Ferrocene-based hypercrosslinked polymers derived from phenolic polycondensation with unexpected H2 adsorption capacity

Metal-doped porous organic polymers often display unique properties for applications in gas uptake owing to the incorporation of the metal elements in the polymer networks. In this study, a series of novel ferrocene-based hypercrosslinked polymers were prepared by phenolic polycondensation (Fc-PR-HCPs). To generate the hypercrosslinked polymers, 1,1′-ferrocenedicarboxaldehyde (Fc(CHO)₂) and bisphenol A (BPA) were used as the building blocks. The maximum value of BET and micropore surface area is determined to be 1111.4 and 487.4 m²/g for Fc-PR-HCP3. A significant H₂ adsorption capacity of 3.11 wt% was achieved for Fc-PR-HCP3 at 77 K/1.0 bar, which was noted to be higher than the porous organic polymers with even higher BET surface area value. The high micropore surface area value and the adsorption sites (aromatic rings and metal ion-active sites) provided by two building blocks were used to explain the significant H₂ adsorption capacity successfully. Overall, the findings from this study indicate that Fc-PR-HCPs highlighted prospective applications in the field of H₂ capture.     

<Emphasis Type="Italic">Tetra</Emphasis>-armed conjugated microporous polymers for gas adsorption and photocatalytic hydrogen evolution

Two novel tetra-armed conjugated microporous polymers with different geometries have been designed and synthesized via Suzuki-Miyaura cross coupling polycondensation. Both polymers are stable in various organic solvents tested and are thermally stable. The pyrene-containing polymer of PrPy with the rigid pyrene unit shows a higher Brunauer-Emmet-Teller specific surface area of 1219 m² g^?1 than the tetraphenylethylene-containing polymer of PrTPE (770 m² g^?1), which leads to a high CO₂ uptake ability of 3.89 mmol g^?1 at 1.13 bar/273 K and a H₂ uptake ability of 1.69 wt% at 1.13 bar/77 K. The photocatalytic hydrogen production experiments revealed that PrPy also shows a better photocatalytic performance than PrTPE due to the higher conjugation degree and planar structure, the broader UV-visible (UV-Vis) absorption, the lower photoluminescence lifetime, and the higher specific surface area.     

Synthesis of Davankov‐type hypercrosslinked resins using different isomer compositions of vinylbenzyl chloride monomer,and application in the solid‐phase extraction of polar compounds

Two different gel‐type resins have been prepared by suspension polymerization using 2 wt % divinylbenzene (DVB) with either p‐vinylbenzyl chloride (pVBC) or a mixture of VBC isomers (～ 70% m‐; ～ 30% p‐). Significant difference in the chlorine content was observed, which was attributed to a more favored hydrolysis process when p‐VBC was used. The presence of hydroxyl groups has been confirmed by elemental microanalytical data and solid‐state ¹³C cross‐polarization/magic angle spinning (CP‐MAS) nuclear magnetic resonance (NMR) spectra. Hypercrosslinked resins were prepared from both gel‐type precursors by treatment with FeCl₃ in 1,2‐dichloroethane (DCE) at 80 °C. The resultant resins showed differences in specific surface area and degree of hydrophilicity. The performance of the hypercrosslinked resins was evaluated in solid‐phase extraction (SPE) of polar compounds, and better results were obtained for the hypercrosslinked resin prepared from p‐VBC that combines a relatively high specific surface area (908 m² g^?1) and somewhat higher oxygen content (3.96 wt % O). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1718–1728, 2005     

Hybrid azobenzene-doped nanoporous polymers derived from cubic octavinylsilsesquioxane

A series of novel hybrid porous polymers (HPPs) with high specific surface areas were first prepared by one-step ternary cross-linking copolymerization of octavinylsilsesquioxane (OVS), 1,3,5-tribromobenzene, and 4,4´-dibromoazobenzene via the Heck reaction. The porosities and the CO₂ uptake capacities of resulting azobenzene-doped porous polymers could be tuned by modulating the molar percentage of the azo units. At 273 K and 101 kPa, the sample with the specific surface area of ~700 m² g^–1 (data of Brunauer—Emmett—Teller (BET) surface area analysis) showed the highest CO₂ uptake of 5.45 wt.% (1.20 mmol g^–1) among the fabricated HPPs.

