Esterification deacidification of Zanthoxylum bungeanum seed oil

摘要

Effects of mole rate of methanol/oil, reaction time and technology on the free fatty acid (FFA) level decrease of Zanthoxylum bungeanum seed oil with sulfuric acid as catalyst was investigated. Results show that, the acid level decreases with the mole rate of methanol/oil increases when the sulfuric acid is 2% based on the weight of Zanthoxylum bungeanum seed oil and reacting at 60°C for 2h. When the mole rate is 20～35:1, the final acid value is less than 2 mg KOH/g which meets the requirement for biodiesel production. When the mole rate is 25:1, with sulfuric acid dosage 2% and reacting at 60°C, the acid value decreases fast at the beginning of the acid esterification. The acid value of ZSO was reduced to 1.56 mg KOH/g from 78.91 mg KOH/g by only one-step acid-catalyzed esterification with methanol-to-oil molar ratio 30:1, H_2SO_4 2%, temperature 60°C and reaction time 60 min, which was selected as optimum for the acid-catalyzed esterification.