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Catechol, a structure widely found in nature with a strong interaction with iron (Fe) ions, was used as a monomer to prepare a hypercrosslinked polymer (HCP) as a solid adsorbent for Fe removal from water. The catechol-based HCP (Catechol-HCP) was synthesized via Friedel–Crafts alkylation and characterized by FT-IR spectroscopy, elemental analysis, and BET surface area analysis. The HCPs based on toluene, phenol, and hydroquinone monomers were also prepared to compare their Fe adsorption efficiency. Comparing to toluene-, phenol-, and hydroquinone-based HCPs, Catechol-HCP showed a significantly higher Fe adsorption indicating the important of the strong interaction of catechol unit to the Fe ion. Factors including adsorbent dose, contact time, initial solution concentration, and temperature were studied on their effects on the adsorption efficiency. The Catechol-HCP could remove Fe from water more than 40 mg g−1 or 94%. The adsorption isotherm was fitted to the Langmuir model with the RL value between 0 and 1 indicating the favorable adsorption. The kinetics study suggested the adsorption occurred as a pseudo-second-order mechanism. Moreover, the material showed a good reusability demonstrating the cost effectiveness of the material which would be beneficial for further practical utilizations. [ABSTRACT FROM AUTHOR]

Heterogeneous microporous acid (sulfonic acid) and base (benzylamine) catalysts with high surface areas were synthesized using simple aromatic compounds through one-step external cross-linking reaction. The direct induction and control of catalytic sites were achieved by functionalized monomers using an appropriate amount of acid/base monomers. This strategy provides an easy approach to produce highly stable and acid/base functionalized microporous organic polymers. The structure and composition of the catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption, Fourier transform infrared spectroscopy (FT-IR), solid-state 13 C cross polarization magic angle spinning (CP/MAS) NMR, thermogravimetric analysis (TGA), and element mapping analysis. The stable porous skeleton and the accurate manipulation of the catalyst structure allowed us to use the obtained polymers as compatible and efficient acid/base co-catalysts for one-pot cascade reactions. We demonstrated the use of these microporous heterogeneous catalysts for the cascade deacetalization/Henry and deacetalization/Knoevenagel reactions. The results demonstrated that preparing microporous materials from simple aromatic compounds through one-step external cross-linking reaction is indeed a cost-effective and easy-to-handle method to produce functionalized heterogeneous catalysts. The microporous heterogeneous catalysts produced by this method are highly stable and the amount of catalytically active sites can easily be controlled to form a catalytic system with two antagonistic centers. [ABSTRACT FROM AUTHOR]

A hypercrosslinked polymer (HCP)-immobilized ruthenium catalyst (HCP-PPh3-Ru) was prepared from benzene and triphenylphosphine (PPh3) through a one-step external cross-linking reaction. The structure and composition of the catalyst were fully characterized by many physicochemical methods. HCP-PPh3-Ru was found to possess high Brunauer-Emmett-Teller (BET) surface area, large pore volume, and low skeletal density. Moreover, the Ru catalyst was also featured some advantages, such as low synthetic cost and good chemical and thermal stability. HCP-PPh3-Ru was then used as a recoverable and effective catalyst for the synthesis of 2,4-diaryl-substituted pyridines from acetophenones, ammonium acetate (NH4OAc) and dimethylformamide (DMF), and the cycloaddition reaction of diazodicarbonyl compounds with olefins to afford dihydrofurans. In addition, a combination of HCP-PPh3-Ru and Amberlyst-15 enabled us to establish a simple protocol for the direct synthesis of carbazole derivatives from diazodicarbonyl compound, alkyl vinyl ether and indole. In these selected reactions, the catalyst was easily recovered and reused several times without significant activity loss. [ABSTRACT FROM AUTHOR]

• Hypercrosslinked polymers with abundant CO 2 chemisorption sites were prepared. • Moderate chemisorption effect on CO 2 with high Qst value of 34.7 kJ/mol. • The porous catalysts exhibit excellent CO 2 chemical conversion efficiency. • The porous catalysts show good stability for the cycloaddition reaction. The weak physical adsorption of CO 2 in porous organic polymers (POPs) leads to the low utilization of CO 2 in catalysis, calling for the need to develop materials to ensure higher adsorption of CO 2 to achieve high conversion efficiency. In this regard, hydrazine (HZ) was successfully introduced into metalloporphyrin-based hypercrosslinked polymers (HCPs) by post-modification to create abundant CO 2 chemisorption sites in structures for efficient adsorption (Qst value up to 34.7 kJ/mol) and chemical conversion of CO 2 under ambient conditions. The HZ-modified material (HCP-TPP-Co-HZ) exhibits high catalytic performance for different molecular sizes of epoxide substrates with excellent yields (reaching 98 % of propylene oxide), much superior than that of HCP-TPP-Co-SO 3 H (64 %), which can be ascribed to the abundant chemisorption sites for CO 2 reactants. Moreover, HCP-TPP-Co-HZ has good stability and shows excellent recycling performance (more than 5 times) for the coupling of CO 2 with substituted epoxides at room temperature and atmospheric pressure. This strategy to introduce amine groups as CO 2 chemisorption sites has been demonstrated to be a new pathway for the design of efficient HCPs catalysts for chemical conversion of CO 2. [ABSTRACT FROM AUTHOR]

Metal deposition with photocatalyst is a promising way to surmount the restriction of fast e - /h + recombination to improve the photocatalytic performance. However, the improvement remains limited by the existing strategies adopted for depositing metal particles due to the serious aggregation and large unconnected area on photocatalyst surface. Here, a strategy is proposed by directly grafting hypercrosslinked polymers (HCPs) on TiO 2 surface to construct Pd-HCPs-TiO 2 composite with uniform dispersion of ultrafine Pd nanoparticles on HCPs surface. This composite with surface area of 373 m 2 g -1 exhibits improved photocatalytic CO 2 conversion efficiency to CH 4 with an evolution rate of 237.4 µmol g -1 h -1 and selectivity of more than 99.9%. The enhancement can be ascribed to the grafted porous HCPs with high surface area and N heteroatom on TiO 2 surface for the stabilization of Pd nanoparticles, favoring the electron transfer and CO 2 adsorption for selective CH 4 production. This strategy may hold the promise for design and construction of porous organic polymer with semiconductor for efficient photocatalytic conversion., (© 2021 Wiley-VCH GmbH.)

Hydrogen (H2) is one of the best candidates to replace current petroleum energy resources due to its rich abundance and clean combustion. However, the storage of H2 presents a major challenge. There are two methods for storing H2 fuel, chemical and physical, both of which have some advantages and disadvantages. In physical storage, highly porous organic polymers are of particular interest, since they are low cost, easy to scale up, metal-free, and environmentally friendly. In this review, highly porous polymers for H2 fuel storage are examined from five perspectives: (a) brief comparison of H2 storage in highly porous polymers and other storage media; (b) theoretical considerations of the physical storage of H2 molecules in porous polymers; (c) H2 storage in different classes of highly porous organic polymers; (d) characterization of microporosity in these polymers; and (e) future developments for highly porous organic polymers for H2 fuel storage. These topics will provide an introductory overview of highly porous organic polymers in H2 fuel storage. [ABSTRACT FROM AUTHOR]