Hypercrosslinked Polystyrene Research Articles

TARGETED SCREENING OF PHENOLIC TOXICANTS IN WATERS AND BOTTOM SEDIMENTS OF THE MIDDLE REACHES OF THE DON RIVER

The targeted screening of 11 phenolic toxicants (phenol, chlorophenols, 2,4-dichlorophenoxyacetic acid, octylphenol, nonylphenol, bisphenol A) has been carried out over river water and bottom sediments (BS) in the middle reaches of the Don river within the boundaries of the Voronezh Region. Three sampling points were selected for quantitative chemical analysis: in the zone affected by the discharge of sewage treatment plants of a large city (Voronezh), in the district centre (the city of Liski), and in an area with insignificant anthropogenic influence. The concentrations of phenolic compounds were determined using gas chromatography - mass spectrometry (GC-MS), the analytes were preconcentrated on a magnetic sorbent functionalised with aminated hypercrosslinked polystyrene. Sampling was carried out four times a year, taking into account seasonal climatic fluctuations and precipitation. The maximum concentrations were established in the spring for 2,4-dichlorophenoxyacetic acid (1022 ng/L) and 2,4-dichlorophenol (557 ng/L). In bottom sediments, the highest concentrations are achieved for alkylphenols: 1.99 and 7.84 μg/g for octylphenol and nonylphenol, respectively. Bisphenol A has not been found in detectable amounts in waters, however, a significant concentration of this compound has been found in bottom sediments: 3.18 μg/kg. The bottom sediments were also determined to contain 2,4,5-trichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol. The maximum concentrations of phenolic pollutants in river water are usually observed in spring during high water and after heavy rainfall. Phenol concentrations in bottom sediments are less susceptible to seasonal fluctuations. The hydrophobicity of substances and an increase in their stability against degradation significantly affect their accumulation in BS.

Comprehensive Utilization of Fossil Energy: Fabrication of Fire-Retardant Building Materials from Waste Plastic

As one of the most common fossil derivatives, plastics are widely used for their exceptional chemical stability, low density, and ease of processing. In recent years, there has been a significant increase in the production of waste plastics, coupled with a low recycling rate, resulting in serious environmental pollution. To enhance the use of waste plastics, this research synthesized flame-retardant materials from hypercrosslinked polystyrene with different molar fractions of flame retardants. Waste polystyrene foam was used as the raw material, while aniline, triphenylphosphine, and melamine were employed as flame-retardant additives. The flame-retardant additives were successfully doped into the porous skeleton structure of hypercrosslinked polystyrene through a chemical reaction or physical mixing to achieve in situ flame retardancy, and the materials were shaped by a phenolic resin prepolymer. Then, the samples were characterized in detail, and the results indicate that the addition of a flame retardant enhances the flame retardancy of the material. In addition, the material has excellent thermal insulation performance, with a minimum thermal conductivity of 0.04176 W/(m·K).

Magnetic carbonaceous adsorbents derived from nanocomposites of hypercrosslinked polystyrenes

Two groups of porous composite adsorbents with magnetic properties were obtained by pyrolysis of nanocomposites of hypercrosslinked polystyrenes with immobilized iron and cobalt oxides. The structure of the adsorbents is characterized by electron microscopy, X-ray phase analysis, Raman spectroscopy, adsorption of N2, CO2. The carbonaceous adsorbents (granules 0.1–0.3 mm) possess magnetic properties and have a developed porous structure (three ultramicropore fractions of 0.3–0.9 nm, a specific surface area of up to 600 m2 g−1). The crystalline phase of the magnetic adsorbents consists of iron, cementite, maghemite (41, 49, 9 wt%), or cobalt, graphite (9, 87 wt%). Iron/cementite nanoparticles 30–200 nm or cobalt nanoparticles 9–40 nm are distributed uniformly in the carbon matrix of the adsorbents. Carbon nanosized layered structures form the shells (2–7 nm). The magnetic adsorbents are capable of absorbing toxic organic compounds up to 0.64 cm3 g−1. The resulting adsorbents can be applied in magnetic separation adsorption technologies.

