Substituent effect and enthalpy-entropy compensation on the inclusion ofβ-cyclodextrin with 1-substituted naphthalenes

The inclusion complexation of-CD with 1-substituted naphthalenes has been investigated by fluorescence spectroscopy. It was observed that the association constants were influenced by the molar refraction (R _m), hydrophobic constant ( _x ), and Hammett constant ( _x ) of substituents in the guest compounds. The thermodynamic parameters G⁰, H ⁰, and S ⁰ determined by measuring the temperature-dependentK _a values shows that inclusion complex formation is enthalpy driven. The results are discussed in terms of enthalpy-entropy compensation.     

Voltammetric Assay of Naproxen in Pharmaceutical Formulations Using Boron‐Doped Diamond Electrode

The electrooxidation of naproxen was studied, for the first time, using boron‐doped diamond (BDD) electrode by cyclic and differential pulse voltammetry (CV and DPV) in nonaqueous solvent supporting electrolyte system. The results were also compared with glassy carbon electrode (GC) under the same conditions. Naproxen undergoes one electron transfer resulting in the formation of cation radical for the first electrooxidation step, which follows other chemical and electrochemical steps such as deprotonation, removal of another electron and the attack of nucleophile (ECEC mechanism). BDD electrode provided higher signal to background ratio, well resolved and highly reproducible cyclic voltammograms than the GC electrode. With a scan rate of 50 mV s^?1 and pulse height of 50 ms, respectively, the DPV technique was able to determine the naproxen concentrations in the range of 0.5 to 50 μM with a detection limit of 30 nM. The influence of interference compounds namely 2‐acetyl‐6‐methoxy naphthalene (AMN) on naproxen oxidation can also be followed successfully. Moreover, the percentage of AMN present in the standard chemical form of a mixture containing naproxen can be found accurately. Rapidity, precise and good selectivity were also found for the determination of naproxen in pharmaceutical formulations.     

以工业萘和粗甲基萘为主要原料合成萘系高效减水剂

工业萘、粗萘、甲基萘或萘残油等均可作为制取萘高效减水剂的原料。目前 ,其主要原料工业萘出现全球性紧缺 ,价格不断上扬[1] 。而攀枝花粗甲基萘比工业萘便宜许多 ,如果能用粗甲基萘代替工业萘生产萘系高效减水剂 ,可降低成本 ,使之具有更大的市场竞争力。前期实验表明单独使用粗甲基萘制备的减水剂 ,其减水率虽然较高 ,但产品含气量较大且引气不均匀 ,使混凝土抗压强度达不到要求。为了将工业萘和粗甲基萘混合物作为原料制备高效减水剂 ,并尽量用粗甲基萘替代工业萘 ,我们做了大量的实验 ,寻求到了工业萘和粗甲基萘混合物作为原料制备高效…     

A Solution‐processible,n‐dopable polypyrrole derivative

In this study, soluble, n‐dopable, florescent, electrochromic polypyrrole derivative was synthesized through both chemical and electrochemical polymerization of 2‐[6‐(1H‐pyrrol‐1‐yl)hexyl]‐1H‐benzo[de]isoquinoline‐1,3(2H)‐dione (PyNI). The polymer synthesized through chemical polymerization had PL emission maxima at 471 and 543 nm and exhibited two redox couples at E_1/2,p = ?1.48 V and E_1/2,p = 1.12 V due to n‐type and p‐type doping, respectively. Electrochromic properties of electrochemically synthesized poly(PyNI) (PPyNI) were investigated via spectroelectrochemistry, kinetic studies, coloration efficiency, and colorimetry measurements. The optical band gap of PPyNI was calculated as 2.99 and 2.37 eV. Spectroelectrochemistry analysis of PPyNI reflected electronic transitions at 330–418 nm and 704 nm due to π–π* transition and charge carrier band formation, respectively. The polymer exhibited a switching time of 1.63 s and an optical contrast of 33.37%. Furthermore, dual‐type, complementary‐colored polymer electrochromic device in ITO/PPyNI/PEDOT/ITO configuration was assembled and characterized. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Extractive Separation and Spectrophotometric Determination of Traces of Ruthenium from Mixtures Containing Excess Platinum Group Metals

Abstract

A highly selective, sensitive, and rapid method has been developed for the spectrophotometric determination of ruthenium with 5-chloro-2-hydroxythiobenzhydrazide after extraction into molten naphthalene. Ruthenium was determined in the range 1.2–4.5 ppm. The complex was stable for more than 12 h with molar absorptivity of 1.516 × 10⁴ L mol^?1 cm^?1 and detection limit of 0.0066 ppm. The method was found to be selective for ruthenium in the presence of a large number of diverse ions. Ruthenium was determined in various synthetic mixtures. The method permits the sequential separation and determination of ruthenium, osmium, and platinum from their mixtures.     

