负载型Au催化剂的研究进展

金一直被认为是一种相对惰性的化学元素，但是近年来的研究发现，金催化剂对于CO及VOCs的低温氧化表现出很高的催化活性。本文综述了近年来金催化剂研究的进展情况，系统介绍了金催化剂的制备方法，以及金催化剂在不同反应中的催化活性和反应的机理。     

Synthesis, characterization, and catalytic properties of polysiloxanes with pendant 4-(3-pyridinyl)butyl and 4-(1-oxypyridin-3-yl)butyl groups

New silane monomers with the pendant 4-(3-pyridine)butyl group have been synthesized by hydrosilation of 3-(3-butenyl)pyridine with Me _n Si(OEt)_3-n H (n=0, 1) using a platinum catalyst. Only -addition products were observed. The products were characterized by elemental analysis, infrared,¹H- and¹³C-NMR spectroscopy, and gas chromatography-mass spectrometry. Hydrolysis-polycondensation of the difunctional monomer with a basic catalyst, Me₄NOH, gave a mixture of cyclic oligomers, principally cyclic tetramer, and linear homopolymer. Under similar reaction conditions, the trifunctional monomer gave crosslinked material which was soluble in common organic solvents. The linear homopolymer and crosslinked polymer were trimethylsilyl end-blocked with hexamethyldisilazane. The cyclic and end-blocked polymers were characterized by elemental analysis and spectroscopic methods. Molecular weights of the polymers were obtained by end-group analysis using¹H-NMR spectral data, size exclusion chromatography, and direct insertion-probe mass spectrometry. The cyclic, linear, and crosslinked materials were N-oxidized withm-chloroperoxybenzoic acid and characterized by spectroscopic methods. The polymeric N-oxide derivatives were shown to be effective transacylation catalysts in the synthesis of mixed carboxylic acid anhydrides in immiscible solvents (H₂O/CH₂Cl₂) under phase-transfer conditions. The implications of the results on the mechanism of catalysis are discussed.     

Production of agrochemical from waste polyesters

In this study, agrochemical was produced from waste polyesters. Reactions of waste polyesters [poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT)] powder with ethylene glycol (EG) in the presence of tetrahydrofurane (THF) using 0.003 mol lead acetate as a catalyst were carried out in a batch reactor at 470 K and at atmospheric pressure conditions. Reactions were undertaken with various particle size ranges from 50 to 512.5 μm, and reaction time from 30 to 70 min for reactions of polyesters. Low molecular weight product of polyester was obtained during this process. In the next stage, hydroxylamine hydrochloride (HAHC), cyclohexylamine (CHA), and potasium hydroxide (KOH) solution were introduced to convert low molecular weight product of polyester into terephthalohydroxamic acid (TPHA) by introduction of HCl (Hydrochloric Acid) as per stoichiometric requirement. TPHA can be used as an agrochemical (insecticide) with appreciable efficiency. To increase the polyester conversion rate, external catalyst (0.003 mol lead acetate) was introduced during the reaction. The product was deposited on the surface of unreacted polyester, which was removed from the surface by introducing dimethyl sulfoxide (DMSO). To accelerate the reaction rate, DMSO, CHA, and THF were introduced during the reaction, which has an industrial significance. Depolymerization of polyester was proportional to the reaction time. Depolymerization of polyester was inversely proportional to the particle size of polyester. Analyses of value‐added product (TPHA) and byproducts [EG and BD (1,4‐butanediol)] as well as polyesters were undertaken. A kinetic model is developed, and experimental data simulated with it, which was consistent with the model. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2504–2510, 2006     

含给电子Z-N催化剂催化乙烯/1-丁烯共聚的研究

研究了两种含有给电子体分别为对硝基苯胺、乙二醇二甲醚的Ziegler-Natta催化剂催化乙烯与1-丁烯高压的共聚反应性能,主要考察了反应条件对聚合活性、聚合物物理性质的影响,同时采用红外光谱法测定了聚合物的支化度.研究表明,给电子体为乙二醇二甲醚的催化剂催化活性高于对硝基苯胺.反应条件如反应压力、温度、铝钛比对聚合活性、丁烯的插入率以及聚合物性质都有明显影响.高的反应压力有利于1-丁烯插入和聚合物堆密度的提高;反应温度在50℃时的聚合活性最大,聚合物的支化度较高,聚合物熔点较低;铝钛比为500时聚合活性高于低铝钛比的聚合活性.     

