Oxydehydrogenation of cyclohexanol over carbon catalysts

Silva, I.F.; Vital, J.; Ramos, A.M.; Valente, Humberto; Rego, A.M. Botelho do; Reis, Márcio José dos

doi:10.1016/s0008-6223(98)00093-1

Cited by 30 publications

(6 citation statements)

References 19 publications

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“…It is well known that nitric acid oxidation creates a large amount of carboxylic groups on AC surface. 10,11,34,38,48,66 Moreover, some studies report creation of phenol and carboxylic groups on the surface on AC in higher orders. 40,41,67,68 However, it should be noted that Oxygen Index is an index of total oxygen groups, not exactly acidic surface groups.…”

Section: Resultsmentioning

confidence: 99%

Tailoring the Surface Chemistry of Activated Carbon by Nitric Acid: Study Using Response Surface Method

Houshmand¹,

Daud

Shafeeyan³

2011

Bulletin of the Chemical Society of Japan

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Tailoring the surface chemistry of adsorbents, especially activated carbons, make them suitable to specific applications. Many times oxidation is the first step and greatly affects the next steps of tailoring. We modified the surface chemistry of a microporous activated carbon (AC) by nitric acid solutions at different conditions of acid concentration, time, and oxidation temperature. The oxidized AC samples were inspected with the aid of physical adsorptiondesorption of nitrogen at 77°C and temperature-programmed desorption (TPD). It was shown that oxidation by nitric acid lowers surface area of the studied AC even at mild severity. Moreover, different instrumental analysis pointed out creation of a considerable amount of oxygen-containing functional groups, especially acidic ones on the surface. Central composite design (CCD) was applied to evaluate the individual and interactive effects of oxidation parameters and to provide a compromise between the amount of oxygen groups and BET surface area as two of studied responses. The significant factors and interactions on each response were recognized by Analysis of Variance (ANOVA). A linear model and a two factor interaction (2FI) model were developed to correlate the oxidation conditions to BET surface area and the amount of oxygen surface groups. In addition, optimized oxidation conditions were established.

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Section: Resultsmentioning

confidence: 99%

Tailoring the Surface Chemistry of Activated Carbon by Nitric Acid: Study Using Response Surface Method

Houshmand¹,

Daud

Shafeeyan³

2011

Bulletin of the Chemical Society of Japan

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“…They investigated three types of CNFs, with varying orientations of the graphene sheets and found that fishbone fibers produced higher conversions of ethanol compared to platelet and ribbon fibers, which yielded similar results to one another. 15.12(b) represents a suggestion for the redox model of cyclohexanol ODH over quinone groups [74], similar to the C-H activation in hydrocarbons (Section 15.3.1). The mechanism depicted in Fig.…”

Section: Dehydrogenations Of Alcoholsmentioning

confidence: 79%

“…12: (a) Acid-base mechanism of alcohol dehydrogenation. Reprinted with permission from[74]. Copyright (1993) Pergamon (Elsevier).…”

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confidence: 99%

15. Nanocarbon materials for heterogeneous catalysis

Frank¹

2014

Nanocarbon-Inorganic Hybrids

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Heterogeneous catalysis is of paramount importance in many areas of the chemical and energy industries as more than 90 % [1] of the chemical manufacturing processes in use throughout the world utilize catalysis and primarily heterogeneous catalysis. Catalytically active metal (oxide) nanoparticles are often dispersed on a mechanically stable high surface area support to maximize and stabilize their specific surface area as well as to fine-tune their properties and minimize the materials usage, e.g., of expensive noble metals. Among the different types of supports used in heterogeneous catalysis the carbon materials attract a permanent interest due to their specific characteristics, which are mainly: (i) resistance to acidic/basic media and thermal sintering, (ii) control over macroscopic shape, porosity, and surface chemistry, and (iii) disposal or recovery of precious metals by support burning, which results in a low environmental impact. The use of, e.g., graphite, carbon black, activated carbon, activated carbon fibers, glassy carbon, pyrolytic carbon, or polymer-derived carbon has a long history in this field of research [2][3][4]. Carbon materials providing a distinct structure on the nanometer scale, hereinafter referred to as nanocarbons, are equipped with further exceptional physical and chemical properties. Thus, the discovery of lowdimensional nanostructured carbon allotropes, such as carbon nanotubes (CNTs), nanofibers (CNFs), graphene, or fullerenes, ushered in a new era of cutting-edge applications for elemental carbon with a wide-ranging impact also on heterogeneous catalysis. The development of large-scale synthesis processes for multi-walled CNTs [5, 6] stimulated a vital research activity in academia and industry. It is recognized that carbon as a catalyst support as well as a catalyst on its own offers unparalleled flexibility in tailoring catalyst properties to specific needs. Carbon-supported noble metals for fine chemicals production are well established, but only a few large-volume processes currently use these systems.Besides the practical application, the diversity of nanostructured carbon allotropes makes nanocarbon also an ideal model system for the investigation of structure-function correlations in heterogeneous catalysis. Nanocarbons can be tailored in terms of their hybridization state, curvature, and aspect ratio, i.e., dimensions of stacks of basic structural units (BSU), Chapters 1 and 2. The preferred exposition of two types of surfaces, which strongly differ in their physico-chemical behavior, i.e., the basal plane and prismatic edges, can be controlled. Such controlled diversity is seldom found for other materials giving carbon a unique role in this field of basic research. The focus of this chapter is set on the most prominent representatives of the

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“…Besides, these materials could also be directly used as catalysts for some acidbase and oxidation reactions [5][6][7][8][9][10][11][12]. Particularly, it was reported that a few kinds of carbon materials could be active catalysts in some selective oxidation reactions involving molecular oxygen as oxidant, for instance, the dehydrogenation of ethylbenzene or butane, wet oxidation of phenol, and liquid-phase oxidation of cylohexanone under pressure [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%