Effect of dielectric constant, cavities in series, and cavities in parallel on the product distribution of the oligomerization of methane via microwave plasmas

Journal Article · Thu Nov 07 04:00:00 UTC 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp960955x· OSTI ID:420742

Marun, C; Suib, S L ^[1]; Dery, M; Harrison, J B; Kablaoui, M ^[2]

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1. Univ. of Connecticut, Storrs, CT (United States)
2. Texaco, Inc., Beacon, NY (United States)

The use of microwave-induced plasmas as a method to oligomerize methane to higher hydrocarbons has been studied. The pressure range used was 10-20 Torr and the applied power was 60 W. The microwave power is coupled to the plasma by means of either an Evenson or a Beenakker cavity, the Beenakker being the most effective. We explored the effect of the presence of a dielectric material on the product distribution for this reaction. The values of the dielectric constants for these materials varied from 2.6 for Pb(Ac){sub 2} to 10,000 for MnO{sub 2} relative to the vacuum. No direct correlation was found, but in some cases the selectivities toward C{sub 6s}to C{sub 8s} were enhanced. TiO{sub 2}and Li{sub 2}CO{sub 3} increased the selectivities toward C{sub 6s}. SnO{sub 2} was the best for selectivities to C{sub 7s}and C{sub 8s}. When a coating of Si/SiC on the reactor walls was present in the plasma zone, the selectivities toward C{sub 6s} and C{sub 7s} increased with respect to both materials (Si and SiC) by themselves. We also studied the effect of cavities in series and cavities in parallel on the oligomerization of methane with and without dielectric material in between the cavities. When methane and iodine are activated separately and then recombined, it seems that the oligomerization of methane is enhanced toward higher hydrocarbons. We found that when a dielectric material is placed in between and when the distance between the two cavities in series is the largest, the oligomerization of methane toward high molecular weight hydrocarbons is maximized. 45 refs., 9 figs., 1 tab.

• OSTI ID: 420742
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 45 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
CAVITIES
CHEMICAL VAPOR DEPOSITION
COMPRESSION
CONVERSION
DIELECTRIC PROPERTIES
EXPANSION
LITHIUM CARBONATES
METHANE
MICROWAVE RADIATION
MOLECULAR WEIGHT
NUMERICAL DATA
PLASMA PRODUCTION
SILICON
SILICON CARBIDES
TITANIUM OXIDES