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准确测定废弃环保催化剂中铂、钯、铑含量,是实现废弃环保催化剂贵金属高效回收和处置的重要保障技术条件之一,对回收铂族金属、湿法冶金生产物料平衡考察、保证买卖双方公平、公正交易等都具有重要的意义。采用碱熔分解废弃环保催化剂样品,碲共沉淀富集铂、钯、铑并与共存离子分离,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定铂、钯、铑含量。结果表明,在1.2~2.7 mol/L盐酸体系中,加入碲沉淀剂,以二氯化锡为还原剂,能完全沉淀富集铂、钯、铑。铂、钯、铑校准曲线的线性范围为0.50~50.00 μg/mL,线性相关系数分别为0.99998、0.99996、0.99997;铂、钯、铑的检出限分别为2.6 μg/g、0.9 μg/g、1.2 μg/g;方法中铂、钯、铑的测定范围为25~25000 μg/g。按照实验方法测定废弃环保催化剂中铂、钯、铑,结果相对标准偏差(RSD,n=11)为0.2%~3.6%;加标回收率为96%~109% 相似文献
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5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯与铑显色反应的研究 总被引:11,自引:0,他引:11
本文报道以5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯(5-NO_2-PADAT)作分光光度法测定铑的新显色剂.结果表明,在PH 4.1及~6.5的乙酸-乙酸钠缓冲介质中,5-NO_2-PA-DAT与铑形成 2:1的紫红色络合物.该络合物在 1.8 mol/L高氯酸溶液中则转变为另一型体的蓝色络合物,最大吸收波长红移至583nm,表观摩尔吸光系数增至1.7×10_5L·mol_(-1)·cm(-1).以EDTA为掩蔽剂,大量的常见金属离子对测定无干扰.铑浓度在0~0.64μg/mL范围内遵守比尔定律.所建立的方法用于催化剂中微量铑的测定,结果满意. 相似文献
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高分子铑配合物(PYBRh)催化甲醇羰基化为乙酸和乙酸酐的动力学研究 总被引:4,自引:1,他引:4
采用2-乙烯吡啶-丁烯酮共聚物为配体,与四羰基二氯二铑形成顺二羰基铑(I)配合物(PYBRh),用于催化甲醇羰基化制备乙酸和乙酸酐的反应动力学研究。结果表明,其对反应物甲醇和一氧化碳均为零级反应,在一定范围内,对高分子铑催化剂及助催化剂碘甲烷均为一级反应,极性溶剂的加入可以提高甲醇羰基化速度。通过实验结果计算了其反应活化能,活化熵和热焓研究证明其反应机理与小分子铑催化剂相似。 相似文献
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4-(5-硝基-2-吡啶偶氮)-1,3-二氨基苯与铑(Ⅲ)显色反应的研究及其应用 总被引:1,自引:0,他引:1
研究了新合成试剂4-(5-硝基-2-吡啶偶氮)-1,3-二氨基苯(5-NO2-PADAB)与铑(Ⅲ)的显色反应.结果表明,在pH 3.3~4.7的乙酸-乙酸钠缓冲介质中,5-NO2-PADAB与铑形成2∶1的紫红色络合物,其最大吸收波长位于524 nm.该络合物在1.2 mol/L HClO4介质中可质子化转变为另一种型体的紫蓝络合物,最大吸收波长红移至580 nm,其表观摩尔吸光系数提高至1.52×105 L·mol-1·cm-1,以EDTA为掩蔽剂,大量常见金属离子不干扰测定.铑含量在0~0.8 μg/mL内符合比尔定律.所拟方法可应用于催化剂中微量铑的测定. 相似文献
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[顺-二羰基(N-2-(2-吡啶)乙基对取代苯胺)铑]的四苯硼酸盐作为催化剂,用于催化甲醇羰基化反应,在温和的条件下,可顺利催化甲醇羰基化反应得到乙酸和乙酸甲酯而无其它副产物.若以甲醇和乙酸的混合液作反应物,则得到乙酸酐和乙酸甲酯.即使在大量水存在下,也仅有微量的水煤气转换反应发生.实验证明对位取代基团的电子效应对铑配合物的催化活性影响甚微.在不同位置以不同链长相联的二吡啶配体对铑阳离子配合物性能的影响是明显的.其中α,α'-联吡啶铑阳离子结构不利于催化反应的进行.由此证明,作为催化剂活性物种除必须的Rh-CO键存在外,配体的空间结构是影响配合物活性的决定因素.羰基化发生在碘甲烷的氧化加成与乙酰碘的还原消除之间,同时还伴有一个在配位的乙酰基与铑的顺-空配位之间甲基的1,2移动变化. 相似文献
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双金属配合物催化甲醇羰基化反应 总被引:2,自引:0,他引:2
铑的配合物用于催化甲醇羰基化反应以制备乙酸及乙酸酐,已被成功地应用于工业生产。然而,由于铑的价格昂贵,非铑型催化剂的研究引起人们极大的兴趣。对于甲醇羰基化反应而言,多种过渡金属的相应配合物都表现出一定的活性[1]。其中两种金属共存的双金属催化剂的性能... 相似文献
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T. M. Ivanova A. V. Shchukarev A. V. Naumkin A. A. Sidorov M. A. Kiskin V. M. Novotortsev I. L. Eremenko 《Russian Journal of Inorganic Chemistry》2008,53(12):1929-1933
