The Radiation Chemistry Of Organic Substances

Collinson, E.; Swallow, A. J.

doi:10.1021/cr50009a003

Cited by 98 publications

(22 citation statements)

References 240 publications

(393 reference statements)

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“…Instead, these experiments provide some evidence that a t higher temperatures the cathode deposit loses hydrogen under ion bombardment. These considerations lead to the conclusion that the solid product on the cathode is an acetylene polymer similar to the cuprene formed in the high-energy irradiation of acetylene (11,12). There is a considerable amount of evidence that the cuprene forlued in these irradiation studies depends 011 ionization for its formation (12,13,14).…”

Section: Discussionmentioning

confidence: 98%

The Decomposition of Methane in the Negative Glow

Tickner¹

1961

Can. J. Chem.

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The decolnposition of methane was studied in the negative glow of a d-c. discharge a t pressures of 0.30 and 0.050 mm. The discharge tube was cooled by liquid or solid nitrogen.The main products were ethane, ethylene, and acetylene in addition to hydrogen and a nonvolatile product which appeared mainly on the cathode as a solid having the formula (CH),. Smaller amounts of propane, propene, propyne, butane, butene, butadiene, and pentene were also found. Lowering the temperature of the discharge tube from -196" t o -210" C greatly increased the amount of ethylene recovered.The solid product is apparently transported t o the cathode in the form of ions and may result from ionic polymerization of the acetylene. Acetylene is the volatile product formed closest t o the cathode which suggests that it may also be fornled by ionic processes. The formati011 of the remaining products is consistent with an excitation mechanism in which the C:! products are formed first and the higher hydrocarbons are formed from them. INTRODUCTIONThe decomposition of methane in the glow discharge has been studied for many years; the early work is summarized in reference 1. More recently, Yeddai~apalli (2) studied the decomposition of methane in a d-c. glow discharge using a discharge tube cooled in liquid air. He worked a t pressures of a few millimeters and found that the products consisted of ethane, ethylene, and acetylene as well as hydrogen and a nonvolatile product having the forinula (CH?),. Wiener and Burton (3), using a d -~. glow discharge a t atmospheric pressure, showed that under conditions of high conversion and relatively high temperature the only significant products were acetylene, hydrogen, and carbon. McCarthy (4) found that, in addition to acetylene, etllyleile and ethane were obtained as products when the gas from a microwave discharge in inethaile was allowed to impinge directly on a wall cooled by liquid nitrogen.The low-pressure d-c. glow discharge is suitable for investigations of this type because it permits studying the decomposition in a number of different discharge regions for which the electrical processes are reasonably well understood ( 5 , 6). In addition, the vapor pressures of methane and its decomposition products are such that most of the products can be removed rapidly from the reaction by freezing thein out on the discharge tube wall. There is thus the possibility of obtaining direct information about the primary products of the decon~position. This approach was used by Yeddanapalli (2), whose work, however, had two main wealcnesses: ( a ) a t the temperature of liquid air the vapor pressure of ethylene is sufficiently high that much of it would have remained in the gas phase, and (b) his method of analysis was such that the products were determined as acetylene and ethylene with the remainder assumed t o be ethane. Any higher hydrocarbons which might have been formed would thus not have been detected.The negative glow was chosen as a suitable region with which t o begin a study of the decomp...

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Section: Discussionmentioning

confidence: 98%

The Decomposition of Methane in the Negative Glow

Tickner¹

1961

Can. J. Chem.

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“…This was also supported by the nuclear magnetic resonance (NMR) results shown later. Therefore, radical recombination between C and Cl was expected to occur; when the chloromethyl group density is low, the radical recombination between C and Cl generated through C-Cl dissociation often dominantly occurs instead of the generation of Cl2 molecules, owing to the so-called "cage effect" in liquid media [31]. Radicals formed through bond scission in a condensed phase tend to recombine, as radicals surrounded by a medium cannot easily diffuse and separate from each other.…”

Section: Photoinduced C-cl Bond Dissociation Of Chloromethyl Group Obmentioning

confidence: 99%

Simple Process for Sidewall Modification of Multi-Walled Carbon Nanotubes with Polymer Side Chain Radicals Generated by Ultraviolet-Induced C–Cl Bond Dissociation of Polystyrene Derivatives

Takada

Baba

Abe

2016

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Abstract:In this work, we investigated a simple one-step process for the formation of chemical bonds between multi-walled carbon nanotubes (MWCNTs) and benzyl-type side chain radicals generated by UV photolysis of polystyrene derivatives containing the chloromethyl (-CH 2 Cl) group. Poly(4-chloromethyl)styrene, or styrene/4-(chloromethyl)styrene random copolymer, was mixed with MWCNTs in 1-methyl-2-pyrrolidone and irradiated with ultraviolet (UV) light. Films of polymer/MWCNT mixtures before and after UV irradiation were fabricated, and then examined by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. According to the XPS analysis, the amount of Cl atoms in the mixture was found to decrease upon UV irradiation, indicating that the Cl atoms generated by photolysis of chloromethyl groups escaped from the reaction system in the form of gaseous Cl 2 . The structural change of CNTs after UV irradiation was also observed by comparing the G/D ratios (the intensity ratio of the G to D bands) of the Raman spectra obtained before and after UV irradiation. Similar phenomena were also confirmed in the case of the polymer/MWCNT mixture containing hydroxylammonium chloride as a dispersant of MWCNTs. These results confirmed the UV-induced covalent bond formation between polymer side chains and MWCNTs.

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“…With the development of commercial and medical uses of radioactive isotopes and nuclear radiation, extensive studies have been undertaken to explore the chemical changes responsible for the observed biological effects. Since biological systems are essentially aqueous systems, the reactions of radicals produced by radiation in water are of primary importance [79]. One of the radicals generated in the radiolysis of water is the H atom.…”

Section: Reactions Of H Atoms With Thiols and Disulfides Of Biologicamentioning

confidence: 99%