Hypervalent iodine‐mediated direct azidation of polystyrene and consecutive click‐type functionalization

Polystyrene was directly azidated in 1,2‐dichloroethane or chlorobenzene using a combination of trimethylsilyl azide and a hypervalent iodine (III) compound, (diacetoxyiodo)benzene. 2D NMR HMBC experiments indicated that the azide groups were attached to the polymer backbone and also possibly to the aromatic pendant groups. The amount of introduced azide groups was estimated by semi‐quantitative IR spectroscopy and elemental analysis. Approximately 1 in every 11 styrene units could be modified by using a ratio of hypervalent iodine compound to trimethylsilyl azide to styrene units of 1:2.1:1 at 0 °C for 4 h followed by heating to 50 °C for 2 h in chlorobenzene. The azidated polymers were further used as backbone precursors in the synthesis of polymeric brushes with hydrophilic side chains via a copper‐catalyzed click grafting‐onto reaction with poly(ethylene oxide) monomethyl ether 4‐pentynoate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 966–974, 2010     

二氧化氯在油田污水处理中的应用研究

由于二氧化氯具有良好的氧化杀菌作用,可以有效地去除油田污水中铁、硫等具有腐蚀性和结垢性的还原性物质,以及杀灭油田污水中的各种细菌。本文考察和报告了二氧化氯在中原油田注水采油废水的应用结果,并展望了它在油田注水采油中应用前景。     

Synthesis and characterization of water‐soluble barbiturate‐ and thiobarbiturate‐functionalized polystyrene

The synthesis and characterization of barbiturate‐ and thiobarbiturate‐functionalized polystyrene from polystyrene homopolymer by polymer‐modification reactions is discussed. Polystyrene homopolymer quantitatively functionalized at the para postion with diethyl oxomalonate functionality was subjected to a condensation reaction with urea and thiourea in the presence of sodium methoxide in methanol. This reaction proceeded essentially to quantitative conversion to the barbiturate‐ (BAPS) and thiobarbiturate‐functionalized polystyrenes (TBAPS) as estimated by ¹H NMR, UV, and IR spectroscopies. Thus, several copolymers of styrene with barbiturate‐ and thiobarbiturate‐functionalized styrene were synthesized. The detailed characterizations of quantitatively functionalized polystyrene using gel permeation chromatographic, IR, UV, and ¹H NMR spectroscopic techniques as well as thermogravimetric analysis are discussed. An application of the newly synthesized polymer in removing Cu(II) ions from aqueous solution is demonstrated. This is the first report on the synthesis of BAPS and TBAPS by the polymer‐modification route or otherwise. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 731–737, 2002; DOI 10.1002/pola.10154     

Study of relaxation processes in polyethylene and polystyrene by positron annihilation

Relaxation processes in polyethylene (PE) and polystyrene (PS) were studied by positron annihilation technique. For PE, above the glass transition temperature, T_g, the size of free volumes and its concentration were increased by the micro-Brownian motion of molecules. For PS, local motions of molecules in backbone chains were found to start above 260 K. However, these local motions were suppressed by an interphenyl correlation. For both PE and PS, below 250–260 K, the formation probability of positronium atoms increased with decreasing temperature. This fact was assigned to the freezing in of the local motions of molecules. For PS, an onset of the local motions of molecules was observed above 100 K. These motions were expected to be associated with liberation of phenyl groups. © 1996 John Wiley & Sons, Inc.     

Organic Ion Exchangers. Synthesis and Their Behaviour in the Retention of Some Metal Ions

