Catalytic synthesis of DnOP by niobic acid

The di n octyl phthalate(DnOP)was synthesized with catalyst H 2SO 4 traditionally, the synthesis of DnOP with catalyst niobic acid is introduced in this paper now. The effects of reaction time, reaction temperature and etc., are investigated. The experimental results show that the optimal reaction conditions are n (octanol)∶ n (phthalic anhydride)=2.4∶1,with 5 g/mol catalyst and 2 hours' reflux. Under these conditions the yield of ester is up to 99.4%. The niobic acid catalyst features high catalytic activity, and longevity. The catalyst can be repeatedly used for several times, and the final product is excellent in quality.