铝合金中锌、铁的快速测定--原子吸收分光光度法

样品以盐酸溶解，加入过氧化氢助溶，蒸至近干．加入1 1盐酸提取，移入100mL容量瓶中，分取部分溶液于50mL容量瓶中，调整盐酸酸度为5％，用水稀至刻度，摇匀后，以空气-乙炔火焰水相直接测定锌和铁。为了消除大量基体元素的影响，在标准系列中加入相当量的铝。此方法快捷、简便，亦可用于锰、镁、铜、铅、镍的测定。     

以888-JH为催化剂Na_2CO_3为碱源的脱硫技术

本文着重介绍以888-JH为催化剂,Na2CO3为碱源焦炉煤气(COG)湿式氧化法脱硫工艺的脱硫原理、影响因素,并介绍了现场试验结果。认定单独使用888-JH可以替代PDS+RTS获得脱硫效率99%以上和出口H2S含量小于5mg/m3的较佳脱硫效果。     

An EXAFS study of the Mo/TiO2 hydrodesulphurization catalysis

In-situ EXAFS studies of sulphided Mo/TiO₂ catalysts have shown that at low Mo loadings (2–4 wt%), an active species with a short Mo-S distance of 2.25 Å is formed, while on Mo/TiO₂ with high Mo loadings as well as on Mo/-Al₂O₃, bulk MoS₂ (Mo-S, 2.42 Å) is formed. The species with the short Mo-S distance has Mo in an oxidation state close to 6 + and is likely to result from the sulphidation of the tetrahedral molybdate species present in the oxidic precursor at low Mo loadings. The calcination temperature of the oxidic precursor appears crucial, a high calcination temperature of 973 K favouring the formation of MoS₃ on sulphidation, and a low calcination temperature of 623 K favouring MoS₂.Contribution No. 790 from the Solid State and Structural Chemistry Unit.     

熟料烧结过程中氧化铁反应行为的热力学分析

通过对Fe2O3与碳酸钠、氧化钙以及硅酸钙反应的热力学分析,明确Fe2O3在铝土矿炉料烧结过程中的热力学反应规律。热力学计算、分析结果表明:Fe2O3在正常烧结温度范围内能与Na2CO3或CaO发生反应,但更易与CaO反应形成2CaO.Fe2O3或CaO.Fe2O3,Fe2O3和Na2O.Fe2O3能使2CaO.SiO2和3CaO.2SiO2转变为CaO.SiO2,CaO.SiO2进一步与Na2O.Al2O3或Na2O.Fe2O3反应生成不溶的三元化合物而造成烧结法生产氧化铝过程中Na2O和Al2O3的损失。4CaO.Al2O3.Fe2O3不能由铁酸钙和铝酸钠相互反应产生,而可能是CaO、Al2O3和Fe2O3三者直接反应的产物,且在烧结条件下Na2O.Fe2O3可分解4CaO.Al2O3.Fe2O3。     

Ni-Cr-Fe-Si-B合金涂层及铝青铜基体熔合区组织的研究

采用钨极氩弧焊方法在铝青铜基体上施焊了Ni—Cr-Fe-Si—B合金涂层，并运用金相显微镜、扫描电子显微镜及能谱分析了喷涂层、熔合区及热影响区的组织形貌和成分分布。结果表明，喷焊时，在涂层与基体界面两侧各组元均发生了明显的扩散，Cu、Ni组元间可相互取代，基体融合区组织的基本组成仍为α (α γ2)，但同时也形成了Cu2FeAl7、NiAl3等新相，且融合区组织细小，涂层与基体间为冶金态结合。