COORDINATION COPOLYMERIZATION OF STYRENE WITH MALEIC ANHYDRIDE BY RARE-EARTH COORDINATION CATALYSTS

The study on coordination copolymerization of styrene (S) with maleic anhydride (MA) by rare-earth coordination catalysts, NdL_3-Al(i-Bu)_3, has been successfully carried out for the first time. Some features, kinetic behavior, and mechanism of the SMA copolymerization by Nd(naph)_3-Al(i-Bu)_3 system are described and discussed. The copolymex of styrenemaleic anhydride prepared by the NdL_3-Al(i-Bu)_3 systems in benzene at 50℃ is an alternating-rich white powder having high number-average molecular weight of 6—8.5×10~5. The overall activation energy for the polymerization was found to be 10.5KJ/mol. The polymerization was not suppressed by addition of hydroquinone. The catalytic activity of various ligands in NdL_3 for the copolymerization decreases in the following order: Nd (naph)_3>Nd-(P_(507))_3～NdCl_3-6H_2O>Nd(P_(204))_3>Nd(acac)_3. 3H_2O. The experimental results are explained based on a mechanism to be the coordination-type copolymerization in terms of the participation of a monomer-monomer c     

多齿胺膦钌配合物催化苯乙酮的氢转移氢化

利用Ｃ２－对称的双胺双膦钌（Ⅱ）配合物ＲｕＣｌ２（Ｐ２Ｎ２Ｈ４）为催化剂，研究了苯乙酮的氢转移还原反应。在苯乙酮、钌配合物和异丙氧基钾的摩尔比为２００：１：１２的条件下，于６５℃反应２ｈ后，苯乙酮的转化率高达９９％。讨论了苯乙酮的氢转移氢化机理。     

低温陈化法制备SO_4~(2-)/WO_3-TiO_2固体超强酸及性能研究

0引言固体超强酸的研制是近20年来催化领域中的热点研究课题之一。起初,人们所研制的SO42-/MxOy型固体超强酸中,MxOy多为ZrO2。近年来,研究者们为得到高酸强度和高催化活性的固体超强酸催化剂,以ZrO2为主体,引入第二组分、第三组分组成复合型催化剂,这方面的研究者颇多[1~4],也     

克拉霉素漂浮-生物粘附微囊的制备及性能研究

选用乳化-溶剂挥发法制备乙基纤维素载药微球(EMs), 并通过内部凝胶化法进行包衣制得海藻酸钠-乙基纤维素载药微囊(AEMs), 最后通过离子交联法进一步包衣制得壳聚糖-海藻酸钠-乙基纤维素载药微囊(CAEMs). 研究克拉霉素漂浮\|生物粘附微囊的制备工艺, 并考察微囊的体外漂浮性能、 粘附性能及体内滞留性能. 结果表明, CAEMs球形度较好, 药物包封率为72.3%~78.2%, 载药量为7.1%~12.7%. 在pH=5的醋酸缓冲液中, 6 h时的累积释放率为56.6%~70.6%, 漂浮率大于70%, 4 h时的体内滞留率为60.5%. CAEMs有望通过延长药物胃内滞留时间, 在临床用于根除幽门螺旋杆菌, 从而降低消化道溃疡的复发率.     

阿奇霉素片及胶囊剂溶出度考察

采用硫酸显色法对两家药厂生产的阿奇霉素片及胶囊剂进行了溶出度考察。结果表明，阿奇霉素在10－100μg/mL范围内线性关系良好，平均 回收率为99．83％（n=6)。阿奇霉素片及胶囊剂在45min时的溶出量均不低于标示量的80％。而两厂产品体外溶出度结果均达到要求。     

Studies on the phase properties of lyotropic liquid crystals of Brij35/sodium oleate/oleic acid/water system:By means of polarizing microscope,SAXS,~2H-NMR and rheological methods

The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/water systems has been investigated, and the liquid crystal area has been identified, which covers about two thirds of the whole phase diagram. The liquid crystal structure and behavior have been also studied by using polarizing texture, small angle X-ray scattering, 2H-NMR and rheometer etc. The result shows that when the composition of the system changes along the line of AA′ in this large liquid crystal region, the structural change is cubic→cubic/lamellar→lamellar→lamellar/hexagonal→hexagonal. Meanwhile, we made the first attempt of systematic study of the rheological properties of the above system. The lattice constants of cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.     

高效毛细管电泳间接紫外检测血浆中钾、钙、镁

用高效毛细管电泳法,在pH 5.5的缓冲介质中用酒石酸作为络合剂,使血浆中钾、钠、钙、镁4种阳离子达到很好分离,用咪唑作为背景试剂进行了紫外检测.对电泳分离及紫外检测的各分析条件(包括背景缓冲溶液的pH值,咪唑溶液的浓度及酒石酸溶液的浓度等)作了试验并予以优化,上述4种离子的相互分离在4.5 min内顺利完成.文中给出了K 、Ca 、Mg2 的线性回归方程,其相关系数在0.998 4～0.999 4之间,证明了在各离子的峰面积与其浓度之间呈线性关系,3种离子的检出限(S/N=3)依次为0.20,0.12,0.06 mg·L-1.用迁移时间检测和用峰面积检测所得的RSD值(n=6)依次小于0.76%和2.83%.由于钠离子的吸收峰与系统峰重叠,钠的测定无法进行.回收率试验的结果在95.3%至104.2%.     

A Large Conformational Change of a Bridged β-Cyclodextrin Dimer in Aqueous Solution

A novel bridged β-CD dimer in which two β-cyclodextrins were linked by a naphthalene at positions 2 and 7 has been synthesized. 1H and 13CNMR measurements showed that a large change in the conformation of the dimer occurred in aqueous solution. The dimer interacted with methyl and ethyl orange to form stable inclusion complexes via "induced fit" mechanism.     

白术挥发油中苍术酮氧化反应的动力学

白术挥发油;苍术酮;动力学方程;活化能;反应机理     

制备参数对Au／Fe2O3催化剂水煤气变换性能的影响

 采用共沉淀法制备了Au／Fe2O3催化剂，并系统地考察了制备参数对其催化WGS性能的影响．通过BET，XRD，XRF，H2－TPR和HRTEM等表征手段，初步考察了Au／Fe2O3催化剂具有高催化活性的原因．结果表明，金负载量、沉淀剂种类、沉淀方式、沉淀pH值、焙烧气氛和焙烧温度对Au／Fe2O3催化剂的催化性能均具有较大的影响．Au／Fe2O3催化剂的低温高活性是纳米Au与Fe3O4协同作用的结果；Au／Fe2O3催化剂的高温活性是由于活性相Fe3O4起主要作用的结果．纳米Au粒子的烧结会降低其催化活性．