     

Separation of p‐Divinylbenzene by Selective Room‐Temperature Adsorption Inside Mg‐CUK‐1 Prepared by Aqueous Microwave Synthesis

A new Mg^II‐based version of the porous coordination polymer CUK‐1 with one‐dimensional pore structure was prepared by microwave synthesis in water. Mg‐CUK‐1 is moisture‐stable, thermally stable up to 500 °C, and shows unusual reversible soft‐crystal behavior: dehydrated single crystals of the material selectively adsorb a range of organic molecules at ambient temperature and pressure. Both polar and apolar aromatic compounds, including pyridine, benzene, p‐xylene, and p‐divinylbenzene (p‐DVB), are all readily adsorbed, while other isomers from complex mixtures of xylenes or DVBs are selectively excluded. The solvent‐loaded structures have been studied by single‐crystal X‐ray diffraction. Time‐dependent liquid sorption experiments using commercially available DVB demonstrate a high and rapid selective adsorption of p‐DVB and exclusion of m‐DVB and ethylvinylbenzene isomers.     

An Azo-Group-Functionalized Porous Aromatic Framework for Achieving Highly Efficient Capture of Iodine

The strong radioactivity of iodine compounds derived from nuclear power plant wastes has motivated the development of highly efficient adsorbents. Porous aromatic frameworks (PAFs) have attracted much attention due to their low density and diverse structure. In this work, an azo group containing PAF solid, denoted as LNU-58, was prepared through Suzuki polymerization of tris-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)-amine and 3,5-dibromoazobenzene building monomers. Based on the specific polarity properities of the azo groups, the electron-rich aromatic fragments in the hierarchical architecture efficiently capture iodine molecules with an adsorption capacity of 3533.11 mg g⁻¹ (353 wt%) for gaseous iodine and 903.6 mg g⁻¹ (90 wt%) for dissolved iodine. The iodine uptake per specific surface area up to 8.55 wt% m⁻² g⁻¹ achieves the highest level among all porous adsorbents. This work illustrates the successful preparation of a new type of porous adsorbent that is expected to be applied in the field of practical iodine adsorption.     

Synthesis of Porous Covalent Quinazoline Networks (CQNs) and Their Gas Sorption Properties

The development of different classes of porous polymers by linking organic molecules using new chemistries still remains a great challenge. Herein, we introduce for the first time the synthesis of covalent quinazoline networks (CQNs) using an ionothermal synthesis protocol. Zinc chloride (ZnCl₂) was used as the solvent and catalyst for the condensation of aromatic ortho‐aminonitriles to produce tricycloquinazoline linkages. The resulting CQNs show a high porosity with a surface area up to 1870 m² g^?1. Varying the temperature and the amount of catalyst enables us to control the surface area as well as the pore size distribution of the CQNs. Furthermore, their high nitrogen content and significant microporosity make them a promising CO₂ adsorbent with a CO₂ uptake capacity of 7.16 mmol g^?1 (31.5 wt %) at 273 K and 1 bar. Because of their exceptional CO₂ sorption properties, they are promising candidates as an adsorbent for the selective capture of CO₂ from flue gas.     

A ferrocene‐containing porous organic polymer linked by tetrahedral silicon‐centered units for gas sorption

A novel ferrocene‐containing porous organic polymer (FPOP) has been prepared by Sonogashira‐Hagihara coupling reaction of 1,1′‐dibromoferrocene and tetrakis(4‐ethynylphenyl)silane. Compared with other polymers, the resulting polymer possesses excellent thermal stability with the decomposition temperature of 415°C and high porosity with Brunauer–Emmett–Teller (BET) surface area of 542 m² g^?1 as measured by nitrogen adsorption‐desoprtion isotherm at 77 K. For applications, it shows moderate carbon dioxide uptakes of up to 1.42 mmol g^?1 (6.26 wt%) at 273 K/1.0 bar and 0.82 mmol g^?1 (3.62 wt%) at 298 K/1.0 bar, and hydrogen capacity of up to 0.45 mmol g^?1 (0.91 wt%) at 77 K/1.0 bar, indicating that FPOP might be utilized as a promising candidate for storing carbon dioxide and hydrogen. Although FPOP possesses lower porosity than many porous polymers, the gas capacities are higher or comparable to them, thereby revealing that the incorporation of ferrocene units into the network is an effective strategy to enhance the affinity between the framework and gas.     

