Physical properties and their corresponding changes of mixing for the ternary mixture acetone + n-hexane + water at 298.15 K

Experimental density and the refractive index of the ternary mixture acetone + n-hexane + water, and their binary systems were experimentally measured and correlated at 298.15 K and atmospheric pressure. A maximum in refractive indices has been observed for the acetone + water system while the excess molar volume and the molar refraction change are all negative. For the mixture acetone + n-hexane, the excess molar volume is always positive and the molar refraction change of mixing showed a S-shaped dependence on acetone composition. The excess molar volumes and molar refraction changes of mixing were correlated using the Redlich-Kister expression and Cibulka equation. The coefficients and standard deviation between the experimental and fitted values were estimated. Good agreement between both results was obtained.     

Synthesis of (±)-2-Methoxy-9a-Carbamorphinan and (±)-2-Methoxy-9a-Carba-14α-Morphinan: Acid Catalyzed Cyclizations of 1-m-Methoxybenzyl-4, 4a,5,6,7,8-Hexahydronaphthalen-2(3H)-ONE and 1 -m-Methox Ybenzyloctalins

The bridged-ethers, (±)-2-methoxy-9a-carbamorphinan (1b) and (±)-2-methoxy-9a-carba-14α-morphinan(2b) have been synthesized. The acid-catalyzed cyclizations of 1-m-methoxy benzyloctalone 3b and 1-m-methoxybenzyloctalins 4b proceed with high regio-and stereoselectivities leading mostly to the bridged-ketone 14 and ether 1b respectively, along with o-methoxy-tetracyclic ketone 15 and the ether 17, in addition to other minor products.     

Potassium Carbonate–Mediated Efficient and Convenient Synthesis of 3-Methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones

Unprecedented cyclization was observed during N-sulfonylation of 3-[1-(phenylhydrazono)-ethyl]-chromen-2-one in pyridine, affording 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones. To avoid use of noxious pyridine, reaction was tried in different basic conditions and the best results were obtained with potassium carbonate in acetone. A wide range of substrates bearing either electron-donating or electron-withdrawing substituents on phenylhydrazine ring were compatible with the developed methodology. Rapid access of starting material, 3-acetylcoumarin, excellent yields of products, and use of environmentally benign base and solvent for the cyclization make this strategy an efficient and convenient method for synthesis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones.     

La2O3/γ-Al2O3在柠檬醛与丙酮缩合反应中的催化性能研究

用La2O3负载量不同的La2O3/γ-Al2O3催化柠檬醛和丙酮反应,采用GS/MS、LC/MS、13C NMR等方法鉴定反应产物,并研究了La2O3负载量对反应产物分布、La2O3/γ-Al2O3催化剂的结构性质和酸碱性质的影响.得出以下结论:La2O3是以无定形态负载在γ-Al2O3上;随着La2O3负载量的增加,催化剂比表面积减少,孔径分布趋于均一.La2O3/γ-Al2O3表面增加的弱酸位点密度有利于柠檬醛转化率的提高,增加的中强碱位点密度有利于PSI产率提高;而强碱位点的形成和密度增加对柠檬醛自身缩合生成PCS有促进作用.催化剂循环使用性较好.     

Synthesis of carbon dots with a tunable photoluminescence and their applications for the detection of acetone and hydrogen peroxide

Carbon dots(CDs) with multi-color emissive properties and a high photoluminescent quantum yield(PLQY) have attracted great attention recently due to their potential applications in chemical,environmental,biological and photo-electronic fields.Solvent-dependent effect in photoluminescence provides a facial and effective approach to tune the emission of CDs.In this study,green emissive nitrogen-doped carbon dots(N-CDs) are synthesized from p-hydroquinone and ethylenediamine through a simple hydrothermal method.The as-prepared N-CDs possess a robust excitation-independent green luminescence and a high PLQY of up to 15.9%.Further spectroscopic characterization indicates that the high PLQY is achieved by the balance of nitrogen doping states and the surface passivation extent in CDs.The N-CDs also exhibit solvent-dependent multi-color emissive property and distinct PLQY in different solvents(the maximum can reach up to 25.3%).Furthermore,the as-prepared N-CDs are applied as fluorescence probes to detect acetone and H2O2 in water.This method has exhibited a low detection limit of acetone(less than 0.1 %) and a quick and linear response to the H_2O_2 with the concentration from 0 to 120 μmol/L.This work broadens the knowledge of applying CDs as probes in the bio and chemical sensing fields.     

