Conversion of fatty aldehyde dimethyl acetals to the corresponding alk-1-enyl methyl ethers (substituted vinyl ethers) during gas-liquid chromatography.

The behavior of palmitaldehyde and linolealdehyde and of their dimethyl acetals during gas-liquid chromatography on beta-cyclodextrin acetate (beta-CDX acetate) and ethylene glycol succinate polyester-phosphoric acid (EGSP) columns was studied. The aldehydes were well separated from their dimethyl acetals on the beta-CDX acetate column. However, on the EGSP column the retention times of palmitaldehyde and its dimethyl acetal were identical; a mixture of linolealdehyde and its dimethyl acetal gave a split peak. The aldehydes were recovered unchanged in 80-85% yield by preparative GLC from both columns, but the dimethyl acetals were quantitatively converted to the corresponding alk-1-enyl methyl ethers. The structure of these compounds was elucidated by infrared spectroscopy, mass spectrometry, and chemical means. Upon hydrolysis at low temperatures with 100% H(2)SO(4) they yielded the corresponding aldehydes, which were identified as 2,4-dinitrophenylhydrazones.