Exploiting Neoteric Solvents for Sustainable Catalysis and Reaction Engineering: Opportunities and Challenges

Abstract

The modern refinery relies primarily on feedstocks based on fossil fuels (such as petroleum, natural gas, and coal) to produce fuels and chemicals. Several megaton catalytic processes (such as homogeneous hydroformylation of higher olefins, epoxidation of light olefins, and p-xylene oxidation to produce terephthalic acid) exist that produce the essential chemical intermediates for everyday products but present sustainability challenges with respect to reducing environmental footprints and enhancing energy efficiency. Meeting the increasing demand for such chemicals, through either fossil-based feedstock or plant-based biomass, will require the development of novel sustainable processes. This article highlights the role and promise of neoteric solvents such as compressed CO2, ionic liquids, and water, with an emphasis on gas-expanded liquids (GXLs), for the development of sustainable catalytic processes and the challenges thereof. It is also shown that chemical reaction engineering is the critical link to bring the promise of green chemistry to the marketplace.

Kinetics of 1-dodecene hydroformylation in a thermomorphic solvent system using a rhodium-biphephos catalyst

“…It could be shown that high aldehyde yields at simultaneously high olefin conversions could be achieved e.g. with nonaqueous ionic liquids (Deshpande et al, 2011;Jakuttis et al, 2011;Webb et al, 2003), supercritical carbon dioxide (Guha et al, 2007;Koeken et al, 2011a;Subramaniam, 2010;Subramanian and Akien, 2012;Ye et al, 2012) and combinations of those solvents (Haji and Erkey, 2002;Hintermair et al, 2007;Mokhadinyana et al, 2012). As a very promising alternative was demonstrated the application of thermomorphic multicomponent solvent (TMS) systems allowing to perform the reaction under homogeneous conditions at elevated temperature and to recover the catalyst in the polar phase formed after reaction by spontaneous phase separation at lower temperature .…”

Model-Based Identification and Experimental Validation of the Optimal Reaction Route for the Hydroformylation of 1-Dodecene

“…= r k T C C ( ) 4 4,0 iC12en H2 5 5,0 iC12en H2 CO 6 6,0 nC12en H2 CO (6) The temperature behavior of the rate constants k j (T) is modeled via an Arrhenius equation with temperature correction (eq 7) about the reference temperature T ref = 378.15 K, which is the average temperature in the operation range considered.…”

Sustainable catalytic reaction engineering with gas-expanded liquids

“…Neoteric solvents have been investigated extensively in recent years for performing chemical reactions [8,9]. Examples of such media include supercritical CO 2 (scCO 2 ) [10,11], water [12,13], gas-expanded liquids (GXLs) [14,15 ,16,17 ], ILs [18,19] and switchable solvents [20].…”