Tetrazole-Functionalized Silica for Hydrophilic Interaction Chromatography of Polar Solutes

In this work, tetrazole-functionalized stationary phase was prepared with nitrile-modified silica by an ammonium-catalyzed (3 + 2) azide-nitrile cycloaddition reaction. The prepared stationary phase was used for separation of nucleobases and nucleosides by hydrophilic interaction chromatography (HILIC) mode. A typical HILIC mechanism was observed at higher content of acetonitrile (>85%, v/v) in the mobile phase. The retention mechanism of the column was investigated by the models used for describing partitioning and surface adsorption through adjustment ratio of water in the mobile phase, and by the influence of salt concentration, buffer pH, and temperature on the retention of solutes. The results illustrated that the surface adsorption through hydrogen bonding dominated the retention behavior of nucleobases/nucleosides under HILIC mode. From the separation ability, the tetrazole-functionalized stationary phase could become a valuable alternative for the separation of the compounds concerned.     

预聚物复合助稳定剂条件下含氟丙烯酸酯共聚物的细乳液聚合

以甲基丙烯酸三氟乙酯(TFMA)、苯乙烯(St)和丙烯酸丁酯(BA)为共聚单体,在十二烷基硫酸钠(SDS)/磺酸盐型阴离子氟表面活性剂(S100)/辛基苯基聚氧乙烯醚(OP-10)组成的乳化体系中,采用预聚物和十六醇(HDL)共同组成的复合助稳定剂,对细乳液聚合制备St/BA/TFMA三元共聚物的过程进行了研究.通过F...     

(±)-Glovanon和(±)-5-O-Methylglovanon的首次全合成及其抑菌活性研究

以廉价的异香草醛和2,4,6-三羟基苯乙酮为起始原料,经过C-异戊烯基化、选择性甲基化、甲氧甲基化、羟醛缩合、去保护基、催化环化以及脱除甲基等步骤,分别以13.3%和23%的总收率首次完成了天然异戊烯基黄烷酮Glovanon(1)和5-O-methylglovanon(2)的全合成.合成的关键步骤是2,4,6-三羟基苯乙酮的单C-异戊烯基化.所有新化合物的结构都经过1H NMR,IR,MS确认.抑菌活性研究表明,两种新合成的化合物对藤黄微球菌(M.luteus)和大肠杆菌(E.coli)均有良好的抑制作用.     

Metal-reinforced sulfonic-acid-modified zirconia for the removal of trace olefins from aromatics

Metal-reinforced sulfonic-acid-modified zirconia catalysts were successfully prepared and used to remove trace olefins from aromatics in a fixed-bed reactor. Catalysts were characterized by ICP-OES, N₂ adsorption–desorption, X-ray diffraction, thermogravimetric analysis (TGA), and pyridine-FTIR spectroscopy. Different metals and calcination temperatures had great influence on the catalytic activity. Alumina-reinforced sulfated zirconia exhibited outstanding catalytic performance, stable regeneration activity, and giant surface area, and are promising in industrial catalysis. TGA showed that the decomposition of methyl could be attributed to Brønsted acid sites, and pyridine-FTIR spectroscopy proved the weak Brønsted sites on these synthesized metal-reinforced sulfated zirconia. Also, a relation between the reaction rate and weak Brønsted acid density is proposed.     

原子转移自由基聚合法用于以单分散树脂为基质的强阳离子交换色谱固定相的制备及其色谱性能研究

以7μm单分散交联聚甲基丙烯酸环氧丙酯树脂表面键合溴异丁酰溴为引发剂,以CuCl/CuCl2/2,2-联二吡啶(Bpy)为催化体系,采用封闭体系,在氮气保护下,以乙烯基苯磺酸钠(NaSS)为单体、N,N-二甲基甲酰胺(DMF)水溶液为溶剂,制备了强阳离子交换色谱(SCX)固定相,并用元素分析与红外光谱法对其进行了表征....     

