Heteropoly Tungstate Supported on Metal Oxide Catalysts for Liquid Phase Oxidation of Benzyl Alcohol with Hydrogen Peroxide

Han, Xiaoxiang; Kuang, Yingying; Chunhua, Xiong; Tang, Xiujuan; Chen, Qing; Wang, Kuiwu; Chin-Te, Hung; Liu, Lili; Liu, Shang-Bin

doi:10.21577/0103-5053.20170117

Cited by 3 publications

(4 citation statements)

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“…[54][55][56] A autorização para uso destes dados foi gentilmente cedida pela PubliSBQ. A particularidade dos artigos escolhidos está relacionada com a possibilidade de exemplificar 4 estratégias de utilização de planejamento fatorial na análise de experimentos: (1) planejamento fatorial completo, (2) fracionário e planejamentos para geração de modelos de regressão constituídos por matrizes do tipo (3) Doehlert 42 e (4) Box-Behnken.…”

Section: Descrição Dos Conjuntos De Dadosunclassified

“…56 Esse quarto exemplo contou com 4 variáveis e a melhor condição de trabalho proposta pelo modelo de regressão foi identificada com a ferramenta Solver disponível no Microsoft Excel e com a realização de derivadas parciais no Octave ou no Excel.…”

Section: Descrição Dos Conjuntos De Dadosunclassified

“…O exemplo 4 56 O primeiro modelo estabelecido mostra que dois coeficientes não são significativos ao nível de confiança de 95%: b14 (0,19 ± 1,27, décimo segundo coeficiente) e b34 (0,22 ± 1,27, décimo quinto coeficiente). A retirada desses dois coeficientes não permitiu a formação de novas réplicas.…”

Section: Exemplounclassified

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Aplicação De Programa Computacional Livre Em Planejamento De Experimentos: Um Tutorial

Pereira¹,

Pereira-Filho²

2018

Quim. Nova

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publicado na web em 28/06/2018 APPLICATION OF FREE COMPUTATIONAL PROGRAM IN EXPERIMENTAL DESIGN: A TUTORIAL. This tutorial intends to show to the readers a step-by-step guide to perform a factorial design in their experiments. The examples used here cover most of doubts and questions related to teaching classes at graduation course. Free computational software was applied, as well as, codes were designed by the authors for the calculations. The complexity of each example is attached to the challenges and decisions that the experimentalist faces in its research. In addition, 24 videos were prepared to help the readers. The authors hope to foster the factorial design as an easy and helpful tool for chemists and general researchers in academia and industry.Keywords: Octave; factorial design; analysis of variance; regression model; template surface. INTRODUÇÃOA aplicação de ferramentas quimiométricas relacionadas ao planejamento fatorial de experimentos é uma realidade em diversos laboratórios de pesquisa e também no setor industrial.1,2 Tais ferramentas têm contribuído para aprimorar processos de fabricação e de síntese, bem como na proposição rápida de métodos analíticos mais sensíveis e com alta frequência de amostragem. [3][4][5][6][7][8][9] As vantagens da aplicação do planejamento fatorial são inquestionáveis e amplas, podendo ser resumidas em: (1) execução de um número reduzido de experimentos quando comparado com o procedimento univariado convencional; (2) economia de recursos financeiros; (3) obtenção de resultados com maiores confiabilidades química e estatística; (4) possibilidade de obter um modelo matemático que permitirá a realização de previsões em condições que não foram testadas. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Na literatura científica nacional e internacional é frequente encontrar relatos de inúmeras aplicações, além de quase uma dezena de revisões, livros e tutoriais sobre o assunto. Adicionalmente, desde 2015 vários livros em língua portuguesa 25,45 têm sido publicados sobre o tema, agregando mais conhecimento à produção pioneira publicada por Barros Neto et al. 48 Estes aspectos mostram a popularidade, a importância e a consolidação do tema. Entretanto, apesar de todos os esforços oriundos de diferentes autores brasileiros na proposição de experimentos didáticos para o ensino de planejamento fatorial, um tópico ainda precisa ser complementado: a utilização de programas livres e de fácil acesso, além da viabilização e da popularização do emprego de tais ferramentas pelos usuários. [49][50][51] Novaes et al. 52publicaram em 2017 uma revisão abordando a utilização de planejamento fatorial na otimização de variáveis de processo. Os autores efetuaram uma excelente compilação dos principais programas comerciais disponíveis e apontaram também a faixa de preços dos mesmos. Entretanto, exemplos que utilizam planejamento fatorial e programas livres são inexistentes na literatura científica nacional e também internacional. Assim, a principal proposta deste tutorial é apres...

