The role of elastic scattering analysis in studies of anodic oxidation

Résumé L'analyse par diffusion élastique peut détecter de microquantités à condition qu'elles soient concentrées dans des films minces. En outre, la méthode peut directement fournir des indications sur l'emplacement des éléments. Ces caractéristiques ont été mises à profit pour apporter un instrument utile à l'étude des processus d'oxydation.      

Preparative method of obtaining L- and D-2-hydroxy-3-methylbutyric acids

Summary A preparative method was developed for obtaining L-and D-2-hydroxy-3-methylbutyric acids by the separation of racemic 2-hydroxy-3-methylbutyric acid with the aid of D-and L-threo-2-amino-1-p-nitrophenyl-1,3-propanediols.     

Protonated Sodium 1-Hydroxyethane-1,1-diphosphonates

Powder X-ray diffraction study of sodium salts of 1-hydroxyethane-1'1-diphosphonic acid (H₄L)of the compositions NaH₃L·H₂O, Na₂H₂L·4H₂O, Na₃HL·5.5H₂O showed that these compounds aresingle-phase. Some of their properties were determined. The possibility of preparing salts of other compositionswas examined.     

The effect of thermal processing on PVC—VI. The role of hydrogen chloride

The reaction between cumene hydroperoxide (CHP) and anhydrous hydrogen chloride under various conditions of temperature and concentration has been studied in an inert solvent (chlorobenzene) and in an oxidisable medium (cumene). The kinetics were first order with respect to each reactant; the energy of activation of the overall second-order reaction was 53.4 kJ mol^?1 K^?1. Competing ionic and free radical mechanisms were found to operate, the latter predominating at relatively high HCl concentrations, leading to rapid pro-oxidation in cumene. The effect of typical organo-tin PVC stabilizers on the pro-oxidant process were examined. It was found that dibutyltin maleate neutralized the HCl thus eliminating the pro-oxidant effect when used in stoichiometric proportions, but had little other effect. Dioctyltin bis(isol-octylthioglycollate) on the other hand not only neutralized the HCl stoichiometrically but gave additional oxidative stabilization over a wide concentration range.     

Reaction of 3,4-diaminofurazan with β-keto esters

The reaction of some linear and cyclic -keto esters with 3,4-diaminofurazan was investigated. Products of condensation at the keto group and the corresponding furazanodiazepinones were isolated and characterized. The structures of the compounds obtained are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1196–1199, September, 1978.