Enhanced Corrosion Resistance and Discharge Performance of Mg-MnO2 Battery by Na2SiO3 Additive

Corrosion resistance and delayed action are major obstacles that severely limit the practical application of Mg alloy in battery fields. In this work, the effects of Na2SiO3 on the electrochemical behavior of the AZ31B Mg alloy in MgSO4-Mg(NO3)2 composite solution[0.14 mol/L MgSO4,1.86 mol/L Mg(NO3)2] were investigated. Electrochemical tests were carried out using electrochemical impedance spectroscopy, galvanostatic discharge, and linear sweep voltammograms. The results indicate that the impedance value increases by nearly fourfold, and the delayed time decreases from 2.1 s to 0.6s. Battery perfoniiance test reveals that the addition of Na2SiO3 significantly improves the discharge specific capacity of Mg-MnO2. The surface morphology and composition of corrosion products from Mg alloys were studied by scanning electron microscopy(SEM) and Fourier translonn infrared spectroscopy(FTIR), respectively. The SEM images of the AZ31B Mg alloys in composite solution with or without Na2SiO3 additive have an evident distinction due to the ionnation of new insoluble compound.FTIR result confirms that the corrosion products accumulated on the alloy surface in the electrolyte containing Na2SiO3 are mainly composed of Mg(OH)2, MgCO3, and MgSiO3.     

Lubrication of the mixed system of Triton X-100/n-C10H21OH/H2O lamellar liquid crystal and ZnS nanoparticles

ZnS nanoparticles could be synthesized, when two kinds of Triton X-100/n-C₁₀H₂₁OH/H₂O lamellar liquid crystal were mixed, in which Zn(CH₃COO)₂ and Na₂S were dissolved in the solvent layer, respectively. The size of ZnS nanoparticles was about 10 nm and limited by the thickness of the solvent layer of the lamellar liquid crystal. The lubrication properties of the mixed system of Triton X-100/n-C₁₀H₂₁OH/H₂O lamellar liquid crystal and ZnS nanoparticles were determined. The results showed that the presence of ZnS nanoparticles could improve the anti-wear ability of the Triton X-100/n-C₁₀H₂₁OH/H₂O lamellar liquid crystal and decrease its friction coefficient.     

表面活性离子液体溴化N-十二烷基异喹啉与非离子表面活性剂Triton X-100在水溶液中的混合胶束

用等温滴定微量热法测定表面活性离子液体溴化N-十二烷基异喹啉([C₁₂iQuin]Br)与非离子表面活性剂Triton X-100混合物在水溶液中的临界胶束浓度。并以¹H核磁共振(NMR)和二维核Overhauser效应增强谱(2D NOESY)研究[C₁₂iQuin]Br与Triton X-100在混合胶束中的作用机理。研究结果显示：混合胶束中,Triton X-100分子的苯环定位于混合胶束的内核,聚氧乙烯链卷曲在异喹啉环周围。本文还应用规则溶液理论和浊点法对比研究了十二烷基三甲基溴化铵(DTAB)-Triton X-100混合胶束体系的相关性质。     

Alumina Solubility in Na3AlF6-K3AlF6-AlF3 Molten Salt System Prospective for Aluminum Electrolysis at Lower Temperature

The alumina solubility in the title system within the composition range of KR{m(K₃AlF₆)/[m(K₃AlF₆)+ m(Na₃AlF₆)]} 10%―50%, a ternary Na₃AlF₆-K₃AlF₆-AlF₃ molten system with 23%―29%(mass fraction) AlF₃ was investigated by measuring the mass loss of a rotating sintered corundum disc. And the following empirical equation was derived when superheat degree was no more than 60 ℃: w(Al₂O₃)_sat=A×(T/1000)^B, where A= –1.85774+ 26.754234w(AlF₃)^–0.3683–0.00783KR^2.363+0.010266KR^2.3048+0.7902w(AlF₃)^0.00652, B=112.4625–53.2567w(AlF₃)^0.4236+ 5.1079w(AlF₃)^0.9241+0.01542w(AlF₃)^1.3540. Considering both higher alumina solubility and not too high superheat degree are required, alumina solubility of different compositions at not the same temperature but the same superheat degree was studied, which will be more industrial helpful for selecting prospective compositions. The results show that the composition deserved to be further tested in lower temperature cells is 10%―30% KR and 23%―26%(mass fraction) AlF₃.     

