Synthesis of Rhus succedanea lacquer film and analysis by pyrolysis-gas chromatography/mass spectrometry

Laccol, a major component of lacquer sap from Rhus succedanea, was synthesized by a Witting reaction, and then mixed with acetone powder separated from raw lacquer sap to synthesize lacquer films. The resulting lacquer films were analyzed by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), and the results were compared with that of natural lacquer film to evaluate the polymerization mechanism and film structure. The results showed that saturated and monoenyl laccol components were present only in the natural lacquer film, but not in the synthesized lacquer films. Meanwhile, alkylphenols, alkebulphenols, alkanes, and alkenes having longer carbon chains than the side chains were detected in the synthesized laccol, suggesting that the polymerization of synthetic laccol proceeds through the laccase-catalyzed nucleus-side chain CO coupling and autoxidative side chain to side chain CC coupling like natural lacquer film. The synthesized laccol films showed shallow color and hardness, which would make them useful as good preservative surface-coating materials.