Dual Functional Groups Research Articles

Dual Cross-Linked Self-Healing and Recyclable Epoxidized Natural Rubber Based on Multiple Reversible Effects

Generally, self-healing research based on commercial rubber is of great significance in sustainable development by extending the lifetime of materials. However, it is still a great challenge so far to prepare recyclable rubber that combine excellent self-healing properties with good mechanical strength and is also recyclable. Herein, we report the use of epoxidized natural rubber (ENR), a reactive polymer presenting dual functional groups (unsaturated double bonds and epoxy sites) available for cross-linking, to prepare a dual cross-linked self-healing ENR based on dynamic disulfide metathesis and thermoreversible hydrogen bonding. Specifically, different structures of aromatic disulfide compounds are introduced into the same system to promote the disulfide metathesis and thus improving the self-healing efficiency of the material. As a result, the dual cross-linked ENR shows high mechanical strength (9.3 ± 0.3 MPa), high self-healing efficiency (up to 98%), and ideal recyclability. In addition, cyclic fatigue tensile test shows that the self-healing properties of the present material are not affected by the damage forms, whether it is complete fracture or cyclic fatigue damage. These outcomes are expected to promote the development of self-healing technology in the sustainable application of cross-linked rubber materials.

Fluoroalkyl POSS with Dual Functional Groups as a Molecular Filler for Lowering Refractive Indices and Improving Thermomechanical Properties of PMMA.

The dual-functionalized polyhedral oligomeric silsesquioxane (POSS) derivatives, which have the seven fluorinated alkanes and the single acrylate ester on the silica cube, were designed as a filler for lowering the refractive index (RI) and improving thermomechanical properties in poly(methyl methacrylate) (PMMA). The desired dual-functionalized POSS fillers were prepared, and because of its high miscibility, homogeneous films were readily obtained, by the casting method, with the mixture solutions containing the modified POSS and the polymers. From optical measurements, it was found that the larger effects of lowering the RIs of the PMMA matrices were observed from the modified POSS than those of the octa-substituted POSS derivatives with the homogeneous substituents. It should be mentioned that the degradation temperatures and the storage moduli were able to be greatly elevated by loading the present POSS fillers. Finally, it was demonstrated that the methacrylate ester-tethered POSS should be the most effective filler for modulating PMMA (Δn = −0.020, ΔTd20 = +53 °C, ΔE’/E’ = +72%).

Radical Addition Cascade Cyclization of 1,6-Enynes with DMSO To Access Methylsulfonylated and Carbonylated Benzofurans under Transition-Metal-Free Conditions.

A mild and direct addition/cyclization cascade to construct methylsulfonylated and carbonylated benzofurans was accomplished using oxygen-linked 1,6-enynes as the starting materials. The interaction of NH4I and DMSO promoted the generation of sulfur-containing radical and initiated the radical addition to the C═C double bond of 1,6-enyne cascade intramolecular 5- exo- dig cyclization. A wide range of oxygen-linked 1,6-enynes bearing various substituents were found to be suitable in this cascade process, providing benzofurans with dual functional groups in moderate to high yields. This method could also be utilized to synthesize benzothiophenes from sulfur-linked 1,6-enynes.

Formation of organosilica nanoparticles with dual functional groups and simultaneous payload entrapment

A mixed organosilane system for simultaneous formation of organosilica nanoparticles has been systematically studied for loading of various compounds with a wide range of log P values. The molecule-entrapping system was understood by investigating the effects of adjusting various experimental parameters on particle formation and molecule entrapment. Particularly, rhodamine 6 G (R6G) loaded colloidal particles were prepared and characterised in detail. The results show that whereas most molecules had entrapment efficiency (EE%) in the range of 20–80%, R6G exhibited near 100% efficiency. Moreover, the colloidal system can be tuned to incorporate R6G with the extent of entrapment spanning at least 2 orders of magnitude (i.e. from 0.04 to 4 mg) and a maximum EE% of 98%. In conclusion, the study demonstrates the promise of the proposed mixed organosilane system in forming colloidal particles containing multiple functional groups with selective loading of highly hydrophobic molecules.

