Heterogeneous esterification of fatty acids with methanol catalyzed by Lewis acidic organozirconium complexes with Keggin-type mono-aluminum-substituted polyoxotungstates

Abstract Two Lewis acidic organozirconium complexes with α-Keggin-type mono-aluminum-substituted polyoxotungstates, [( n -C 4 H 9 ) 4 N] 6 [α-PW 11 Al(OH)O 39 ZrCp 2 ] 2 (Cp =  η 5 -C 5 H 5 − ) ( TBA-P-Al-Zr ) and [( n -C 4 H 9 ) 4 N] 6 [α-SiW 11 Al(OH) 2 O 38 ZrCp 2 ] 2 ·2H 2 O ( TBA-Si-Al-Zr ), were used as heterogeneous catalysts for the esterification of various fatty acids with methanol. For the esterification of linoleic acid at 80 ± 2 °C, TBA-P-Al-Zr exhibited 83% conversion after 6 h, approximately six times higher than that of TBA-Si-Al-Zr . TBA-P-Al-Zr also exhibited 69–90% conversion for the esterification of oleic acid, palmitic acid, myristic acid, and lauric acid with methanol at 80 ± 2 °C.