Synthesis and evaluation of N,O‐doped hypercrosslinked polymers and their performance in CO2 capture

A series of N, O‐doped hypercrosslinked microporous polymers (HCPs) with high surface area and rich microporosity were constructed via facile Friedel‐Crafts alkylation promoted by anhydrous ferric chloride (FeCl₃), which used benzyl alcohol (BA) and 2‐phenylimidazole (PID) as the basic building blocks. The effects of structural composition on the pore properties and gas adsorption properties of prepared HCPs were systematically investigated. The results show that by adjusting the ratio of PID to BA, the Brunauer–Emmett–Teller (BET) specific surface area and pore volume of the prepared HCPs can be controlled, and the BET specific surface area of the polymers range from 732–992 m²/g. Gas uptake experiments indicate that the obtained HCPs exhibit very high CO₂ adsorption capacity up to 3.55 mmol/g at 273 K/1.0 bar. Simultaneously, these N, O‐doped HCPs also show quite high isosteric heat of CO₂ sorption at the low coverage (up to 33 kJ/mol). In addition, the prepared HCPs have excellent selective adsorption performance, and the optimal selective adsorption of CO₂/N₂ is 62. These results demonstrate that these prepared HCPs are potential candidates for applications in CO₂ capture.     

High capacity gas capture and selectivity properties of triazatruxene-based ultramicroporous hyper-crosslinked covalent polymer

Tuning the selective sorption features of microporous organic networks is of great importance for subsequent applications in gas uptake and hiding, while it is more attractive in terms of being both time and cost effective to realize these optimizations without using functional groups in the core and linker. “Knitting” is one of the easiest and most used method to obtain a broad scope of hyper-crosslinked polymers on a large scale from aromatic structures that do not contain functional groups for polymerization. By the use of Knitting method, a hypercrosslinked covalent ultramicroporous organic polymer was obtained via stepwise process from using triazatruxene (TAT) as core -a planar indole trimer- through anhydrous FeCl₃ catalyzed Friedel–Crafts alkylation using dimethoxybenzene as a linker. The resulting microporous polymer, namely TATHCCP was completely identified by analytical and spectral techniques after examined for gas properties (CO₂, CH₄, O₂, CO, and H₂) and selectivity (CO₂/N₂, CO₂/O₂, for CO₂/CO and CO₂/CH₄) up to 1 bar and increased temperatures (273 K, 296 K and 320 K). Although it has a relatively low (Brunauer–Emmett–Teller) BET specific surface area around 557 m²/g, it was seen to have a high CO₂ capture capacity approaching 10% wt. at 273 K. In accordance with (ideal adsorbed solution theory) IAST computations, it was revealed that interesting selectivity features hitting up to 60 for CO₂/N₂, 45 for CO₂/O₂, 35 for CO₂/CO, 13 for CO₂/CH₄ at lower temperatures revealed that the material has much better selectivity values than many HCP (hyper-crosslinked polymer) derivatives in the literature even from its most similar analog dimethoxymethane derivative TATHCP, which has a surface area of 950 m²/g.     

Synthesis of a hybrid MIL-101(Cr)/ZTC composite for hydrogen storage applications

Metal–organic frameworks (MOFs) hybrid composites have recently attracted considerable attention in hydrogen storage applications. In this study a hybrid composite of zeolite templated carbon (ZTC) and Cr-based MOF (MIL-101) was synthesised by adding the templated carbon in situ during the synthesis of MIL-101(Cr). The obtained sample was fully characterized and hydrogen adsorption measurements performed at 77 K up to 1 bar. The results showed that the surface areas and the hydrogen uptake capacities of individual MIL-101 (2552 m² g^?1, 1.91 wt%) and zeolite templated carbon (2577 m² g^?1, 2.39 wt%) could be enhanced when a hybrid MIL-101(Cr)/ZTC composite (2957 m² g^?1, 2.55 wt%) was synthesized. The procedure presents a simple way for enhancement of hydrogen uptake capacity of the individual Cr-MOF and templated carbon samples.     

