The preparation of α‐bis and α,ω‐tetrakis aromatic oxazolyl‐ and carboxyl‐functionalized polymers using 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene in atom transfer radical polymerization reactions

The preparation of new compounds, 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethanol and a new symmetrically disubstituted 1,1‐diphenylethylene derivative, 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene, is described. 1,1‐Bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene was utilized as a dioxazolyl initiator precursor for the polymerization of styrene by atom transfer radical polymerization (ATRP) methods to produce α‐bis(oxazolyl) polystyrene. The kinetic study of the polymerization process indicated that the free radical polymerization reaction for the preparation of α‐bis(oxazolyl) polystyrene follows first‐order rate kinetics with respect to monomer consumption. α,ω‐Tetrakis(oxazolyl) polystyrene was prepared by a new, in situ, controlled/living, post‐ATRP chain‐end‐functionalization reaction which involves the direct addition of 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene to the ω‐terminus of the α‐bis(oxazolyl) polystyrene derivative, without the isolation and purification of the polymeric precursor. α‐Bis(carboxyl) and α,ω‐tetrakis(carboxyl) polystyrene derivatives were obtained by the quantitative chemical transformation of the oxazoline groups of the respective aromatic oxazolyl chain‐end‐functionalized polystyrene derivatives to the aromatic carboxyl groups. The organic precursor compounds, the dioxazolyl‐functionalized 1,1‐diphenylethylene derivative and the functionalized polymers were characterized using ¹H NMR and ¹³C NMR spectrometry and Fourier transform infrared spectroscopy, size‐exclusion and thin‐layer chromatography and non‐aqueous titration measurements. © 2014 Society of Chemical Industry     

FTIR在淬火油检测中的应用

FTIR是从傅立叶级数转换而来的红外定性和定量分析法的缩写,能有效监测淬火油在使用过程中的老化过程和监控基础油的质量,对于稳定淬火剂质量和监测淬火剂在使用过程的变化具有重要作用。     

Development of a bifunctional Ni/HZSM-5 catalyst for converting prairie cordgrass to hydrocarbon biofuel

Ni/HZSM-5 catalysts were prepared using the impregnation method. The HZSM-5 and impregnated Ni/HZSM-5 catalysts were characterized by Brunauer–Emmett–Teller and X-ray diffraction. The HZSM-5 and Ni/HZSM-5 catalysts were used for prairie cordgrass (PCG) thermal conversion in a two-stage catalytic pyrolysis system. The products contained gas, bio-oil, and bio-char. The gas and bio-oil were analyzed by gas chromatography and gas chromatography–mass spectrometry separately. Higher heating values and elemental composition of bio-char were determined. The results indicated that 12% Ni/HZSM-5 treatment yielded the highest amount of gasoline fraction for hydrocarbons and showed a robust ability to upgrade bio-oil vapor.     

石油烃中微量含氧化合物的检测

根据Deans Switch中心切割原理,建立了一种采用微板流路控制的毛细管气相色谱切割反吹技术分析石油烃中微量含氧化合物的方法。以非极性DB-1石英毛细管色谱柱(简称DB-1柱)为预分析柱、强极性CP-Lowox石英毛细管色谱柱(简称CP-Lowox柱)为分析柱,通过设置电磁阀的切换时间可将DB-1柱中需检测的含氧化合物组分切割至CP-Lowox柱进一步分离,Deans Switch切割时带入的烃在CP-Lowox柱上与含氧化合物的分离效果良好,不干扰石油烃中含氧化合物的检测。采用外标法定量,通过标准试样线性效果验证,各含氧化合物的标准工作曲线的相关系数均达到0.99以上,相对标准偏差为0.73%~1.05%,回收率为89.68%~101.40%,具有良好的精密度和准确度。通过对实际试样进行测定,定量结果准确。     

Influence of different smoke generation methods on the contents of polycyclic aromatic hydrocarbons (PAH) and phenolic substances in Frankfurter-type sausages