Terahertz Time-Domain Spectroscopy of Naphthalene and Naphthols

Low-energy vibrational modes have been investigated in polycrystalline naphthalene and its derivatives naphthols using terahertz time-domain spectroscopy (THz-TDS) over the frequency range from 17 to 73 cm^–1 (0.5–2.2 THz) at room temperature. We propose that naphthalene and naphthols show spectral features originating from intermolecular vibrational modes. Because of the collective origin of the observed modes, the absorption spectra are highly sensitive to the overall structure and configuration of the molecules, as well as their environments. For light-sensitive materials, the THz-TDS procedure can avoid effects like photobleaching.     

气相色谱法检测大孔吸附树脂中的有机残留物

建立了同时检测大孔吸附树脂中苯、甲苯、二甲苯、苯乙烯、二乙苯、二乙烯苯、萘、癸烷、十一烷和十二烷等10种有机残留物的测定方法。以二氯甲烷为提取溶剂,采用超声提取法对样品进行前处理。采用气相色谱法检测,色谱柱为DB-624毛细管柱,检测器为氢火焰离子化检测器。上述10种有机残留物在12 min内能很好地分离,样品的加标回收率(n=3)为73.8%～107.9%,相对标准偏差为1.3%～4.4%,最低检测限为0.007～0.03 mg/L。本方法具有灵敏、准确、快速等特点。对9种商品树脂及其预处理品的有机残留物进行了测定,结果表明树脂预处理前后有机残留物的含量相差很大,经过预处理的树脂可以安全地应用于中药的生产。     

Development of naphthalene and quinoxaline‐based donor–acceptor conjugated copolymers for delivering high open‐circuit voltage in photovoltaic devices

Two new quinoxaline‐based polymers, poly[1,5‐didecyloxynaphthalene‐alt‐5,5′‐(5,8‐dithiophen‐2‐yl)‐2,3‐bis(4‐octyloxyphenyl)quinoxaline (PNQx‐p) and poly[1,5‐didecyloxynaphthalene‐alt‐5,5′‐(5,8‐dithiophen‐2‐yl)‐2,3‐bis(3‐octyloxyphenyl)quinoxaline (PNQx‐m), were synthesized by Suzuki coupling reaction and characterized. Thermogravimetric analysis revealed that these polymers are thermally stable with degradation temperature up to 320 °C. As evident from the electrochemical and optical studies, the copolymers have comparable optical band gap (～2 eV) and nearly similar deep highest occupied molecular orbital (HOMO) energy levels of ?5.59 (PNQx‐p) and ?5.61 eV (PNQx‐p). The resulting copolymers possessed relatively low HOMO energy levels promising good air stability and high open circuit voltage (V_oc) for photovoltaic applications. The optimized photovoltaic device with a structure of ITO/PEDOT:PSS/PNQx‐m:PC₇₁BM (1:2, w/w)/LiF/Al shows a power conversion efficiency up to 2.29% with a short circuit current density of 5.61 mA/cm², an V_oc of 0.93 V and a fill factor of 43.73% under an illumination of AM 1.5, 100 mW/cm². The efficiency of the PNQx‐m polymer improved from 2.29 to 2.95% using 1,8‐diiodoocane as an additive (0.25%). © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

贵金属铂对镍基催化剂上萘转化性能的影响

 在常压连续流动固定床反应器上，以萘作为生物质气化气中焦油的模型化合物，研究了Pt对Ni／Al2O3催化剂上萘的转化率、CO和H2的选择性及收率的影响，比较了Ni－Pt／Al2O3和Ni／Al2O3两种催化剂上萘的水蒸气转化所产生的积碳量和副产物的种类，并初步考察了Ni－Pt／Al2O3催化剂上萘的水蒸气转化反应的动力学．