Thermodynamic Characteristics and Selectivity of the Liquid-Phase Adsorption of Aromatic Compounds on Hypercrosslinked Polystyrene Networks with Ultimate-High Crosslinking Densities by Data of Liquid Chromatography.

This study delves into the thermodynamics of liquid-phase adsorption on hypercrosslinked polystyrene networks (HPSNs), widely recognized for their distinct structure and properties. Despite the considerable progress in HPSN synthesis and characterization, gaps persist regarding the chromatographic retention mechanism, thermodynamics of adsorption, and their impact on the adsorption selectivity, especially in the case of networks with ultra-high crosslinking densities (up to 500%). Utilizing high-performance liquid chromatography (HPLC), we have explored, for the first time, the thermodynamic intricacies of liquid-phase adsorption onto HPSNs crosslinked in the entire range of the crosslinking degree from 100 to 500%. Our findings reveal the dependences of thermodynamic characteristics and selectivity of adsorption on the crosslinking degree, textural features, and liquid-phase composition in the region of extremely low adsorbent surface coverages (Henry's range). We have detected that, in the case of HPSNs, the dependence of the thermodynamic characteristics of adsorption on the liquid-phase composition is different than for classical HPLC stationary phases. Moreover, we scrutinize the impact of the molecular structure of the studied aromatic compounds on the thermodynamic characteristics and selectivity of the liquid-phase adsorption on HPSNs. Investigating liquid-phase adsorption selectivity, we demonstrate the pivotal role of π-π interactions in separating aromatic compounds on HPSNs. Eventually, we unveil that the thermodynamic characteristics of adsorption peculiarly depend on the crosslinking degree due to the profound impact of the crosslinking on the electronic density in benzene rings in HPSNs, whereas the separation throughput peaks for the polymer with a 500% crosslinking degree, attributed to its exceptionally rigid network structure, moderate swelling and micropore volume, and minimum specific surface area.

A Sorption–Spectrometric Method for Quantitation of Catecholamines in Urine and Plasma Using Hypercrosslinked Polystyrene and Gold Nanorods or Their Nanocomposites

A Sorption–Spectrometric Method for Quantitation of Catecholamines in Urine and Plasma Using Hypercrosslinked Polystyrene and Gold Nanorods or Their Nanocomposites

Influence of the structure of quinoline derivatives on their sorption on hypercrosslinked polystyrene

The article is devoted to the study of the chromatographic behaviour of quinoline and tetrahydroquinoline derivatives. The purpose of the study was to investigate the patterns of sorption of these compounds from aqueous-acetonitrile solutions on hyper-cross-linked polystyrene using reverse-phase high-performance liquid chromatography. The volume, polarizability, lipophilicity, and dipole moment of molecules of quinoline derivatives were calculated, which significantly depended on the nature and position of functional groups and substituents in the main nucleus. It has been established that the appearance of functional groups and substituents leads to an increase in the volume and polarizability of the molecules of quinoline derivatives compared to unsubstituted quinoline and methylquinoline, while the lipophilicity and dipole moment change depending on the nature of the substituent and its position in the main fragment. The dependences of sorption characteristics on the structure and physicochemical properties of sorbates were obtained. It has been shown that, in accordance with the laws of the reversed-phase version of liquid chromatography, the retention of substances changes symbatically with the change in the characteristics of the molecules responsible for dispersion interactions. In this case, the presence in the molecules of halogen atoms, phenyl radicals and other substituents capable of π-interactions with the surface of hyper-cross-linked polystyrene led to a significant increase in retention, and the presence of a carboxyl group or carboxyalkyls prone to interaction with the polar eluent significantly weakens retention. The appearance of an ester group in sorbate molecules generally significantly increased the volume, polarizability and lipophilicity of the corresponding derivatives, but had virtually no effect on retention, and therefore it was suggested that the presence of a carbonyl oxygen atom, capable of interacting with the polar components of the eluent, neutralizes the effect of physical-chemical factors that determine the sorption of these substances due to dispersion interactions. Thus, despite the symmetry in changes in the physicochemical parameters of the studied compounds and their retention, there was no strict proportionality, since, on the one hand, the retention of sorbates was carried out in accordance with the change in their physicochemical parameters, and on the other hand, it was determined by the tendency molecules of these compounds to competitive interactions with the components of the mobile phase. The presented results of the study can be useful in the development and optimization of methods for analysing compounds with similar structures, as well as for developing the theory of sorption of polyfunctional compounds from multicomponent solutions and establishing the relationship between sorption characteristics, other physicochemical parameters and the structure of molecules.