The contents of polycyclic aromatic hydrocarbons (15 + 1 EU priority PAH) and phenolic substances (guaiacol, 4-methylguaiacol, syringol, eugenol, and trans-isoeugenol) in smoked Frankfurter-type sausages were investigated depending on the smoke generation method applied in a total of 63 smoking experiments. The smoke was generated by smouldering with different air supplies (smouldering smoke), by leading overheated steam through wood chips (steam smoke), by friction of a log (friction smoke), and by heating plates (touch smoke). The type of smoke generator had a noticeable influence on the contents of PAH and phenolic compounds. The highest mean content of PAH4 (2.6 μg/kg) was observed for sausages when intensive smouldering smoke was applied, the lowest (0.3 μg/kg) in friction-smoked sausages. The highest mean sum content of the five phenolic compounds was observed for sausages smoked with steam smoke (45 mg/kg) whereas the contents in friction- (15 mg/kg) and touch- (18 mg/kg) smoked products were relatively low.     

Potential Chemical Markers for the Identification of Irradiated Sausages

Abstract: Hydrocarbons, gas compounds, and off‐odor volatiles were determined for irradiated (0 or 5 kGy) commercial sausages with different fat contents (16% and 29%) during a 60‐d storage period at 4 °C. Total of 4 hydrocarbons (C14:1, C15:0, C16:2, and C17:1) were detected only in irradiated sausages: the amount of C16:2 was the highest, followed by C17:1, C14:1, and C15:0. The concentrations of hydrocarbons decreased significantly (P < 0.05) with storage, but were still detectable at the end of 60‐d storage. Irradiated sausages produced significantly higher amounts of CO than the nonirradiated ones. CH₄ was detected only in irradiated sausages. Dimethyl disulfide was detected only in irradiated sausages and its concentration decreased significantly (P < 0.05) with storage. Fat content of sausages showed a significant effect on the production and retention of hydrocarbons, gas compounds, and sulfur volatiles in irradiated sausages during storage. Some hydrocarbons (C16:2, C17:1, C14:1, and C15:0), CH₄, and dimethyl disulfide were only found in irradiated sausages indicating that these compounds can be used as potential markers for irradiated sausages.     

Synthesis of highly soluble and transparent polyimides

A novel aromatic diamine, 3,3′‐diisopropyl‐4,4′‐diaminophenyl‐4″‐methyltoluene with a 4‐methylphenyl pendant group and isopropyl side groups, was designed and synthesized in this study. Then it was polymerized with various aromatic dianhydrides including pyromellitic dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride via a one‐pot high temperature polycondensation procedure to produce a series of aromatic polyimides. These polyimides exhibited excellent solubility even in common organic solvents, such as chloroform and tetrahydrofuran. The flexible and tough films can be conveniently obtained by solution casting. The films were nearly colorless and exhibited high optical transparency, with the UV cutoff wavelength in the range 302–365 nm and the wavelength of 80% transparency in the range 385–461 nm. Moreover, they showed low dielectric constants (2.73–3.23 at 1 MHz) and low moisture absorption (0.13%–0.46%). Furthermore, they also possessed good thermal and thermo‐oxidative stability with 10% weight loss temperatures (T_10%) in the range 489–507 °C in a nitrogen atmosphere. The glass transition temperatures of all polyimides are in the range 262–308 °C. Copyright © 2012 Society of Chemical Industry     

Evaluation of thermal and mechanical properties of rubber compositions based on SBR extended with safe oils

The extender oil usually employed in compositions of rubbers based on styrene and butadiene (SBR) 1712 is the distilled aromatic extract (DAE). In this work, this oil was substituted by oils with low levels of polycyclic aromatic hydrocarbons (PAHs): treated residual aromatic extract (TRAE) and two naphthenic oils from different suppliers (HN1 and HN2). This substitution was performed in response to REACH Regulation (EC No. 1907/2006 European Parliament and the Council of December 18, 2006, Annex XVII), which state that the sum of individual PAHs should be below 10 mg/kg and the levels of benzo (a) pyrene (BaP) should not exceed 1 mg/kg. Infrared spectroscopy was employed to characterize the structure of crude oils and respective SBR compositions. Thermal properties of the materials were evaluated by thermogravimetry and differential scanning calorimetry. Mechanical properties as tension tests, hardness, abrasion resistance, and resilience were also determined. The final results showed that it is possible to replace the extender oil DAE for any of the oils tested, specially the naphthenic HN1, without any loss of the properties evaluated in this study for the SBR compositions. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012