Ion exchange resins in steel analysis

The metals vanadium, chromium and molybdenum may be separated from the other constituents of steel by passing an acetate buffered solution of the steel through a strongly basic onion exchanger and selectively eluting the above metals from the resin column with aqueous solutions of 0.6 N sodium hydroxide, 8 N hydrochloric acid and 1 N hydrochloric acid, respectively.     

Internal rotation and pyramidal inversion in triacylphosphines

MO calculations predict a P-C rotation barrier in triformylphosphine of less than 6 kcal/mol, and an inversion barrier of ca 14 kcal/mol.     

Phosphoryl chloride induced ring contraction of 1,4-benzodiazepinones to chloromethylquinazolines

A ring contraction of 1,4-benzodiazepin-2-one to 2-chloromethylquinazoline in phosphoryl chloride is described. The intermediacy of an aziridinoquinazoline is proposed.     

The electrochemistry of cephalosporin C derivatives: Part II. Cephalothin,sodium salt

The electrochemical behavior of cephalothin has been studied by a.c. and d.c. polarography, cyclic voltammetry, and coulometry in both aqueous and nonaqueous media in order to gain a greater understanding of the reaction pathways involved in cephalosporin reduction. The reductive allylic cleavage of the 3′-acetoxy function has been found to produce Δ³-deacetoxy and 3-exomethylene cephalothin compounds (geometric isomers) and stereochemical isomers of the 3′-exomethylene compound at the 4-position. The ratio of these compounds to one another is dependent on the experimental conditions used, with adsorption playing an important role. The reductive allylic cleavage of the S₁?C₂ bond is a competitive reaction pathway. Δ³-Deacetoxy cephalothin may undergo further reduction, depending on the electrolysis potential selected.     

Nachweis und colorimetrische Bestimmungsmethoden des Molybd?ns

Ohne Zusammenfassung     

Apparate zur Wasseruntersuchung

Ohne Zusammenfassung     

Germanium

Ohne Zusammenfassung