手性赖氨酸基Gemini表面活性剂的表面性能

用表面张力法、电导法和稳态荧光法研究了手性Gemini表面活性剂[C₁₂-m-C₁₂] Na₂（m=2,4,6）和[C₁₂-T-C₁₂] Na₂的表面性能及临界胶束聚集数,并计算胶束形成的热力学参数,用圆二色谱法考察了[C₁₂-2-C₁₂] Na₂在不同浓度下的立体构型. 结果表明,手性Gemini表面活性剂的临界胶束浓度（cmc）和临界表面张力γ_cmc随着连接基链长增加或刚性增强而增大;ΔG_m⁰和ΔH_m⁰为负值,|ΔH_m⁰|比|-TΔS_m⁰|小很多,说明胶束化过程为熵驱动的自发放热过程;随着连接基链长增加或刚性增强,ΔG_m⁰和ΔH_m⁰逐渐增大,ΔS_m⁰和临界胶束聚集数逐渐减小,表明其胶束化能力随之降低;当浓度大于cmc时,手性Gemini表面活性剂可形成手性超分子聚集体.     

Effect of complexones and tensides on selectivity of nitrogen dioxide determination in air with a chemiluminescence aerosol detector

Modification of the luminol solution by means of addition of various complexones and surfactants has been investigated to eliminate interferences from gaseous co-pollutants in the determination of ambient nitrogen dioxide using a chemiluminescence aerosol detector. The simultaneous presence of EDTA and triton X-100 or X-405 together with sulphite and iodide in the luminol solution suppressed interferences from ozone and peroxyacetyl nitrate to a negligible level and no scrubbers or corrections of the NO₂ measurements were needed.

In general, the best composition of the reagent solution included luminol, KOH, Na₂SO₃, KI, Na₂EDTA and triton X-100. From the point of view of selectivity of NO₂ determination, an optimum reagent solution consisted of luminol (0.002 M), KOH (0.5 M), Na₂SO₃ (0.2 M), KI (0.1 M), Na₂EDTA (0.05 M) and triton X-100 (0.5 vol.%). Interferences from ozone (170 ppb (v/v)) and peroxyacetyl nitrate (81 ppb (v/v)) were 0.2 and 1.2%, respectively, for nitrogen dioxide at a concentration of 50 ppb (v/v) and 0.25 and 1.7%, respectively, for 0.5 ppb (v/v) NO₂. The calibration graph was linear for NO₂ concentrations ranging from 3 to 665 ppb (v/v). Below 3 ppb (v/v) NO₂ the detector response to nitrogen dioxide can be fitted with a linear equation of the third order.     

Catalytic effects of eight inorganic additives on pyrolysis of pine wood sawdust by microwave heating

In this paper, pyrolysis of pine wood sawdust was carried out by microwave heating at ca. 470 °C under dynamic nitrogen atmosphere. Eight inorganic additives (NaOH, Na₂CO₃, Na₂SiO₃, NaCl, TiO₂, HZSM-5, H₃PO₄, Fe₂(SO₄)₃) were investigated in terms of their catalytic effects on the pyrolysis. All of the eight additives have increased yields of solid products greatly and decreased yields of gaseous products more or less. Yields of liquid products have not subjected to dramatic change. The incondensable gases produced from pyrolysis consist mainly of H₂, CH₄, CO and CO₂. All of the eight additives have made these gases evolve earlier, among which the four sodium additives have the most marked effect. All the additives have made the amount of CH₄ and CO₂ decrease, while all of them except NaCl, TiO₂ and Fe₂(SO₄)₃ have made that of H₂ increase and all of them except Na₂SiO₃ and HZSM-5 have made that of CO decrease. Alkaline sodium compounds NaOH, Na₂CO₃ and Na₂SiO₃ favor H₂ formation most. The most abundant organic component in the liquid products from pyrolysis of untreated sample and samples treated by all the additives except H₃PO₄ and Fe₂(SO₄)₃ is acetol. All the four sodium compounds favor acetol formation reaction and the selection increasing effect follows the order of NaOH > Na₂CO₃ ≈ Na₂SiO₃ > NaCl. TiO₂ goes against the formation of acetol, HZSM-5 has no marked effect on acetol formation. The two dominant organic components identified in the liquid products from pyrolysis of H₃PO₄ and Fe₂(SO₄)₃ treated samples are both fufural and 4-methyl-2-methoxy-phenol. A possible pathway for acetol formation is tentatively proposed.     

