Application of Methoxy‐Bromomercuric‐Adduct Fractionation to the Study of Cyclic Fatty Acid Monomers from a Heated Linseed Oil

A linseed oil was heated at 275° C for 12 hr under nitrogen. The triglycerides were isolated from the polymers by gel permeation chromatography on 2μ‐styragel columns using tetrahydrofuran (THF) as solvent. One part of the isolated triglyceride fraction was submitted to HPLC on a C 18 reverse phase column. The resulting 8 fractions were transformed into methyl esters and hydrogenated on PtO 2 The content of cyclic fatty acid monomers (CFAM) in the different hydrogenated fractions was determined by gasliquid chromatography (GLC) on a Silar‐10 C column. The other part of the isolated triglyceride fraction was submitted to the action of BF 3 /MeOH. The resulting methyl esters were fractionated by thin‐layer chromatography of the corresponding methoxybromomercuric adducts. Five bands were obtained using a mixture of hexane: dioxane (60:40) as the solvent system. A band between the diene and the triene bands contained 40.6% of the total cyclic fatty acid monomers (CFAM) while the diene and the monoene band contained respectively 38.9 and 11.2% of these cyclic components. The diene band and the band between the diene and the triene bands were hydrogenated on PtO 2 The structures of the resulting hydrogenated cyclic fatty acid monomers were studied using a gas‐liquid chromatograph coupled with a mass spectrometer (GC‐MS).