Isomerization of Rosin Acids Catalyzed by Perfluorosulfonic Acid Resin

HUANG Dao-zhan,WU Zhi,WANG Xue-lian(1.College of Chemistry and Ecological Engineering,Guangxi University for Nationalities,Nanning,Guangxi 530006,China;2.Key Laboratory of Development & Application of Forest Chemicals of Guangxi,Nanning,Guangxi 530006,China)

perfluorosulfonic acid resin;rosin acids;catalystic isomerization;abietic acid;direct separation by crystallization

Isomerization reaction of rosin acids catalyzed by rejected perfluorosulfonic acid resin(PFSR) in 95 % alcohol for direct separation of abietic acid by crystallization was studied.The results showed that isomerization of rosin acids catalyzed by PFSR could be easily carried out under conventional heating condition.The isomerization reaction rate of rosin acids and equilibrium content of abietic acid were greatly improved by the amount of PFSR and reaction temperature.The isomerization equilibrium of rosin acids was reached,and abietic acid content was up to 78% under the optimum condition,i.e.,rosin 20 g,95% alcohol 30 mL,the mass percentage of PFSR(based on rosin mss) 20%,5 h of maintaining the boiling state of the mixtures for reaction.After the catalyst was simply separated from the isomerized rosin acids solution by filtration,a crude product was collected by direct cool crystallization and gave abietic acid by three times of re-crystallization in 95% alcohol.The purity and the yield were 95% and 35%,respectively.