Louis Gordon

The infrared spectra of chelate compounds—I: A study of some metal chelate compounds of 8-hydroxyquinoline in the region 625 to 5000 cm −1

Abstract The infrared spectra of 8-hydroxyquinoline and its copper, zinc, manganese, magnesium and calcium chelate compounds have been determined between 2 and 16 μ. As far as possible, assignments of peaks have been made and correlations between peak position and stability constants have been drawn up. On the basis of the correlations the structure of the different chelates is discussed. From a study of the variation of peak height with concentration, it has been shown that the technique has considerable analytical value. A procedure is presented for the determination of copper and zinc as oxinates.

Co-precipitation in some binary sulphate systems

Abstract Studies have been made of the distribution behaviour of tracers with alkaline earth sulphates, using the technique of precipitation from homogeneous solution. The co-precipitation of strontium with barium sulphate and of lead, lanthanum, and yttrium, separately, with barium sulphate, and with strontium sulphate, were investigated. Although there was qualitative correlation between the observed values of the distribution coefficient and the theoretical solubility product ratios for each of the binary systems studied, the divergence between theory and observation was so great that it seems unlikely that there is any quantitative correlation.

The infrastructure of chelate compounds—III: A study of some tervalent metal chelate compounds of 8-hydroxyquinoline in the region 5000–250 cm−1

Abstract The infrared spectra of 8-hydroxyquinoline and of its complexes with aluminium, gallium and indium have been determined in the region 500–150 cm −1 . The spectra shows similarities, but differences between the aluminium complex and the other two occur in the region 625–250 cm −1 . A discussion of the spectra and of the structures of the oxinates is presented.

Nucleation in analytical chemistry

Abstract Precipitation involves two processes, nucleation and subsequent crystal growth. The nucleation process is of extreme importance in determining the number and size of the final crystalline particles. The significance of experimental studies of nucleation is discussed and the need for further research indicated.

Nucleation in analytical chemistry—II: Nucleation and precipitation of silver chloride from homogeneous solution☆

Abstract The nucleation and precipitation of silver chloride from homogeneous solution have been examined. Critical supersaturations of silver chloride were determined ; however, they were observed to be qualitatively different from the critical supersaturation of classical nucleation theory, and were interpreted as being dependent on the rates of both nucleation and crystal growth. The precipitation rate is not constant throughout a precipitation from homogeneous solution, but varies considerably during the early portion of the precipitation. Both this early variation in precipitation rate and the number of particles and their size distribution can be controlled to some extent by varying the concentrations of the reactants.

Precipitation of metal 8-hydroxyquinolates from homogeneous solution—VI: Zinc☆

Abstract The precipitation of zinc 8-hydroxyquinolate from homogeneous solution with 8-acetoxyquinoline results in a precipitate with superior physical characteristics in comparison with that produced by the conventional method, and furnishes a much better separation of zinc from lead, calcium and magnesium.

Precipitation of metal 8-hydroxyquinolates from homogeneous solution—IV uranium

Abstract UraniumVI 8-hydroxyquinolate can be precipitated from homogeneous solution with 8-hydroyxquinoline generated by the hydrolysis of 8-acetoxyquinoline. The composition of the uranium chelate formed is not the same for the two procedures described for the quantitative precipitation of the uranium.

Reflectance spectra of two solvated uranium 8-hydroxyquinolates

Abstract On precipitation of uranyl 8-hydroxyquinolate from homogeneous solution, two different chelates are obtained. UO2(C9H6NO)2·C9H6NOH is dark red whereas [UO2(C9H5NO)2]2·C9H6NOH is orange. On grinding, the dark-red chelate becomes orange. Reflectance spectra are used to explain the initial colour difference as well as the change in colour of the dark-red compound to orange on grinding.

Precipitation of nickel dimethylglyoximate from homogeneous solution

Abstract By reacting biacetyl and hydroxylamine in the presence of nickelII, large, well-developed and readily filterable crystals of nickel dimethylglyoximate were precipitated from homogeneous solution. The needle-like crystals were frequently up to several mm in length. Large amounts of nickel—of the order of 200 mg—were easily handled. The usefulness of this method of precipitation from homogeneous solution is shown with results obtained for nickel in the presence of a few selected diverse substances, namely, cobalt, copper, iron, and in National Bureau of Standards steel samples.

The oximation of biacetyl

Abstract Spectrophotometric evidence indicates that the reaction of biacetyl with hydroxylamine proceeds through the formation of two carbinolamine intermediates. The second of these intermediates is also encountered in the reaction of biacetyl monoxime with hydroxylamine. The rate-limiting step in the oximation of biacetyl is the slow dehydration of the initially formed intermediate, as is evidenced from the various rate constants obtained for the two reactions over the range 0–10°. When niekel(II) is present in the biacetyl-hydroxylamine system, the formation of nickel dimethylglyoximate proceeds by two independent mechanisms, whereas only a single mechanism is responsible for precipitate formation in the biacetyl monoxime-hydroxylamine system.