The Preparation of Urushiol Acetal from Lacquer Sap and Its Hydrogenation Process Mechanism

Urushiol acetal was prepared from the acetone extracted lacquer sap by acetalation which decreased the polarity of urushiol. Thus it is easy to be separated from dimmer and oglimer of urushiol. The tri-unsaturated urushiol were obtained through silica gel column. The rushiol acetal products were analysed by IR and NMR. IR absorptance at 3100-3650 cm-1 indicates phenol to disappear while ether 1049 cm-1 was found after acetalation. The absorption of 5.92 in 1H NMR represents methylene ether group in rushiol acetal. The tri-unsaturated urushiol acetal was hydrogenised. Its hydrogenation process was detected by HPLC. It was found that tri-unsaturated urushiol acetal gradually became di-unsaturate and mono-unsaturate, and turned into saturate state after 8 h.