Acetylene graphite-like

The most satisfactory mechanism used to date to convert the acetylene gas into graphite-like carbon has been electrical dissociation. The apparatus is shown in figure 9. The efficiency of the mechanism of dissociation is strongly dependent upon gas pressure, and after experimentation a pressure of about 10 torr has been selected as optimum. At this pressure, a hard black carbon deposit is observed on the substrate with a thickness of more than 0.1 mm. In the current source, samples produce several microamperes after about 1 hour of running, and this current remains very steady for several hours of operation. 

The B-C-N compounds are attractive materials due to their unique properties associated with their layered, graphite-like structures [246, 247]. Such compositions can be deposited by the CVD of a mixture of BCI3, ammonia and a hydrocarbon (usually acetylene) at temperatures between 700-1700 °C [247-249]. A compound with the composition BC2N has been obtained by the CVD of a mixture of BCI3 and acetonitrile... 

The CFx material is mixed with a conductive carbon, like acetylene black or graphite, and a binder to maintain the mechanical integrity of the electrode. Typical electrolyte solutions are comprised of lithium tetrafluoroborate (LiBF4) dissolved in one or more organic solvents, generally propylene carbonate (PC) or gamma-butyrolactone (GBL) with 1,2-dimethoxyethane (DME). 

One or more conductive carbon powders, like acetylene black and graphite, and a binder such as PTFE are added to the Mn02 to yield the cathode mix. 

In principle, carbon nanotubes can be grown from any gaseous hydrocarbons or CO, onto Fe, Co, or Ni particles dispersed on a substrate under appropriate reaction conditions. Higher temperatures and slower growth rates favor graphitic filament formation, while lower temperatures and fast rates lead to nongraphitic forms (Baker and Harris, 1978). Beside Fe, Co, and Ni, filaments can also be formed on other metals such as Pt and Cu. Acetylene is among the most reactive hydrocarbon precursors. Unsaturated hydrocarbons like propylene and butadiene are more reactive than the saturated hydrocarbons such as methane and... 

In this study, a spectrographic analysis of the by-products of the decomposition of methane revealed the presence of large amounts of acetylene, ethylene, and benzene, plus a variety of compounds consisting mostly of the polyaromatic hydrocarbons (PAH) such as naphthalene, anthracene, phenantrene, acenaphthylene, pyrene, and fluoranthene, in addition to the deposited pyrolytic graphite. Some of these compounds form the soot and tar-like deposits which are often observed on the wall of CVD reactors during carbon deposition. 

Pure structured carbon exists in nature predominantly in the form of the three-dimensional diamond (all sp ) and two-dimensional graphite (all sp see also Real Life 15-1). The onedimensional version of a polymeric acetylene chain (all sp) has remained elusive, but synthetic chemists have come close by making well-defined oligomers containing up to 44 contiguous ip-hybridized carbons The NMR spectrum shows a range of peaks centered around 63.7 ppm, extrapolated to be the likely chemical shift of the infinite polymer. 

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