High-performances membranes for pervaporation I. Poly(vinyl alcohol)–poly(N-vinyl pyrrolidone) blends

Dense membranes were prepared from poly(vinyl alcohol)–poly(N-vinyl pyrrolidone) (PVA–PVP) blends of different compositions and studied in swelling and dehydration by pervaporation of three organic solvents contaminated by 5 wt% water. The swelling generally increases with the PVP content. No extraction occurs in water–tetrahydrofuran (THF) and water–methyl ethyl ketone (MEK) mixtures. In ethanol containing 10 wt% of water, there is no extraction for blends containing less than 40 wt% PVP and an increasing extraction beyond this PVP content. The pervaporation flux of the water–ethanol mixture increases drastically at the same threshold whereas the water permselectivity falls to a low level. The values of the diffusion and permeability coefficients determined from transient permeation of the test water–ethanol mixture exhibit a similar sudden increase at the same PVP content threshold. This singular behavior of the blend membranes is interpreted by a strong affinity of the PVP component to ethanol, combined with a disappearance of crystallites in the blend at this threshold. Consequently the amorphous membrane can swell freely according to the affinity of the PVP component, leading to the observed behavior.     

有机锗(锗-132)的示差脉冲极谱研究

用示差脉冲极谱法,在pH1.30H_2SO_4和3,4-二羟基苯甲醛(DHB)底液中,获得了有机锗(Ge-132)和无机锗Ge(Ⅳ)二个配位吸附极谱波,波峰分别为E_P2-0.62V和E_pl=-0.47V(υs.AgCI/Ag),Ge-132浓度在2.6×10_(-5)～3.1×10_（-3）mol/L范围内,Ge(Ⅳ)浓度在 3.1×10_（-5）～2.1×10_（-4）mol/L范围内分别与峰电流星线性关系.利用该示差脉冲极谱法可同时测定Ge-132和Ge(Ⅳ),用于有机锗营养口服液中Ge-132和Ge(Ⅳ)的测定结果满意.还探讨了Ge-132极谱波的性质,测定了有关动力学参数.     

铁系元素冠醚配合物的研究——V.三氯化铁与4′-溴苯并-15-冠-5固态配合物的合成和性质

本文报导了三氯化铁(水合物)与4′-溴苯并-15-冠-5(L)固态配合物的合成,对合成的新配合物,进行了元素定量分析及摩尔电导测定,并作了红外光谱、紫外光谱,热重和差热以及X-射线粉末衍射分析的性质表征。从而证明,该配合物中FeCl₃与配体L比为1:1,是溶化剂,含有结晶水的固态配合物。     

THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT

Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p-nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate.     

Chemically Sensitive Field‐Effect Transistors and Chemiresistors: New Materials and Device Structures

Electronic sensor technology remains of widespread and intense interest. There are compelling needs to detect chemical species ranging from small molecules dispersed in the gas phase to complex biopolymers in aqueous solution. This review describes some recent advances in three main areas: chemically sensitive resistors (chemiresistors, CRs) including inorganic and organic based devices, field effect transistors (FETs) with semiconducting layers and/or gates with chemical sensitivity, and sensors based on the differential conductivity of nanotubes and nanowires. Results reported in the last two to three years are emphasized, highlighting some current trends in the development of sensors for applications such as diagnostics, process monitoring, and security.     

用XPS研究我国一些煤中有机硫的存在形态

本文用电子能谱（xps）方法研究了我国九个不同牌号煤中有机硫的存在形态，并得到这些煤中各种不同形态硫的结合能数据。根据Lindberg等人所做模型化合物结果，给出了这些煤中硫元素结构能的化学归属。各种煤中硫的存在形态是不同的，有硫醇、硫醚、双硫醚、硫杂环、硫桥和取代基上的硫等。这一研究结果为今后研究煤的分子结构及脱硫方法提供了重要的科学依据。     

希土取代苯基化合物的合成

1970年Hart等利用苯基锂的乙醚溶液与希土氯化物的四氢呋喃悬浮液反应,首次合成了希土苯基化合物(C_6H_5)_3Ln(Ln=Sc、Y),LiLn(C_6H_5)_4(Ln=La、Pr),但没有得到满意的碳氢分析数据,碳的实测值仅为计算值的三分之二左右。其他希土苯基化合物的合成也有报道。为了进一步探索希土芳基化合物的合成方法,希土和芳基之间成键的可能性,我们使用邻甲氧基苯基锂和对甲基苯基锂与希土氯化物反应,试图合成新的希土取代苯基化合物。     

可溶性聚苯胺的合成及研究

本文报道了可溶性聚苯胺(PAn)的合成方法。通过对比可溶和不可溶PAn的导电性、电化学行为及IR光谱,说明它们的分子链基本结构相同。并测得了PAn在DMF-d_7中的~13C-NMR 谱。     

X-ray crystallographic structure and physical properties of the pentacoordinated [TPAFeCl] complex

A new pentacoordinated ferrous compound [TPAFeCl]⁺ (TPA = tris(2-pyridylmethyl)amine) was synthesized from the reaction between H₃TPA(ClO₄)₃ and Fe(PⁿPr₃)₂Cl₂ in MeCN. The unique trigonal bipyramidal [TPAFeCl]⁺ complex was characterized as a S = 2 high spin complex based on the crystallographic structure, magnetic susceptibility, ¹H NMR spectrum and semi-empirical ZINDO/S calculations. Crystal of [TPAFeCl]₂(FeCl₄)(MeCN)₂ was monoclinic with a = 12.019(2) Å, b = 27.550(5) Å, c = 14.138(2) Å, β = 94.168(3)°, V = 4668.9(13) Å³, space group C/c, and the unit cell contained a racemic mixture of Δ and Λ isomers with ferrous tetrachloride anion.     

Chemoenzymatic Synthesis of Cellular Adhesion Tripeptide RGD Precursor in Organic Media

IntroductionA characteristic tripeptide sequence Arg-Gly-Asp(RGD) that is found within fibronectin and other rela-ted adhesion molecules in extracellular matrices(ECM)has received considerable attention from researcherssince it was proved to be a recognit…