Heterogeneous Catalysis in Supercritical Media, Part 3: Other Media

Kruse, Andrea; Vogel, Herbert

doi:10.1002/ceat.200800086

Cited by 12 publications

(1 citation statement)

References 65 publications

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“…[ 38 ] Physicochemical properties of fluids can be changed significantly in response to small fluctuations in temperature and pressure, near the critical points, resulting in favorable conditions such as enhanced dissolution of feedstock components, higher mass and heat transfer, and facile product separation. [ 33,39–43 ] During the past few years, supercritical water (SCW, 220.5 bar, 374.2 °C) has been gaining interest as a suitable reaction medium for biomass fractionation in a biorefinery. [ 9,44 ] Supercritical carbon dioxide (ScCO 2 ) is also recognized for processing of woody biomass in recent years because of its role as an autocatalyst in the presence of water in modern biorefineries.…”

Section: Introductionmentioning

confidence: 99%

Conversion of Lignocellulosic Biomass to Reducing Sugars in High Pressure and Supercritical Fluids: Greener Alternative for Biorefining of Renewables

Kumar

Kermanshahi-pour

Brar

et al. 2021

Advanced Sustainable Systems

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Supercritical fluids offer great potential to be employed in lignocellulosic biomass (LCB) fractionation in biorefinery. Supercritical carbon dioxide and water are greener alternatives compared with conventional reagents and have been investigated for the pretreatment and hydrolysis of lignocellulosic biomass. This review is focused on examining the fundamentals that govern the function of supercritical fluids in the pretreatment stage, as well as in the main hydrolysis reaction. Sub/supercritical carbon dioxide is used in pretreatment and sub/supercritical water has been the solvent of choice in hydrolysis of LCB. Significant research has gone into understanding the effect of process parameters such as temperature, pressure, cosolvent, and use of external catalyst on the sugar yield in biorefining of the LCB in supercritical fluids. It is shown that processes with reduced environmental impact and energy consumption can significantly enhance biorefining of LCB at commercial scale. Enzymatic hydrolysis of LCB in supercritical carbon dioxide is a promising approach that can accommodate mild reaction conditions. Developing an understanding of the performance of enzymes in high pressure systems and designing carriers for enzyme immobilization and further recycling is expected to enable one pot pretreatment and hydrolysis and is an important milestone in processing renewable resources for deriving biofuel and value‐added chemicals.

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Section: Introductionmentioning

confidence: 99%

Conversion of Lignocellulosic Biomass to Reducing Sugars in High Pressure and Supercritical Fluids: Greener Alternative for Biorefining of Renewables

Kumar

Kermanshahi-pour

Brar

et al. 2021

Advanced Sustainable Systems

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Supercritical Phase Catalysis—Heterogeneous

Subramaniam¹,

Ford²

2010

Encyclopedia of Catalysis

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The potential applications of supercritical reaction media in heterogeneous catalysis have greatly expanded in recent years to include industrially significant reactions such as selective catalytic oxidations (fine and agricultural chemicals), fixed‐bed hydrogenations (pharmaceuticals, chemical intermediates), polymerizations, hydroformylations (petrochemical), and solid‐acid catalyzed alkylations (petroleum refining). The near‐critical region (roughly 1.05‐1.2 Tc; and 0.9 ‐ 2.0 Pc) provides access to unique fluid properties (liquid‐like densities and gas‐like transport properties) that have been exploited in heterogeneous catalytic systems in numerous ways such as these: eliminating oxygen or hydrogen solubility limitations in the liquid phase of multiphase reaction systems; enhanced desorption and transport of heavy molecules (such as coke precursors) in mesoporous catalysts alleviating pore‐diffusion limitations and improving catalyst effectiveness; in situ removal of primary reaction products maximizing their selectivity; enhanced heat capacity ameliorating the problem of parametric sensitivity in exothermic fixed‐bed reactors; and facile separation of reactants and products. Supercritical reaction systems are thus excellent examples of the ‘multifunctional reactor’ concept. This chapter provides an overview of recent advances in each of these areas including fundamental and experimental aspects. Barriers and challenges confronting application of CO2‐based processes in industrial catalysis, and advances in overcoming these barriers are highlighted.

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Process Intensification, 2. Phase Level

Freund

Sundmacher

2011

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Thermodynamic Methods 1.1. Property Shifting by Molecular Design 1.1.1. Ionic Liquid Systems 1.1.2. Perfluorinated Systems 1.1.3. Solid‐Bound Systems 1.2. Property Shifting by Pressure, Temperature, and Solvent Composition 1.2.1. Supercritical Fluids 1.2.2. Thermoregulated Phase‐Transfer Catalysts 1.2.3. Thermoregulated Microemulsion Systems 1.2.4. Temperature‐Dependent Multicomponent Solvent Systems 2. Kinetic Methods 2.1. Electromagnetic Tools 2.1.1 Photochemical Induction 2.1.2 Microwave Dielectric Heating 2.2. Fluid‐Mechanical Tools 2.2.1. Acoustic Cavitation 2.2.2. Hydrodynamic Cavitation 2.2.3. Supersonic Flows 2.2.4. Centrifugal Forces

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Heterogeneous Catalysis in Supercritical Media, Part 3: Other Media

Cited by 12 publications

References 65 publications

Conversion of Lignocellulosic Biomass to Reducing Sugars in High Pressure and Supercritical Fluids: Greener Alternative for Biorefining of Renewables

Conversion of Lignocellulosic Biomass to Reducing Sugars in High Pressure and Supercritical Fluids: Greener Alternative for Biorefining of Renewables

Supercritical Phase Catalysis—Heterogeneous

Process Intensification, 2. Phase Level

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