High activity of acid-treated quail eggshell catalysts in the transesterification of palm oil with methanol

The transesterification of palm oil with methanol was investigated over calcium oxide catalysts prepared by calcining eggshells of quail and chicken. Compared to chicken eggshell, the palisade layer of quail eggshell had more closely dispersed micron-sized pores. Following treatment with 0.005 M HCl solution for 2 h to remove its dense cuticle layer and subsequent calcination above 800 °C, the quail eggshell had a large amount of strong basic sites and showed high catalytic activity comparable to that of potassium methoxide in the transesterification. The acid-treated, quail eggshell catalyst steadily maintained high conversions of over 98% during repeated fivefold usage at 65 °C with a reactant composed of methanol/oil (as mol) = 12/1 and oil/catalyst (as g) = 2/0.03.