Modification and characterization of aluminosilicates used for nucleophilic addition of alcohols to epoxidized oils Original Research Article

Modifications to the double bonds of plant oils were done by addition of alcohols, using the corresponding epoxides as intermediates. Both, crystalline and amorphous aluminosilicates were studied as catalysts and they were thoroughly characterized using 29Si and 27Al MAS NMR as well as FT-IR, XRD, inductive couple plasme atomic emission spectroscopy (ICP-AES) and nitrogen adsorption, to link catalyst properties to catalytic behavior. Aluminosilicates where found to be suitable catalysts for the nucleophilic addition of alcohols to epoxidized oils. Zeolites with higher mesopores content, such as steamed ones, were more active because the active Brönsted sites are more accessible to the bulky substrate. Aluminosilicates in lamellar form, like clays of the type montmorillonite, showed to be the most active aluminosilicates for the epoxide alcoholysis. Clays with a higher degree of Al3+ substitution for Si4+ in the SiO2 layers proved to be superior to those with a higher degree of Fe2+ or Mg2+ substitution for Al3+ in the Al2O3 layers. The analysis indicate that this better performance is due to a higher Brönsted acid strength present in the former clays.