Phosphate assisted integrated carbon dioxide capture and conversion to methane

Koch, Christopher J.; Alagaratnam, Anushan; Goeppert, Alain; Prakash, G. K. Surya

doi:10.1039/d3se00390f

Cited by 4 publications

(3 citation statements)

References 55 publications

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“…Au/Al 2 O 3 was inactive for hydrogenation of N-formyl piperidine. Similar to previous reports (Kothandaraman et al, 2021;Koch et al, 2023), Ru/Al 2 O 3 catalyst selectively formed methane after hydrogenation with no detectable amounts of methanol or N-methyl piperidine (Entry 15, Table 2).…”

Section: Resultssupporting

confidence: 89%

Mechanistic insights to drive catalytic hydrogenation of formamide intermediates to methanol via deaminative hydrogenation

Kothandaraman,

Heldebrant,

Lopez

et al. 2023

Front. Energy Res.

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Amine-promoted hydrogenation of CO2 to methanol typically proceeds via a formamide intermediate when amines are used as additives or if the hydrogenation is performed in carbon capture solvents. The catalysts used for the hydrogenation of the formamide intermediate dictate the selectivity of the products formed: 1) Deoxygenative hydrogenation (C–O bond cleavage) resulting in N-methylation of amine and deactivation of the solvent, 2) Deaminative hydrogenation (C–N bond cleavage) resulting in formation of methanol and regeneration of the solvent. To date, catalytic reductions of CO2 with amine promoters suffer from poor selectively for methanol which we attribute to the limiting formamide intermediate, though to date, the conditions that favor C–N cleavage have yet to be fully understood. To better understand the reactivity of the formamide intermediates, a range of heterogenous catalysts were used to study the hydrogenation of formamide. Well-known gas phase CO2 hydrogenation catalysts catalyze the hydrogenation of formamide to N-methyl product via C–O bond cleavage. However, the selectivity can be readily shifted to selective C–N bond cleavage by addition of an additive with sufficient basicity for both homogenous and heterogeneous catalytic systems. The base additive shifts the selectivity by deprotonating a hemiaminal intermediate formed in situ during the formamide hydrogenation. This prevents dehydration process leading to N-methylated product, which is a key capture solvent deactivation pathway that hinders amine use in carbon capture, utilization, and storage (CCUS). The findings from this study provide a roadmap on how to improve the selectivity of known heterogenous catalysts, enabling catalytic reduction of captured CO2 to methanol.

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Section: Resultssupporting

confidence: 89%

Mechanistic insights to drive catalytic hydrogenation of formamide intermediates to methanol via deaminative hydrogenation

Kothandaraman,

Heldebrant,

Lopez

et al. 2023

Front. Energy Res.

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“…The heterogeneous Cu/ZnO/Al 2 O 3 catalyst is used industrially for methanol synthesis and in the methanol steam reforming process. Yet utilizing such heterogeneous catalysts in ICCC to produce many C1 products is still a nascent area of research. − Previously reported systems commonly employed homogeneous catalysts based on precious metals for the conversion of captured CO 2 to methanol. Notably, homogeneous Ru-pincer catalysts have demonstrated efficient conversions to methanol from capture solutions of alkali hydroxides and amines (Figure a,b). , A Ru-MACHO-BH catalyst was used for a tertiary amine-ethylene glycol-based ICCC .…”

Section: Introductionmentioning

confidence: 99%

Integrated Carbon Dioxide Capture and Conversion to Methanol Utilizing Tertiary Amines over a Heterogenous Cu/ZnO/Al₂O₃ Catalyst

Suhail,

Koch,

Goeppert

et al. 2024

Langmuir

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Increasing carbon dioxide emissions has sparked a growing interest in capturing these emissions at the source of their release. For such processes, amines can be used as carbon dioxide capture agents. Herein, CO2 was captured under ambient conditions using solutions of amines and polyamines in ethylene glycol. The captured solutions were then successfully hydrogenated to methanol under hydrogen pressure with a heterogeneous Cu/ZnO/Al2O3 industrial catalyst. An extensive amine scope found that tetramethyl-1,6-hexanediamine, with two tertiary amine sites, provided the highest methanol productivity. This reaction was then optimized to achieve up to 89% methanol yield under relatively mild conditions of 250 °C and 80 bar H2 pressure. The catalyst was shown to be recyclable over five reaction cycles.

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“…[30,32] Phosphate salts have also been investigated for the capture of CO 2 , but the subsequent conversion of the captured CO 2 species is not well studied. [33][34][35][36] Metal hydroxide salts were reported as well for the capture and conversion of CO 2 . [23,37] However, in organic solvents hydroxide bases can interact with the solvent and lead to degradation of the base over the course of the reaction, limiting their applications in these organic solvents.…”

Section: Introductionmentioning

confidence: 99%

CO₂ Capture and Direct Air CO₂ Capture Followed by Integrated Conversion to Methane Assisted by Metal Hydroxides and a Ru/Al₂O₃ Catalyst

Koch,

Suhail,

Goeppert

et al. 2023

ChemCatChem

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Rising CO2 levels are leading to an increase in atmospheric greenhouse gas effect. Hydroxide salts have previously been shown to be promising reagents for capturing CO2. Utilizing a 5%Ru/Al2O3 catalyst, the carbonates obtained through CO2 capture can then be hydrogenated to methane. This conversion occurs at relatively mild temperatures from 200°C to 250°C under 40 to 70 bar H2 with yields of up to 100%. Natural sources of calcium carbonate, like eggshells and seashells, can also be partially converted to methane. The direct air CO2 capture and conversion of CO2 to methane was achieved as well in quantitative yields.

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Phosphate assisted integrated carbon dioxide capture and conversion to methane

Abstract: CO2 captured species with aqueous metal phosphates are converted to methane in an integrated hydrogenation process over a heterogeneous catalyst.

Cited by 4 publications

References 55 publications

Mechanistic insights to drive catalytic hydrogenation of formamide intermediates to methanol via deaminative hydrogenation

Mechanistic insights to drive catalytic hydrogenation of formamide intermediates to methanol via deaminative hydrogenation

Integrated Carbon Dioxide Capture and Conversion to Methanol Utilizing Tertiary Amines over a Heterogenous Cu/ZnO/Al₂O₃ Catalyst

CO₂ Capture and Direct Air CO₂ Capture Followed by Integrated Conversion to Methane Assisted by Metal Hydroxides and a Ru/Al₂O₃ Catalyst

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Phosphate assisted integrated carbon dioxide capture and conversion to methane

Abstract: CO2 captured species with aqueous metal phosphates are converted to methane in an integrated hydrogenation process over a heterogeneous catalyst.

Cited by 4 publications

References 55 publications

Mechanistic insights to drive catalytic hydrogenation of formamide intermediates to methanol via deaminative hydrogenation

Mechanistic insights to drive catalytic hydrogenation of formamide intermediates to methanol via deaminative hydrogenation

Integrated Carbon Dioxide Capture and Conversion to Methanol Utilizing Tertiary Amines over a Heterogenous Cu/ZnO/Al2O3 Catalyst

CO2 Capture and Direct Air CO2 Capture Followed by Integrated Conversion to Methane Assisted by Metal Hydroxides and a Ru/Al2O3 Catalyst

Contact Info

Product

Resources

About

Integrated Carbon Dioxide Capture and Conversion to Methanol Utilizing Tertiary Amines over a Heterogenous Cu/ZnO/Al₂O₃ Catalyst

CO₂ Capture and Direct Air CO₂ Capture Followed by Integrated Conversion to Methane Assisted by Metal Hydroxides and a Ru/Al₂O₃ Catalyst