浓度对硫酸性质影响的实验研究

通过实验研究了浓度对硫酸性质的影响,结果表明浓度大于等于12 mol·L-1（72%）的硫酸具有明显的吸水性、脱水性、强氧化性和能使铁、铝钝化。浓硫酸与常见指示剂作用颜色变化有各自的变色特点,和常见酸与指示剂作用的颜色变化规律不同。     

基于透明质酸的缺氧响应型胶束的制备及性能研究

以透明质酸（HA）及硝基咪唑（NI）衍生物为原料,通过酰胺反应合成了一种两亲性接枝聚合物（HA-NI）.该聚合物具有缺氧响应性和肿瘤靶向性.利用傅里叶红外光谱（FT-IR）和核磁共振（NMR）对接枝聚合物的结构进行了表征,同时基于¹H NMR计算出接枝聚合物中NI的取代度.HA-NI在水中自组装形成胶束,利用动态光散射仪（DLS）表征胶束大小并对胶束的稳定性进行了研究,利用原子力显微镜（AFM）和透射电镜（TEM）观察胶束形貌.载药胶束的载药率（DL）和包封率（EE）通过紫外-可见吸收光谱（UV）测试并计算得到.胶束的缺氧响应性利用DLS、AFM、TEM、UV等探究.实验证明,该聚合物胶束具有缺氧响应性并对药物表现出良好的控制释放能力,在常氧环境下,胶束稳定存在;而在缺氧环境下,胶束散开,药物快速且完全地释放.     

An efficient metal catalyst free approach to synthesize 5-(4-(1,2,4,5 tetrazin-3-yl)benzylamino)-5-oxopentanoic acid

Despite the wide use of 1,2,4,5- tetrazines in biomaterials and materials science, currently there does not exist synthetic method(s) that can yield significant amount of 1,2,4,5- tetrazines without the use of potentially toxic metal catalysts. Here, we report a less energy intensive and more efficient metal catalyst free approach for the synthesis of an asymmetric tetrazine. A range of operating parameters such as extraction pH and temperature were regulated to achieve a practical yield nearly 1.5 times greater than the yields reported in the literature for similar synthetic procedures.     

One-pot,microwave-assisted synthesis of polymethylene-bridged bis(1H-1,2,4-triazol-5(3)-amines) and their tautomerism

A highly selective and efficient method for the synthesis of 3,3′(5,5′)-polymethylene-bis(1H-1,2,4-triazol-5(3)-amines) was developed using the reaction of dicarboxylic acids and aminoguanidine in an aqueous medium. This one-pot, microwave-promoted method was proved to be scalable affording the desired products in good yields and purity. The scope of the method was successfully explored by the preparation of a small library of polymethylene-bis(1H-1,2,4-triazol-5(3)-amines) with different alkyl chain linkers. The annular prototropic tautomerism in the prepared compounds was studied using NMR spectroscopy and X-ray crystallography.     

Mn/Cu catalyzed addition of arylboronic acid to nitriles: Direct synthesis of arylketones

A direct and efficient synthesis of arylketones via arylboronic acid addition to nitriles in presence of inexpensive Mn/Cu catalytic system is reported. The use of non-precious Mn and Cu salts has been found to be highly advantageous both in terms of accessibility as well as cost effectiveness. A series of arylboronic acids as well as nitriles were used to synthesize a variety of symmetrical and unsymmetrical arylketones. Based on the literature studies, the reaction mechanism is anticipated to go through an aryl radical intermediate which reacted with the copper activated nitrile to give the desired arylketones after the hydrolysis of the imine intermediate.     

