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Ultramicroporous CO2 adsorbents with tunable mesopores based on polyimines synthesized under off-stoichiometric conditions
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
2016 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 222, 80-86 p.Article in journal (Refereed) Published
Abstract [en]

A series of porous polymers with ultramicropores and tunable mesopores were synthesized by condensation reaction (Schiff base) of triamine and trialdehyde monomers. They had specific surface areas and pore volumes of up to 694 m2/g and 0.67 cm3/g. The ultramicropores seemed to have been templated by the solvent (DMSO) primarily. The size of the mesopores depended strongly on the amine-to-aldehyde ratio used during synthesis. With a moderate aldehyde excess, the irregular mesopores of the porous polymers increased in size. The polymers’ capacities to adsorb CO2 were large (0.93–1.58 mmol/g at 0.15 bar and 2.20–3.28 mmol/g at 1 bar; 0 °C) due to their large ultramicropore volumes, and the estimated CO2-over-N2 selectivities were also relatively high (31-90 for CO2/N2 mixtures with 15v%/85v% at 0 °C). The uptake of CO2 on the polymers was quite rapid, and it appears advantageous to have a combination of meso- and ultramicropores in this class of polymers for applications in carbon capture and storage.

Place, publisher, year, edition, pages
2016. Vol. 222, 80-86 p.
Keyword [en]
Porous polymers, ultramicroporous, mesoporous, adsorbents, CO2 capture
National Category
Polymer Chemistry
Research subject
Materials Chemistry
Identifiers
URN: urn:nbn:se:su:diva-121203DOI: 10.1016/j.micromeso.2015.09.041ISI: 000370109400010OAI: oai:DiVA.org:su-121203DiVA: diva2:857332
Available from: 2015-09-28 Created: 2015-09-28 Last updated: 2017-12-01Bibliographically approved
In thesis
1. Imine/azo-linked microporous organic polymers: Design, synthesis and applications
Open this publication in new window or tab >>Imine/azo-linked microporous organic polymers: Design, synthesis and applications
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Microporous organic polymers (MOPs) are porous materials. Owing to their high surface area, tunable pore sizes and high physicochemical stability, they are studied for applications including gas capture and separation and heterogeneous catalysis. In this thesis, a series of imine/azo-linked MOPs were synthesized. The MOPs were examined as potential CO2 sorbents and as supports for heterogeneous catalysis.

The MOPs were synthesized by Schiff base polycondensations and oxidative couplings. The porosities of the imine-linked MOPs were tunable and affected by a range of factors, such as the synthesis conditions, monomer lengths, monomer ratios. All the MOPs had ultramicropores and displayed relatively high CO2 uptakes and CO2-over-N2 selectivities at the CO2 concentrations relevant for post-combustion capture of CO2. Moreover, the ketimine-linked MOPs were moderately hydrophobic, which might increase their efficiency for CO2 capture and separation.

The diverse synthesis routes and rich functionalities of MOPs allowed further post-modification to improve their performance in CO2 capture. A micro-/mesoporous polymer PP1-2, rich in aldehyde end groups, was post-synthetically modified by the alkyl amine tris(2-aminoethyl)amine (tren). The tethered amine moieties induced chemisorption of CO2 on the polymer, which was confirmed by the study of in situ infrared (IR) and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. As a result, the modified polymer PP1-2-tren had a large CO2 capacity and very high CO2-over-N2 selectivity at low partial pressures of CO2.

Pd(II) species were incorporated in the selected MOPs by means of complexation or chemical bonding with the imine or azo groups. The Pd(II)-rich MOPs were tested as heterogeneous catalysts for various organic reactions. The porous Pd(II)-polyimine (Pd2+/PP-1) was an excellent co-catalyst in combination with chiral amine for cooperatively catalyzed and enantioselective cascade reactions. In addition, the cyclopalladated azo-linked MOP (Pd(II)/PP-2) catalyzed Suzuki and Heck coupling reactions highly efficiently.

Place, publisher, year, edition, pages
Stockholm: Stockholm University, 2015. 83 p.
Keyword
Microporous organic polymers, CO2 capture and separation, post-modification, chemisorption, heterogeneous catalysis
National Category
Materials Chemistry
Research subject
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-121209 (URN)978-91-7649-274-1 (ISBN)
Public defence
2015-11-13, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 7: Manuscript.

Available from: 2015-10-22 Created: 2015-09-28 Last updated: 2015-10-21Bibliographically approved

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