Highly Selective Dehydroaromatization of n-Alkanes to Aromatics and Hydrogen Gas
Jingyi Lu1,2, Jie Zhang3,4,5, Bo Liu1
1Green Chemical Engineering Technology Research Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
Abstract:
Transformation of available and inexpensive alkanes to high-value aromatics and hydrogen gas represents an atom-economical route of great interest. However, concurrent C-C bond scission and recombination side reactions severely challenge the selectivity and efficiency of conventional catalytic systems. Herein, we report a phosphorus-doped carbon (P@C) catalyst that enables the metal-free, acceptorless dehydroaromatization of linear C6-C8 alkanes with exceptional selectivity. The reaction proceeds via a unique β-C-H bond activation pathway, yielding 2-hexene as the primary intermediate, and culminates in a cascade of consecutive dehydrogenation and cyclization steps. This catalyst's remarkable propensity for selective C-H bond activation over C-C bond cleavage effectively suppresses side reactions. Consequently, n-hexane is converted to benzene with >99% selectivity at 96% conversion, while n-heptane and n-octane are transformed into toluene and C8 aromatics (o-xylene, ethylbenzene), respectively, with ∼90% selectivity at near-complete conversion. This work highlights a highly atom-efficient, metal-free catalytic strategy for coproducing aromatics and hydrogen.
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