摘要:

The viscosities, densities, and refractive indices at 20, 25, 30, and 35 °C were determined for the systems: methyl isobutyl ketone–n-butanol (MIK–B1), methyl isobutyl ketone–sec-butanol (MIK–B2), and methyl isobutyl ketone–isobutanol (MIK–B3). From the experimental results the excess volume, excess viscosity, and excess molar free energy of activation of flow were calculated. The deviations from ideality for the excess thermodynamic function are more important for the system (MIK–B2) than for the systems (MIK–B3) and (MIK–B1). This fact is explained by the existence of hydrogen bonds in the alcohols, stronger in the primary alcohols than insec-butanol.

ISSN:0008-4042    

DOI:10.1139/v81-488

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The exchange between the H atoms of cyclopentane (3) or cyclohexane (4) and the labeled acid protons of CF3SO3D (2-d), [3H]CF3SO3H (2-t), [3H]H2SO4(1-t), or ZnCl2−[3H]HCl (5-t) has been investigated. Results from the treatment of3or4with2-dat 0° or 20 °C, respectively, gave rise to polydeuterated cycloalkanes, indicating that all H atoms of3or4could be involved in the exchange. The rates of incorporation of the T-label into the hydrocarbon layer from the tritiated acids were found to be directly related to acid strength. After treatment of3or4with2-t, quenching of the acid layer and analysis by isotope dilution showed the presence of cyclopentanol or cyclohexanol. A carbocationic chain mechanism for the exchange, as well as the mechanism for the formation of the cycloalkyl cation from the cycloalkane, are discussed.

ISSN:0008-4042    

DOI:10.1139/v81-489

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

N-(2′-Deoxy-β-D-erythropentofuranosyl) formamide is an ionizing radiation-induced degradation product of 2′-deoxythymidine. This work describes a facile chemical synthesis of this molecule, and discusses the results of an1H and13C nmr study. The rotational barrier tocis–transisomerization about the amide linkage is calculated, and details of the molecular conformation of thecisandtransisomers in aqueous solution are presented.

ISSN:0008-4042    

DOI:10.1139/v81-490

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v81-491

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The reactions of tetraammineplatinum(II) complex ion with the hydrated electron and hydrogen atom have been investigated in aqueous media using the technique of pulse radiolysis coupled with absorption and conductivity detection. Analysis has also been carried on pulse-irradiated solutions for the formation of free ammonia and for changes in concentration of Pt(II). The hydrated electron and hydrogen atom react with the complex at near diffusion-controlled rates, with the respective rate constant being 1.9 ± 0.1 × 1010 M−1 s−1and 2.8 ± 0.3 × 1010 M−1 s−1. The nascent products of these reactions are shown to be different transitory species. For the electron reaction, the initial product is Pt(NH3)4+in which the metal center is formally Pt(I). In acidic media, there is a subsequent and rapid release of two ammonia ligands, with only the second step being measurable (k = 4.2 ± 1.7 × 104 s−1). In the reaction of H atom, the results support the occurrence of an addition process, giving rise to a hydrido type product. This species undergoes a first-order reaction (k = 2.2 ± 0.6 × 104 s−1); however the process is not associated with a change in conductivity, and thus it is not one involving loss of ammonia. Subsequent to this process, the loss of one ammonia ligand is observed, withk = 2.0 ± 0.6 × 103 s−1. The natures of these transients and the long term behavior of these systems are discussed.

ISSN:0008-4042    

DOI:10.1139/v81-492

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The theory of square wave voltammetry for reversible electrode reactions is expanded to include average currents and currents flowing to a growing drop (single drop square wave polarography) using an expanding plane model. Excellent agreement between theory and experiment was found for the reduction of Fe(III), good agreement for the reduction of Cd(II). The expanding plane model proved superior, but not greatly superior to the simpler theory. For the case of average current the effect on the polarogram of the times at which integration is started and stopped is discussed. Integration decreases sensitivity but increases signal-to-noise ratio. The conditions for maximum analytical usefulness are presented.

ISSN:0008-4042    

DOI:10.1139/v81-493

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Reduction peaks in single drop square wave polarography (SDSWP) for metal ions such as Cd(II) and Pb(II) in the presence of picolinic acid gave peak currents that can be an order of magnitude or more greater than diffusion-limited peaks. Various studies using techniques such as controlled-potential electrolysis, tast polarography, staircase voltammetry, and SDSWP demonstrated that this enhancement effect was due to the adsorption of metal–picolinate complexes on the electrode surface. Since it provides a detection limit of about 0.2 ppb with ions such as Cd(II), adsorption enhancement appears to be of use in trace analysis under certain circumstances. Linearity is observed only up to 1 × 10−5 Mand any substance capable of adsorption is a potential interferent.

ISSN:0008-4042    

DOI:10.1139/v81-494

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The vibrational frequencies of chloro-3 triazole-1,2,4[4H] and its deuterated derivatives have been used to calculate a valence force field. Previous assignments are discussed.

ISSN:0008-4042    

DOI:10.1139/v81-495

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The electrochemical reduction of a series of water-insoluble aromatic nitro compounds with coulometrically generated chromium(II) has been investigated. Samples ranging from 0.2 to 0.5 μmol could be determined for several substances with a precision and accuracy of about 1%. The number of electrons involved in the reductions corresponded in most cases to the formation of hydroxylamines or amines, but in some instances to dihydrazo products.

ISSN:0008-4042    

DOI:10.1139/v81-496

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A study related to the biological detoxification of Kraft pulp mill effluent is presented. Several fungal and bacterial preparations were evaluated for their action on isopimaric acid (IPA), one of the effluent constituents toxic to fish.Mortierella isabellinawas the organism selected for the biodegradation of IPA and subsequent chemical studies established the structures of three diterpenoid substances with very much lower acute toxicity.

ISSN:0008-4042    

DOI:10.1139/v81-497

出版商:NRC Research Press    

年代:1981

数据来源: NRC