Perspectives on exploiting near-critical fluids for energy-efficient catalytic conversion of emerging feedstocks

•Energy-intensive chemical industry needs resource-efficient technologies.•Near-critical fluids with pressure-tunable properties enable sustainable catalysis.•Gas-expanded liquids facilitate low C footprint technologies for plastic intermediates.•Emerging feedstocks (biomass, shale gas) will benefit from such technologies.

Near-critical fluids possess unique tunability of the physical and transport properties for performing resource-efficient catalysis (i.e., conserving feedstock and energy) characterized by process intensification, high product selectivity, enhanced safety and facile separation steps. Alternative technology concepts for energy-intensive and waste-generating megaton industrial processes (such as ethylene and propylene epoxidations, p-xylene oxidation and olefin hydroformylations) that employ gas-expanded liquids or supercritical fluids to demonstrate such process attributes are highlighted. In particular, continuous or flow processes that employ either homogeneous or supported ionic liquid phase (SILP) catalysts are emphasized. Economic and LCA analyses based on plant-scale simulations reveal clear potential for practical viability and lowered environmental impacts of these alternative processes (relative to the conventional technologies). The emerging biomass and shale gas based chemical industry, where new catalytic technologies are needed to make equivalent petrochemical intermediates, may be receptive to adopt and implement such new resource-efficient technologies.

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