Summary: Three pyridine strong base anion exchangers as beads were obtained by quaternization reactions of a 4-vinylpyridine : 8% divinylbenzene copolymer of gel type. These resins possess methyl / ethyl / butyl radicals as substituents on N⁺ atoms and have exchange capacities of 4.80 mEq/g and 2.10 mEq/mL. For pyridine strong base anion exchangers, the behaviours in the retention processes of Cr(VI) as oxyanions and Ga(III) as [GaCl₄]⁻ complex anion were evaluated with the bath method. All the resins exhibited retention properties, but the retained amounts of the metal cations are different as a function of the alkyl length as substituent on N⁺ atoms and the complex anion nature. Thus, Cr(VI) oxyanions are best retained by the resin with  CH₃ as substituent on N⁺ atoms while [GaCl₄]⁻ complex anion by the resin with  C₄H₉ as substituent on N⁺ atoms. By aminolysis reaction of an ethylacrylate : acrylonitrile : divinylbenzene copolymer as beads of macroporous type with NH₂OH · HCl in the presence of C₂H₅OH a new chelating ion exchanger was performed which contains both amidoxime and hydroxamic acid functional groups. This ion exchanger has the retention property for different metal cations but its retention capacities values are strongly dependent of the nature of metal cation and the counterion as well as pH of the solution. Thus, in the static conditions Zn(II) cation with NOequation/tex2gif-stack-1.gif anion as counterion is retained with the best result at pH = 5. As an example, for the aqueous metal cation solution of 10⁻² M concentration for Zn(NO₃)₂ the resin possess at equilibrium a retention capacity of 6.70 mmol Zn/g dry resin and for Cu(II) from Cu(NO₃)₂ solution of same concentration, the retention capacity is 0.22 mmol Cu/g dry resin and Fe(III) from Fe(NO₃)₃ solution is not retained.     

A method for the analysis of sucralose with electrospray LC/MS in recipient waters and in sewage effluent subjected to tertiary treatment technologies

A method for the analysis of the artificial sweetener sucralose in sewage water and recipient water was developed. Extraction and clean up was performed with solid-phase extraction utilising Oasis HLB columns. Detection was made by liquid chromatography electrospray mass spectrometry (LC/MS). The triple-quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM) mode. However, ‘pseudo MRM’ was used, a technique where the two quadrupoles monitor the same m/z. The sodium adduct of sucralose was used for quantification, since lower detection limits were obtained as compared to the sucralose quasi-molecular ion in negative ion mode. The two ions with highest intensity in the chlorine isotope pattern were monitored. The reduction of matrix effects with this approach is discussed. The method limit of quantification (MLOQ) for sewage water was 0.2?µg?L^?1, whereas for recipient water MLOQ was 0.02?µg?L^?1. The method was used to analyse effluent samples from an experimental sewage treatment plant (STP) to assess the efficiency of tertiary treatment techniques for removal of sucralose. Filtration through activated carbon was shown to be efficient, while ozonation, advanced oxidation techniques and membrane bioreactors were less efficient. Analyses of receiving waters showed low dilution of sucralose emitted from the STPs.     

液相色谱-串联质谱法测定污水处理厂水样中双酚A、四溴双酚A及烷基酚类化合物

近年来,双酚A、四溴双酚A及烷基酚类化合物由于其对水生生物的内分泌干扰作用受到越来越广泛的关注。污水处理厂是处理这类化合物的重要途径,研究目标物在其中的浓度分布对于探明此类物质在环境中的暴露水平具有重要意义,而建立相应的分析测定方法则是开展上述研究的基础。本研究建立了同时测定污水处理厂水样中双酚A、四溴双酚A及6种烷基酚类化合物的反相液相色谱-电喷雾串联质谱分析方法。结果发现,以ZORBAX Eclipse Plus C18色谱柱（150 mm×2.1 mm,3.5 μm）为分离柱,乙腈和0.02%（v/v）氨水溶液为梯度洗脱的流动相,电喷雾质谱负离子模式下目标化合物在11 min内分离;在1~100 μg/L范围内,双酚A、四溴双酚A及6种烷基酚类化合物的峰面积与质量浓度的线性关系良好（R²≥0.998）,方法定量限为2.0~20 ng/L;添加水平分别为0.2、2、20 μg/L时,目标化合物的平均回收率分别为64.3%~118.0%、65.9%~100.5%、70.3%~102.7%,相对标准偏差均小于7.1%。基于上述方法,对江苏省某工业园区污水处理厂水样中相关物质进行检测,出水中检出5种目标化合物,质量浓度范围为11.9~3015.3 ng/L。结果表明,该方法准确可靠、灵敏度高,适用于污水处理厂水样中相关烷基酚类化合物的检测。     

Thiol‐epoxy “click” chemistry: Application in preparation and postpolymerization modification of polymers