Chromatographic separation of phenyllactic acid from crude broth using cryogels with dual functional groups

Phenyllactic acid (PLA) is an important organic acid with wide antimicrobial activities against gram-positive and gram-negative bacteria and some fungi. This interesting compound can be synthesized by the microbial fermentation or the bioconversion using phenylpyruvic acid (PPA) as the key substrate and microorganisms as the whole-cell biocatalysts. However, the isolation of high-purity PLA with a high recovery from the crude fermentation or conversion broth is a challenging task. In this work, the separation of PLA from the crude conversion broth prepared by employing Lactobacillus buchneri cells as the whole-cell catalysts was achieved by the chromatography using the poly(hydroxyethyl methacrylate) (pHEMA)-based cryogel with a combination of anion-exchange and hydrophobic benzyl groups. The static adsorption behaviors of PLA under different salt concentrations and the adsorption capacities of PLA on the cryogel were measured experimentally. The chromatographic performance of PLA from the crude conversion broth was compared with that from the clarified broth. The results showed that the pHEMA-based cryogel has a high capacity of PLA, i.e., 14.64 mg mL−1 cryogel, and the adsorption of PLA was influenced by the salt concentration. By using deionized water as running buffer, PLA with a high purity of 97.6% was obtained with one step elution using 0.3 M NaCl as the elution solution with the recovery at the range of 80.2–90.8% from crude feedstock without any pretreatment at various flow velocities. These values were close to those obtained for the clarified broth, i.e., the purity of 98.4% and the recovery of 92.3% under the same chromatography conditions at 1 cm min−1. The cryogel was then applied to separate PLA from clarified feedstock, high purity (>96.7%) and recovery (>91.4%) of PLA were found with 20 cycles, which verified the selectivity and robustness of prepared pHEMA-VBTAC cryogel. Therefore, the chromatography using pHEMA-based cryogel with the dual functional groups is an effective approach for the isolation of PLA directly from the crude bioconversion broth and thus could be interesting in the separation and production of high-purity PLA in industry.

Nicotinium methane sulfonate (NMS): A bio-renewable protic ionic liquid and bi-functional catalyst for synthesis of 2-amino-3-cyano pyridines

In this work, a simple approach was used to quantitative preparation of nicotinum methane sulfonate (1-methyl-2-(pyridin-3-yl)pyrrolidin-1-ium methanesulfonate (NMS)) from nicotine and methane sulfonic acid. NMS, as a novel, mild, efficient, economic, and task-specific ionic liquid (TSIL) with dual acid and base functional groups, has been characterized by NMR, FT-IR, acidity measurements, and elemental analysis. This protic ionic liquid shows excellent catalytic activity in one-pot synthesis of 2-amino-3-cyanopyridines in 78–98% from malononitrile, aromatic aldehydes, methyl ketones, and ammonium acetate under solvent-free conditions. NMS is a nature-based recyclable and reusable catalyst.

Copper-Catalyzed Direct, Regioselective Arylamination of N-Oxides: Studies To Access Conjugated π-Systems.

An efficient copper(I)-catalyzed direct regioselective arylamination of various heterocyclic N-oxides was achieved successfully under redox-neutral conditions using anthranils as arylaminating reagents. The developed protocol is simple, straightforward, and economic with a broad range substrate scope. The dual functional groups in the final molecules were utilized to construct structurally and functionally diverse nitrogen-containing organic π-conjugated systems.

Carboxylic-acid-functionalized UiO-66-NH2: A promising adsorbent for both aqueous- and non-aqueous-phase adsorptions

UiO-66 functionalized with –NH– and –COOH groups was obtained by postsynthetic modification of aminated UiO-66. In order to introduce uncoordinated carboxyl groups into metal–organic frameworks (MOFs), UiO-66-NH2 was treated with oxalyl chloride to form UiO-66 functionalized with –NH– and –COOH groups (UiO-66-NH-CO-COOH). The successful functionalization of the MOF with uncoordinated carboxyl group was confirmed using some characterization techniques. The obtained MOFs were applied in liquid-phase adsorptions for both water and a model fuel. The UiO-66-NH-CO-COOH, consisting of dual functional groups (–NH– and –COOH), showed better performance than pristine UiO-66, UiO-66-NH2, and commercial activated carbon (AC) in the removal of several organics, e.g. triclosan (TCS) from water, and indole (IND) and quinoline (QUI) from model fuel. The UiO-66-NH-CO-COOH adsorbed ∼2.4 and 5.5 times more TCS and IND, respectively, than AC and its adsorption performances were comparable with other reported adsorbents. The maximum adsorption capacity of UiO-66-NH-CO-COOH for IND was 402mg·g−1, which was the highest among all reported UiO-66 MOFs. The remarkable adsorption efficiency of the MOF for both aqueous and non-aqueous phases was explained in terms of H-bonding: UiO-66-NH-CO-COOH and adsorbates act as H-bond acceptor and H-bond donor, respectively. Moreover, UiO-66-NH-CO-COOH can be regenerated by simple solvent washing and can be reused several times for the removal of the studied adsorbates. Therefore, UiO-66-NH-CO-COOH having both –NH– and –COOH groups is recommended as a versatile adsorbent for both aqueous- and non-aqueous-phase adsorptions.

