No abstract

A method was developed for the direct conversion of 2,4-dinitrophenylhydrazones (2,4-DNPHS) of n-alkanals and methylketones into ethylenethioacetals and ethylenethioketals for analysis by gas liquid chromatography (GLC). The method depended on heating the 2,4-DNPHS and 1,2-ethanedithiol with boron fluoride (BF3) ethyl ether at 125 C for 12 min or with p-toluenesulfonic acid at 200 C for 15 min. The reaction was extracted with pentane, and after evaporation, the product was dissolved in o-xylene and injected into the GLC. High yields of above 90% were obtained from long chain 2,4-DNPHS and somewhat lower yields of about 80% were obtained from short chain 2,4-DNPHS. Eight standard ethylenethioacetats and ethylenethioketals were synthesized; their elemental analysis, bp, rap, and retention times on FFAP and SE-30 GLC columns were determined.

2,4‐Dinitrophenylhydrazone (I) von n‐Alkanalen und Methylketonen lassen sich mit 1,2‐Äthandithiol in Gegenwart von Borfluoridätherat bei 125°C oder in Gegenwart von p‐Toluolsulfonsäure bei 200°C mit 80‐90% Ausbeute in die Thioacetale bzw. Thioketale (II) umwandeln.