Base‐catalyzed reaction between a thiol and an epoxide group is a simple fusion process that leads to the formation of a β‐hydroxythio‐ether linkage. This reaction is efficient, regio‐selective, and fast. In addition, it produces a reactive hydroxyl group upon completion. Therefore, it is of considerable potential in synthesis of reactive and functional soft materials. Here, we discuss the fundamental aspects of this process, the so‐called thiol‐epoxy “click” reaction, and its utility in the preparation and post‐polymerization functionalization of polymers and crosslinked networks. Furthermore, its application in surface modification of solid substrates is also considered. Finally, utility of multifunctional materials created using the thiol‐epoxy reaction is discussed in the biomedical arena. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3057–3070     

Synthesis,Characterization, and thermoresponsive properties of Helical Polypeptides Derivatized from Poly(γ−4‐(3‐chloropropoxycarbonyl)benzyl‐L‐glutamate)

A series of side‐chain‐functionalized α‐helical polypeptides, i.e., poly(γ‐4‐(3‐chloropropoxycarbonyl)benzyl‐_L‐glutamate) (6) have been prepared from n‐butylamine initiated ring‐opening polymerization (ROP) of γ‐4‐(3‐chloropropoxycarbonyl)benzyl‐_L‐glutamic acid‐based N‐carboxyanhydride. Polypeptides bearing oligo‐ethylene‐glycol (OEG) groups or 1‐butylimidazolium salts were prepared from 6 via copper‐mediated [2+3] alkyne‐azide 1,3‐dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α‐helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side‐chains showed reversible LCST‐type phase transition behaviors in water while polymers bearing 1‐butylimidazolium and I^? counter‐anions exhibited reversible UCST‐type transitions in water. Variable‐temperature UV‐vis analysis revealed that the phase transition temperatures (T_pts) were dependent on the main‐chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2469–2480     

Synthesis and dielectric properties of photoreactive polystyrene containing [1‐(3‐isopropenyl‐phenyl)‐1‐methyl‐ethyl]‐carbamate in the side chain

Novel polystyrene derivatives comprising [1‐(3‐isopropenyl‐phenyl)‐1‐methyl‐ethyl]‐carbamate in the side chain were synthesized as photoreactive copolymers. Poly(4‐vinylphenol) was made to react with 1‐(1‐isocyanato‐1‐methyl‐ethyl)‐3‐isopropenyl‐benzene (m‐TMI) and the unreacted hydroxyl groups were protected with acetyl chloride. The copolymers are highly sensitive to the radical photoinitiators that can be activated by irradiation of UV light (λ = 300–365 nm). FTIR spectroscopy was employed to monitor the structural changes in the copolymers exposed to UV irradiation. The dielectric properties of the copolymers were investigated by measuring the capacitance and calculating the permittivity as a function of frequency, along with the I–V characteristics. Their properties were compared with those of thermally crosslinkable poly(4‐vinylphenol) blended with poly(melamine‐co‐formaldehyde), which is frequently used as a dielectric layer in organic field‐effect transistors (OFETs). No significant dielectric dispersion was observed in the frequency range of 1 kHz–1 MHz. The dielectric constant was determined to be in the range of 4.2–6.0, which offers a potential for the application of these copolymers to OFET gate insulators. These soluble dielectrics exhibit good film uniformity and can also be patterned using a standard photolithographic technique. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1710–1718, 2008     

Analysis of nitrosamines in water by automated SPE and isotope dilution GC/HRMS Occurrence in the different steps of a drinking water treatment plant, and in chlorinated samples from a reservoir and a sewage treatment plant effluent

A method based on automated solid-phase extraction (SPE) and isotope dilution gas chromatography/high resolution mass spectrometry (GC/HRMS) has been developed for the analysis of nine nitrosamines in water samples. The combination of automated SPE and GC/HRMS for the analysis of nitrosamines has not been reported previously. The method shows as advantages the selectivity and sensitivity of GC/HRMS analysis and the high efficiency of automated SPE with coconut charcoal EPA 521 cartridges. Low method detection limits (MDLs) were achieved, along with a greater facility of the procedure and less dependance on the operator with regard to the methods based on manual SPE. Quality requirements for isotope dilution-based methods were accomplished for most analysed nitrosamines, regarding to trueness (80–120%), method precision (<15%) and MDLs (0.08–1.7 ng/L).Nineteen water samples (16 samples from a drinking water treatment plant {DWTP}, 2 chlorinated samples from a sewage treatment plant {STP} effluent, and 1 chlorinated sample from a reservoir) were analysed. Concentrations of nitrosamines in the STP effluent were 309.4 and 730.2 ng/L, being higher when higher doses of chlorine were applied. N-Nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were the main compounds identified in the STP effluent, and NDEA was detected above 200 ng/L, regulatory level for NDMA in effluents stated in Ontario (Canada). Lower concentrations of nitrosamines were found in the reservoir (20.3 ng/L) and in the DWTP samples (n.d. −28.6 ng/L). NDMA and NDEA were respectively found in the reservoir and in treated and highly chlorinated DWTP samples at concentrations above 10 ng/L (guide value established in different countries). The highest concentrations of nitrosamines were found after chlorination and ozonation processes (ozonated, treated and highly chlorinated water) in DWTP samples.     