Synthesis of novel magnetic nanoparticles with urea or urethane moieties: Applications as catalysts in the Strecker synthesis of α‐aminonitriles

Four novel magnetic nanoparticle catalysts with urea or urethane moieties are reported. The silica‐coated magnetic nanoparticles were simply functionalized via addition of 3‐(triethoxysilyl)propylisocyanate (TESPIC), amine or amino alcohol. TESPIC with dual labile functional groups was used as a suitable precursor for the synthesis of urethane‐based catalysts. The newly synthesized catalysts were fully characterized using a variety of techniques. These functionalized magnetic nanoparticles were used as reusable catalysts in the Strecker synthesis of α‐aminonitrile derivatives under solvent‐free conditions at 50 °C.

Ag-Catalyzed Oxidative Cyclization Reaction of 1,6-Enynes and Sodium Sulfinate: Access to Sulfonylated Benzofurans.

A convenient protocol for the synthesis of sulfonylated benzofurans via Ag-catalyzed oxidative cyclization has been established. Chemically stable and easily available sodium sulfinates were used as the sulfonylation reagents and building block for the heterocycle construction. With this novel strategy, various benzofurans bearing dual functional groups could be obtained in good yields with high chemo- and regioselectivities under mild conditions.

Adsorptive denitrogenation of model fuel by functionalized UiO-66 with acidic and basic moieties

Metal-organic frameworks (MOFs) are usually neutral in nature, even though they can be modified by introducing acidic or basic sites for various applications. However, MOFs with both acidic and basic sites are less common and have not been extensively studied. Here, for the first time, we have applied a MOF (UiO-66) containing both basic and acidic surface groups to the adsorptive removal of nitrogen-containing compounds (NCCs) from a model fuel. In order to introduce both acidic and basic sites in a MOF, aminated UiO-66 (UiO-66-NH2) was treated with 1,4-butanesultone to form UiO-66 functionalized with –NH– and –SO3H groups (UiO-66-NH-SO3H). The UiO-66-NH-SO3H MOF, bearing dual functional groups, exhibited much better performance in the removal of indole (IND) compared with the pristine (UiO-66), acidic (UiO-66-SO3H), and basic (UiO-66-NH2) MOFs. The maximum adsorption capacities of UiO-66-NH-SO3H for IND were 1.63 and 2.22 times to that of UiO-66 based on unit weight and surface area of MOFs, respectively. The superior performance of UiO-66-NH-SO3H (among all UiO-66 MOFs investigated) was attributed to the higher availability of H-bond acceptor sites in this material, compared with the other MOFs. Even though UiO-66-NH-SO3H showed lower adsorbed amounts of basic NCCs (such as quinoline, QUI), it exhibited improved adsorption performances at low (<600ppm) QUI concentrations (relevant for industrial applications), due to acid-base interactions. The UiO-66-NH-SO3H adsorbent can be reused several times by washing it with common solvents, such as ethanol. Therefore, MOFs functionalized with both acidic and basic sites, such as UiO-66-NH-SO3H investigated here, might be used in various applications, including adsorption and separation.

Dual‐Functionalized Hollow Polymer Particle as a pH‐Responsive Adsorbent for Selective Removal of Basic Dye

AbstractIn the present work, novel dual‐functionalized hollow polymer particles (DF‐HPP) with high density of carboxylate and amino dual functional groups have been specially designed and fabricated to serve as high‐performance adsorbent for selective removal of basic dye (methylene blue, b‐MB, as a model dye). Due to both the high surface area and the extremely high density of carboxylate and amino groups, the DF‐HPPs exhibited excellent adsorption property for methylene blue (b‐MB), including high adsorption capacity, fast adsorption/desorption rates, unique pH‐sensitivity and easy recovery. The equilibrium adsorption data of b‐MB on the DF‐HPPs were evaluated using Freundlich and Langmuir isotherm models, and the equilibrium isotherm was better fit with Langmuir model with a maximum adsorption capacity of 538.8 mg/g at pH 12. More interestingly, the DF‐HPPs showed a significant pH‐dependent equilibrium adsorption capacity, which decreased dramatically from 516.1 mg/g to 24 mg/g as the solution pH decreased from 12 to 3. The dye‐adsorbed DF‐HPPs can be facilely and rapidly regenerated under mild condition (under weak acidic solution, pH 3, in 30 min) to recover both b‐MB and the DF‐HPPs, and the regenerated DF‐HPPs can be reused for dye removal with high efficiency, indicating the exceptional recyclability of the DF‐HPPs.

