锰的催化光度法测定现状与展望

介绍催化光度法测定锰的分析方法，讨论各显色体系中的灵敏度、测定范围和干扰情况，比较了测定锰的显色剂。引用文献58篇。     

1,10-双(1′-苯基-3′-甲基-5′-氧代吡唑-4′-基)癸二酮-[1,10]与三苯基氧化膦对钐(Ⅲ)的协同萃取行为研究

研究了１，１０－双（１′－苯基－３′－甲基－５′－氧代吡唑－４－基）癸二酮－［１，１０］（ＢＰＭＰＤＤ，Ｈ２Ａ）与三苯基氧化膦（ＴＰＰＯ，Ｂ）的氯仿溶液从硝酸介质中对Ｓｍ（Ⅲ）的协同萃取行为，计算了体系的酸性协萃系数ＲＡ和协萃系数Ｒ，用斜率法测得协萃合物的组成为ＳｍＡ·ＨＡ·Ｂ，计算了协萃平衡常数，用萃取法制得了固态协萃合物，并对其组成、ＩＲ及ＴＧ－ＤＴＡ进行了研究     

Ein Beitrag über Oxide vom Typ AMO4 (A = Ti3+, Cr3+; M = Nb5+, Ta5+)

A Contribution on Ternary Oxides of the AMO₄-Type (A = Ti³⁺, Cr³⁺; M = Nb⁵⁺, Ta⁵⁺ ) CrNbO₄, CrTaO₄, TiNbO₄, and TiTaO₄ were prepared by CO₂-laser technique. X-ray single crystal investigations show a random distribution of the metal ions in Rutil type structure, space group D–P4₂/mnm. Calculations of the free energy of reaction between Ti₂O₃ and Nb₂O₅ show higher stability of TiO₂ beside NbO₂. In TiNbO₄ both metals exhibit the oxidation state +4.     

光谱复杂的稀土基体中稀土杂质ICP光谱测定的一些问题

ICP激发光源以其独特的功能使ICP/AES技术在稀土分析中的应用日益广泛,在一定程度上取代了经典的直流电弧光谱法,但应指出,由于常规雾化器的低雾化效率(≤5％)和试样的高倍稀释,ICP/AES技术的实际检测能力的改善并不明显,本文用ICP光谱法测定了     

碱改性γ－Al_2O_3催化剂表面碱强度分布与COS水解活性的研究

用非水滴定法和Ｈａｍｍｅｔｔ系列指示剂测定了ＣＯＳ水解碱改性γ－Ａｌ_２Ｏ_３催化剂的表面碱强度分布．发现表面碱强度分布不均匀与表面能量分布不均匀相呼应．采用零点酸碱强度（Ｈ_（０，ｍａｘ））及碱中心区域分析法，Ｂｒｏｎｓｔｅｄ催化定律，进一步证实ＣＯＳ水解反应具有明显碱催化特征，较高活性催化剂的Ｈ_（０，ｍａｘ）一般为１０左右，对ＣＯＳ水解反应起主要作用的碱性中心的碱强度（Ｈ_０）为４．８≤Ｈ_０≤９．８．对碱金属氧化物改性后的γ－Ａｌ_２Ｏ_３催化剂，Ｂｒｏｎｓｔｅｄ规律在每个碱强度分区域内是适用的．     

碳酸氢铵沉淀法制备氧化钇粉体时反应条件对产物粒度的影响

研究了碳酸氢铵沉淀法的反应条件对氧化钇粒度的影响,探讨了粒度变化规律。发现在沉淀反应中,晶型碳酸钇铵的形成与否是影响氧化钇粒度的关键因素。在较低的反应温度下,当碳酸氢铵和氯化钇的浓度大于0.25mol·L-1,摩尔比大于5,陈化时间大于60min时得到碳酸钇铵沉淀,经煅烧可获得粒度(D50)大于1μm的氧化钇。当反应物浓度较低、摩尔比小,陈化时间较短时得到无定型碳酸钇沉淀,煅烧沉淀可获得粒度(D50)小于0.5μm的氧化钇。实验证明选择适当的沉淀反应条件,可制备D50在0.3～10μm范围内的不同粒度级别的氧化钇粉体。     

Composition catalysts of ethylbenzene oxidation based on bis(acetylacetonato)nickel(ii) and phase transfer catalysts as ligands 1. Macrocyclic polyethers

The addition of the macrocyclic polyether 18-Crown-6 (18C6) increases the selectivity of oxidation of ethylbenzene to -phenylethylhydroperoxide (PEH) in the presence of Ni(acac)₂. The initial oxidation rate, selectivity and degree of conversion of ethylbenzene to PEH are greater than those catalyzed by Ni(acac)₂ only. The efficiency of the macrocyclic ligand as an activator of Ni(acac)₂ exceeds that of monodentate donor ligands. The high selectivity of the process is due to both the primary Ni(acac)₂ · 18C6 complexes and the products of their transformation in the course of oxidation. The mechanism of ethylbenzene oxidation catalyzed by Ni(acac)₂ · 18C6 complexes is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1406–1411, August, 1994.     

The preparation and X-ray structural study of complexes that catalyze isocyanate cyclotrimerization

A 11-complex of trinitrophenol with benzyldimethylamine (1) and a 111-complex, the product of the interaction of benzyldimethylamine, glycidyl phenyl ether, and phenol (2), have been synthesized and characterized by means of X-ray analysis. Complex1 is a precursor for the catalysts of selective isocyanate cyclotrimerization, while complex2 is one of those catalysts. In the crystal structure complex1 forms H-bonded cationic-anionic aggregates with proton transfer from phenol to the N-atom of the tertiary amine. Complex2 crystallizes as a monohydrate (2a) with a strong H-bond between the quaternary ammonium and phenolic components, and exists in crystals in the form of globular H-bonded dimeric hydrates. Possible pathways of dissociation of complex2a are discussed. The data obtained may be used as a basis for further interpretation of the regularities of cyclotrimerization of isocyanates catalyzed by complexes of this type.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No 1, pp. 92–97, January, 1993.     

Modeling Studies of the Formation and Destruction of NO in Pulsed Barrier Discharges in Nitrogen and Air

This paper presents the results of modeling studies on the formation and destruction of NO in pulsed barrier discharges in nitrogen and air. The goals of this work are to identify the major processes involved in the formation and destruction of NO in air discharges, to distinguish between oxidative and reductive paths for NO destruction, to explore the potential importance of excited state reactions, to evaluate the role of water in such systems, and to identify the final products in the absence of heterogeneous processes. In all cases, the systems were modeled with 100×10^–4% (100 ppm) of added NO, with and without 3% added water. The focus in all of this work is chemistry in the post-pulse regime.     

2-Quinazolylguanidines in Heterocyclization Reactions. 2. Condensation with α,β-Unsaturated Carbonyl Compounds

4,6,6-Trimethyl-1,4-dihydropyrimidines have been synthesized by condensation of 2-quinazolylguanidines with mesityl oxide. The analogous reaction with benzalacetone leads to unstable 4-methyl-6-phenyl-1,4-dihydropyrimidines, which are oxidized to the corresponding 4-methyl-6-phenylpyrimidines.