Spot Tests for Phenol Vapors and for Aromatic Compounds Containing Oxygen

The unusual behavior of the Gibbs’ reagent versus Nitrofural

“…The mechanism of the reactions is, however, not so uniform with regard to all participants (including aldehyde hydrazones) since it usually depends on the type of the particular compound involved. Contrary to expectations, however, no positive (color) reaction has been found to take place between the used chloroimide reagent and the plurality of ketophenylhydrazones (А), semicarbazones (B), and acylaldehyde hydrazones (C) (6).…”

“…2). 6 The absorption assignments were made by comparing the UV-Vis spectrum of the green coloured product thus obtained (ABC1) with these of the reaction precursors (A and B).…”

Coatings

“…Feigl and Jungreis (30) have suggested a more direct spot test paper of the well-known Gibbs indophenol test as applied to resin classification. A filter paper treated with a saturated benzene solution of the reagent is exposed to the pyrolysis vapors, then exposed to ammonia fumes.…”

Vapor-programmed thin-layer chromatography, a technique for improved separations

“…Recent work (1,2) on the influence of solvent vapor in thin layer chromatography has shown that if development of the plate is done in unsaturated chambers then separations with multicomponent solvents are more efficient than in saturated chambers. The improvements are caused by a concentration gradient of adsorbed vapor on the dry part of the plate, with the gradient mainly dependent on the rate of evaporation of the solvent components and on their affinity for the adsorbent used.…”