Gas chromatographic investigation of rose concrete, absolute and solid residue

The chemical composition and physical properties of the rose absolute produced from rose concretes and the extract, supplied by three different companies, were determined by GC and GC-MS. It was found that rose absolute consists mainly of beta-phenylethyl alcohol, citronellol, geraniol, nerol, eugenol, methyl eugenol, geranyl acetate, benzyl alcohol, nonadecane, nonadecene and farnesol. The solid residue, which is the by-product of absolute production, was further divided on a silica gel column into three fractions by solvents having different polarities (n-hexane, 5% diethyl ether in n-hexane, and diethyl ether alone). A fraction eluated with n-hexane was analysed directly by GC and GC-MS. Two other fractions, after saponification, were converted to their methyl ester derivatives and then analysed by GC and GC-MS. It was observed that the solid residue contains mainly straight-chain saturated hydrocarbons with high molecular weight (C-15-C-31) and the esters of carboxylic acids and a homologous series between them exists. It was also concluded that the extract obtained by solvent extraction from the residue of rose flower (Rosa damascena Mill.) which was subjected to steam distillation is also a valuable raw material. Copyright (C) 2005 John Wiley & Sons, Ltd.