Kinetic investigation of the textile bleaching process

Volumetric H₂-uptake measurements on an Mo₂N (79 m²g^–1) sample reduced at 673 K have been carried out and the uptake isotherms in the temperature range of 308–623 K have been determined. Both the total and reversible hydrogen uptake increased with the uptake temperature. The irreversible hydrogen uptake increased abruptly when the uptake temperature was raised up to 423 K. The maximum of irreversible hydrogen uptake was measured at 473 K. The H_IR/Mo ratio calculated from the uptakes obtained in the temperature range of 308–623 K varies in the range of 0.0010–0.0202. One possible mechanism for hydrogen adsorption is proposed to be heterolytic dissociation on Mo-N paris, in which the molybdenum atoms are in unsaturated coordination.     

新显色剂二溴硝基苯基重氮氨基偶氮苯的合成及与镉的显色反应的研究

作者合成了新显色剂2,6-二溴-4-硝基苯基重氮氨基偶氮苯(DBNDAA)。在pH8.5的硼砂-盐酸缓冲介质中,在Tween 80-SDBS存在下,该试剂与镉(Ⅱ)生成络合比为3:1的红色络合物,λ_(max)=500nm,ε_(500)=1.52×10~5L·mol~(-1)·cm~(-1)。镉量在0～28μg/25ml范围内遵守比耳定律。并测定了试剂的表观离解常数和络合物的表观不稳定常数。方法有良好的选择性。用该试剂测定了铝合金标样、环境水样及废水中的痕量镉,结果满意。     

Determination of silicon by an indirect atomic-absorption method using carbon-rod electrothermal atomization

An indirect procedure has been developed for the determination of trace amounts of silicon by atomic-absorption with carbon-rod electrothermal atomization. After dissolution, the silicon is extracted as silicomolybdic acid into a mixture of diethyl ether and pentan-1-ol (5 + 1). The co-extraction of excess of molybdate reagent is prevented by the addition of citrate, which also destroys phosphomolybdic and arsenomolybdic acids. The organic layer is washed with hydrochloric acid, mul quantities are transferred to the electrothermal atomizer and the molybdenum is measured. The method has been applied to analysis of several steels.     

某些含二维液晶基元的热致液晶高分子的向列态纹影响构

发现某些含二维液晶基元的热致液晶高分子容易产生反向壁织构与含有高强度有错点（│Ｓ│大于１）的向列态纹影织构。这类液晶高分子的织构与形态学特点与含一维棒状液晶基元的其他液晶高分子不同。     

Design,Synthesis, and Characterization of Photolabeling Probes for the Study of the Mechanisms of the Antiviral Effects of Ribavirin

Ribavirin, the only small molecule available so far for treating hepatitis‐C‐virus infection, was recently used in an emergency context to treat patients with severe acute respiratory syndrome (SARS) in the early stages of the disease. To study the mechanisms responsible for the antiviral effects of ribavirin by using a photolabeling approach, we designed, synthesized, and characterized the azidotriazole nucleosides 1 and 2 as photolabeling probes of ribavirin. These probes were synthesized either by performing nucleophilic substitution of the corresponding bromotriazole nucleoside with NaN₃ (Scheme 2) or by directly coupling the azidotriazole with the protected ribose sugar (Scheme 4). The azidotriazole nucleosides 1 and 2 showed a fast, clear‐cut photochemical reaction, which suggests that they are promising candidates for use in photolabeling studies.     

μ酰基铁硫配合物亲核取代反应的研究——若干三苯膦或三苯胂μ酰基铁硫配合物的合成及结构

μ-酰基铁硫配合物(μ-ArCO)(μ-RS)Fe_2(CO)_6和PPh_3在苯中迴流2小时, 或和AsPh_3在苯中迴流12小时可分别制得相应的单取代衍生物(μ-ArCO)(μ-RS)Fe_2(CO)_5 PPh_3(Ar=Ph, R=Et或B_u~t; Ar=p-ClC_6H_4, R=B_u~t)和(μ-ArCO)(μ-RS)Fe_2(CO)_5AsPh_3(Ar=Ph, R=Et或B_u~t).除用碳氢分析, IR和~1HNMR光谱表征了这五个新取代衍生物的结构外, 还测得一个代表物(μ-p-ClC_6H_4CO)(μ-B_u~t S)Fe_2(CO)_5 PPh_3的单晶结构. 该晶体属三斜晶系, 空间群P1. 晶胞参数a=1.0536(2), b=1.1714(4), c=1.4841(8) nm; α=98.47(4), β=102.70(4), γ=105.78(3)°; V=1.6771 nm; Z=2; D_C=1.468 g·cm~(-3). 最终偏离因子R=0.065.     

Synthesis, Characterization and Catalysis of New Pillared Anionic Clays by [GaW_(11)O_(39)M(H_2O)]~(7-)(M=Mn~(2 ),Co~(2 ) or Ni~(2 ))

ＩｎｔｒｏｄｕｃｔｉｏｎＡｎｉｏｎｉｃｃｌａｙｓ（ｌａｙｅｒｅｄｄｏｕｂｌｅｈｙｄｒｏｘｉｄｅｓ）ａｒｅｉｍｐｏｒｔａｎｔｌａｙｅｒｅｄｍａｔｅｒｉａｌｓ．Ｔｈｅｇｅｎｅｒａｌｆｏｒｍｕｌａｉｓ［Ｍ２＋（１－ｘ）Ｍｘ３＋（ＯＨ）２］ｘ＋Ａｎ－ｘ／ｎｍ...     

Determination of V(V), Nb(V) and Ta(V) as their 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol chelates by reversed-phase HPLC

This paper reports the separation and determination of V(V), Nb(V) and Ta(V) by RP-HPLC using 5-Br-PADAP as a precolumn derivatizing reagent. On C(18) column, the three metal chelates can be separated on a baseline in 9 min with the mobile phase of methanol-water (59:41, v/v) containing tartaric acid (0.2%) and acetate buffer (pH 3.5, 10 mM). The detection limits of V(V), Nb(V) and Ta(V) are 0.13 ppb, 0.22 ppb and 1.79 ppb, respectively when S/N is 3. This method is simple and rapid, and has been used in mineral analysis with satisfactory results.     

Nickel-promoted ligand-free palladium-catalyzed Suzuki coupling reaction

Summary A Ni-promoted ligand free palladium catalyst system for Suzuki coupling of aryl bromides has been developed in high efficiency under mild reaction conditions. It was obtained in situ by introducing NiCl₂ to PdCl₂/PVP using a parallel high-throughput screening technique. A wide range of aryl bromides bearing a variety of functional groups was evaluated.     

CeO2—LnO1.5固溶体的表征及其甲烷催化燃烧性能

向CeO2中引入Ln3 离子后形成的CeO2－LnO1.5（Ln=La，Nd，Sm，Gd）固溶体（n（Ce）：n（Ln）=1：1）是一种无贵金属的新型高效甲烷燃烧催化剂．比表面、XRD、Raman、TEM等分析证实，这类固溶体具有部分畸变的萤石结构，Ln3 进入晶格后诱发的结构变化使得团溶体的表面和本体能同时参与氧化还原反应．实验表明，该固态溶液体系是甲烷催化燃烧的良好催化剂．