Acetic Acid/Propionic Acid Conversion on Metal Doped Molybdenum Carbide Catalyst Beads for Catalytic Hot Gas Filtration

Abstract

Catalytic hot gas filtration (CHGF) is used to precondition biomass derived fast pyrolysis (FP) vapors by physically removing reactive char and alkali particulates and chemically converting reactive oxygenates to species that are more easily upgraded during subsequent catalytic fast pyrolysis (CFP). Carboxylic acids, such as acetic acid and propionic acid, form during biomass fast pyrolysis and are recalcitrant to downstream catalytic vapor upgrading. This work developed and evaluated catalysts that can convert these acids to more upgradeable ketones at the laboratory scale. Selective catalytic conversion of these reactive oxygenates to more easily upgraded compounds can enhance bio-refinery processing economics through catalyst preservation by reduced coking from acid cracking, by preserving carbon efficiency, and through process intensification by coupling particulate removal with partial upgrading. Two metal-doped molybdenum carbide (Mo 2 C) supported catalyst beads were synthesized and evaluated and their performance compared with an undoped Mo 2 C control catalyst beads. For laboratory scale acetic acid conversion, calcium doped Mo 2 C supported catalyst beads produced the highest yield of acetone at~96% at 450 • C among undoped and Ca or Ni doped catalysts.

Catalytic ketonization of palmitic acid over a series of transition metal oxides supported on zirconia oxide-based catalysts

“…However, higher reaction temperatures are also reported to accelerate the product degradation due to the thermal instability of formed ketones that decrease the desired product yield. 79,80 Furthermore, Lu et al (2018) recorded a sharp diminution in the pentanone selectivity aer increasing the reaction temperature above 400 C. Hence, an optimum reaction temperature is vital to maximise the ketone yield. However, due to reactor limitation we only studied reaction temperature up to 340 C and the ascending trend of palmitone yield agreed with literatures.…”

Mechanistic Insights and Rational Design of Ca-Doped CeO2 Catalyst for Acetic Acid Ketonization

“…However, carboxylic acids have low economic values and can cause undesired polymerization reactions during downstream pyrolysis and hydrotreating and result in catalyst deactivation. 5−9 The ketonization reactions (2 R-COOH → R 2 CO + CO 2 + H 2 O, R: Alkyl group) can be integrated to the catalytic hot gas filtration that converts carboxylic acid into ketone, carbon dioxide, and water, without the addition of hydrogen, 10 and therefore can be beneficial for providing a sustainable solution to the above engineering process.…”

“…38,39 The new active centers were introduced during the doping process, and this modifies the catalytic activity, selectivity, and stability. 10,39,40 Numerous studies have been performed to investigate the dopant effect in the CeO 2based catalyst for ketonization reactions. 34,41,42 For example, Lu et al 41 proposed that Ti-doped CeO 2 catalyst exhibits better ketonization performance, likely due to the formation of a Ce−O−Ti structure compared to the parent catalysts of CeO 2 and TiO 2 .…”

“…Catalytic hot gas filtration is a technology used for removing the char, alkali metals, and highly reactive chemical species to convert bio-oxygenates to more upgradeable species before fast pyrolysis (FP) or catalytic fast pyrolysis (CFP), relieve FP/CFP catalyst deactivation due to coke formation, and improve catalyst lifetime in downstream operations. − Among bio-oxygenate components, carboxylic acids (e.g., acetic acid) are one of the main intermediates for the conversion of biomass into fuels and chemicals through fermentation, hydrothermal liquefaction, pyrolysis, and hydrotreating. However, carboxylic acids have low economic values and can cause undesired polymerization reactions during downstream pyrolysis and hydrotreating and result in catalyst deactivation. − The ketonization reactions (2 R-COOH → R 2 CO + CO 2 + H 2 O, R: Alkyl group) can be integrated to the catalytic hot gas filtration that converts carboxylic acid into ketone, carbon dioxide, and water, without the addition of hydrogen, and therefore can be beneficial for providing a sustainable solution to the above engineering process.…”

Optimisation of Propane Production from Hydrothermal Decarboxylation of Butyric Acid Using Pt/C Catalyst: Influence of Gaseous Reaction Atmospheres

“…Long-chain fatty acids obtained from lipids (vegetable oils and animal fats) have been investigated to produce liquid hydrocarbons products as alternatives to conventional fossil-derived diesel and kerosene fuels. In addition, C 2 -C 5 carboxylic acids can undergo decarboxylation to produce C 1 -C 4 hydrocarbon fuel gases [11,12]. Furthermore, for C 3+ carboxylic acids, the choice of catalysts and reaction environment can determine whether the final hydrocarbon products are alkenes (via decarbonylation) or alkanes (via decarboxylation) [13,14].…”