Catalytic Para‐Xylene Maximization. V. Toluene Methylation with Methanol and Disproportionation of Toluene Using Pt/ZSM‐5 and Pt/Mordenite Catalysts

Toluene was methylated with methanol and disproportionated using catalysts containing different Pt contents (0.2, 0.4 and 0.6%) supported on H‐ZSM‐5 or H‐mordenite (H‐M) zeolites in a fixed‐bed flow‐reactor operated atmospherically at temperatures of 300–500 °C in a flow of hydrogen. Platinum dispersion in the zeolite supports and acid sites strength distribution were evaluated using hydrogen chemisorption (1:1 stoichiometry) and ammonia temperature programmed desorption (TPD) in a differential scanning calorimeter (DSC). Toluene methylation was much faster on all catalysts than toluene disproportionation (DISP). Both reactions were more accelerated using H‐ZSM‐5 containing catalysts than H‐M containing catalysts. The yield of xylenes, and in particular para‐xylene, was significantly influenced by the yield of trimethylbenzenes (TMBs) in product. The selectivities for para‐, ortho‐ and meta‐xylenes production were found largely dependent on the Pt content in the catalysts, particularly when supported on H‐ZSM5‐zeolite. However, using Pt/H‐M catalysts, these selectivities were not strictly controlled by Pt content in the catalysts.     

熔融萃取法富集痕量铂和铑─石墨炉原子吸收光谱测定

本文报道以２－硫基苯并噻唑（ＭＢＴ）为络合剂，用熔融萘萃取痕量的铂和铑，继用石墨炉原子吸收光谱法直接测定之。文中曾对一些有关参数作了试验，并找出各参数的最优值，对共存离子的允许量也作了试验。最后用国家标样和部级管理样核对本法，结果令人满意。     

A New Family of Binary Layered Compounds of Platinum with Alkali Metals (A = K,Rb, Cs)

By reacting platinum with alkali metals (A = K, Rb, Cs) a new family of binary alkali metal platinides has been synthesized and characterized by chemical analysis, X‐ray powder diffraction, thermal analysis (DTA and DSC), and magnetic measurements. All three compounds exhibit similar XRD‐patterns with strong reflections that can be indexed on the basis of a rhombohedral crystal system (K_xPt: a = 2.6462(1), c = 17.123(1); Rb_xPt: a = 2.6415(1) Å, c = 17.871(1) Å; Cs_xPt: a = 2.6505(1) Å, c = 18.536(1) Å; x < ½. The a lattice constant is independent on the alkali metal used and of value close to the Pt–Pt distance in NaPt₂ (2.645Å). The c parameter increases monotonically with the growing atomic radius of the alkali metal. The average structure of the alloys consists of cubic close packed layers of platinum atoms with layers of disordered alkali metals in between. For all compounds besides the strong reflections small satellites are observed which cannot be indexed together with the rhombohedral peaks in any rational 3‐dimensional lattice. However, these satellites can be indexed as incommensurate modulations within the ab plane (found propagation vectors k = (0.1011, 0.2506, 0) for Cs_xPt, and k = (0.0168, 0.2785, 0) for Rb_xPt).     

Determination of impurities in highly pure platinum by inductively coupled plasma-atomic emission spectrometry

In this work, a cyclone spray chamber system is used in conjunction with an inductively coupled plasma-atomic emission spectrometer instead of the conventional Scott-type chamber system to reduce the lower limit of detection achieved by the instrument, and an internal standard element (Y) is introduced to eliminate the effects caused by the drift in the plasma background level. An ICP-AES method for the determination of 13 impurity elements in a highly pure platinum sample has been developed. In this method, it is not necessary either to add a platinum matrix to the calibration standard or to separate and concentrate the elements to be determined in the samples. The effect of the platinum matrix on the elements to be analyzed is corrected for by a background equivalent concentration subtraction method. The determination ranges of the method are as follows: 0.00010-0.0050% for Mg, Mn, Cu, Ag, Fe and Zn; 0.00030-0.015% for Au, Ir, Ni and Pb; 0.00050-0.025% for Rh and Al; and 0.00080-0.040% for Pd. The method is simple, rapid and accurate, and can be applied to the analysis of 99.9–99.995% pure platinum.     