An Overview of Heterogeneous Catalysts Based on Hypercrosslinked Polystyrene for the Synthesis and Transformation of Platform Chemicals Derived from Biomass.

Platform chemicals, also known as chemical building blocks, are substances that serve as starting materials for the synthesis of various value-added products, which find a wide range of applications. These chemicals are the key ingredients for many fine and specialty chemicals. Most of the transformations of platform chemicals are catalytic processes, which should meet the requirements of sustainable chemistry: to be not toxic for humans, to be safe for the environment, and to allow multiple reuses of catalytic materials. This paper presents an overview of a new class of heterogeneous catalysts based on nanoparticles of catalytically active metals stabilized by a polymer matrix of hypercrosslinked polystyrene (HPS). This polymeric support is characterized by hierarchical porosity (including meso- and macropores along with micropores), which is important both for the formation of metal nanoparticles and for efficient mass transfer of reactants. The influence of key parameters such as the morphology of nanoparticles (bimetallic versus monometallic) and the presence of functional groups in the polymer matrix on the catalytic properties is considered. Emphasis is placed on the use of this class of heterogeneous catalysts for the conversion of plant polysaccharides into polyols (sorbitol, mannitol, and glycols), hydrogenation of levulinic acid, furfural, oxidation of disaccharides, and some other reactions that might be useful for large-scale industrial processes that aim to be sustainable. Some challenges related to the use of HPS-based catalysts are addressed and multiple perspectives are discussed.

In-situ pyrolysis synthesis of multi-element (F, N, S) co-doped porous carbon nanospheres as lubricating additives with improved tribological behaviors

Herein, hyper-crosslinked polystyrene nanospheres (HPSs) were synthesized via emulsion polymerization and Friedel-Crafts reaction utilizing styrene as the primary raw material. The multielement (F, N, S) co-doped carbon nanospheres with enriching microporous structures were synthesized using ionic liquid ([EMIM]NTf2) assisted carbonization of HPSs under 400 °C. The fabricated carbon nanospheres exhibit excellent dispersion stability as well as remarkable anti-friction and anti-wear properties. In comparison to pure 500SN, the friction coefficient of the multielement (F, N, S) co-doped carbon nanospheres is reduced to 0.108, resulting in 81.9 % reduction in wear volume. Furthermore, the friction coefficient shows minimal fluctuation under different frequency and temperature conditions, which is significantly lower by 21.4 % and 31.6 % respectively compared to 500SN, while exhibiting an improved carrying capacity of up to 550 N. Through Raman spectroscopy, XPS, as well as FIB-TEM analysis, the result revealed that tribochemical reactions occur between the active elements within the nanospheres and the friction pairs leading to the formation of the composite protective film (40–70 nm) composed mainly of the deposition film and the frictional chemical protective film, achieving superior frictional performance.

