Ruthenium(II)-salen complexes-catalyzed olefination of aldehydes with ethyl diazoacetate

Several salen-ruthenium(II) complexes, which are derived from commercial ligands or simply ethylenediamine, can be successfully applied as catalysts for the olefination of a broad variety of aldehydes. Depending on the electron richness of the applied aldehydes, good to very good olefin yields and high E:Z selectivities are reached at 60 or 80 °C reaction temperature with ethyl diazo acetate being the reaction partner. The reaction rate depends on the electron donor capabilities of the aldehydes. Electron poor aldehydes undergo faster reactions than electron rich aldehydes, but both electron rich and bulky aldehydes can be transformed to corresponding olefins in very good yields and high E-selectivity.     

Simultaneous sample preparation for high-performance liquid chromatographic determination of Vitamin A and β-carotene in emulsified nutritional supplements after solid-phase extraction

Determination of small amounts of the fat-soluble species Vitamin A (VA) (2.5 μg/g) and β-carotene (9 μg/g) from emulsified nutritional supplements containing 50 kinds of co-existing compounds and a fat content between 2000 and 8000 times higher was performed by solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) with fluorescence detection set at ex. 350 nm and em. 480 nm, and visible detection at 450 nm using an Inertsil ODS 80A (5 μm) analytical column. Mobile phases of methanol-ethanol (50:50) and acetonitrile-ethanol (70:30) were used for the both vitamins. A Bond Elut C₁₈ cartridge was chosen for SPE after comparison with eight other types of SPE cartridge. Retention time of VA and β-carotene was 7 and 8 min, respectively, giving a limit of detection of ca. 0.1 ng per injection at a signal-to-noise ratio 3:1. Recoveries of VA and β-carotene were over 90% by the standard addition method. Relative standard deviation of VA and β-carotene were ca. 2.9 (n=5) and 2.3% (n=5), respectively.     

二(2,4,4-三甲基戊基)膦酸萃取分离稀土元素(Ⅲ)的研究

本文研究了二(2,4,4-三甲基戊基)磷酸(Cyanex 272)的煤油溶液在不同介质(HCI,HNO_3)中对三价混合稀土的萃取分离性能.观测了平衡水相酸度对萃取平衡的影响,由酸度曲线求出相邻元素的平均分离系数,并考察了酸度对反萃取平衡的影响.比较了HCI和HNO_3介质中,Cyanex 272对混合稀土(Ⅲ)的萃取性能.     

纳米Re2O7的萃取法制备及光催化特性研究

本工作从N235-正庚烷萃取体系中，以饱和萃取法制得前体物和纳米粉体Re₂O₇，平均粒径30 nm。以此纳米粉为光催化剂，研究了光降解甲基橙染料的最佳条件，并在相同条件下，与非纳米Re₂O₇及工业常用的纳米TiO₂进行比较，光降解甲基橙能力大小为：纳米Re₂O₇ > 锐钛矿型纳米TiO₂ > 非纳米Re₂O₇。     

一种新型可溶性高聚物负载手性配体的合成及其催化烯烃的不对称双羟化反应研究

在碱性条件下, 聚乙二醇单甲醚(HO\|OPEG\|OMe)与1,4-二氟蒽醌进行亲核单取代反应生成中间体F\|AQN-OPEG-OMe, 产率88%. F-AQN-OPEG-OMe与奎宁锂进行亲核取代反应, 以95.6%的产率得到新型手性配体QN\|AQN\|OPEG-Me. QN-QN\|OPEG-Me与OsO4原位配位生成的均相催化剂在4种烯烃的不对称双羟化反应中表现出较高的对映选择性(92%~99%e.e.)和化学产率(80%~94%). 催化活性和立体选择性与Sharpless手性配体(DHQ)2AQN相当. 反应结束后, 配体可用乙醚沉淀回收, 循环使用5次, 催化剂的催化活性和立体选择性无明显改变, 配体的回收率均在95%~97%之间.     

毛细管电泳法研究提取剂对黄连-黄柏共煎剂中生物碱含量的影响

用毛细管电泳法,对黄连与黄柏配伍后共煎剂中的主要生物碱进行了分析。以50 mmol/L Na2B4O7(pH=7)-CH3OH(85:15,V/V)为背景电解质,操作电压为14 kV,电迁移进样10 kV×5s,柱上223 nm检测,5种主要生物碱9 min内可在50 cm×75μm毛细管上实现基线分离。以小檗碱、巴马汀的提取量为指标,分析了提取剂对提取效果的影响。以30％的乙醇水溶液为提取剂,可得到最大煎出量。     

流动注射在线液—液萃取原子吸收光谱法测定生物样品中的铅

本文利用所设计的一种新型流动注射液－液萃取重力分相器，建立了流动注射液溶剂萃取原子吸收光谱法测定铅的新方法，详细地研究了流动注射在线萃取的实验条件及流路系统，方法的精密度和检出限分别为２．５％（ｎ＝１１）和２．８μｇ／Ｌ（ｋ＝３）。用拟定的方法测定了峰蛹，粮食等生物样品中的铅，结果与参考值相吻合。     

Cloud point extraction of napropamide and thiabendazole from water and soil

The micellar extraction and enrichment of napropamide and thiabendazole using Genapol X 80 is described. Combined with their quantification by fluorescence, detection limits below 0.2 g/l with recovery rates of up to 95% were achieved. The recovery could be improved by lowering the extraction temperature and purificaton of the surfactants. This extraction method has been applied to the isolation and preconcentration of napropamide from standard soils. Experimental parameters affecting the recovery rates were examined.     

褐煤超临界流体抽提产物中脂肪烃组成结构的特征

用硅胶-氧化铝柱色谱预分离和色谱-质谱分析研究了两种褐煤超临界流体抽提物中脂肪烃馏分组成结构特征。结果表明,除主要成份正构烷烃(C_(13)～C_(33))外,尚有少量的类异戊二烯烃(姥鲛烷、植烷等)和萜烷。其中萜烷以五环三萜为主(C_(27)、C_(29)～C_(32)藿烷类化合物),并有一定量的C_(27)、C_(29)和C_(30)藿烯,倍半萜和三环二萜烷含量很少。未检出甾烷。此外,还检出一完整系列的烯烃。试验结果表明,超临界流体抽提条件对褐煤抽出物各组分、含量及其分布有一定的影响。     

8-羟基喹哪啶固相萃取光度法测定水样中的铁

研究了8-羟基喹哪啶与铁的显色反应，在pH为8．0的氯化氨-氨水缓冲介质中，在十六烷基三甲基溴化铵(CTMAB)存在下，8-羟基喹哪啶与铁反应生成3：1稳定的蓝紫色络合物，该络合物可被Waters Sep-Park-C18固相萃取小柱萃取，用乙醇洗脱后用光度法测定，络合物λmax=600nm。在此波长下其它金属离子的络合物无光吸收，对铁选择性很好，铁含量在0-5mg/L内符合比尔定律，方法用于水样中痕量铁的测定，结果令人满意。