Synthesis and Characterization of Nanostructured Fe3O4 Micron‐Spheres and Their Application in Removing Toxic Cr Ions from Polluted Water

We present a simple and effective method for the synthesis of nanostructured Fe₃O₄ micron‐spheres (NFMSs) by annealing hydrothermally formed FeCO₃ spheres in argon. The phase structure, particle size, and magnetic properties of the product have been characterized by X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and by means of a superconducting quantum interference device (SQUID). The results have shown that the as‐obtained NFMSs have a diameter of about 5 μm and are composed of nanometer‐sized porous lamellae. The NFMSs have a large specific surface area (135.9 m² g^?1), reductive Fe²⁺ incorporated into their structure, and intense magnetic properties. These properties suggest that NFMSs have potential application in removing toxic Cr⁶⁺ ions from polluted water. At 25 °C, each gram of NFMSs product can remove 43.48 mg of Cr⁶⁺ ions, as compared to just 10.2 mg for nanometer‐sized Fe₃O₄ and 1.89 mg for micron‐sized Fe₃O₄. The enhanced removal performance can be ascribed to the structural features. Moreover, the Cr⁶⁺ ion removal capacity of the NFMSs can reach up to 71.2 mg g^?1 at 50 °C. The influencing parameters in the removal of Cr⁶⁺ ions, such as contact time, pH, and temperature, have been evaluated. The Cr⁶⁺‐removal mechanism has been investigated. We have found that the NFMSs product not only serves as an effective adsorbent to remove toxic Cr⁶⁺ ions from polluted water, but also as an effective reductant in reducing the adsorbed toxic Cr⁶⁺ ions to much less toxic Cr³⁺ through the Fe²⁺ incorporated into its structure.     

Introduction of reactive functionality by the incorporation of divinylbiphenyl in ethylene copolymerization with styrene or 1‐hexene using aryloxo‐modified half‐titanocenes and MAO catalysts

An efficient introduction of vinyl group into poly (ethylene‐co‐styrene) or poly(ethylene‐co?1‐hexene) has been achieved by the incorporation of 3,3′‐divinylbiphenyl (DVBP) in terpolymerization of ethylene, styrene, or 1‐hexene with DVBP using aryloxo‐modified half‐titanocenes, Cp′TiCl₂(O?2,6‐ⁱPr₂C₆H₃) [Cp′ = Cp*, ^tBuC₅H₄, 1,2,4‐Me₃C₅H₂], in the presence of MAO cocatalyst, affording high‐molecular‐weight polymers with unimodal distributions. Efficient comonomer incorporations have been achieved by these catalysts, and the content of each comonomer could be varied by its initial concentration charged. The postpolymerization of styrene was initiated from the vinyl group remained in the side chain by treatment with n‐BuLi. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2581–2587     

Application of capillary gas chromatography with electron capture detection and split-splitless injection to the evaluation of volatile halogenated hydrocarbon removal using hydrogen peroxide after break-point chlorination in drinking water treatment

In this paper we report a way to evaluate the removal of volatile halogenated hydrocarbons formed after break-point chlorination in the Arno river raw water at the Mantignano Utility, Florence, Italy, following dechlorination by hydrogen peroxide. The removal evaluation is performed by GC-ECD on fused silica capillary columns with split-splitless injection on n-pentane extracts and by other analytical techniques such as UV₂₅₄ absorption, TOC and TOX. Both laboratory and pilot plant data on Arno river raw water are reported and discussed.