Molecular Mechanisms behind Acetylene Adsorption and Selectivity in Functional Porous Materials

Abstract

Since its first industrial production in 1890s, acetylene has played a vital role in manufacturing a wide spectrum of materials. Although current methods and infrastructures for various segments of acetylene industries are wellestablished, with emerging functional porous materials that enabled desired selectivity toward target molecules, it is of timely interest to develop new efficient technologies to promote safer acetylene processes with a higher energy efficiency and lower carbon footprint. In this Minireview, we, from the perspective of materials chemistry, review state-of-the-art examples of advanced porous materials, namely metal-organic frameworks and decorated zeolites, that have been applied to the purification and storage of acetylene. We also discuss the challenges on the roadmap of translational research in the development of new solid sorbent-based separation technologies and highlight areas which require future research efforts.

Boosting Acetylene Packing Density within an Isoreticular Metal–Organic Framework for Efficient C2H2/CO2 Separation

“…C 2 H 2 is commonly manufactured by the thermal cracking of hydrocarbons or the partial combustion of methane, wherein a small amount of carbon dioxide (CO 2 ) impurity inevitably coexists and decreases the subsequent utilization efficiency. − Therefore, it is essential to eliminate the CO 2 impurity from the C 2 H 2 /CO 2 mixture to produce pure C 2 H 2 gas to better meet the implementation demands of the different domains. However, the close boiling points (189.3 K for C 2 H 2 and 194.7 K for CO 2 ) and highly similar molecular sizes (3.3 × 3.3 × 5.7 Å 3 for C 2 H 2 and 3.2 × 3.3 × 5.4 Å 3 for CO 2 ), along with the same kinetic diameters (both are 3.3 Å) of the linear-shaped CO 2 and C 2 H 2 molecules, − make C 2 H 2 /CO 2 separation a challenging task. Currently, cryogenic distillation and solvent extraction are the two primary methods to achieve highly effective separation of C 2 H 2 /CO 2 mixtures, but these processes often come with potential security risks and are more energy-intensive. − In this context, the development of novel adsorptive separation technology employing porous solid adsorbents based on a physical adsorption mechanism is strongly driven by the significant reduction in the energy footprint.…”

Isoreticular Contraction of Cage-like Metal–Organic Frameworks with Optimized Pore Space for Enhanced C2H2/CO2 and C2H2/C2H4 Separations

“…Therefore, the selective C 2 H 2 separation from CO 2 and C 2 H 4 is of great importance to obtain poly grade C 2 H 2 and C 2 H 4 feedstocks for highly safe and efficient production of chemicals. The separation or purification of C 2 H 2 from CO 2 and C 2 H 4 is typically realized through cryogenic distillation or solvent extraction in industry, involving intensive cost and energy consumption owing to their similar boiling points (boiling point: 189.3 K for C 2 H 2 , 194.7 K for CO 2 , and 169.5 K for C 2 H 4 ), which has spurred the development of more efficient technology as alternatives to achieve this daunting challenge. − At present, adsorptive separation technology based on porous solid materials has been proven to be one of the most promising approaches due to its energy efficiency and its being environmentally friendly. However, the similar physicochemical properties of C 2 H 2 , CO 2 , and C 2 H 4 (kinetic diameter: 3.3 Å for C 2 H 2 and CO 2 , 4.2 Å for C 2 H 4 ; quadrupole moment: 7.2 × 10 26 e.s.u.…”

Deciphering Mechanisms of CO2-Selective Recognition over Acetylene within Porous Materials

“…C 2 H 2 is primarily produced from the steam cracking of hydrocarbons like petroleum or naphtha and through the partial combustion of methane, processes that inadvertently introduce CO 2 as an impurity, leading to a compromised quality of C 2 H 2 that impedes its utility in downstream processes. − Therefore, effective CO 2 removal is essential to ensure the high-grade quality of C 2 H 2 necessary for creating high-value chemicals. The challenge in separating CO 2 from C 2 H 2 lies in their closely aligned physical properties and molecular dimensions (Table ), making traditional separation methods like solvent extraction and cryogenic distillation not only energy-intensive but also environmentally burdensome, contributing to high carbon emissions and potential equipment corrosion. − In alignment with global sustainability goals, there is a heightened demand for more eco-friendly and energy-conserving purification strategies for C 2 H 2 . Adsorptive separation, utilizing porous adsorbents designed to selectively bind CO 2 , offers a streamlined and targeted approach to purifying C 2 H 2 by effectively removing CO 2 contaminants.…”