离子液体中钯催化烯烃串联碳酯化构建官能团化的β和γ-内酯

正β-和γ-内酯作为关键母核结构单元广泛存在于具有生理活性的天然产物以及药物分子中.另外,作为有机合成中重要的合成子,β-和γ-内酯的结构单元也被广泛应用于合成结构复杂的多官能团以及稠环化合物.然而,已报道的合成方法中,在某种程度上存在着诸如反应条件苛刻、使用有毒溶剂或催化剂以及底物官能团兼容性窄等缺点,极大地限制了其广泛应用.因此,随着绿色化学与环境友好化学的发展,探寻简洁、高效以及绿色的构建β和γ内酯骨     

Investigation on the Percutaneous Enhancing Permeation Mechanism of Azone for Ketoprofen Based on the Intermolecular Hydrogen-bonding Interaction

The permeation enhancing activity of Azone for ketoprofen through excised cavia skins was investigated using Franz diffusion cell. The possible hydrogen-bonded complexes formed between ketoprofen and the model molecule of Azone as azacyclopentane-2-one were fully optimized at the B3LYP/6-311++G** level. The intermolecular hydrogen-bonding interactions were calculated using the B3LYP/6-311++G**, B3LYP/6-311++G(2df, 2p), MP2(full)/6-311++G** and MP2(full)/6-311++G(2df, 2p) methods, respectively. The results show that the steady-state permeation rate of ketoprofen through excised cavia skins enhances over 9 times in the solvent with 2% Azone as compared with the solvent without Azone. The stable O–H···O=C and N–H···O=C hydrogen-bonded complexes could exist between azacyclopentane and ketoprofen. The hydrogen-bonding interaction energy follows the order of(a) (b) (c) (d) (g)(e) (h) (f). The formation of the complexes leads to the change of the conformation and molecular polarity of ketoprofen, and thus causes a better percutaneous permeation for the drug. The analyses of AIM(atom in molecule) and shift of electron density were used to further reveal the nature of the enhancing permeation activity of Azone for ketoprofen. The investigations of the temperature and solvent effects confirm that ketoprofen might enter into the skin by means of the Azone complex.     

Polyamides containing thiadiazole units: Synthesis and optical properties

Highly refractive and transparent polyamides containing thiadiazole units have been developed.These polymers were prepared by a polycondensation reaction of 4,4'-(1,3,4-thiadiazole-2,5-thio) bis(methylene) dibenzoyl chloride(TDTBM-DC) and diamine which contained thioether(―S―) and sulfone units.They showed good thermal stabilities such as a relatively high glass transition temperature of 206-233 °C and a 5% weight-loss temperature(T5%) of 376-395 °C.The optical transmittance of the polymer at 450 nm is higher than 83%.The heterocycle units and plural ―S― linkages provide the polymer with a high refractive index of 1.716-1.725 at 633 nm and a low birefringence of 0.003-0.004.Also they showed improved solubility in polar aprotic solvents and could form moderate strength films with tensile strength of 72.8-83.1 MPa and storage modulus of 1.0-1.8 GPa(at 200 °C).     

Effect of Solvent Annealing Temperature on Crystal Modifications and Phase Transition Behavior of Regioregular Poly（3-octylthiophene）

In present study, the effect of the solvent annealing temperature on the crystal modifications and the phase transition behavior of the subsequently dried poly（3-octylthiophene） （P3OT） film has been investigated by the combination of DSC, WAXD and FTIR techniques. When chloroform is employed as the solvent, it is unexpectedly found that form I and form II crystal modifications of P3OT could be respectively obtained by room temperature and low temperature annealing. Comparing to the mostly used solvent reported for preparing form II, i.e. carbon disulfide （CS2） which is toxic and corrosive, chloroform is less toxic and corrosive and more suitable for solution processing of P3OT. Therefore, this finding provides an alternative way to obtain form II. By temperature dependent IR spectroscopy, the structural evolution of P3OT during the form II to form I phase transition process has also been studied in detail.     