Crystal Engineering of Multiple-component Organic Compound:Organic co-Crystals of the Functional Groups of Carboxyl and Amino with Persistent Hydrogen Bonding Motifs

Three small organic molecular co-crystal compounds (C₃N₆H₆)·(C₆H₁₀O₄)·H₂O(1), C₃H₈N₂O(3) and (H₄btec)₂·(4,4'-bipy)(4)(H₄btec=1,2,4,5-benzenetetracarboxylic acid, 4,4'-bipy=4,4'-bipyridine) and one coordination supramolecular compound [Mn(C₂O₄)(H₂O)₂]·C₆H₁₁NO₂(2) were synthesized by hydrothermal reaction. They were characterized by elemental analysis, infrared(IR) spectroscopy and single crystal X-ray diffraction(XRD). Structural analyses reveal that these 2D or 3D supramolecular networks of the compounds were formed by C―H···O, N―H···O, N―H···N, O―H···O and O―H···N hydrogen bonds. Therein, the functional groups of ―COOH, ―NH₂ and ―OH play important roles in constructing supramolecular architectures.     

Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry

An accurate and sensitive method for the simultaneous determination of gibberellic acid(GA₃), gibberellin A₄(GA₄) and gibberellin A₇(GA₇) residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS) with electrospray ionization based stable isotope dilution analysis(SIDA). The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression. After extraction from methanol, hydrophile lipophilic balance(HLB) solid phase extraction(SPE) column was tested for the capacity of the cleanup of the tomato paste in compared with C₁₈ SPE column which is the common way to the detection of GAs, and the former gained better result. Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA₃, GA₄ and GA₇ were 42.6%―75.0% in external standard method(ESM) and 91.1%―103.8% in internal standard method(ISM) respectively. The validities of this method were investigated and good analytical performance for the three GAs was obtained, including low limits of method detection(2 ng/g for GA₃ and GA₄, 0.3 ng/g for GA₇), excellent linear dynamic ranges(5―500 ng/g for GA₃ and GA₄, 1―100 ng/g for GA₇) and good relative standard deviation ranges(4.8%―9.4% for the intra-day test and 3.5%―11.9% for the inter-day test).     

Surfactant-sensitized post-column reaction with xylenol orange for the determination of lanthanides by ion chromatography

The presence of the cationic surfactants cetylpyridinium chloride and hexadecyltrimethylammonium bromide in an alkaline 40% methanol medium was found to enhance sensitivity when xylenol orange is employed as the post-column reaction reagent for the determination of lanthanides by dynamic ion chromatography. Detection of individual lanthanides was carried out at 618 nm after separation by cation-exchange chromatography with gradient elution on a C₁₈ column. The eluent was -hydroxyisobutyric acid-sodium octanesulfonate, pH 3.8. Sensitivity enhancements by factors of three to six, compared with xylenol orange alone, were achieved at a cationic surfactant concentration of 2.4 mM. The calibration response was linear in the 0.05 to 5 μg ml⁻¹ analyte concentration range. Limits of detection below 3 ng were obtained for all the natural lanthanides and lanthanum. No sensitivity enhancement effects were observed with anionic (sodium dodecyl sulfate) and non-ionic (Triton X-100) surfactants under the conditions tested.     

γ辐射下CMPO/[C2mim][NTf2]的辐解及其对Eu3+萃取的影响

主要考察了辛基(苯基)-N, N-二异丁基胺甲酰基甲基氧化膦(CMPO)在1-乙基-3-甲基咪唑双三氟甲基磺酰胺酸盐([C₂mim][NTf₂])中的γ辐解行为,同时考察辐射对CMPO/[C₂mim][NTf₂]萃取能力的影响。通过超高效液相色谱-四极杆飞行时间质谱联用仪(UPLC/Q-TOF-MS)进行定量分析、辐解产物认定以及产物半定量分析。CMPO/正十二烷作为对比条件进行了相同研究。结果表明：CMPO在[C₂mim][NTf₂]中的辐解率低于其在正十二烷中,并且辐解路径不同。在正十二烷体系中,CMPO主要发生C―P、C―N键的断链,而在离子液体体系中CMPO主要发生异丁基脱除反应,并与[C₂mim]^+·、·CF₃等离子液体产生的自由基发生取代反应。综合辐解研究结果,我们提出CMPO/[C₂mim][NTf₂]的辐解路径,这加深了CMPO在离子液体中辐解机理的认识。最后,通过萃取实验发现,当硝酸浓度为0.01 mol·L^-1,辐照剂量为800 kGy时,CMPO/[C₂mim][NTf₂]对Eu³⁺的萃取率依旧达到99%以上。     