Rapid multi-residue LC-MS/MS determination of nitrofuran metabolites, nitroimidazoles, amphenicols, and quinolones in honey with ultrasonic-assisted derivatization – magnetic solid-phase extraction

A rapid multi-residue LC-MS/MS method for the identification and determination of banned veterinary drugs in honey was developed. A total of 31 investigated veterinary drugs belonging to 4 classes including nitrofurans metabolites, nitroimidazoles, amphenicols, and quinolones were quantified by LC-MS/MS with ESI using one single injection. The sample preparation included treatment with 5-nitro-2-furaldehyde (5-NFA) in a thermostated ultrasonic bath (80 °C, 0.5М НСl, 20 min) to liberate matrix-bound residues of nitrofurans. Magnetic hypercrosslinked polystyrene (HCP/Fe3O4) was proposed for the solid-phase extraction and clean-up of target analytes prior to LC-MS/MS analysis. To evaluate and validate the performance of method, the criteria of the Decision (EC) no 2002/657 were applied. The LOQs of the examined analytes range from 0.3 to 1 μg kg−1, which indicates good sensitivity to quantify the target compounds in honey. The recoveries of veterinary drugs from 1 g of honey with 50 mg of the sorbent are 97–109% for nitrofuran metabolites, 84–115% for nitroimidazoles, 86–103% for amphenicols, and 97–118% for quinolones. The relative standard deviations of intra-day and inter-day precision analyses (RSD) are less than 16%. This methodology was applied to real honey samples and trace levels of some veterinary drugs were detected.

Polystyrene-derived porous graphite carbon nanospheres with corrosion resistance as a lubricant additive for efficient friction and wear reduction

Herein, the porous graphite carbon nanospheres loaded with corrosion resistance (MBT@PCNs) were fabricated by carbonizing hypercrosslinked polystyrene nanospheres at 2450 °C, and then loaded and bonded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) via the hierarchical porous structure of PCNs and grafting polydopamine layer. Porous carbon nanospheres (PCNs) are highly graphitized at ultrahigh carbonization temperature of 2450 °C, which is helpful to improve the wear resistance of 500SN due to the weak interlaminar shear force. Moreover, the MBT@PCNs have a sustained-release performance for corrosion inhibitor MBT. MBT molecule can be adsorbed on the substrate surface to achieve good anti-corrosion properties. Hence, MBT@PCNs can effectively enhance the anti-friction and anti-wear performance of 500SN under the combined effects of ball bearing, filling, and protective film.

Building Porous Ni(Salen)-Based Catalysts from Waste Styrofoam via Autocatalytic Coupling Chemistry for Heterogeneous Oxidation with Molecular Oxygen.

The development of robust and industrially viable catalysts from plastic waste is of great significance, and the facile construction of high performance heterogeneous catalyst systems for phenol-quinone conversions remains a grand challenge. Herein, a feasible strategy is demonstrated to reclaim Styrofoam into hierarchically porous nickel-salen-loaded hypercrosslinked polystyrene (PS@Ni-salen) catalysts with high activities through an unusual autocatalytic coupling route. The salen is immobilized onto PS chain by Friedel-Crafts alkylation of benzyl chloride derivatives, and the generated hydrogen chloride coordinately promotes the simultaneous crosslinking and bridge formation between aromatic rings via a Scholl coupling route, leading to hierarchically porous networks. After the metallization with Ni, the resultant networks exhibit high catalytic activity for the oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-1,4-benzoquinone under mild conditions (303 K, 1bar of O2 ). This catalyst also demonstrates attractive recycling performance without an obvious loss of catalytic efficiency over five consecutive cycles. This methodology might provide a potential sustainable alternative to construct environmentally benign and cost-effective catalysts for specific organic transformation.

Doped Ruthenium/Hypercrosslinked Polystyrene (HPS) Catalysts in the Modification of Fatty Acid Methyl Esters

The modification of fatty substrates using heterogeneous catalysts have extensive industrial application and has an emphatic position in a sustainable context. Herein ruthenium, nickel, cobalt and copper-doped ruthenium, supported on hypercrosslinked polystyrene (HPS) catalysts were prepared by wet impregnation, characterized and applied on the modification of canola fatty acid methyl esters (FAME). The characterization showed a dispersive effect of doping metals over the ruthenium particles, the presence of acid sites and overall surface morphology, which allows targeting potential applications. The chosen modifications consisted of hydrogenation, hydroformylation, oxidative cleavage and deoxygenation, resulting in superb catalytic activities of over 99% conversions for hydrogenation and deoxygenation. The simplicity of the canola FAME composition allows the understanding of the catalytic processes and allows the upscale of more complex FAME matrixes. Finally, the obtained data stimulates further optimization studies for each application with a variation on the catalysts and the usage of residual fatty substrates, greatly enhancing the sustainability profile of the systems.

