两种形貌的介孔SiO2对纤维素内切酶吸附性能的研究

以EDTA2-、SO42-作为反离子分别合成了具有管状和圆盘状结构的介孔SiO2,并测定了2种介孔SiO2焙烧至不同温度时的表面积、孔体积参数,及其等电点;通过752分光光度计在550nm处测定纤维素内切酶的吸光度,研究了2种形貌的介孔SiO2对纤维素内切酶的吸附性能,同时测定了固定酶的活性。结果表明,管状和圆盘状结构的介孔SiO2对纤维素内切酶的吸附等温线分别为Ⅱ和Ⅰ型;介孔SiO2焙烧至700℃时,两者皆为Ⅱ型;至850℃时,前者转化为Ⅰ型,而后者转化为Ⅴ型。吸附等温线类型与介孔SiO2的结构、等电点以及酶分子尺寸与介孔尺寸的相匹配有关。酶经过介孔SiO2吸附固定后,稳定性明显提高;其中,管状结构的介孔SiO2对酶具有最大的负载量,但固定酶的活性却较低。     

Eco-friendly synthesis of 2-substituted-2,3-dihydro-4(1H)-quinazolinones in water

2-Substituted-2,3-dihydro-4(1H)-quinazolinones were synthesized in high yield by condensation of 2-anthranilamide with aromatic aldehydes or ketones in refluxing water without catalyst.This protocol has advantages of high yield,simple work-up and environmental friendly procedure.     

The first catalytic asymmetric addition of diethylzinc to aldehyde promoted by chiral thiourea

A series of C₂-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial L-phenylalanine.All of the new compounds have been fully characterized by IR,¹H NMR,¹³C NMR,MS spectra and elemental analyses.The chiral thioureas were used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc,the corresponding sec-alcohols were gained with excellent enantioselectivities（up to 87.1%ee） and high yields（up to 76.7%） after the conditions were optimized.     

Melamine-(H_2SO_4)_3 and PVP-(H_2SO_4)_n as solid acids:Synthesis and application in the first mono-and di-nitration of bisphenol A and other phenols

Melamine and poly vinylpyrrolidone（PVP） reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-（H₂SO₄）₃ and PVP-（H₂SO₄）_n.These solid acids were used for the first nitration of bisphenol A as well as other phenols in the presence of NH₄NO₃.Mono- and di-nitro bisphenol A have been characterized with IR and ¹H NMR techniques.     

Study on supported combined liquid membrane containing HEH（EH）P and HNO3 for trivalent gadolinium transfer

A novel kind of supported combined liquid membrane（SCLM） has been studied for the Gd（Ⅲ） transfer.SCLM contained polyvinylidene fluoride membrane（PVDF） as the liquid membrane support and renewal solution including HNO₃ solution as the stripping solution and 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester（HEH（EH）P） as the carrier dissolved in kerosene. The mixed solution of carrier and kerosene was membrane solution.The optimum transport conditions of Gd（Ⅲ） were that concentration of HNO₃ solution was 4.00 mol/L,concentration of carrier was 0.16 mol/L,and volume ratio of membrane solution to stripping solution was 30:30 of the renewal phase,and pH value was 4.80 of the feed phase.Under the optimum condition studied, when initial concentration of Gd（Ⅲ） was 1.00×10^-4 mol/L,the transfer rate of Gd（Ⅲ） was 96.8%during 130 min.     

A highly selective and easy-to-synthesize Zn(Ⅱ) fluorescent probe based on 6-methoxyquinolin

A novel fluorescent Zn²⁺ probe based on 6-methoxyquinolin was synthesized in four steps from inexpensive starting materials.It exhibits very strong fluorescence responses and has a remarkably high selectivity to Zn²⁺ than other physiological relevant metal ions.This new compound could be used as low-priced yet high-quality Zn²⁺ probe.     

Lu2O3纳米粉体和透明陶瓷中掺杂Nd3+的局域结构研究

利用扩展X射线吸收精细结构光谱(EXAFS)研究了不同掺杂浓度Nd3+:Lu2O3纳米粉体和透明陶瓷中Nd3+的局域结构.结果表明,在不同条件下Nd3+均以固溶取代Lu3+的方式进入Lu2O3基质晶格,掺杂Nd3+原子的第一配位键长约为0.225 nm,小于Nd2O3纳米粉中Nd-O第一近邻键长0.251 nm,而大于...     

4-氧-3-氮杂-三环[5.3.1.02,5]十一烷-9-甲酸甲酯的合成及晶体结构

以2-金刚烷酮为起始原料,通过烯烃与氯磺酰异氰酸酯的[2+2]环加成等5步反应合成了新型双环β-内酰胺类化合物5.采用1H NMR,IR和MS等手段对所得化合物的结构进行了表征.此外,还通过将化合物5酰化并采用X射线单晶衍射分析方法进一步测定了化合物5的空间立体结构.结果表明,烯烃3与氯磺酰异氰酸酯的[2+2]环加成反...     

中空Fe203/G-NS纳米复合材料的制备和储锂性能

以三氯化铁和氧化石墨烯(Graphite oxide,GO)为原料,采用水热法一步合成了中空Fe2O3/石墨烯(Graphene nanoslheet,GNS)纳米复合材料.研究结果表明,Fe2O3/GNS纳米复合材料的形成是由于Fe3+催化氧化GO中的羧基等官能团释放出CO2,并以原位形成的CO2气泡为模板形成了中空...     

以泡沫镍载NiCo2O4纳米线阵列为阴极催化剂的Al-H2O2半燃料电池

研究了以泡沫镍载NiCo2O4纳米线阵列为阴极催化剂的Al-H2O2半燃料电池的性能. 以无模板生长法制备了泡沫镍载NiCo2O4纳米线阵列阴极材料, SEM测定结果表明, NiCo2O4纳米线几乎垂直于泡沫镍载体表面生长. 以电压和功率密度-电流密度曲线研究了H2O2浓度、电解液流速和温度对电池性能的影响, 结果显示, 以铝片为阳极, 0.6 mol/L H2O2为氧化剂的电池的开路电压约为1.40 V; 在室温和57 ℃下, 电流密度为98和172 mA/cm2时, 最大功率密度分别达到79和120 mW/cm2.  在5000 s的测试时间内, 0.70 V的恒电流密度和75 mA/cm2 的恒电压值几乎为一常数, 这表明以泡沫镍载NiCo2O4纳米线阵列为催化剂电还原H2O2具有很好的活性、稳定性和传质性能.