Active solid base catalyst was prepared from waste eggshell and characterized by TGA-DTA and BET analysis, and then applied to produce methyl esters of soybean oil from soybean oil and methanol. The effects of reaction temperature, molar ratio of methanol to soybean oil, catalyst dosage (weight ratio of catalyst to oil) and reaction time on the transesterification performance were investigated. A high biodiesel yield (98.9%) can be obtained at a molar ratio of methanol to oil 10∶1, the mass fraction of catalyst 3.0%, firing temperature 950 ℃ for 3.0 h. Further, reusability of the prepared catalyst was investigated under the optimal reacting condition, the experimental results show that the catalyst maintained high catalytic activity and higher biodiesel yield (>98%) is obtained even after recyc1ing 13 times.

Solid acid catalyst NaHSO ₄·SiO ₂ was prepared by sol-gel method from NaHSO ₄·SiO ₂, TEOS and isopropyl alcohol, and applied in the biodiesel production with the esterification reaction of oleic acid and methanol. The factors including catalyst calcination temperature, NaHSO ₄ loading, reaction time, catalyst amount, reactants molar ratio methanol to oleic acid on the biodiesel yield were investigated. The experimental results show that solid acid catalyst NaHSO ₄·SiO ₂ has high catalytic activity, the esterification reaction conversion can reach 95.19% under the following optimal conditions: catalyst calcination temperature 200 ℃, NaHSO ₄ loading 15.0%, reaction time of 5.0 h, n(methanol)∶n(oleic acid)= 10∶1 and weight ratio of catalyst to oleic acid 10∶1. 