Thin-layer chromatography of steroisomeric 2,4-dinitrophenylhydrazones of aliphatic aldehydes.
Abstract The stereoisomeric forms of 2,4-dinitrophenylhydrazones (2,4-DNP) of some aliphatic aldehydes and unsymmetrical detones were separated by several reverse phase thin-layer chromatographic procedures. Evidence indicated that the reaction to produce the 2,4-DNP produces both the syn and anti form, but that repeated recrystallization in ethanol yielded the pure syn crystalline form. Racemizaton of the crystalline syn form could be stimulated by dissolving it in chloroform or by the addition of a small amount of hydrochloric acid to an acetone or methanol solution. Certain thin-layer chromatographic systems separated the homologous series to the greatest extent and the isomers the least (undecane/75% methanol-25% water). Another system separated the isomers to a considerable extent but was not too effective in separating the homologous series (dimethylformamide/heptane). Combinations of these systems should be of value in resolving mixtures of syn and anti forms of mixtures of aliphatic aldehyde 2.4-DNP.
Some carbonyl flavor compounds of oxidized soybean and linseed oils
Evidence is presented that 2,3-pentanedione, as well as diacetyl, contributes to the buttery flavor found in the early stages of oxidation of soybean oil. Components with a fishy and potatoey flavor were found in distillates from soybean oil that had a fishy or paint-like flavor. Linseed oil proved a reliable source of these flavor compounds. The fishy compound was identified ascis-4-heptenal and the potatoey compound is probably 2,4-pentadienal. Mechanisms for the production of these compounds are suggested.
Die Dünnschicht-Chromatographie auf dem Fettgebiet I: Trennung von Modell-Mischungen†
Mit Hilfe der Dunnschicht-Chromatographie lassen sich die Lipoide in Stoffklassen auftrennen, und ihre qualitative Analyse ist in kurzer Zeit durchfuhrbar. Untersucht werden Gemische von Mono-, Di- und Triglyceriden, Hydroxy, Epoxy- und Episulfido-Fettsauren, Aldehyden und Amiden. Hierdurch wird eine Moglichkeit gegeben, verschiedene chemische Prozesse, wie z. B. Oxydations-, Verseifungsvorgange usw., zu untersuchen. Ferner wird die Trennung der verschiedenen Stoffklassen auf hydrophobierten Platten in ihre homologen Glieder besprochen. Getrennt wurden Fettsauren, Diglyceride, Epoxy- und Episulfido-Fettsauren, Fettalkohole sowie Triglyceride. 
 
 
 
Separation of Lipids by Thin-Layer Chromatography 
 
 
 
The thin-layer chromatography makes possible the separation of the lipids in the different groups of substances and their qualitative analysis can be carried out in a short time. Mixtures of mono-, di- and triglycerides, hydroxy-, epoxy- and episulfido-fatty acids, aldehydes and amides have been examined. It is possible to investigate some chemical processes, such as oxydation-, saponification processes etc. The separation of the different groups of substances on hydrophobic plates into their homologous components are further discussed. Fatty acids, diglycerides, epoxy- and episulfido-fatty acids, fatty alcohols as well as triglycerides were separated.