Mixed oxides of Ca, Mg and Zn as heterogeneous base catalysts for the synthesis of palm kernel oil methyl esters

Transesterification of rapeseed oil by Mg–Al mixed oxides with various Mg/Al molar ratio

“…Mg-Al mixed oxides possess strong surface basicity, high surface area and high quantity of defects resulting from incorporation of Al 3+ in the MgO lattice [8]. These catalysts are attractive catalysts for reactions such as the transesterification [9][10][11][12], aldol or Knoevenagel condensation [13][14][15] and the others [16][17][18].…”

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

“…In particular, heterogeneous catalysts including calcium, manganese and zinc oxides as such or as mixtures are widely used to convert natural triglycerides into FAMEs or FAEEs (fatty acid methyl or ethyl esters) with methanol or ethanol, respectively [10]. The most commonly used system is CaO, which is obtained by calcination of readily available and cheap resources including waste products such as shells and even livestock bones [11–14].…”

Seashell-derived mixed compounds of Ca, Zn and Al as active and stable catalysts for the transesterification of palm oil with methanol to biodiesel

“…Our previous work demonstrated that the surface area and basicity of ZSA-500 were higher than those of pure CaO obtained from calcination of waste mixed seashells at 800°C [14]. It can be seen that the ZSA-x catalysts possessed meso-scale porosities, which should be defined as interparticle voids similarly to other CaO-based catalysts [5,16,18]. Further increasing the calcination temperature increased the crystallite size of CaO and decreased the total basicity, which is due to the agglomeration of CaO clusters at high temperatures and that the majority of large CaO crystallites were generated directly from the decomposition of CaCO 3 in the original seashells.…”

“…Combining CaO with other metal oxides, such as those of magnesium (MgO) [15], zinc (ZnO) [16] and zirconium [17], as binary mixed oxides is an effective route to improve the specific surface area, basicity and catalytic performance of the CaO-based catalysts. Moreover, three-component mixed oxides of Ca, Mg and Zn have been reported to be highly active catalysts in the methanolysis of palm kernel oil to FAME [18]. A stable CaO catalyst with an enhanced mechanical strength was obtained by forming a Ca/Al composite of CaO and Ca 12 Al 14 O 33 at high temperatures [11], whilst a spinel mixed ZnO and aluminium oxide (Al 2 O 3 ) catalyst was preferred in the first commercial biodiesel production plant using heterogeneous catalysis [4].…”