卤素取代与溶剂效应对荧光素的荧光光谱的影响

基于卤族元素对荧光素荧光性能的影响作用,采用甲磺酸为催化剂,分别以4-卤代(氟、氯、溴)间苯二酚为原料通过Friedel-Crafts酰化/环化脱水反应合成了2',7'-二卤代荧光素(DFF、DCF、DBF)。分析了不同卤族元素取代对荧光素的紫外-可见吸收和荧光发射光谱的影响,结果表明,与荧光素光谱相比,氟原子和氯原子取代对增强荧光发射强度效果明显,溴原子的引入降低荧光发射强度。考察了荧光染料浓度对其荧光强度的影响,结果发现,三种卤代荧光染料的浓度在1×10-5mol/L时均具有最大荧光发射强度。研究了染料的溶剂效应,发现荧光光谱随溶剂类型而变化,在极性溶剂中染料的荧光强度高、荧光发射波长较长,此外,在极性质子溶剂中斯托克斯位移比极性非质子溶剂中的大。     

有机磷酸酯阻燃电解液的研究进展

随着锂离子电池的市场拓展,安全性问题已成为电动汽车、大规模储能等应用领域关注的首要问题. 目前商品化的锂离子电池普遍采用低沸点碳酸酯类电解液,其易燃性成为电池不安全性的主要隐患. 为了提高锂离子电池的本征安全性,阻燃或不燃性电解液成为近年来研究的热点,其中以磷酸酯为溶剂的阻燃型或不燃型电解液受到广泛关注. 本文主要介绍磷酸酯阻燃和不燃电解液的研究状况,分析了这类电解液与锂离子电池正负极的兼容性问题,讨论了改善磷酸酯电解液电化学兼容性的途径,提出了发展高效、安全、稳定的不燃电解液的一些思路.     

低共熔溶剂预处理木质纤维素生产生物丁醇

生物丁醇被认为是一种能够直接代替汽油的生物燃料,可满足经济发展对可持续液体燃料的需求。木质纤维素可再生,来源广泛且廉价,是生产生物丁醇的理想原料。但木质纤维素结构复杂,难以直接水解利用,高效的预处理方式是其商业化应用的关键。低共熔溶剂(DES)是一种环境友好的新型溶剂,具有成本低、绿色低毒、溶解能力强、良好的选择性和生物相容性等优点,有着较高的生物质预处理潜力。本文首先介绍了DES的种类和性质;其次,综述了木质纤维素中各组分在DES中的溶解效率,讨论了DES预处理木质纤维素对酶水解和丁醇发酵过程的影响;再次,通过对各种生物加工过程的梳理,对整合生物过程在生产生物丁醇领域的应用潜力进行了评述;最后,对DES预处理木质纤维素生产生物丁醇领域今后的工作做出了展望。     

铀酰离子在羟基化α-石英(101)表面的吸附

采用周期性密度泛函理论研究羟基化α-石英(101)面的铀酰离子吸附行为.通过对铀酰离子的水合作用考虑水溶剂对结构的短程溶剂化效应,并通过类导体屏蔽模型(COSMO)考虑水溶剂对结构的远程溶剂化效应.吸附能计算结果和电子结构数据均表明水合铀酰离子吸附构型比氢氧化铀酰吸附构型稳定,并且在液相中两种类型的稳定吸附位均为dia-Os1Os2位.两种形式在电子结构上有很大的差异,主要是由于铀与表面作用后成键强弱程度不同,使5f轨道宽化和略微红移存在差异.在铀酰离子吸附的基础上利用卤素离子改变铀酰离子配位环境可调整体系的带隙.     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

非极性溶剂微波萃取-气相色谱-质谱法测定白豆蔻中挥发油成分

提出了非极性溶剂微波萃取-气相色谱-质谱法测定白豆蔻中的挥发油成分的方法。优化的试验条件如下:①微波吸收介质为0.35g石墨粉;②提取溶剂为正己烷;③样品质量与溶剂容积之比为2g比25mL;④提取时间为30min。在气相色谱分离中用DB-5石英毛细管柱为固定相,在质谱分析中采用全扫描检测模式。以α-甲基苯甲醇丙酸酯为内标物。方法用于白豆蔻样品的分析,共鉴定出60种挥发性化学成分,主要化合物为桉油精(70.34%)、β-蒎烯(6.81%)、α-松油醇(3.36%)和α-蒎烯(2.54%)等。