从头计算方法比较研究B_2Au_4,Al_2Au_4和BAlAu_4的几何和电子结构(英文)

Au/H相似性的研究是现代化学中的一个热门话题.我们从理论上报道Au/H相似的新成员:共价化合物B2Au4,离子化合物Al2Au4和BAl Au4.采用密度泛函和波函数理论方法对比研究了缺电子体系B2Au4、Al2Au4和BAl Au4的几何和电子结构.详细讨论了它们基态结构的轨道、适应性自然密度划分(Ad NDP)和电子局域函数(ELF)分析.计算结果表明稍微扭曲变形的C2B2Au4是基态结构,在这个共价化合物中含有两个B―Au―B三中心二电子(3c-2e)键.然而C3vAl+(Al Au4)-和C3vAl+(BAu4)-被研究证明是含有三个X―Au―Al三中心二电子键的类盐化合物(在Al2Au4中X=Al,BAl Au4中X=B).Al2Au4和BAl Au4是至今为止首例报道的在离子缺电子体系中含有金桥键的化合物.同时计算了B2Au4-、Al2Au4-和BAl Au4-阴离子基态结构的绝热剥离能和垂直剥离能,为实验表征提供依据.文中报道的金桥键为共价键和离子键相结合的缺电子体系提供了一个有趣的键合模式,有助于设计含有高度分散金原子的新材料和催化剂.     

(C26H40N2O4)[Ln(NO3)5H2O]的合成及其铕缔合物的晶体结构

合成了4个新型的稀土化合物(C₂₆H₄₀N₂O₄)[Ln(NO₃)₅H₂O](Ln=Pr,Nd,Sm,Eu),采用元素分析和红外光谱表征,用四圆衍射仪测定了其中(C₂₆H₄₀N₂O₄)[Eu(NO₃)₅H₂O]的晶体结构,属三斜晶系,P1空间群,晶胞参数:α=0.9100(4)nm,b=1.3560(3)nm,c=1.6463(4)nm;α=68.62(2)°,β=74.84(3)°,γ=87.50(2)°;Z=2.中心铕离子由5个硝酸根的10个氧原子和1个水分子中的氧原子配位,配位数是11.1,7,10,16-四氧-4,13-二氮杂-N,N'-二苄基环十八烷(N,N'-二苄基穴醚(2,2))未参与配位.     

离子色谱法测定甘油磷酸制剂中的β-甘油磷酸根和L-苹果酸根

建立了离子色谱等度洗脱检测甘油磷酸制剂中的β-甘油磷酸根和L-苹果酸根的分析方法。实验采用Metro sep A Supp7离子色谱柱(250 m m×4.0 m m,5μm)分离,3.6 m m o l/L碳酸钠(Na_2CO_3)溶液等度洗脱,流速为0.7 m L/min,柱温为35℃,电导检测器测定,外标法定量。该方法可将甘油磷酸制剂中的α-甘油磷酸根与β-甘油磷酸根完全分离。β-甘油磷酸根和L-苹果酸根的加标回收率为90.73%~106.27%。该方法简单、快速、灵敏,适用于甘油磷酸制剂中β-甘油磷酸根和L-苹果酸根的检测。     

Cloud point extraction equilibrium of lanthanum(III), europium(III) and lutetium(III) using di(2-ethylhexyl)phosphoric acid and Triton X-100

The cloud point extraction behaviors of lanthanoids(III) (Ln(III) = La(III), Eu(III) and Lu(III)) with and without di(2-ethylhexyl)phosphoric acid (HDEHP) using Triton X-100 were investigated. It was suggested that the extraction of Ln(III) into the surfactant-rich phase without added chelating agent was caused by the impurities contained in Triton X-100. The extraction percentage more than 91% for all Ln(III) metals was obtained using 3.0 × 10⁻⁵ mol dm⁻³ HDEHP and 2.0% (v/v) Triton X-100. From the equilibrium analysis, it was clarified that Ln(III) was extracted as Ln(DEHP)₃ into the surfactant-rich phase. The extraction constant of Ln(III) with HDEHP and 2.0% (v/v) Triton X-100 were also obtained.     

