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Hyper‐Cross‐Linked Polyacetylene‐Type Microporous Networks Decorated with Terminal Ethynyl Groups as Heterogeneous Acid Catalysts for Acetalization and Esterification Reactions
Author(s) -
Sekerová Lada,
Lhotka Miloslav,
Vyskočilová Eliška,
Faukner Tomáš,
Slováková Eva,
Brus Jiří,
Červený Libor,
Sedláček Jan
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201802432
Subject(s) - monomer , catalysis , chemistry , mesoporous material , microporous material , polyacetylene , aldehyde , brønsted–lowry acid–base theory , polymerization , ketone , polymer chemistry , carboxylic acid , organic chemistry , polymer
Heterogeneous catalysts based on materials with permanent porosity are of great interest owing to their high specific surface area, easy separation, recovery, and recycling ability. Additionally, porous polymer catalysts (PPCs) allow us to tune catalytic activity by introducing various functional centres. This study reports the preparation of PPCs with a permanent micro/mesoporous texture and a specific surface area S BET of up to 1000 m 2 g −1 active in acid‐catalyzed reactions, namely aldehyde and ketone acetalization and carboxylic acid esterification. These PPC‐type conjugated hyper‐cross‐linked polyarylacetylene networks were prepared by chain‐growth homopolymerization of 1,4‐diethynylbenzene, 1,3,5‐triethynylbenzene and tetrakis(4‐ethynylphenyl)methane. However, only some ethynyl groups of the monomers (from 58 to 80 %) were polymerized into the polyacetylene network segments while the other ethynyl groups remained unreacted. Depending on the number of ethynyl groups per monomer molecule and the covalent structure of the monomer, PPCs were decorated with unreacted ethynyl groups from 3.2 to 6.7 mmol g −1 . The hydrogen atoms of the unreacted ethynyl groups served as acid catalytic centres of the aforementioned organic reactions. To the best of our knowledge, this is first study describing the high activity of hydrogen atoms of ethynyl groups in acid‐catalyzed reactions.