Chromatographic behavior of benzimidazole derivatives on hypercrosslinked polystyrene by reverse-phase HPLC

Abstract

An important part in the research of separation of various compound classes is the study of relationship between structure and property by describing the effect of structure on compounds’ chromatographic retention. The aim of this work was to study the chromatographic retention of the firstly synthesized benzimidazoles from water-acetonitrile and water-methanol solutions on hypercrosslinked polystyrene (HCP) by high-performance liquid chromatography (HPLC). The effect of water-methanol and water-acetonitrile solutions’ composition on the benzimidazole derivative retention factors on HCP was studied. The thermodynamic characteristics of sorption of benzimidazoles’ transition from water-organic solutions onto the surface of HCP phase were obtained. The thermodynamic compensation effects were studied. It has been shown that the benzimidazole nitro derivative realizes additional specific interactions with the aromatic network of HCP. The slope ratio of the Soczewiński–Wachtmeister equation was calculated. It was shown that 1-hydroxymethylbenzimidazole and 2-aminobenzimidazole characterized by small volumes and containing hydrophilic substituents do not subordinate Soczewiński–Wachtmeister model under ranging from 75 to 85% concentrations of acetonitrile.     

Synthesis and Gas Adsorption Properties of Tetra‐Armed Microporous Organic Polymer Networks Based on Triphenylamine

Two novel tetra‐armed microporous organic polymers have been designed and synthesized via a nickel‐catalyzed Yamamoto‐type Ullmann cross‐coupling reaction or Suzuki cross‐coupling polycondensation. These polymers are stable in various solvents, including concentrated hydrochloric acid, and are thermally stable. The homocoupled polymer YPTPA shows much higher Brunauer–Emmet–Teller‐specific surface area up to 1557 m² g⁻¹ than the copolymer SPTPA (544 m² g⁻¹), and a high CO₂ uptake ability of 3.03 mmol g⁻¹ (1.13 bar/273 K) with a CO₂/N₂ sorption selectivity of 17.3:1. Both polymers show high isosteric heats of CO₂ adsorption (22.7–26.5 kJ mol⁻¹) because the incorporation of nitrogen atoms into the skeleton of microporous organic polymers enhances the interaction between the pore wall and the CO₂ molecules. The values are higher than those of the porous aromatic frameworks, which contain neither additional polar functional groups nor nitrogen atoms, and are rather close to those of previously reported microporous organic polymers containing the nitrogen atoms on the pore wall. These data show that these materials would be potential candidates for applications in post‐combustion CO₂ capture and sequestration technology.

     

Epoxy‐Functionalized Porous Organic Polymers via the Diels–Alder Cycloaddition Reaction for Atmospheric Water Capture

The synthesis of highly microporous, epoxy‐functionalized porous organic polymers (ep‐POPs) by a one‐pot, catalyst‐free Diels–Alder cycloaddition polymerization is reported. The high oxygen content of ep‐POPs offer efficient hydrogen‐bonding sites for water molecules, thus leading to high water‐uptake capacities up to 39.2–42.4 wt % under a wide temperature range of 5–45 °C, which covers the span of climatic conditions and manufacturing applications in which such materials might be used. Importantly, ep‐POPs demonstrated regeneration temperatures as low as 55 °C, as well as excellent water stability, recyclability, and high specific surface areas up to 852 m² g⁻¹.     

Polyacetylene‐Type Networks Prepared by Coordination Polymerization of Diethynylarenes: New Type of Microporous Organic Polymers

Microporous organic polymers (MOP) of a new type have been synthesised in high yields by a simple coordination polymerization of 1,3‐diethynylbenzene, 1,4‐diethynylbenzene and 4,4′‐diethynylbiphenyl catalysed by [Rh(cod)acac] and [Rh(nbd)acac] complexes. The new MOPs are non‐swellable polyacetylene‐type conjugated networks consisting of ethynylaryl‐substituted polyene main chains that are crosslinked by arylene linkers. Prepared MOP samples have a mole fraction of branching units (by ¹³C CP/MAS NMR) from 0.30 to 0.47 and exhibit the BET (Brunaer‐Emmett‐Teller) surface up to 809 m² g⁻¹ and hydrogen uptake up to 0.69 wt% (77 K, H₂ pressure 750 torr).     