延胡索酸泰妙菌素在碳糊电极上的电化学性质及电分析方法

运用循环伏安法(CV)、计时电流法(CA)和计时电量法(CC)研究了延胡索酸泰妙菌素(Tiamulin fumarate,TF)在碳糊电极(Carbon Paste Electrode,CPE)上的电化学及其电化学动力学性质。结果表明,TF在CPE上的电化学过程是一不可逆的氧化过程,氧化峰电位Ep为0.772 V。在扫描速度10～1 000 mV.s-1范围内,其氧化峰电流Ip与扫描速度v呈良好的线性关系,表明TF在CPE上的伏安行为是一受吸附控制的过程。方波伏安(SWV)法结果表明TF氧化峰电流与其浓度在5.0×10-7～1.0×10-5mol.L-1及1.0×10-5～1.0×10-4mol.L-1范围内均呈良好的线性关系,相关系数r分别为0.9980及0.9966,检出限(S/N=3)为5.8×10-8mol.L-1,相对标准偏差(RSD)为0.8%～2.8%,加样回收率为97.6%～102.0%。据此建立了TF含量的电化学测定方法。该方法简便快捷,测定结果令人满意。     

热处理对La4MgNi19储氢电极合金结构和性能的影响

以感应熔炼和不同的热处理工艺制备了La₄MgNi₁₉合金, 用X射线衍射(XRD)和电化学测试系统研究了该合金的相结构和电化学性能. 结构分析表明: 当热处理工艺为900 °C+水淬时, 合金主要由CaCu₅结构的LaNi₅相和少量未知相组成; 当热处理工艺为900 °C退火时, 合金主要由Pr₅Co₁₉、Ce₅Co₉结构的(La, Mg)₅Ni₁₉相及少量CaCu₅结构的LaNi₅相组成. 淬火和退火后合金的电化学循环稳定性(S₁₀₀)分别为49.7%及76.0%, 合金电极的电化学性能和相结构密切相关. 退火热处理有利于生成Pr₅Co₁₉、Ce₅Co₉型相. 在La-Mg-Ni 系储氢合金中, La₄MgNi₁₉合金电化学循环稳定性不及La₃MgNi₁₄合金.     

First Total Synthesis of(±)-Puyanin and(±)-4'-Omethylbonannione

A facile approach for the first total synthesis of two naturally occurring geranylated flavonoids, (±)‐puyanin ( 1 ) and (±)‐4′‐O‐methylbonannione ( 2 ) has been obtained with total yields of 27% and 17.8%, respectively. The key steps were regioselective cyclization of geranylated trihydroxychalcone and regioselective geranylation of 2,4,6‐trihydroxyacetophenone.     

一类新型冠醚稀土配合物的合成、表征及与DNA作用研究

合成了四种双(N,N′-乙基,苯基)-2,3-萘-二(氧杂乙酰胺)(L=C30H30N2O4)稀土配合物。通过元素分析、红外光谱、差热-热重及摩尔电导值的分析,确定配合物的组成为[RE(pic)3L],RE=Eu(Ⅲ),Tb(Ⅲ),Ce(Ⅲ),Y(Ⅲ)。电化学实验表明:配体无电化学活性,配合物则呈现出一准可逆的氧化还原过程,在10～1000 mV.s-1扫速范围内配合物的氧化还原峰电流与扫描速度的平方根(ν1/2)呈良好的线性关系,表明其在玻碳电极(GCE)上的伏安行为受扩散控制。另外,通过循环伏安法、光谱法及粘度法研究了配合物与DNA的作用方式,结果表明:配合物均以插入方式与DNA作用,并且作用大小次序是Ce(pic)3L>Tb(pic)3L>Y(pic)3L>Eu(pic)3L。在pH=3.0适宜酸度条件下,建立了以Ce(pic)3L为探针定量测定DNA的分析方法。