Physicochemical and thermodynamic properties of imidazolium ionic liquids with nitrile and ether dual functional groups

Synthesis of new dual functionalized imidazolium ionic liquids (ILs) containing nitrile functionality and ether group were synthesized and characterized. Bis(trifluoromethylsulfonyl)imide, trifluoroacetate and dicyanamide were used as the anion. The combination of two functional groups on an imidazolium cation was mainly developed to assess their potential in desulfurization of fuel oil. Although ILs based on this individual functional group has been reported to improve the desulfurization efficiency, no effort has been made to combine nitrile and ether functional groups on the same cation to enhance the desulphurization potential. In this report, we tailored both nitrile and ether functionality on imidazolium cation and studied their physicochemical properties in details. NMR (1H and 13C) spectroscopy and elemental analysis were used to characterize the synthesized ILs. Physical properties and optical properties of the ILs were investigated in a wide temperature range. The synthesized ILs showed good thermal stability. COSMO-RS was effectively utilized to discuss the σ surface, σ potential and σ profile of the synthesized ILs.

Introduction of a novel basic ionic liquid containing dual basic functional groups for the efficient synthesis of spiro-4H-pyrans

In this research the synthesis of 1,1′-(butane-1,4-diyl)bis(1,4-diazabicyclo[2.2.2]octan-1-ium) hydroxide as an effective basic ionic liquid containing dual basic functional groups is reported. After characterization using FT-IR, 1H NMR, 13C NMR and mass analyses, this reagent is efficiently used for promotion of the synthesis of spiro-4H-pyrans via one-pot three-component condensation through a domino Knoevenagel/Michael/cyclization sequence. The attractive features of this process are simple procedure, short reaction times, high yields, no column chromatographic separation, commercial availability of the starting materials and recyclability of the catalyst.

Ammonium-Functionalized Hollow Polymer Particles As a pH-Responsive Adsorbent for Selective Removal of Acid Dye.

In this work, a novel type of ammonium-functionalized hollow polymer particles (HPP-NH3(+)) with a high density of ammonium groups in the shell has been specially designed and synthesized. Benefiting from both the high surface area and from the high density of positively charged ammonium groups, the as-prepared HPP-NH3(+) can serve as a selective adsorbent for the removal of negatively charged acid dye (e.g., methyl blue a-MB). The equilibrium adsorption data of a-MB on the HPP-NH3(+) were evaluated using Freundlich and Langmuir isotherm models, and Langmuir isotherm exhibited a better fit with a maximum adsorption capacity of 406 mg/g. Most importantly, because of the presence of dual functional groups (ammonium and carboxyl groups), the HPP-NH3(+) showed a significant pH-dependent equilibrium adsorption capacity, which increased dramatically from 59 mg/g to 449 mg/g as the solution pH decreased from 9 to 2. This uniqueness makes the dye-adsorbed HPP-NH3(+) can be facilely regenerated under mild condition (in weak alkaline solution, pH 10) to recover both a-MB and the HPP-NH3(+), whereas the recovery of conventional adsorbents is commonly performed under particularly severe conditions. The regenerated HPP-NH3(+) can be reused for dye removal and the dye removal efficiency remained above 98% even after five adsorption-desorption cycles. Because of its high adsorption capacity, pH-sensitivity, easy regeneration, and good reusability, the HPP-NH3(+) has great potential for the application in the field of water treatment, controlled drug release, and pH-responsive delivery.

