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- Title
Low Temperature Direct Conversion of Methane using a Solid Superacid.
- Authors
Kanitkar, Swarom; Ding, Kunlun; Spivey, James J.; Hutchings, Graham J.; Carter, James H.
- Abstract
The direct conversion of methane to higher hydrocarbons and hydrogen can be catalyzed using "superacids": nCH4→CnHm+xH2. The first report of catalytic oligomerization of methane using superacids was that of Olah et al. who demonstrated the superacidity of FSO3H−SbF5, which is a liquid. More recently, Vasireddy et al. showed that gas‐phase HBr/AlBr3 was an active superacid. The only reported solid superacid for methane oligomerization is sulfated zirconia (SZ). Here, we report a new class of Br‐based solid superacids, AlBrx/H‐ZSM‐5 ("ABZ‐5", x=1 or 2). ABZ‐5 is based on gas‐phase HBr/AlBr3, with the objective of synthesizing a heterogeneous analogue of the gas‐phase superacid HBr/AlBr3. The results show that ABZ‐5 is significantly more active than SZ. Perhaps more significantly, results here show methane conversions of ∼1 % at 300 °C using ABZ‐5. By comparison with SZ, 350 °C is the lowest temperature reported in the literature at which measurable conversions are shown, and the corresponding methane conversions were <0.15. Here, we demonstrate direct conversion of methane using a solid superacid catalyst, AlBrx/H‐ZSM‐5. This solid catalyst is synthesized using a vapor‐phase process in which AlBr3 vapor is grafted on to solid H‐SZM‐5. This catalyst is characterized using NH3‐TPD, XRD, and DRIFTS. Hydrocarbon products observed in the temperature range of 200–400 °C include both C2–C6 hydrocarbons and aromatics. Superacid for super effort! Superacid catalyst for methane conversion: Methane can be activated through variety of ways including use of oxidants, without oxidants. Superacidic systems possess high enough acidity to protonate methane and start oligomerization of it through oligo‐condensation mechanism. Products can include C2, C3 feedstocks as well as aromatics.
- Subjects
METHANE; DIRECT conversion receivers; SUPERACIDS; LOW temperatures; OLIGOMERIZATION; ZIRCONIUM oxide
- Publication
ChemCatChem, 2018, Vol 10, Issue 21, p5033
- ISSN
1867-3880
- Publication type
Article
- DOI
10.1002/cctc.201801310