ESR study of hypercrosslinked polystyrene carbonizate—organic solvent—oxygen systems

Carbonizates of hypercrosslinked polystyrenes were studied by ESR spectroscopy. Conditions for preparation of paramagnetic carbon sorbents used as oxygen sensors were determined. These sorbents are characterized by an intense narrow ESR singlet for air desorption by pyridine, glycerol, ethanol, methanol, and water. For the carbonizates of nonionogenic biporous hypercrosslinked polystyrenes (I) or sulfonic cation-exchange resins based on biporous hypercrosslinked polystyrenes (II), the ESR line width decreases from 10 G in oxygen to 0.4–1.2 G (0.4 G for glycerol) upon solvent introduction, and the signal amplitude increases by two-three orders of magnitude. When solvents with the linear structure of molecules (alkanes, their mono-and dichlorosubstituted derivatives, alcohols) are introduced, the ESR line can decrease to 2.3±0.3 G. Carbonizates I and II obtained by pyrolysis at temperatures 580–620 °C possess a large internal surface (up to 680 m² g⁻¹) and contain packets of condensed aromatic polycycles with delocalized π-electrons. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 824–831, May, 2006.     

Fluorinated Porous Poly(spirobifluorene) Via Direct C‒H Arylation: Characterization,Porosity, and Gas Uptake

Considering intrinsic properties of conjugated polyfluorenes and special functions of porous polymers, synthesis of fluorinated porous poly(spirobifluorene) via direct C?H arylation polycondensation is explored. Owing to the contorted structure and cross-linking nature, the obtained polymer FPSBF shows permanent porosities with Brunauer–Emmett–Teller specific surface area up to 700 m² g^?1 and exhibits a narrow pore size distribution with the dominant pore size at about 0.63 nm, which is more suitable for adsorption of small gas molecules. Based on the measured gas physisorption isotherms with pressure up to 1.13 bar, the obtained polymer shows good uptaking capacities for hydrogen (1.30 wt% at 1.0 bar and 77 K) and methane (4.80 wt% 1.0 bar and 273 K). Moreover, FPSBF has significant adsorption selectivity for CH₄ against N₂ and the estimated ideal adsorption selectivity ratio is up to 30/1 at 1.0 bar and 273 K, which makes the material possess potential application in gas separation.     

多孔聚合物贮氢材料的研究进展

微孔聚合物由于具有较高的比表面积,因此可用作物理吸附贮氢材料.本文通过比较0.1MPa、77K下自具微孔聚合物、超交联聚合物等多孔聚合物与其它多孔贮氢材料(如碳材料、金属有机网络等)的贮氢性能,阐述了比表面积、孔尺寸及孔形貌、与氢气的作用力等因素对多孔聚合物贮氢量的影响,由于合成超交联聚合物的单体多且孔形貌容易控制,因此超交联聚合物成为具有发展潜力的贮氢聚合物.     

One-pot solvothermal synthesis of hypercrosslinked porous ionic polymer and its catalytic activity

The hypercrosslinked porous ionic polymer has been synthesized via one-pot polymerization and quaternization of vinyl pyridine and chloromethyl styrene under solvothermal condition. The effects of solvents and synthetic process on the polymer structure were investigated. Polymer from n-butanol showed the highest BET surface area of 555.6 m²/g. The catalytic activities were investigated though the aza-Michael addition and the results showed that the polymer owned even higher activity than homogenous ionic liquid. The high BET surface area, high catalytic activity and high stability made the polymer hold great potential for green chemical processes.     

Sol–gel synthesis of mesoporous silicas containing albumin and guanidine polymers and its application to the bilirubin adsorption

The organic–inorganic composite materials based on mesoporous silica were synthesized using sol–gel method. The surface area of silicas was modified by bovine serum albumin (BSA) and guanidine polymers: polyacrylate guanidine (PAG) and polymethacrylate guanidine. The mesoporous silicas were characterized by nitrogen adsorption–desorption analysis, Fourier transform infrared spectroscopy, transmission electron microscopy. The obtained materials were used as adsorbents for selective bilirubin removal. It was shown that the structural properties and surface area of modified materials depend on the nature of polymers. Incorporation of polymers in silica gel matrix during sol–gel process leads to the formation of mesoporous structure with high pore diameter and a BET surface area equals to 346 m²/g for SiO₂/BSA and 160 m²/g for SiO₂/PAG. Analysis of adsorption isotherms showed that modification of silica by BSA and guanidine polymers increases its adsorption ability to bilirubin molecules. According to Langmuir model, the maximum bilirubin adsorption capacity was 1.18 mg/g.