Manganese trimethylacetate complexes with different ligand environments were studied by X-ray photoelectron spectroscopy (XPS). Changes in the Mn 2p, C 1s, O 1s, and N 1s X-ray photoelectron spectra caused by the substitution of Mn → N coordination bonds for Mn → O coordination bonds were examined. In the spectra of manganese trimethylacetate complexes, the satellite component was identified, which is evidence of the high-spin state of manganese atoms. An increase in the magnetic moment of the manganese complexes, both with the oxygen and mixed oxygen-nitrogen environment, is accompanied by an increase in the spin-orbit splitting, the difference in E b between the satellite and the Mn 2p 3/2 line, and the ratio between the integrated intensities of the satellite and the Mn 2p 3/2 line (I sat3/2/I Mn 2p 3/2). The XPS data made it possible to determine the measure of covalence of the metal-ligand bond. The XPS results are consistent with X-ray crystallography data. 相似文献
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A. V. Belyaev 《Russian Journal of Inorganic Chemistry》2018,63(2):162-168
A simple method is developed for synthesizing [Rh(H2O)6]F3. 3H2O with a yield of 80–90%. 19F, 103Rh, and 17О NMR spectroscopic studies show that the following three processes simultaneously run in the Rh(III)–HF/K–H2O system via parallel routes: the formation of mononuclear aquafluoro complexes [Rh(H2O)6]3+ + F–→ [Rh(H2O)5F]2+ + H2O; the formation of aquahydrofluoro complexes [Rh(H2O)6]3+ + HF2-→ [Rh(H2O)5HF2]2+ + H2O; and hydrolysis of the aqua ion followed by coordination of fluoride ion and condensation of the hydroxo species [Rh(H2O)6]3+ + 2F– → [Rh(H2O)4(OH)F]+ + HF → condensation. [Rh(H2O)6]3+ and [Rh(H2O)5F]2+ are the two species making a major contribution to the material balance at high acidity under equilibrium conditions. Parameters of the 19F NMR spectra of individual complex species are presented. 相似文献
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T. N. Aksamentova N. N. Chipanina M. G. Voronkov E. A. Grebneva A. I. Albanov O. M. Trofimova S. A. Mukha B. G. Sukhov 《Russian Journal of General Chemistry》2009,79(1):98-103
A new six-coordinate silicon compound, (C=O→Si←O′=C′)bis(2-methyl-4-oxopyran-3-yloxy)-difluoro(λ6)siliconium, containing two five-membered rings closed by C=O→Si coordination bonds, forms o protodesilylation trifluoro(phenyl)silane with 3-hydroxy-2-methylpyran-4-one (maltol). According to multinuclear NMR and IR spectral data and quantum-chemical calculations, the silicon atom in this compound has an octahedral environment with two cis-arranged C=O→Si bonds 相似文献
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Gas phase catalytic reactions involving the reduction of N(2)O and oxidation of CO were observed at the molecular level on isolated neutral rhodium clusters, Rh(n) (n = 10-28), using mass spectrometry. Sequential oxygen transfer reactions, Rh(n)O(m-1) + N(2)O → Rh(n)O(m) + N(2) (m = 1, 2, 3,…), were monitored and the rate constant for each reaction step was determined as a function of the cluster size. Oxygen extraction reactions by a CO molecule, Rh(n)O(m) + CO → Rh(n)O(m-1) + CO(2) (m = 1, 2, 3,…), were also observed when a small amount of CO was mixed with the reactant N(2)O gas. The rate constants of the oxygen extraction reactions by CO for m ≥ 4 were