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991.
A method was developed for the recovery and determination of cyanide ion in organic sample matrices. To facilitate the solubilization of cyanide ions, cetyltrimethylammonium bromide (CTAB) was added at concentrations above the critical micelle concentration. Sample cyanation reaction products consisted of solvent mixtures of a hydroxynitrile in DMF-toluene or DMF-isopropylacetate (IPAC). Spectrophotometric determination of cyanide ion at 578 nm by the pyridine-barbituric acid method was automated by flow injection analysis. Recovery of cyanide ion from spiked samples was 93.2% in DMF-IPAC solvent matrix and 93.9% in DMF-toluene. Low alkali concentration was observed to favor solubilization of cyanide ion in the micellar solution. 相似文献
992.
Vibrational and Electronic Spectra of Bond-Isomeric Hexakis(thiocyanato-isothiocyanato)ruthenates(III) Well resolved IR, Raman, and Electronic spectra of the bond isomeric complexes (TBA)3[Ru(NCS)n(SCN)6?n], n = 1–5, including the pairs of geometric isomers n = 2, 3, 4, are recorded at low temperatures (10 and 80 K). Characteristic vibrations of the N- or S-coordinated ambident ligand SCN? occur as listed: νCS(N): 810–850, νCS(S): 690–710, δNCS: 450–490, δSCN: 420–450, νRuN: 300–350, νRuS: 270–295 cm?1. The assignment of the complexes is based on stepwise increasing intensities of the νCS(N) modes with increasing number of N-coordinated ligands. Characteristic shifts and splittings in the spectra allow to distinguish the geometric bond isomers according to their different symmetries. Even the absorption spectra in the visible range show within the series of bond isomers and for the cis/trans pairs systematic alternations. 相似文献
993.
Iron(II), cobalt(II) and nickel form complexes of the formula [Me(TTA)2B1] with 1-(2′-thenoyl)-3,3,3-trifluoroacetone (HTTA) and 2-pyridinalphenylimines (B1) or bis-(2-pyridinal-R-diimines) (B2) and — in dependence of the -R group in the B2 compounds — complexes of the formula [Me2(TTA)4B2] and [Me2(TTA)2B2]. The octahedral geometry of the complexes can be unequivocally proven by means of electron spectra, IR spectra and from magnetic measurements. The labelling of solid [Ni(TTA)2B1] complexes with the nickel isotopes58Ni or62Ni permits an allocation of the Me-O- and Me-N-valency oscillations in the FIR. 相似文献
994.
Three methods are investigated for obtaining elastic phase shifts in the scattering of electrons from atoms and ions that use a bound-state representation of the scattering wavefunction. Results for singlet p-wave scattering by H and by He+ are compared with previous calculations. 相似文献
995.
996.
The cis fused bicyclic sulfones 1a, 1c and 3a are lithiated in benzene with n-butyllithium under concomitant cis/trans isomerization of the ring fusion, involving intramolecular proton transfer. H/D exchange of the three α-hydrogens in protic solvents proceeds with retention of configuration. The lithiated sulfones are chlorinated with hexachloroethane (HCE) and show a strong preference for introduction of halogen at an equatorial α-position. 相似文献
997.
The polymerization of the system indene-titanium tetrachloride-methylene chloride gave irreproducible kinetics which have been attributed to variable concentrations of impurities in the solvent. Incomplete yields sometimes observed at ?70° are also caused by impurities, but introduction of water and hydrochloric acid then gives complete yields. A new method of solvent purification has been used giving reproducible yields and rates. In such cases, monomer consumption at ?70° follows the rate law log [M]o/[M] = kt. 相似文献
998.
The kinetic salt effect in the 18O-exchange reaction between bromate ion and water has been investigated at 60° in a range of ionic strength from 0.02M < I < 1.9M using NaNO3 or NaClO4 as inert salts. From the experimental data the following relation was deduced for the uncatalysed reaction path In the H+-catalysed reaction path the Brønsted-Davies equation was obeyed up to I ? 0.1M At I > 0.8M the sign of Δ logk2/Δ I1/2 was positive. The theoretical interpretation of these results is consistent with the mechanistic evidence obtained previously from the rate law and the solvent isotope effects. 相似文献
999.
Zusammenfassung Die Aufnahme von Bromid-Ion durch Chlorella pyrenoidosa, die durch aktiven Transport erfolgt, wird durch Glucose gehemmt, obwohl die Atmung stimuliert wird. Die Hemmung tritt bei Energielieferung durch Belüftung oder Belichtung ein. Galactose und Mannit wirken nicht wie Glucose. Offenbar hemmt die Glucose die Nutzbarmachung des Elektronenflusses bei dem System der Atmung oder Photophosphorylierung für die Bromid-Aufnahme.
Mit 3 Abbildungen.
Herrn Prof. Dr.F. Wessely zum 70. Geburtstag in Verehrung gewidmet. 相似文献
The absorption of bromide ion by chlorella pyrenoidosa, which is due to active transport, is inhibited by glucose though respiration is stimulated. Inhibition is observed when energy is supplied either by aeration or by illumination. Galactose or mannitol do not act like glucose. Apparently glucose interferes with the utilization of electron flow in the respiration or photophosphorylation systems for the absorption of bromide.
Mit 3 Abbildungen.
Herrn Prof. Dr.F. Wessely zum 70. Geburtstag in Verehrung gewidmet. 相似文献
1000.
H. Bergseth 《Colloid and polymer science》1965,201(1):58-62
Zusammenfassung Vor und nach Behandlung drei verschiedener Biotite mit H+-, Li+-, Na+- und K+-beladenem Ionenaustauscher (Amberlite Resin IR-120, Standard Grade) wurden deren Kationenaustauschkapazität gemessen und deren Röntgendiffraktionskurven aufgenommen. Nach Behandlung mit H+-, Li+- und Na+-beladenem Ionenaustauscher ergibt sich eine deutliche Steigerung der Kationenaustauschkapazität und eine Gitterstörung in Richtung auf Vermiculit. K+-beladener Ionenaustauscher hat jedoch nur sehr kleine Änderungen verursacht. Es scheint, als ob, je größer das Verhältnis Fe/Mg in einem Biotit ist, um so weniger wird er durch Behandlung mit dem verwendeten kationenbeladenen Ionenaustauscher verändert. Eine Erklärung dieser Erscheinung wird vorgeschlagen, Kontaktzeit und Verhältnis zwischen Ionenaustauscher und Mineral spielen eine wesentliche Rolle für die Veränderungen der Biotite. 相似文献