Synthesis of amphiphilic polycarboxylate copolymer and its notable dispersion and adsorption characteristics onto cement and clay

Zwitterionic (ZI) polymers have great potential for dispersion and adsorption effects because of their dual functional groups (acidic and basic) grafted on polymer matrices. The ZI monomer 3-(2-(methacryloyloxy) ethyl) dimethylammonio-propane-1-sulfonate (DMAPS) and novel amphiphilic polycarboxylate copolymers (APCs) were prepared and characterised. The dispersion and adsorption behaviours of APCs as superplasticisers in a cement system in the absence and presence of clay were investigated. The results indicated that APCs had excellent dispersing ability, and a notable feature was that APCs could effectively inhibit the preferential adsorption of APCs into clay. A mechanistic study including dispersion, adsorption, zeta potential and x-ray diffraction revealed that, compared with traditional polycarboxylate superplasticisers, APCs with ZI groups were more easily adsorbed on the surface of clay but were not incorporated into the layer structure of the clay. This work not only fabricated a new superplasticiser with potential for development, but also provided a concept for preparing new superplasticisers to solve problems involved in their application.

Multi-wall carbon nanotubes chemically modified silica microcolumn preconcentration/separation combined with inductively coupled plasma optical emission spectrometry for the determination of trace elements in environmental waters

ABSTRACTA novel adsorbent of multi-wall carbon nanotubes (MWCNTs) chemically modified silica (MWCNTs-silica) was synthesised and employed as the adsorbent material for solid-phase extraction (SPE) of trace Zn(II), Cu(II), Cd(II), Cr(III), V(V) and As(V) in environmental water samples followed by inductively coupled plasma optical emission spectrometry detection. This material inherits the advantages of nanomaterial MWCNTs and conventional silica with dual functional groups (–NH2 and –COOH), and avoid the problem of nanomaterial in SPE, such as high pressure. The factors affecting the separation and preconcentration of target elements such as pH, sample flow rate and volume, eluent concentration and volume were investigated. Under the optimised conditions, the detection limits for Zn(II), Cu(II), Cd(II), Cr(III), V(V) and As(V) were 0.27, 0.11, 0.45, 0.91, 0.55 and 0.67 μg L−1 with the relative standard deviations of 3.1, 5.9, 4.1, 4.0, 7.3 and 8.6% (c = 10 μg L−1, n = 7), respectively. The adsorption capacity of MWCNTs-silica was 26.6, 70.0, 13.8, 58.0, 20.0 and 20.0 mg g−1 for Zn(II), Cu(II), Cd(II), Cr(III), V(V) and As(V), respectively, and the prepared adsorbent could be reused more than 100 times. In order to validate the developed method, two certified reference materials of GSBZ50009-88 and GSBZ 50029-94 environmental waters were analysed and the determined values were in good agreement with the certified values. The developed method has been applied to the determination of trace elements in environmental water samples with satisfactory results.

Preparation of amino-Fe(III) functionalized mesoporous silica for synergistic adsorption of tetracycline and copper

Finding effective methods for simultaneous removal of antibiotics and heavy metals has attracted increasing concern since both of them are frequently detected in aquatic environments. In this study, a novel mesoporous silica adsorbent (Fe-N,N-SBA15) contained dual-functional groups was synthesized by first grafting di-amino groups on SBA15, and then coordinating Fe(III) onto the adsorbent. The adsorbent was then used in the synchronous elimination of tetracycline (TC) and Cu(II) from water, which was deeply studied by solution pH, kinetics, equilibriums in sole and binary systems. It was found that the adsorbent had high affinity for both TC and Cu(II) and synergistic effects on the adsorption were found. The solution pH remarkably affected the adsorption due to pH-dependent speciation of TC, Cu(II), TC–Cu(II) complex and the surface properties of the adsorbent. Increasing adsorption amount of TC and Cu(II) on the adsorbent could be attributed to the formation of complex TC–Cu(II) bridging or the stronger affinity of the adsorbent for the TC–Cu(II) complex than that for TC or Cu(II) separately. FT-IR and XPS studies revealed that Fe(III) and amino groups on the adsorbent were complexed with the amide of TC and Cu(II), respectively. The recyclabilities of the adsorbent were also evaluated and the Fe-N,N-SBA15 exhibited good reusability for TC and Cu(II) removal. This study shows guidelines and offers an innovative, effective method for the synergistic removal of antibiotics and heavy metals from aquatic environments.

ChemInform Abstract: Supramolecular Architectures with Pyridine‐Amide Based Ligands: Discrete Molecular Assemblies and Their Applications

AbstractReview: 88 refs.

A facile synthetic route to poly(p-phenylene terephthalamide) with dual functional groups.

Claisen rearrangement reaction was employed for the first time to obtain a novel PPTA bearing reactive allyl and hydroxyl groups which may act as a sizing agent of Kevlar fibers to improve the interface structure and interfacial adhesion of rubber or epoxy based composites.