Two New Sterols from Amoora yunnanensis

ThegenusAmooracomprisingabout25-3ospeciesisdistributedinIndiaandtheMalayPeninsula.SixspeciesaredistributedinYunnanprovince.Amoorayunnanensis(H.L.Li)C.YWu,ismainlydistributedintheSouthofYunnanl.AccordingtoPenningtonandStyles',Amooracannotbeconsideredasavalidgenus.UptonoWchemicalconstituentsforthisgenushavenotbeenreportedyet.lnourchemicalstudyonAmoorayunnanensis,tetTanortfiterPenoidsorprotolimonoidsthatwereconsideredaschemotaxonomicmarkersofthefamilyMeliaceae,werenotisolated.lnthispaper…     

含VE微胶囊的制备及其控制释放性能研究

以天然维生素E（VE）为芯材，利用Shirasu porous glass (SPG) 膜乳化结合液中干燥法，制备了粒径单分散的聚苯乙烯（PS）微胶囊.微胶囊的粒径为膜孔径的4倍，粒径单分散系数CV小于0.2.考察了改变PS和VE的比例及微胶囊的粒径对控制释放性能的影响.     

有机元素微量分析标准物质——茴香酸的研制

茴香酸的分子式为C_8H_8O_3,碳含量63.15%、氢含量5.30%、氧含量31.55%、甲氧基含量20.40%。该标样与日本元素分析恳谈会委员会、英国化学协会微量化学委员会所公布的微量化学标样之一——香草醛一样,都具有相同的碳、氢、氧和甲氧基含量,美国国家标准局(NBS)发行SRM142茴香酸作为微量分析中甲氧基的分析标样。     

碳点的性质及其在生物传感器领域的应用

碳点(carbon dots,CDs)作为一种具有优良生物相容性、低毒性和表面功能可调的新型碳基纳米材料,在生物传感领域具有极大的应用潜力.本文对碳点的生物效应、发光性质及其发光机理进行了简述,并根据传感机制的不同,将CDs在生物传感领域的应用分为荧光(fluorescence,FL)传感器、电致发光(electroc...     

分光光度法在制备负载型多糖吸附污水中铅的应用

本文用不同活性炭制备了负载型多糖（活性炭改良）,多糖的负载率用硫酸苯酚法测定,标准曲线回归方程为Y=0.005906X+0.1234（ r=0.9998）,RSD为0.7%,线性范围为5~50.0mg/L,耶壳活性炭多糖负载率最高为65.71%。用自制负载型多糖清除污水中的铅,以甲基百里香酚蓝为显色剂,用光度法测定铅吸附率,测定条件为,室温、波长为610nm、甲醇为增敏剂、pH为6、显色剂用量为1.5mg/L,反应时间50min,方法的标准曲线回归方程为Y=0.0682X+0.1825（r=0.9999）,线性范围为0～8.0mg/L。平均6次的检出限为0.2mg/L,加标回收率在96.8%～102.3%,RSD为0.39%～3.2%,同时作了共存离子的干扰。结果不同负载型多糖对铅离子的吸附不同,其中椰壳活性炭负载多糖对铅的吸附最大为28.61%,比相应活性炭对铅的吸附高了16.08%。将多糖负载在活性炭上,可明显提高对铅离子的吸附,所以该研究为清除实际污水乃至土壤中的铅提供依据。     

Selective Inversion of the Proximal or Distal Hydroxyl Groups in syn,syn-3-[N-(Alkoxycarbonyl)amino] 1,2-Diols via Cyclic Sulfates

The formation of cyclic sulfates (4) from syn,syn-3-[N-(benzyloxycarbonyl)amino] 1,2-diols provides a common intermediate to access other diastereomers via two inversion procedures. Thermolysis of the cyclic sulfates in acetonitrile normally leads to inversion of the distal hydroxyl group to form a 1,3-oxazin-2-one (6). Catalytic hydrogenation of the cyclic sulfates under basic conditions (NEt(3)) results in inversion at the proximal hydroxyl group to form a 1,3-oxazolidin-2-one (5).     

(±)-金锦香酸二甲酯甲醚的合成

本文以呋喃甲酸甲酯为原料, 经羟烷基化反应, 醇解反应和O-甲基化反应合成(±)-金锦香酸二甲酯甲醚。同时, 还发现了制备2-乙烯基呋喃衍生物的新方法。     

Synthesis and characterization of ionic organotin compounds [R2SnCl2(2-quin)](HNEt3) and crystal structures of [(2,4-Cl2-C6H3CH2)2SnCl2(2-quin)](HNEt3)

Eight ionic organotin compounds [R₂SnCl₂(2-quin)]⁻(HNEt₃)⁺ have been synthesized by reactions of 2-quinH with R₂SnCl₂ (R = PhCH₂1, 2-Cl-C₆H₄CH₂2, 4-Cl-C₆H₄CH₂3, 2-F-C₆H₄CH₂4, 4-F-C₆H₄CH₂5, 4-CN-C₆H₄CH₂6, Ph 7, 2,4-Cl₂-C₆H₃CH₂8) in the presence of organic base NEt₃, and their structures have been characterized by elemental analysis, IR and multinuclear NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopies. The structure of [(2,4-Cl₂-C₆H₃CH₂)₂SnCl₂(2-quin)]⁻(NEt₃)⁺ (8) has been determined by X-ray diffraction study. Studies show that compound 8 has a monomeric structure with the central tin atom six-coordinate in a distorted octahedral configuration and the nitrogen atoms of the 2-quin ligands are coordinating to the tin atom in all the eight compounds.     

高效液相色谱整体柱技术的进展

高效液相色谱整体柱（又名连续床）具有制备相对简单、原料易得以及聚合组分在一定范围内可调节的优点,是近年来得到迅速发展的新型色谱柱。本文综述了目前高效液相色谱（HPLC）制备整体柱的典型高聚物体系、制备各种整体柱时反应条件的影响,并简要介绍了它的表征方法和应用。     

Comparative X-ray photoelectron spectroscopic study on the desulfurization of thiophene by Raney nickel and rapidly quenched skeletal nickel

The desulfurization of thiophene on Raney Ni and rapidly quenched skeletal Ni (RQ Ni) has been studied in ultrahigh vacuum (UHV) by X-ray photoelectron spectroscopy (XPS). The Raney Ni or RQ Ni can be approximated as a hydrogen-preadsorbed polycrystalline Ni-alumina composite. It is found that thiophene molecularly adsorbs on Raney Ni or RQ Ni at 103 K. At 173 K, thiophene on alumina is desorbed, while thiophene in direct contact with the metallic Ni in Raney Ni undergoes C-S bond scission, leading to carbonaceous species most probably in the metallocycle-like configuration and atomic sulfur. On RQ Ni, the temperature for thiophene dissociation is about 100 K higher than that on Raney Ni. The lower reactivity of RQ Ni toward thiophene is tentatively attributed to lattice expansion of Ni crystallites in RQ Ni due to rapid quenching. The existence of alumina and hydrogen may block the further cracking of the metallocycle-like species on Raney Ni and RQ Ni at higher temperatures, which has been the dominant reaction pathway on Ni single crystals. By 473 K, the C 1s peak has disappeared, leaving nickel sulfide on the surface.