assuntos relacionados com superfícies, principalmente na área de Química Inorgânica, os interessados se voltam mais diretamente à rotulação dos profissionais atuantes como químicos de materiais. Porém, muitas vezes são esquecidos os aspectos envolvendo as ligações efetuadas entre os átomos, que estão em quantidade maiores ou menores na formação do esqueleto polimérico. Mesmo sem o conhecimento de tais detalhes e ainda sobre a estrutura é possível empregar o material em atividades tanto acadêmicas como tecnológicas, sendo comumente destacada a propriedade da adsorção. Curiosamente, o material derivado da queima ou extraído de minas naturais, após tratamento, deriva o chamado carvão ativado, o qual foi o primeiro material usado para a remoção de metais pesados contidos em efluentes industriais. No entanto, em qualquer processo operacional, o custo envolvido precisa ser examinado para que seja viável o uso, pois o preço cresce em função das especificidades requeridas e, de fato, a purificação é bastante relevante, o que chega a inviabilizá-lo na adsorção, mas que possibilita o emprego mais amplo somente em pequenas escalas laboratoriais 1 . Diante dos aspectos econômicos limitantes na obtenção do carvão de alta pureza, as pesquisas foram paulatinamente direcionadas para outras fontes alternativas. Um ponto marcante neste estudo foi buscar materiais naturais de baixo custo, que pudessem ter alta capacidade de adsorção, o que implicava na existência de centros quimicamente ativos na superfície, para que pudessem atuar com alta eficiência na retenção de cátions indesejáveis existentes em um leito aquoso contaminado. Nesta direção, o progresso do campo passou a ser mais eficaz após o conhecimento das funções quí-micas disponíveis nas superfícies dos materiais e possíveis tipos de ligações que poderiam formar frente a um determinado soluto, no decorrer do processo de adsorção na interface sólido/líquido 2 . Uma maneira de se obter o material com baixo custo é explorar fontes amplamente encontradas na natureza, que exijam operações simples para chegar a um composto final de composição definida e de alta pureza, fato que nem sempre é alcançado. Dentre uma série de materiais, os zeólitos se ajustam com essas...

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Anchored ironporphyrins?the role of talc-aminofunctionalyzed phyllosilicates in the catalysis of oxidation of alkanes and alkenes

Cited by 26 publications

References 37 publications

Synthesis, characterization, and catalytic properties of a mesostructured lamellar xerogel tungsten oxide phase

Synthesis, characterization, and catalytic properties of a mesostructured lamellar xerogel tungsten oxide phase

Degradation of Dyes Catalyzed by Aminophenyl-Substituted Mn-Porphyrin Immobilized on Chloropropyl Silica Gel and Evaluation of Phytotoxicity

A relevante potencialidade dos centros básicos nitrogenados disponíveis em polímeros inorgânicos e biopolímeros na remoção catiônica

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