Isosafrole was synthesized from safrole by PEG-X (polyethylene glycol-X) or PEG-X supported on polystyrene as a phase-transfer catalyst in solvent-free conditions. According to orthogonal experiments, the optimum technological conditions were obtained as follows: m(88.5% safrole)∶m(KOH)∶m(PEG-X)＝1∶0.2∶0.25, temperature 90 ℃ and time 5 h. The yield of isosafrole was 99.9% under such conditions. The PEG-X supported on polystyrene can be used repeatedly for ten times without remarkable loss of catalytic activity. The results showed that this method provides several advantages such as a simple work-up procedure, a shorter reaction time, a lower reaction temperature, a higher yield and environmental friendliness. The structures of isosafrole were determined by ¹H NMR and GC-MS spectra. A possible mechanism for this reaction was proposed by PEG-X supported on polystyrene.

Key words: isomerization, isosafrole, PEG supported on polystyrene, phase-transfer catalyst