液芯光纤光度法在乙醇水溶液中测定铂(Ⅱ)、钛(Ⅳ)

采用氟塑料长光纤管，以４２％乙醇水溶液作液芯，组成液芯光纤，基于铂与氯化亚锡、钛与过氧化氢形成黄色络合物在乙醇水溶液中很稳定，拟定了测定铂、钛的液芯光纤光度法。该法灵敏度高，用 １ｍ长光纤作吸收池，铂的灵敏度为 ４． ８４５ Ａ／ｍｇ· Ｌ－１，钛的灵敏度为１．４１Ａ／ｍｇ· Ｌ－１（Ａ为吸光度），与常规法（１ｃｍ）比色皿相比灵敏度提高了 １００倍。该法测定了催化剂中铂，煤灰粉中钛，结果与推荐值相符。     

Tris(2,2''''-bipyridyl)ruthenium(Ⅱ) electrochemiluminescence (ECL) enhanced by rutin on platinum electrode

Ru(bpy)_(3~(2 )) electrochemiluminescence (ECL) was applied to determination of rutin. ECL intensity of Ru(bpy)_(3~(2 ))could be enhanced in the presence of rutin in basic solution on platinum electrode. At pH 9.9, light emission intensity was found to be linear with rutin in the range of 1-50 mmol/L.     

环境和生物样品中铂族金属的分析研究进展

评述了近年来环境和生物样品中痕量铂族金属的分析研究进展，重点介绍了样品的预处理和分离富集技术以及检测手段等。     

Coordination modes of 2-hydroxynicotinic acid in second- and third-row transition metal complexes

The new Pd(II), Pt(II), Re(V), Mo(VI) and W(VI) complexes of 2-hydroxynicotinic acid (H₂nicO), trans-[PdCl(HnicO)(PPh₃)₂]·0.75CH₃CN (1), K[PdCl(HnicO)₂]·H₂O (2), [Pd(HnicO)₂(bipy)] (3), cis-[PtCl(HnicO)(PPh₃)₂]·0.75CH₃OH·0.5H₂O (4), [PtCl(HnicO)(bipy)] (5), cis-[ReOI₂(HnicO)(PPh₃)] (6), Na₂[Mo₂O₆(HnicO)₂]·5H₂O (7), Na₂[Mo₄O₁₂(HnicO)₂]·2H₂O (8) and Na₂[W₂O₆(HnicO)₂]·5H₂O (9) have been prepared. The crystal structures of 1 and 4, were determined by X-ray diffraction and show the HnicO⁻ ligand coordinated to palladium or platinum through the nitrogen atom only. Infrared, Raman, ¹H and ¹³C{¹H} NMR spectroscopic data for the complexes are presented and are in agreement with the crystallographic results.     

四苯硼钠-甲苯胺蓝缔合物纳米微粒体系减色效应研究

在PH4.0醋酸-醋酸钠介质中，甲苯胺蓝在600nm处有一个吸收峰，随着四苯硼钠浓度的增大甲苯胺蓝在600nm处吸收峰降低，颜色减弱，这是由于甲苯胺蓝-四苯硼钠缔合物分子间存在较强的疏水作用及分子间作用力，聚集形成纳米微粒所致，甲苯胺蓝-四苯硼钠纳米微粒体系亦在600mm处有1个吸收峰，在400mm、470mm和580mm处产生3共振散射峰，其中400mm和580mm为甲苯胺蓝-四苯硼钠复合纳米微粒产生的特征共振散射峰，这也表明有纳米微粒存在，丙酮浓度的影响实验结果等表明，纳米微粒的形成是产生其减色效应的原因。