Two highly sulfonated micro/mesoporous polymers, P(1,3‐DEB)‐SO3H and P(1,4‐DEB)‐SO3H, with permanent porosity, the specific surface area about 550 m2 ⋅ g−1 and the content of SO3H groups of 2.7 mmol ⋅ g−1 were prepared as new acid Porous Polymer Catalysts, PPCs. The PPCs were achieved by easy sulfonation of parent hyper‐cross‐linked micro/mesoporous polyacetylene‐type networks resulting from a chain‐growth homopolymerization of 1,3‐ and 1,4‐diethynylbenzenes. New PPCs are reported as highly active and reusable heterogeneous catalysts of esterification of fatty acids with methanol and ethanol, Prins cyclization of aldehydes with isoprenol and intramolecular Prins cyclization of citronellal to isopulegol. The catalytic activity of the micro/mesoporous PPCs (TON values up to 522 mol ⋅ mol−1) was higher than that of commercial polymer‐based heterogeneous catalyst Amberlyst 15 possessing gel texture without permanent pores and that of p‐toluenesulfonic acid applied as a homogeneous catalyst.

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 of up to 1000 m g 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 . 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.

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