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Unlocking efficient CO2–to–methanol conversion on frustrated Lewis pair-functionalized UiO–67: A synergistic approach using DFT and SISSO
(2025-10-01)
Yodsin, Nuttapon
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Pimbaotham, Pimjai
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Maihom, Thana
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Daengngern, Rathawat
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Tachikawa, Masanori
Metal–organic framework-based catalysts demonstrate considerable promise for converting CO<inf>2</inf> into valuable chemicals, particularly when combined with Frustrated Lewis Pairs (FLPs) to enhance H<inf>2</inf> dissociation during hydrogenation reactions. This study employs density functional theory (DFT) calculations to investigate modified UiO–67 frameworks wherein FLPs are introduced via eight different functional groups (UiO–67–X) into the organic linker to facilitate H<inf>2</inf> activation during CO<inf>2</inf> hydrogenation to methanol (CH<inf>3</inf>OH). The reaction proceeds through three stages: (i) hydrogenation of CO<inf>2</inf> to formic acid (HCOOH), (ii) conversion of HCOOH to formaldehyde (HCHO), and (iii) hydrogenation of HCHO to CH<inf>3</inf>OH. This study specifically focuses on steps (ii) and (iii), analyzing the detailed reaction mechanisms using optimized molecular structures and Gibbs free energy calculations to acquire insights into methanol formation on UiO–67–X. During HCOOH conversion to HCHO, adsorbed H<inf>2</inf> undergoes heterolytic cleavage at the FLP sites, producing a proton (H+) and a hydride (H−) for subsequent HCOOH hydrogenation and dehydration. The energy barriers identified at this stage represent key kinetic limitations hindering efficient CO<inf>2</inf>-to-methanol conversion. Similarly, HCHO conversion to CH<inf>3</inf>OH proceeds via H<inf>2</inf> dissociation, followed by concerted H+/H− transfer. Among the tested UiO–67–X catalysts, UiO–67–B(CH<inf>3</inf>)<inf>2</inf> exhibits the highest catalytic activity for CO<inf>2</inf> hydrogenation to methanol. Kinetic analyses are performed to assess reaction rates across a relevant temperature range, highlighting the notable influence of functional groups on catalytic performance. Additionally, the Sure Independence Screening and Sparsifying Operator (SISSO) machine-learning approach is used to identify optimal physical descriptors and derive a predictive model for the energetic span (δG), considerably lowering the computational cost associated with full reaction pathway calculations. Statistical validation confirms the robustness of these predictions. Overall, these findings underscore the vital role of FLP-assisted H<inf>2</inf> dissociation in promoting CO<inf>2</inf> hydrogenation to CH<inf>3</inf>OH, with UiO–67–B(CH<inf>3</inf>)<inf>2</inf> serving as a promising catalyst.
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Sustainable Production of Biomethanol and Its Environmental Impacts
(2025-01-01)
Detchusananard, Thanaphorn
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Im-Orb, Karittha
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Wiranarongkorn, Kunlanan
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Chen, Yong Song
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Arpornwichanop, Amornchai
Utilizing biomass and biogas sourced from various organic waste materials as renewable feedstocks for biomethanol production offers a sustainable alternative to fossil fuels such as coal, petroleum oil, and natural gas. This chapter provides an exploration of several technologies employed in biomethanol production, including biomass gasification, biomass pyrolysis, and biogas upgrading. Syngas production and conditioning, methanol synthesis and separation, and integrating systems with other renewable energy sources are found to be crucial stages towards achieving sustainable production. The chapter comprehensively evaluates the technical, economic, and environmental aspects of each biomethanol production process. Furthermore, it delves into ongoing efforts to improve and develop biomethanol-production processes to achieve the carbon neutrality goals. The chapter also outlines emerging trends and future research directions in the field of biomethanol production.
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Exergy and exergoeconomic assessment of sustainable light olefins production from an integrated methanol synthesis and methanol-to-olefins system
(2022-05-01)
Detchusananard, Thanaphorn
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Prasertcharoensuk, Phuet
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Patcharavorachot, Yaneeporn
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Maréchal, François
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Arpornwichanop, Amornchai
Integrated methanol synthesis and methanol-to-olefins systems are considered attractive and promising technologies to produce light olefins from syngas derived from biomass feedstock. In this study, a flowsheet model of a proposed system was developed and employed for system design and analysis. The system consists of four main parts: methanol synthesis, methanol-to-olefins process, olefins separation, and power plant. The effects of important operating parameters on the exergy efficiency were investigated to determine the optimal operating conditions to achieve the maximum exergy efficiency of this system. The results indicate that the methanol synthesis process should be operated at temperature, pressure, and recycling ratio of 250 °C, 150 bar, and 0.85, respectively, whereas the methanol-to-olefins process should be operated at a temperature of 480 °C and the power plant should be run at steam temperature and steam pressure of 650 °C and 50 bar, respectively. Heat integration based on a pinch analysis was subsequently performed to improve the system energy usage, resulting in a 9.29% increase in the exergy efficiency of the integrated system. An exergoeconomic analysis of the integrated system with the designed heat exchanger network was performed. The results show that the power plant has the highest cost rate of exergy destruction and total cost rate. Moreover, the syngas feedstock cost has the greatest impact on the exergoeconomic indicators; it is necessary to minimize this cost to achieve economic viability of the process for industrial use. The production of light olefins from the integrated methanol synthesis and methanol-to-olefins system using a renewable syngas feedstock has a potential to reduce greenhouse gas emissions due to the use of renewable sources replacing fossil sources.
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Process and sustainability analyses of the integrated biomass pyrolysis, gasification, and methanol synthesis process for methanol production
(2020-02-15)
Im-orb, Karittha
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Arpornwichanop, Amornchai
Technical and sustainability analyses of the methanol production via the integrated biomass pyrolysis, gasification, and methanol synthesis (IBPGM) process using rice straw as feedstock, are performed. The utilization of emitted CO<inf>2</inf> by recycling to a gasifier as a gasifying agent is investigated for technical and environmental reasons. The effects of CO<inf>2</inf> recirculation on the product distribution and energy consumption of the IBPGM process are examined. The production rate of methanol is improved with the increased CO<inf>2</inf> recycle fraction, while that of bio-oil does not change. The IBPGM is a highly exothermic process, with the largest energy-releasing unit being the methanol reactor. The energy consumption at the gasifier exhibits the same trend and thermal self-sufficiency is consequently achieved when the recycle fraction is raised to 0.76. Environmental assessment using a life cycle analysis tool reveals that the energy management of methanol synthesis unit and syngas processor needs to be improved as they highly contribute toward the carbon footprint and potential environmental impact. The technical and environmental factors of the IBPGM process are evaluated by the analysis hierarchy process, calculated by a multi-criteria decision analysis method. The IBPGM process with the CO<inf>2</inf> recycle fraction of 0.2 offers the best performance. Under this condition, the methanol and bio-oil production rates of 0.23 and 0.09 kmol h−1, respectively, and the energy efficiency of 60.7% can be achieved, based on the biomass feed rate of 1 kmol h−1.

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