Organic Polymers. Correlation between Their Structure and Catalytic Activity in Heterogeneous Systems. I. Pyrolyzed Polyacrylonitrile and Polycyanoacetylene

Manassen, J.; Wallach, Joshua A.

doi:10.1021/ja01090a026

Cited by 67 publications

(8 citation statements)

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“…In this manner, k AA directly predetermines the aging rate and indirectly (via the ratio k 0 AA /k age AA ) confines the scale of the effect. Thus, the coagulation efficiency during aging can be traced with the help of physical properties of the material, such as viscosity and surface tension, the higher surface tension the lower the coagulation efficiency (Manassen and Wallach 1965).…”

Section: Aging Kineticsmentioning

confidence: 99%

Aging of Titan's Aerosols

Dimitrov

Bar‐Nun

2002

Icarus

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Section: Aging Kineticsmentioning

confidence: 99%

Aging of Titan's Aerosols

Dimitrov

Bar‐Nun

2002

Icarus

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“…Acetylene has been observed to decompose at 500°C to give compounds such as vinylacetylene and others (5,6,19]. The fiber may also undergo transformations at these temperatures, such as cyclization of nitrile groups, evolution of gases, and others E3, 5,14,20]. Such processes can disturb the order of the deposition or provide new reactant species.…”

Section: Resultsmentioning

confidence: 99%

“…4. Acetylene treatment-.interaction effects: The acetylene or decomposition products, or both, could react with or deposit on the fiber to produce new stronger compounds or coatings to heal over defects [2,5,6,17,19,20,26].…”

Section: Introductionmentioning

confidence: 99%

Carbon Fiber Production at Low Temperatures from Polyacryonitrile

Cagliostro

1980

Textile Research Journal

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Recent safety considerations have sought to lower the electrical conductivity of carbon fibers. Carbon fibers produced from polyacryonitrile at low carbonization temperatures (600°-900°C) possess low electrical conductivity but do not possess adequate strength. Low-temperature processes are described which improve fiber strength but do not increase electrical conductivity substantially. The processes result in a carbon fiber with nearly twice the tensile strength compared to the old process. Process development and its effect on fiber properties are reported.

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“…The reduced counterpart of quinone active sites is the hydroquinone formed by hydrogen atom abstraction from the organic substrate molecule. For ethylbenzene as the substrate, a transition state with the phenyl group in co-planar orientation with respect to the π-conjugated (a) trimerized phenanthrene quinone [42], (b) benzoquinone biphenyl copolymer [41], (c) polynaphthoquinone [40], (d) polyaniline [43], (e) pyrolyzed polyacrylonitrile [44]. Furthermore, the study of the ODH performance using 4-methyl-4-ethyl-1-cyclohexene as the substrate, which forms different reaction products depending on the acid/base properties of the catalyst, indicates that quinone-catalyzed ODH involves a homolytic C-H bond break rather than an ionic intermediate [40].…”

Section: Dehydrogenation Of Hydrocarbonsmentioning

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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Organic Polymers. Correlation between Their Structure and Catalytic Activity in Heterogeneous Systems. I. Pyrolyzed Polyacrylonitrile and Polycyanoacetylene

Cited by 67 publications

References 0 publications

Aging of Titan's Aerosols

Aging of Titan's Aerosols

Carbon Fiber Production at Low Temperatures from Polyacryonitrile

15. Nanocarbon materials for heterogeneous catalysis

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