Kinetic Aspects of Suzuki Cross-Coupling Using Ligandless Pd Nanoparticles Embedded in Aromatic Polymeric Matrix

During the last decades, palladium nanoparticles (Pd(0) NPs) and Pd(II) compounds were shown to be attractive catalysts for fine organic synthesis. Nanostructured Pd(0) or Pd(II) catalysts have a relatively low environmental impact, but, at the same time, they are indispensable for such processes as Suzuki cross-coupling. This paper describes the preparation of Pd(0) or Pd(II) supported/embedded in hyper-cross-linked polystyrene (HPS) and compares their activity in Suzuki cross-coupling between phenylboronic acid and 4-bromoanisole. Obviously, the palladium charge (Pd(0) ↔ Pd(II)) changes continuously during the reaction catalytic cycle. It would seem that the use of the starting palladium in the form of Pd(0) or Pd(II) should not affect the reaction’s kinetic laws for both catalysts, but their special individuality is manifested between them. Nanoparticulate Pd(0) catalysts are stable during the reaction. In contrast, catalysts based on Pd(II) are extremely active in the initial period of the reaction, but then the “hot form” of the catalyst is rapidly converted into the form of Pd(0), whose activity is identical to that of the preliminarily reduced catalyst. This work discusses the possible nature of this phenomenon. A mathematical model for Suzuki cross-coupling reaction was suggested that was able to adequately describe experimental data. The level of reliability (R2) of the correlation between the experimental and calculated data was R2 = 0.97–0.99.

Combined Physicochemical and Energy Methods to Improve the Recovery of Rare Earth Elements from Eudialyte Concentrate

The parameters for efficient nitric acid leaching were experimentally determined, which ensured the recoveries of Zr and REEs from eudialyte concentrate up to 87.0%–91.7% and 76.0%–81.1%, respectively. The possibility was shown of intensifying the leaching process through preliminary energy treatments to ensure the intensive breakdown of mineral complexes and grains; as a result, the recovery of Zr and REEs increased by more than 10%. A process was developed for the selective recovery of up to 91.5% of zirconium and up to 71.2% of REEs in the form of carbonate compounds from the pregnant solution of nitric acid leaching by chemical precipitation as well as up to 81.1% REEs and up to 91.7% zirconium on hypercrosslinked polystyrene sorbents.

ZnO Particles Stabilized in Polymeric Matrix for Liquid-Phase Methanol Synthesis

ZnO supported on hypercrosslinked polystyrene was developed for liquid-phase methanol synthesis. The synthesized catalyst was characterized using the low-temperature nitrogen physisorption, TEM, XPS, XAS, and CO DRIFT methods. The analysis showed that the catalyst has a high specific surface area (720 m2/g) and is characterized by the micro-mesoporous structure typical of the polymer used. The active phase is represented by ZnO species with a hexagonal wurtzite structure. ZnO-HPS showed high activity, selectivity, and stability in liquid-phase methanol synthesis in comparison with the industrial catalyst. The activity of the proposed catalyst was found to be 1.64 times higher than that of the conventional Cu/ZnO/Al2O3.

Synthesis of Polymeric Sorbents with Magnetic Properties

In this work, a procedure for the synthesis of polymeric sorbents based on hypercrosslinked polystyrene (HPS) with magnetic properties was developed. The technique is based on the reduction of iron salts with polyhydric alcohols at high temperature in an inert atmosphere. The resulting sorbents retain their original characteristics: an extended specific surface area, micro-mesoporous structure, acquiring magnetic properties, which makes it possible to use them as magnetically separable sorbents, supports for the active phase of heterogeneous catalytic systems etc.

