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1.
乙醇-盐-水-5-Br-PADAP体系萃取分离测定钯 总被引:3,自引:0,他引:3
研究了在硫酸铵存在下 ,5 Br PADAP乙醇体系中Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )的萃取行为及乙醇溶液的分相条件 ,讨论了影响萃取率的各种因素 ,试验表明 ,室温下 ,一定 pH范围内 ,该体系中的Pd(Ⅱ )几乎可完全被乙醇相萃取 ,而Rh(Ⅲ )、Pt(Ⅳ )不被萃取或萃取率很低 ,从而可实现Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )混合离子的定量分离 ,同时建立了Pd(Ⅱ )的测定方法。乙醇相中Pd(Ⅱ ) 5 Br PADAP配合物表观摩尔吸光系数为 1.18× 10 5L·mol- 1·cm- 1,钯量在 0~ 9.6 0 μg/10ml范围内符合比耳定律 ,检出限为 0 .0 90 μg/10ml。用该法分离混合样和测定两种活性碳钯催化剂中钯 ,结果满意 相似文献
2.
3.
The chemical fixation of CO2 with mono-substituted terminal epoxides or cyclohexene oxide to form cyclic carbonates under the ZnCl2/[BMIm]Br catalyst system without using additional organic solvents was achieved in excellent selectivity (>98%) and TOF (5410 h−1) and the catalyst could be used six times almost without losing its catalytic activity and selectivity. Besides, the pure cis-cyclic carbonate of cyclohexene oxide was obtained in this catalyst system. 相似文献
4.
István Szilágyi Krisztina Imrik Dariusz Sarzisky Sándor Dóbé Tibor Bérces 《Reaction Kinetics and Catalysis Letters》2002,77(2):341-345
The title reactions have been studied at room temperature by applying the discharge flow method coupled with laser induced fluorescence detection of methoxy radicals and resonance fluorescence detection of bromine atoms. The following rate constants were determined: CH3O + Br Õ products (1) k
1 (298 K) = (3.4 ± 0.4 (1)) × 1013 cm3 mol-1 s-1, CH3O + Br2 Õ products (2) k
2 (298 K) £ 5 × 108 cm3 mol-1 s-1. 相似文献
5.
E. Roman M. Sánchez-Avedillo J. L. de Segovia 《Applied Physics A: Materials Science & Processing》1984,35(1):35-40
In the present work, results of the interaction of O2 with polycrystalline titanium using AES, and ELS techniques, are presented. Changes in the shapes of Ti(LMV) and Ti(LMM) transitions and in the Ti(LM)O(V)/Ti(LMV) and Ti(LMV) Ti(LMM) amplitude ratios as well as a shift of the 34 eV loss peak [Ti(3p level], are studied as function of the oxygen exposure.At O2 pressures equal or less than 10–6 Pa and exposure up to 2000 L(O2) (weak oxidation), the Ti(LM)O(V)/Ti(LMV) and Ti(LMV)/Ti(LMM) ratios show three clearly distinct regions: (i) up to 20L there is a chemisorbed phase with the Ti(LMV)/Ti(LMM) ratio remaining constant and a fast linear increase in the Ti(LM)O(V)/Ti(LMM) ratio. (ii) At exposures higher than 20L the oxidation begins being characterized by a linear variation of the Ti(LM)O(V)/Ti(LMV) and Ti(LMV)/Ti(LMV) ratios, with positive and negative slopes, respectively. (iii) At 125L there is a change in both slopes but no stable value is achieved, despite the O(KLL)/Ti(LMM) ratio remains constant. Hence, it can be concluded that TiO is the final oxide obtained after that treatment, from features like the shape of the transitions and a maximum shift of 3eV of the Ti(3p) level, complemented with ESD experiments.On the other hand, experiments at pressures higher than 10–4Pa with or without the surfaces at 900K (strong oxidation) indicate that the most likely final oxide is TiO2.Work presented to the IXIVC-VICSS. Madrid (1983) 相似文献
6.
Keith E. Johnson Richard M. Pagni John Bartmess 《Monatshefte für Chemie / Chemical Monthly》2007,138(11):1077-1101
Summary. A background for studying acids in various solvents is developed, emphasizing the importance of knowing to what extent a solvent
conducts electricity and is therefore ionized, the dissociation equilibria of common molecular solvents and the acidic and
basic species generated by solvent leveling. Acidity measurements in the atypical solvent water are discussed and the common
method of expressing acidity in other systems – by Hammett values – is introduced. Representative examples of reactions involving Br?nsted acids in ionic liquids are presented and attention paid to the questions of speciation and acidity values. It is found that
the gas phase proton affinity of a base is often a better guide to the acidity of its conjugate acid in an ionic liquid than
is the dissociation constant of the said acid in water. 相似文献
7.
C12-2-En-C12•2Br与SDS混合水溶液的胶团化研究 总被引:5,自引:0,他引:5
与[C12H25N+(CH3)2CH2]2•2Br-(简记为C12-2-C12•2Br)/ C12H25SO4Na(SDS)混合水溶液相比,随着联接链上乙氧基团(E)数目增加,[C12H25N+(CH3)2]2C2H4(OC2H4)n•2Br-(简记为C12-2-En-C12•2Br, n=2,3)与SDS混合水溶液澄清区域明显增大. C12-2-E3-C12•2Br/SDS混合胶团化过程中二组分产生了协同效应,理论预测在澄清区域所能达到的最小临界胶团总浓度(cmcT,min)= 0.0339 mmol•L-1,对应的SDS在溶液体相中的摩尔分数(x2*)=0.447.当水溶液体相中SDS摩尔分数(x2)=0.5时,混合胶团总聚集数(NT)=36,混合胶团中SDS的摩尔分数(x2M)=0.43. 相似文献
8.
Two new series of Nb6 bromides, CsRENb6Br18 (RE = all the lanthanides excepted Eu and Yb, + Y) (type H ) and M2RENb6Br18 (M = Cs, Rb, Tl; RE = Eu, Yb) (type R ) have been isolated. The crystal structures of CsErNb6Br18 and Cs2EuNb6Br18, isotypic with the corresponding chlorides, have been determined by single crystal X-ray diffraction data. The (Nb6Br18) intra-unit strength is related to the nature and the charge of the counter cation. A comparison between the corresponding chlorides and bromides series, based on the chemical properties and the size of the halogen is discussed. 相似文献
9.
Li2Br(NH2): The First Ternary Alkali Metal Amide Halide The pseudobinary system LiNH2/LiBr was investigated by X-ray methods. The crystal structure of the compound Li2Br(NH2) was solved by single crystal data: Li2Br(NH2): Pnma, Z = 8, a = 12.484(2) Å, b = 7.959(1) Å, c = 6.385(1) Å, Z(Fo) with (Fo)2 ≧ 3σ(Fo)2 = 348, Z (parameter) = 51, R/Rw = 0.019/0.021 Li2Br(NH2) crystallizes in a new type of structure. To one another isolated chains of [Li2Li4/2(NH2)22+] show the motif of closest rod packing. They are connected via bromide ions in a distorted cubic primitive arrangement. 相似文献
10.