Construction of a Brönsted-Lewis solid acid catalyst La-PW-SiO2/SWCNTs based on electron withdrawing effect of La(III) on π bond of SWCNTs for biodiesel synthesis from esterification of oleic acid and methanol

A novel solid Brönsted-Lewis acid catalyst La-PW-SiO2/SWCNTs was constructed from the electron withdrawing effect of La(III) on π bond of SWCNTs and used to prepare biodiesel from esterification of oleic acid and methanol. The highest conversion of oleic acid was 93.1% (mass) and maintained as high as 88.7% (mass) after six cycles of La-PW-SiO2/SWCNTs. La-PW-SiO2/SWCNTs can be an efficient and economical catalyst, because it shows good catalytic activity and stability.