Hydrolytic Oxidation of Cellobiose Using Catalysts Containing Noble Metals

Studies of the processes of the hydrolytic oxidation of disaccharides are the first step towards the development of technologies for the direct conversion of plant polysaccharides, primarily cellulose, into aldonic and aldaric acids, which are widely used in chemical synthesis and various industries. In this study, heterogeneous catalysts based on a porous matrix of hypercrosslinked polystyrene (HPS) and noble metals (Pt, Au, Ru, and Pd) were proposed for the hydrolytic oxidation of cellobiose to gluconic and glucaric acids. The catalysts were characterized using low-temperature nitrogen adsorption, hydrogen chemisorption, electron microscopy, and other methods. In particular, it was shown that the Pt-containing catalyst contained, on average, six times more active centers on the surface, which made it more promising for use in this reaction. At a temperature of 145 °C, an O2 pressure of 5 bars, and a substrate/catalyst weight ratio of 4/1, the yields of gluconic and glucaric acids reached 21.6 and 63.4%, respectively. Based on the data obtained, the mathematical model of the cellobiose hydrolytic oxidation kinetics in the presence of 3% Pt/HPS MN270 was developed, and the parameter estimation was carried out. The formal description of the kinetics of cellobiose hydrolytic oxidation was obtained.

Microporous Hypercrosslinked Polystyrene Sorbents in Sorption Purification of Water-Soluble Polymers from Low-Molecular-Weight Compounds

Microporous Hypercrosslinked Polystyrene Sorbents in Sorption Purification of Water-Soluble Polymers from Low-Molecular-Weight Compounds

High Efficiency Membranes Based on PTMSP and Hyper-Crosslinked Polystyrene for Toxic Volatile Compounds Removal from Wastewater.

For the first time, membranes based on poly(1-trimethylsilyl-1-propyne) (PTMSP) with 5–50 wt% loading of hyper-crosslinked polystyrene sorbent particles (HCPS) were obtained; the membranes were investigated for the problem of effective removal of volatile organic compounds from aqueous solutions using vacuum pervaporation. The industrial HCPS sorbent Purolite Macronet™ MN200 was chosen due to its high sorption capacity for organic solvents. It has been found that the membranes are asymmetric when HCPS content is higher than 30 wt%; scanning electron microscopy of the cross-sections the membranes demonstrate that they have a clearly defined thin layer, consisting mainly of PTMSP, and a thick porous layer, consisting mainly of HCPS. The transport and separation characteristics of PTMSP membranes with different HCPS loading were studied during the pervaporation separation of binary and multicomponent mixtures of water with benzene, toluene and xylene. It was shown that the addition of HCPS up to 30 wt% not only increases the permeate fluxes by 4–7 times, but at the same time leads to 1.5–2 fold increase in the separation factor. It was possible to obtain separation factors exceeding 1000 for all studied mixtures at high permeate fluxes (0.5–1 kg/m2∙h) in pervaporation separation of binary solutions.

Hybrid Pd-Nanoparticles within Polymeric Network in Selective Hydrogenation of Alkynols: Influence of Support Porosity.

This work is addressing the selective hydrogenation of alkynols over hybrid catalysts containing Pd-nanoparticles, within newly synthesized hyper-cross-linked polystyrenes (HPS). Alkynols containing C5, C10, and C20 with a terminal triple bond, which are structural analogues or direct semi-products of fragrant substances and fat-soluble vitamins, have been studied. Selective hydrogenation was carried out in a batch mode (ambient hydrogen pressure, at 90 °C, in toluene solvent), using hybrid Pd catalysts with low metal content (less than 0.2 wt.%). The microporous and mesoporous HPS were both synthesized and used as supports in order to address the influence of porosity. Synthesized catalysts were shown to be active and selective: in the case of C5, hydrogenation selectivity to the target product was more than 95%, at close to complete alkynol conversion. Mesoporous catalysts have shown some advantages in hydrogenation of long-chain alkynols.