Ovalbumin-stabilized gold nanoclusters with ascorbic acid as reducing agent for detection of serum copper

Ovalbumin-stabilized gold nanoclusters(OVA@AuNCs) were prepared with ascorbic acid as a reducing agent. This strategy could realize the synthesis of water-soluble OVA@AuNCs within 20 min. The asprepared fluorescent probe showed a red fluorescence emission at 630 nm. Moreover, the properties of the OVA@AuNCs were characterized by transmission electron microscope, dynamic light scattering,ultraviolet-visible spectroscopy, fluorescent spectroscopy. Based on the surface electron density decrease-induced fluorescence quenching mechanism, the OVA@AuNCs provided high sensitivity and selectivity for sensing copper ions. A good linear relationship was obtained between the fluorescence intensity of OVA@AuNCs and the concentration of copper ions in the range of 5.0-100.0 μmol/L(R~2=0.999) with a detection limit of 640 nmol/L Furthermore, the rat serum copper contents were determined by using the OVA@AuNCs based assay, indicating great potential of fluorescent probes for application in biological and clinical analysis.     

Structural characterizations of protonated homodimers of amino acids: Revealed by infrared multiple photon dissociation (IRMPD) spectroscopy and theoretical calculations

Photon affinity can serve as a probe for predicting the structures of protonated homodimers of amino acids.     

铜钼组分对γ-Al2O3负载镍催化剂脂肪酸甲酯加氢脱氧性能的影响

制备一系列包含或不包含铜、钼组分的Ni/γ-Al₂O₃催化剂,并对其进行表征和性能测试。考察了铜、钼负载量,浸渍顺序（包括连续浸渍和共浸渍）,反应条件对脂肪酸甲酯加氢脱氧反应性能的影响。根据TG数据,使用过的20Ni-6Cu/γ-Al₂O₃催化剂其热失重小于20Ni/γ-Al₂O₃催化剂,这表明,铜的引入能够有效抑制反应过程中催化剂表面的积炭行为。对于20Ni-6Cu/γ-Al₂O₃和20Ni-6Cu-nMo/γ-Al₂O₃（n=2、5、8和12）催化剂,NH₃-TPD分析结果显示,钼物相的引入对载体γ-Al₂O₃的酸性位有着显著影响,当钼负载量达到5%时,可以观察到一个新的酸位对应于中强酸位。铜和钼修饰过的催化剂其催化性能要高于Ni/γ-Al₂O₃催化剂。从XPS的分析可以看出,催化剂中的铜主要以正二价形式存在,钼主要以正四价和正六价形式存在,而且不同的浸渍顺序会影响催化剂表面活性组分的实际含量。此外,脂肪酸甲酯的转化率和烷烃产品的收率也和所制备出来的催化剂的浸渍顺序有关。在所有的催化剂中,使用连续浸渍（先浸渍镍铜组分、浸渍钼组分）所制备的三金属20Ni-6Cu-5Mo/γ-Al₂O₃催化剂展现了优异的催化性能。在适宜的反应条件下（350 ℃,2.5 MPa,WSHV=2.0 h^-1,H₂/oil ratio=1250 mL/mL）,脂肪酸甲酯的转化率和烷烃产品的收率分别达到98.4%和94.2%。     

Unusual synthesis of azines and their oxidative degradation to carboxylic acid using iodobenzene diacetate

Reaction of 3-hydrazonobutan-2-one oxime with aromatic aldehydes resulted in the formation of 1,2-bis(arylidene)hydrazine commonly referred as azine as an unexpected product, instead of expected product 3-(aryl)methylenehydrazonobutan-2-one oxime, which were subsequently oxidized to corresponding aromatic acids with an ecofriendly oxidizing agent iodobenzene diacetate. Azines and carboxylic acids were characterized by IR and NMR (¹H, ¹³C, HMBC, and HMQC) studies.     

Efficient syntheses of zoledronic acid as an active ingredient of a drug against osteoporosis

The reaction of 1H-imidazol-1-ylacetic acid and two equivalents of phosphorus trichloride/phosphorous acid at 75?°C in sulfolane, or in the presence of catalytic amounts of [bmim][BF₄] afforded zoledronic acid in yields up to 75%. The joint use of the ionic liquid additive and sulfolane as the solvent was synergetic affording highly valuable zoledronic acid in a record yield of 93%.