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Section: Descrição Dos Conjuntos De Dadosunclassified

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Aplicação De Programa Computacional Livre Em Planejamento De Experimentos: Um Tutorial

Pereira¹,

Pereira-Filho²

2018

Quim. Nova

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“…Keggin heteropolyanions (HPAs) of general formula [XM 12 O 40 ] n − (mainly M = Mo or W and X = P, Si, or Ge) are one of the most explored subsets of POMs in catalytic applications, particularly in the oxidation of organic substrates. − Much of the interest in these anions has emerged from their catalytic efficiency in oxidation reactions when combined with H 2 O 2 as an oxidant. Relevant examples involve homogeneous ,,− ,− and heterogeneous oxidations − catalyzed by Keggin HPAs. One of the most successful routes to prepare active Keggin-based oxidation catalysts lies in the preparation of organic–inorganic hybrid materials.…”

Section: Introductionmentioning

confidence: 99%

Formation, Reactivity, and Catalytic Behavior of a Keggin Polyoxometalate/Bipyridine Hybrid in the Epoxidation of Cyclooctene with H₂O₂

et al. 2023

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The present study further explores the behavior of polyoxometalate-based hybrid compounds as catalysts for liquidphase cyclooctene epoxidation with H 2 O 2 . Precisely, it unveils the nature of the relevant active species derived from the hybrid based on Keggin polyoxometalate (POM) and bipyridines (bpy) of formula (2,2′-Hbpy) 3 [PW 12 O 40 ] (1). Whereas (i) it is generally accepted that the catalytic oxidation of organic substrates by H 2 O 2 involving Keggin HPAs proceeds via an oxygen transfer route from a peroxo intermediate and (ii) the catalytically active peroxo species is commonly postulated to be the polyperoxotungstate {PO 4 [W(O)(O 2 ) 2 ] 4 } 3− complex (PW 4 ), we show that the studied epoxidation reaction seems to be more sophisticated than commonly reported. During the catalytic epoxidation, 1 underwent a partial transformation into two oxidized species, 2 and 3. Compound 3 corresponding to 2,2′-bipyridinium oxodiperoxotungstate of formula [WO(O 2 ) 2 (2,2′-bpy)] was shown to be the main species responsible for the selective epoxidation of cyclooctene since 2 (in which the POM is associated with a protonated mono-Noxide derivative of 2,2′-bpy of formula (2,2′-HbpyO) 3 [PW 12 O 40 ]) exhibited no activity. The structures of 1, 2, and 3 were solved by single-crystal X-ray diffraction and were independently synthesized. The speciation of 1 was monitored under catalytic conditions by 1 H and 1 H DOSY NMR spectroscopies, where the formation in situ of 2 and 3 was revealed. A reaction mechanism is proposed that highlights the pivotal, yet often underestimated, role of H 2 O 2 in the reached catalytic performances. The active species responsible for the oxygen transfer to cyclooctene is a hydroperoxide intermediate species that is formed by the interaction between the anionic structure of the catalyst and H 2 O 2 . The latter operates as a "conservative agent" whose presence in the catalytic system is required to prevent the catalysts from deactivating irreversibly.

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Hydrogen Peroxide as a Green Oxidant for the Selective Catalytic Oxidation of Benzylic and Heterocyclic Alcohols in Different Media: An Overview

2020

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Among a plethora of known and established oxidant in organic chemistry, hydrogen peroxide stands in a special position. It is commercially and inexpensively available, highly effective, selective, and more importantly it is compatible with current environmental concerns, dictated by principles of green chemistry. Several chemicals or their intermediates that are important in our daily life such as pharmaceuticals, flavors, fragrances, etc. are products of oxidation of alcohols. In this review, we introduce hydrogen peroxide as an effective, selective, green and privileged oxidant for the catalyzed oxidation of primary and secondary benzylic and heterocyclic alcohols to corresponding carbonyl compounds in different media such as aqueous media, under solvent-free conditions, various organic solvent, and dual-phase system.

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Heteropoly Tungstate Supported on Metal Oxide Catalysts for Liquid Phase Oxidation of Benzyl Alcohol with Hydrogen Peroxide

Cited by 3 publications

References 26 publications

Aplicação De Programa Computacional Livre Em Planejamento De Experimentos: Um Tutorial

Aplicação De Programa Computacional Livre Em Planejamento De Experimentos: Um Tutorial

Formation, Reactivity, and Catalytic Behavior of a Keggin Polyoxometalate/Bipyridine Hybrid in the Epoxidation of Cyclooctene with H₂O₂

Hydrogen Peroxide as a Green Oxidant for the Selective Catalytic Oxidation of Benzylic and Heterocyclic Alcohols in Different Media: An Overview

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Heteropoly Tungstate Supported on Metal Oxide Catalysts for Liquid Phase Oxidation of Benzyl Alcohol with Hydrogen Peroxide

Cited by 3 publications

References 26 publications

Aplicação De Programa Computacional Livre Em Planejamento De Experimentos: Um Tutorial

Aplicação De Programa Computacional Livre Em Planejamento De Experimentos: Um Tutorial

Formation, Reactivity, and Catalytic Behavior of a Keggin Polyoxometalate/Bipyridine Hybrid in the Epoxidation of Cyclooctene with H2O2

Hydrogen Peroxide as a Green Oxidant for the Selective Catalytic Oxidation of Benzylic and Heterocyclic Alcohols in Different Media: An Overview

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Formation, Reactivity, and Catalytic Behavior of a Keggin Polyoxometalate/Bipyridine Hybrid in the Epoxidation of Cyclooctene with H₂O₂