Liquid-liquid Extraction System Based on Non-ionic Surfactant-salt-H_2O and Mechanism of Drug Extraction

The utilization of solid-liquid extraction system based on polymer-(NH4)2SO4 -H2O on separation of metal ions and bio-active substances has been summarized1. Cloud point extraction (CPE) benefits the environment and has been used in separation of metal chelates, biomacromolecules and in pretreatment of environmental samples2-4. In a 10 mL color comparison tube 20% PEG-1000 and 2.5 g (NH4)2SO4 were chosen as phase separation condition at pH 5.5. The average extraction efficiencies we…     

Two New Steroidal Saponins from Tacca plantaginea

Two new C27 steroidal glycosides, named taccaoside A(1) and B(2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl(1→2)]-[α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranoside(1) and 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl-(1→2)]-[β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranoside(2),respectively.     

New Facile Synthesis of 2-Aryloxy-5-(2-furfurylidene)- 4H-imidazolin-4-ones

Many N-heterocycles including 4H-imidazolin-4-ones exhibit biological activities1-3. Some derivatives of 5-(2-furfurylidene)-4H-imidazolin-4-one were found to show good antiinflammatory activity4. They can be synthesized by condensation of furfural with 5- unsubsituted 4H-imidazolin-4-ones or from corresponding oxazolones5,6. However, no synthesis of 2-aryloxy substituted 5-(2-furfurylidene)-4H-imidazolin-4-one was reported. Recently, aza-Wittig reaction has received increased attention …     

Green-Light Electroluminescence of Conjugated Copolymer Containing p-Phenylene-ethynylene and Oxadiazole

IntroductionSince the first report,in 1 990 ,of the electro-luminescence of the conjugated polymers in the filmof poly(p- phenylenevinylene) (PPV) sandwichedbetween an anode and a cathode of appropriatework functions[1] ,enormous efforts have been de-voted to the synthesis of light emitting poly-mers[2— 4 ] .Having been found potential applicationof conjugated polymers in photoluminescence(PL)and electro- luminescence (EL ) ,their importantproperties,polymer processability,band gap tun-abil…     

Cloning of Promoter of Chinese Bean GRP 1.8 Gene and Characterization of Its Function in Transgenic Tobacco Plants

IntroductionVascular cells that are determined to becometracheary elements undergo a very distinct celldifferentiation.In contrast to many other types ofplant cells that can dedifferentiate and evenultimately form a new plant,cells determined tobecome tracheary elements are programmed to die.Glycine- rich proteins belong to a class ofstructural cell wall proteinsthatcontain about60 %glycine on the molar basis. Glycine- rich proteinsare localized in cell walls of bean[1] .Glycine- richprotein1…     

丙酮一步法合成甲基异丁基酮催化剂研究

用浸渍法制备了丙酮一步法合成甲基异丁基酮负载型催化剂，考察了载体的预处理温度、添加镧助剂对催化剂性能的影响；用BET法测定了催化剂的表面积；采用H2-O2滴定法测定Pd的分散度．结果发现，用经过1．023K焙烧过的Al2O3为载体的催化剂具有较好的催化性能，添加镧助剂后催化剂的分散度、活性有较大的提高．     

有机溶剂中(R)-醇腈酶催化不对称合成(R)-苯乙醇腈

 研究了来源于杏仁的（R）－醇腈酶在有机溶剂异丙醚中催化苯甲醛与HCN不对称合成（R）－苯乙醇腈，初步探讨了来源于不同杏仁的（R）－醇腈酶的筛选、最适酶量的确定以及底物HCN与苯甲醛的配比、底物浓度、酶的微环境pH和反应温度对不对称合成反应的影响．结果发现，来源于苦杏仁的（R）－醇腈酶优于来源于甜杏仁的（R）－醇腈酶．优化的反应条件为：最适酶量150g／L，HCN与苯甲醛的配比2．5，苯甲醛浓度300mmol／L，酶的微环境pH5．4，反应温度0～5℃．在该优化反应条件下，反应平衡转化率和产物的光学纯度均高达99％以上．     

氧化钡促进的Co/SiO2催化剂的还原性能和分解甲烷活性

 利用等体积浸渍法制备了氧化硅负载钴催化剂．通过程序升温还原、氢化学吸附、氧滴定和催化活性评价等手段研究了氧化钡对Co／SiO2的还原性能、钴分散度和颗粒度、分解甲烷活性及其稳定性等的影响．研究结果表明，氧化钡明显地影响Co／SiO2的还原性能；添加2％氧化钡提高了Co／SiO2在中温（450℃）条件下的还原度；氧化钡的还原对Co／SiO2还原的诱导、氧化钡与氧化硅及与氧化钴之间的相互作用是导致Co／SiO2还原性能变化的原因．氧化钡提高了Co／SiO2的初活性和钴的分散度，降低了钴的颗粒度；添加0．5％～1．5％氧化钡有利于提高Co／SiO2的稳定性．钴的分散度和颗粒度影响Co／SiO2的活性和稳定性；氧化钡的强供电效应也是提高Co／SiO2活性和稳定性的重要因素．甲烷分解生成的碳物种覆盖了钴活性中心，导致Co／SiO2初活性下降；但大部分碳物种并不沉积在钴活性中心上，可能形成了碳纤维生长在载体和钴活性中心之间．     

Ni／SiO2催化剂上间二硝基苯液相加氢制间苯二胺

 将等体积浸渍法制备的Ni／SiO2催化剂应用于间二硝基苯液相加氢制间苯二胺反应中，通过BET，XRD，TEM，TPR，H2－TPD和活性评价等方法对催化剂的物化性质及催化性能进行了研究，考察了镍含量对催化剂活性的影响．结果表明，Ni／SiO2催化剂不仅具有很高的催化活性，而且对间苯二胺表现出很高的选择性；催化剂的活性随着镍含量的不同而有所变化．当w（Ni）＜20％时，随着镍负载量的增加，催化剂的活性逐渐升高，而当w（Ni）≥20％时，催化剂的活性和选择性基本趋于稳定．影响催化剂活性及选择性的主要因素是催化剂的活性比表面积．     

含铜三元类水滑石化合物的合成及其性质

 以Cu（NO3）2，Zn（NO3）2和Al（NO3）3为原料，以NaOH为沉淀剂，利用共沉淀法合成了含铜三元类水滑石化合物CuZnAl－HTLcs．从不同Cu／Zn／Al比的混合原料溶液的滴定曲线入手，详细探讨了溶液pH值、原料加入方式、组分配比及水热处理条件对类水滑石合成的影响，利用XRD，ICP及比表面积测定对合成物进行了表征，并以苯酚羟基化为探针反应评价了催化剂的催化性能．结果表明，在体系pH＝5．0～6．2，（Cu＋Zn）／Al摩尔比＝2．0，Cu／Zn摩尔比≤1．0及室温条件下共沉淀后，于100℃水热处理3h，即可得到晶相单一和结晶度高的CuZnAl－HTLcs．变化pH法合成的样品的相对结晶度为100％，低过饱和法为76．5％，高过饱和法为75．9％．合成的CuZnAl－HTLcs中Cu2＋的含量均比原料液中Cu2＋的含量有所增加，这可能是由于在pH＝5．8时Cu2＋对Al（OH）3的同晶取代能力比Zn2＋强．随着CuZnAl－HTLcs中Cu含量的增加，催化剂对苯酚羟化反应的催化活性逐渐增大．