KF/Al~2O~3/PEG 4000(FAP)存在下氯仿的Michael加成反应

在KF/Al~2O~3/PEG4000(FAP)存在下,氯仿可与α,β-不饱和羰基化合物进行Michael加成反应,得到中等产率的三氯甲基化合物。     

A New Application of Carbon Nanotubes Constructing Biosensor

Carbon nanotubes used for constructing biosensor was described for the first time. Single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups were used to immobilize glucose oxidase forming a glucose biosensor. The biosensor response can be determined by amperometric method at a low applied potential (0.40V).     

贵金属同时浮选分离富集行为的研究及ICP－AES的测定

本文通过对贵金属－碘化钾－孔雀绿显色体系的浮选行为研究，建立了一种同时浮选富集分离铂、钯、铑、铱、金的新方法。实验结果表明，在０．３６ｍｏｌ／ＬＨＣｌ０．１ｍｏｌ／ＬＫＩ和２．４×１０￣（－４）ｍｏｌ／ＬＭＧ的溶液中，加入环已烷振荡１ｍｉｎ，铂、钯、铑、铱、金可被定量浮选，继而用ＩＣＰ－ＡＥＳ测定。对含量为５～１５０μｇ的贵金属，浮选回收率分别为铂８８．６％～９５．７％，钯９２．３％～９９．５％，铑９３．７％～１０１％，铱９２％～９８．５％，金８６．４％～９４％。方法应用于铜镍矿、铂网废料等物料中上述贵金属元素的测定，结果满意。     

Kinetics of the transformation process of PbSO4 to PbO2 in a lead anodic film

The kinetics of the nucleation and growth of PbO₂ during the potentiostatic oxidation of PbSO₄ in a lead anodic film was studied using linear sweep voltammetry, potential-step and ac impedance tracing methods. The film investigated is the partially reduced anodic PbO₂ film formed by polarizing a lead electrode in 4.5 M H₂SO₄ solution first at 1.3 V vs. Hg|HgSO₄ for 20 min and then at 0.9 V for 5 min. The nucleation and growth process begins some time after the potential step and is completed within 60 s. The pre- and post-nucleation and growth processes correspond to the growth of the anodic film formed by the oxidation of the lead substrate. The mathematical equations representing the current-time and capacitance-time transients are derived taking the background oxidation current into account. The experimental results are well fitted by these equations. The process obeys the laws of two-dimensional instantaneous nucleation and growth.     

A Study of Multi-order Semidifferential Oscillographic Chronopotentiometry

ASemiintegralelectroanalysishasbeenimprovedanddevelopedsinceOldhamlwhofirstintroduceditinl972,andiswidelyaPpliedtoseveralkindsofpolarographicanalysis"'suchaslinearsweepvoltammetry,cyclicvoltammetryandanodicstrippingvoltanunetry.Anewfieldinelectroanalysis,neopolarographicmethod,isformed.Thismethodhasmanyadvantages,forexample,highsensitivity,goodresolvingpower,simPlicityofinstrUmentstructureandlowcost.Itissuitableforthestudyoffastanalysisandfastelectrodereaction.Determinationcanbecarriedouteve…     

手性双氨基醇-Et2Zn催化的不对称直接羟醛缩合反应

以1,3-二溴丙酮和(2'S)-(二苯基羟甲基)-四氢吡咯为原料,合成了两种新型手性氨基醇1,3-双[(2'S)-(二苯基羟甲基)-1-四氢吡咯基]丙酮(3)和1,3-双[(2'S)-(二苯基羟甲基)-1-四氢吡咯基]-2-丙醇(4),总产率分别为39%和35%.手性双氨基醇3-/4-Et2Zn可催化未修饰醛、酮的不对称直接羟醛缩合反应,对映体过量最高9%.     

小波变换用于高效液相色谱的基线校正

本文根据小波变换将信号分频的性质，用Ｄａｕｂｅｃｈｉｅｓ小波成功地解决了高效液相色谱中基线校正问题，用于定量分析乳酸－稀土络合物体系中的十六个稀土元素，所得结果与仪器给出了结果进行比较，准确度提高，重现性良好。     

十六烷基三甲基溴化铵水溶液热致相变的红外光谱研究

在280～320K的温度范围内考察了30％十六烷基三甲基溴化铵水溶液的红外光谱随温度的变化。结果表明该体系的凝聚胶-液晶相转变温度为300K。在300K以下的凝聚胶相,分子的极性头部基团处于高度“固定”的状态,分子的碳氢链以有序的相互平行方式排列,极性头与碳氢链之间有一定的倾斜角。在300K以上的液晶相,极性头内部CH_3-(N~+)基团以及整个极性头与碳氢链之间发生了旋转,碳氢链变为以六方亚晶胞填充形式存在,旦扭曲式构象异构体数量显著增多,极性头与碳氢链之间已不存在倾斜角,分子的亲水极性头和疏水碳氢链部分都处于“融化”状态。     

K2CO3—KOH溶液中Tb（Ⅲ）氧化产物的组成

由于E_(Tb~(4 )/Tb~(3 ))~0= 3.1V,使得Tb(Ⅳ)很难以简单离子的形式存在于水(E_(1/2O_2 2H~ )= 1.22V)溶液中。要从水溶液中获得稳定的Tb(Ⅳ),必须降低其平衡电位,通常采用生成难溶盐、配合物或溶胶等方法。 Tb(Ⅳ)化合物最初多以焙烧法制备。Prost在2.5mol/L K_2CO_3-0.5mol/LKOH溶液中用电化学氧化法制得了Tb(Ⅳ)的聚合物,并求得在此条件下E_(Tb~(4 )/Tb~(3 ))=     

A Novel Asymmetric Synthesis of （-）-cis-1, 3-Dibenzylhexahydrofuro[3, 4-d]imidazole-2,4-dione

(-)-cis-1, 3-Dibenzyl-hexahydrofuro[3, 4-d]imidazole-2, 4-dione was prepared by a new synthesis method from meso dicarboxylic acid and dehydroabietylamine by asymmetric reduction in good yield with up to 91.6% e.e. value.