Sampling and analysis of volatile organics emitted from wastewater treatment plant and drain system of an industrial science park

Volatile organic compounds (VOCs) were monitored in the different sections of a wastewater treatment plant (WWTP), the outlet of both the WWTP and rainfall water, and the downstream of the WWTP joining the river in the area or vicinity of an industrial science park located in Hsinchu, Taiwan. Levels of VOCs were determined by collecting air samples over several sampling points and analyzed using gas chromatography. Among VOCs identified in the drainage and effluent system in each season, acetone, isopropanol (IPA) and dimethyl sulfide (DMS) were the major emission species and maximum concentrations were 400.4, 22.8 and 641.2 ppbv, respectively. The ambient air and wastewater sample analysis from neighboring wastewater streams identified pollutants being discharged from unaccounted sources other than the industrial park. According to the 24 h semi-continuous monitoring data (27/7/2002-29/7/2002), the total VOC concentration was an average of 93 ppbv (acetone contributed ∼78%) with a dramatic variation during the day and night. The emission rate of measured VOCs estimated using fixed box model projected an average of 2-4 μg m⁻² h⁻¹) during the day and 9-17 μg m⁻² h⁻¹ during the night. In addition, the isopleth maps show that the acetone and DMS emissions influence adversely the nearby residential area located at less than 100 m downwind from the plant. Eventually, based on this study, an on-line monitoring and alerting system could be built for a long-term performance, and with regular information on the varying pollutants over time construction of a green strategy and creation of a sustainable environment can be achieved.     

Ni,Pd／Al2O3对丙酮加氢一步合成甲基异丁基酮性能比较

研究了Ａｌ２Ｏ３负载Ｎｉ、Ｐｄ催化剂上丙酮加氢一步合成甲基异丁基酮的反应活性。考察了不同Ｎｉ含量和不同Ｐｄ含量对活性的影响。结果表明，在载体Ａｌ２Ｏ３中加入不同含量的ＳｉＯ２后，会改善载体的性能，Ｎｉ／Ａｌ２Ｏ３催化剂中添加稀土元素Ｌａ或Ｃｅ后可改善催化剂的稳定性。     

基于纳米ZnO-ZrO2催化发光丙酮传感器的研究

研究了丙酮在纳米ZnO-ZrO2(质量比为4:1)表面催化发光行为,发现基于这种纳米催化剂的气体传感器对丙酮的检测具有高灵敏度和较强的选择性。在波长460 nm,温度219℃,载气流速25 mL/min时进行定量分析,催化发光强度与丙酮浓度在一定范围内呈良好的线性关系,线性范围为0.1～4000 mL/m3(r=0.9996,n=6);检出限为1.6 mL/m3(S/N=3)。传感器工作时间可达106h以上,可用于丙酮的实时在线检测。     

柱切换离子色谱法测定丙酮中痕量阴离子

建立了测定丙酮中痕量阴离子的离子色谱分析方法.采用的是高效液相柱切换进样,其中泵的流速为0.5 mL/min,使低浓度的丙酮水溶液在保护柱上富集,通过离子色谱抑制电导法分离和检测丙酮样品中痕量的阴离子.色谱条件为:以IonPacAG9-HC(50 mm×2 mm)型柱串联在定量环中进行富集,IonPacAG9-HC(50 mm×2 mm)保护柱,IonPac AS9-HC(250 mm×2 mm)阴离子分离柱进行分离,流动相为9 mmol/L Na2CO3-1.667 mol/L NaHCO3,所得回收率在96.21%～101.56%之间,线性良好,且具有较好的重现性和较低的检出限.     

Large-surface mesoporous TiO2 nanoparticles: Synthesis, growth and photocatalytic performance

This study demonstrates a facile and effective method to generate mono-dispersed titanium dioxide spheres at ambient conditions. The size of the colloids can be controlled from 60 to 500 nm by optimizing experimental parameters (e.g., concentration, time, and temperature). Anatase TiO₂ can be obtained through titanium glycolate colloids generated in acetone via two ways: water boiling approach and calcination at a high temperature of 500 °C. Particle characteristics (shape, size, and size distribution) were measured by advanced techniques, including transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), UV/Vis absorption spectrum, nitrogen gas adsorption and desorption isotherms Brunauer-Emmett-Teller (BET) surface area measurement, and X-ray diffraction technique (XRD). The possible mechanism of nucleation and growth of such colloids was discussed. The role of acetone in the formation and growth of titanium glycolate colloids was also investigated by Fourier transform infrared (FT-IR) spectroscopy. Finally, the photocatalysis performance of such anatase TiO₂ particles was tested and proved to be efficient in degradation of organic dyes (e.g., phenolphthalein and methly orange).