found to be two or three orders of magnitude higher than the rate constants for m ≤ 3, which indicates that the catalytic reaction proceeds more efficiently when the reaction cycles turn over around Rh(n)O(m) (m ≥ 4) than around bare Rh(n). Rhodium clusters operate as more efficient catalysts when they are oxidized than non- or less-oxidized rhodium clusters, which is consistent with theoretical and experimental studies on the catalytic CO oxidation reaction on a rhodium surface. 相似文献
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Li‐yu Long Peng Tao Tian‐liang Li Si Wu Xiang‐he Kong Li‐fu Liao Xi‐lin Xiao Chang‐ming Nie 《应用有机金属化学》2019,33(6)
To find new adsorbents for uranyl ions, the density functional theory (DFT) was adopted to design a series of new ligands containing an anthracene and two five‐membered heterocycles with nitrogen family nonmetal elements (N, P, As) or oxygen family nonmetal elements (O, S, Se, Te), for example, ligands N,N′‐bis(2‐five‐membered heterocyclidene)‐1,8‐anthradiamines (BFHADAs). Then the uranyl ions were coordinated with BFHADAs to generate five new coordination complexes (Uranyl‐BFHADAs) with heteroatoms N, S, As, Se and Te, respectively. The five‐membered heterocyclic rings of Uranyl‐BFHADA with oxygen atoms were broken under the structural optimization and Uranyl‐BFHADA with heterocyclic atoms P was not obtained. Several structures and property parameters of the ligands BFHADAs (containing heteroatoms N, S, As, Se and Te) and their uranyl complexes Uranyl‐BFHADAs were theoretically investigated and analyzed. The results showed that uranyl ions could form stable coordination complexes with these five BFHADAs. The formed bonds between uranyl ions and the heteroatoms in BFHADAs were coordination bonds rather than other types of bonds. These results could provide insightful information and theoretical guidance for the coordination of uranyl with the atoms N, S, Se, As and Te in other ligands. 相似文献
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A. A. Korlyukov M. Yu. Antipin Yu. I. Bolgova O. M. Trofimov M. G. Voronkov 《Russian Chemical Bulletin》2009,58(1):25-30
A study has been made of the crystal and molecular structure of 1-hydrosilatrane HSi(OCH2CH2)3N. The quantum chemical calculations of its crystal structure have been carried out. According to an estimate of the energy, the coordination bond N→Si is by 5 kcal mol?1 stronger than that in the crystal of 1-methylsilatrane. The charge values calculated within the framework of the topological analysis of the electron density demonstrate that the electron density of the coordination bond N→Si is primarily transferred to the region of the equatorial bonds Si—O and, to a lesser extent, to the bond Si—H. On going from the isolated molecule of 1-hydrosilatrane to its crystal, the interatomic distance N—Si decreases, mainly owing to the weak intermolecular interaction C—H...O. 相似文献