Maximizing Ether Oxygen Content in Polymers for Membrane CO2 Removal from Natural Gas
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Updated: Jan 28, 2026

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
Junyi Liu1, Gengyi Zhang1, Krysta Clark1
1Department of Chemical and Biological Engineering , University at Buffalo, The State University at New York , Buffalo , New York 14260 , United States.
Abstract:
Membrane materials for CO2 removal from natural gas are based on glassy polymers with a high CO2/CH4 diffusivity selectivity. However, these polymers suffer from competitive sorption by heavy hydrocarbons that decreases CO2 permeability and physical aging that reduces gas permeability with time. We circumvent these issues by designing rubbery, solubility-selective polymers with a ratio of ether/ester oxygen to carbon as high as 0.8 through the use of 1,3-dioxolane and 1,3,5-trioxane. The ether/ester oxygen groups interact favorably with CO2 but do not interact with CH4, leading to a high CO2/gas solubility selectivity that is unaffected by heavy hydrocarbons in the raw natural gas. These polar groups are incorporated in short branches to yield an amorphous and rubbery nature, leading to high gas permeability that is stable over time. A polymer with an O/C ratio of 0.71 (P71) shows a mixed-gas CO2 permeability of 320 Barrers and a CO2/CH4 selectivity of 21 in the simulated natural gas at 50 °C, which is independent of the hexane content and above the upper bound for CO2/CH4 separation at 50 °C.
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Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Crown Ethers
Structure and Nomenclature of Ethers
Ethers are organic compounds with an ether functional group which is characterized by an oxygen atom connected to two — identical or different — alkyl, aryl, or vinyl groups. The C–O–C linkage in dimethyl ether — the simplest ether — has an approximately tetrahedral bond angle of 110.3 degrees. The oxygen atom is sp3- hybridized, with the C–O distance being about 140 pm.
Classification of Ethers
Based on their attached substituent...
Stereotype Content Model