侧链上带有C60基团的聚苯乙烯的光电导性能

近几年来,可溶性高分子C60衍生物的合成已取得明显的进展.Weis等[1]报道了以C60封端的聚苯乙烯大分子衍生物,Hawker等[2]合成出聚苯乙烯C60的共聚物.这些单取代的C60衍生物很好地保持了C60原有的性质,加工性能和机械性能均较好.唐本忠等[3]用紫外光照射聚碳酸酯和C60溶液或在AIBN存在的条件下加热以上溶液,得到可溶的聚碳酸酯C60衍生物,该法产率很高(可达99%),且简单易行.Patil等[5]也用类似的方法通过自由基聚合将C60接枝到聚烯烃的高分子链上.我们已报道了将C60接枝到聚烯烃上所得到的共聚物的性能[5,6],但C60高分子衍生物的用途尚不清楚.     

胶束中的磺化酞菁镓、磺化酞菁的二聚行为研究

本文研究了二磺化酞菁镓(S₂PcGa)、三磺化酞菁(S₃Pc)在胶束(TritonX-100)中的二聚行为。计算了S₃Pc、S₂PcGa在胶束中的二聚常数K_D及分配系数K。并对磺化酞菁在胶束中的增敏,解聚机理进行了探讨。     

Determination of β-sitosterol and cholesterol in oils after reverse micelles with Triton X-100 coupled with ultrasound-assisted back-extraction by a water/chloroform binary system prior to gas chromatography with flame ionization detection

Ultrasonic back-extraction of Triton X-100 reverse micelles by a water/chloroform binary system and gas chromatography with flame ionization detection (GC-FID) was developed for extraction and determination of β-sitosterol and cholesterol in soybean and sunflower oil samples. After the homogenization of the oil samples with Triton X-100, an aliquot of 200 μL of methanol was added to the samples to form two phases. The clear Triton X-100 extract obtained by centrifugation was treated with a mixture of water (1000 μL) and chloroform (300 μL) for back-extraction of the analytes into the chloroform phase by ultrasonication. After centrifugation, the sedimented chloroform layer was withdrawn easily by a microsyringe and directly injected into the GC-FID system. The influence of several important parameters on the extraction efficiencies of the analytes was evaluated. Under optimized experimental conditions, the calibration graphs were linear in the range of 1.0–30.0 mg L⁻¹ with coefficient of determination more than 0.994 for both analytes. The method detection limit values were in the range of 0.2–0.7 mg L⁻¹. The lower limit of quantification values were in the range of 0.7–2.4 mg L⁻¹. Intra-day relative standard deviations were in the range of 1.0–2.7%. This procedure was successfully applied with satisfactory results to the determination of β-sitosterol and cholesterol in spiked oil samples. The relative mean recoveries of oil samples ranged from 93.6% to 105.0%.     

C60乙二胺衍生物铂配合物的合成及其催化硅氢化性能

C₆₀与乙二胺反应,再与氯亚铂酸钾配位,得到了一种以C₆₀衍生物为基的Pt(Ⅱ)配合物,并研究了其在烯烃与三乙氧基硅烷的硅氢加成反应中的催化性能。结果表明,该配合物为硅氢加成反应的高效催化剂,并对苯乙烯有独特的催化性能,以近100%的区域选择性得到α-加成产物。     

Multi-component Hydrogen-bonding Organic Salts Formed from 1-Methylpiperazine with Aromatic Carboxylic Acids: Synthons Cooperation and Crystal Structures

1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [(C₅H₁₄N₂)²⁺·(C₇H₅O₄)_2-·H₂O](1) and [(C₅H₁₄N₂)²⁺(C₁₂H₆O₄)²ˉ·2H₂O](2). These two forms of salts are both monoclinic systems with space group P2₁/c(14). The lattice parameters of salts 1 and 2 are a=1.32666(10) nm, b=0.90527(7) nm, c=1.67107(13) nm, β=103.125(1)° and a=1.4950(2) nm, b=0.75242(15) nm, c=1.6563(3) nm, β=92.834(2)°, respectively. Expected classical hydrogen bonds N―H…O and O―H…O appear in the chargetransfer salts, and asymmetric units of these two forms both contain water molecules which play a significant role in building novel supramolecular architectures. Robust hydrogen-bond interactions between 1-methylpiperazine and aromatic acid provide sufficient driving force to direct the two crystals to three-dimensional structures. Weak interactions C―H…O emerging in salts 1 and 2 further enhance their crystal structures. As a consequence, hydrogen-bonding interactions in these compounds afford diverse 3D net supramolecular architectures. Thermal stability of these compounds was investigated by thermogravimetric analysis(TGA).