双金属镍-锰／γ-Al2O3催化剂对甲烷二氧化碳重整反应的影响

用浸渍法制备γ-Al2O3负载的Ni-Mn双金属催化剂．在500-700。C按照17：17：2的C02／CHa／N2比例,以36mL／min的载气流速进行甲烷二氧化碳重整反应,利用甲烷二氧化碳的转化率、生成的合成气H2／CO比例以及长期稳定性等指标评价了催化剂的催化性能．实验表明,添加Mn提高催化性能并使双金属催化剂的稳定性更高,比单金属催化剂更好地抑制焦炭生成,Mn最合适的添加量为0．5wt％．通过BET、C02-TPD、TGA、XRD、SEM、EDX和FTIR各种技术对催化剂进行了表征．     

氮掺杂长竹节状碳纳米管的制备及其生长机理

采用电弧放电法,通过阳极棒与不锈钢片的共蒸发,制备了氮掺杂长竹节状碳纳米管(NDLBLCNTs)。借助扫描电子显微镜(SEM)、场发射高分辨透射电子显微镜(HRTEM)及其附带能量色散X射线(EDX)光谱仪和电子能量损失谱(EELS)、透射电子显微镜(TEM)等表征方法,对产物的形貌、结构和组成进行表征。表征结果表明,NDLBLCNTs的长度在640~835 nm之间,其内径在23~35 nm之间,外径在28~47 nm之间;且在每一节\"竹节\"与另一节\"竹节\"的连接处形成的内腔中均有一个黑色纳米颗粒,其直径尺寸以及产物中的NDLBLCNTs的含量均与熔化、蒸发的不锈钢片的面积有关。对NDLBLCNTs的生长机理进行了简单的探讨。     

The fate of the tert-butylsulfinyl auxiliary after acid-promoted cleavage—a method for recycling t-BuSONH2

Ellman’s chiral auxiliary is converted into tert-butylsulfinyl chloride on sulfinamide deprotection with HCl and can be recovered in high yield upon treatment with ammonia. The enantiopure auxiliary can be obtained by trapping the sulfinyl chloride with a chiral alcohol followed by treatment of the resulting sulfinate ester with LiNH₂.     

Characterization of ethylene oxide–propylene oxide block copolymers by combination of different chromatographic techniques and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy

Block copolymers of ethylene oxide (EO) and propylene oxide (PO) are characterized by combination of two-dimensional chromatography and MALDI-TOF-MS. Liquid chromatography under critical conditions (LCCC) is used as first dimension and fractions are collected, mobile phase evaporated and diluted in the mobile phase used in second dimension (SEC or LAC). This two-dimensional chromatography in combination of MALDI-TOF-MS gives information about purity of reaction products, presence of the byproducts, chemical composition and molar mass distribution of all the products.     

Determination of Tranexamic Acid Using Ethyl Chloroformate as Derivatizing Reagent in Pharmaceutical Preparations and Blood by GC

Ethyl chloroformate was used as a derivatizing reagent to develop a simple and sensitive gas chromatographic procedure for the determination of tranexamic acid. Analysis was performed on an HP-5 column (30 m × 0.32 mm i.d.) coupled with mass spectrometric detection. Linear response was obtained from 60 to 500 pg with a limit of detection of 20 pg tranexamic acid injected onto the column. Aminocaproic acid was used as an internal standard. Tranexamic acid was determined in pharmaceutical preparations and blood samples after therapy with the drug. Appoximately 2.0 μg mL^?1 was found in blood samples. Relative standard deviation for analysis was within 0.1–0.4% (n = 3). Recovery of tranexamic acid added to deprotenized serum was 99.6% with an RSD of 1.2–1.6% (n = 3). Pharmaceutical additives and amino acids, if also present, did not affect the determination.