Calcium-Incorporated Mesoporous Aluminosilicates: Synthesis, Characterization, and Applications to the Condensation of Long-Chain Fatty Acid with Long-Chain Amine and Alcohol

A comprehensive Study oil a series of highly stable calcium containing mesoporous aluminosilicate molecular sieves (CaAlMMSH) having different acidic properties has been made by varying the Si/Ca ratio in synthesis gels. The structural, physical, and porous properties of these microporous/mesoporous composite materials were characterized by X-ray diffraction, N-2 ad sorption/desorption isotherm measurements, solid-state Al-27 and Si-29 magic angle spinning NMR, and variable-temperature hyperpolarized Xe-129 NMR, Fourier transform infrared (FTIR) and diffuse reflectance FTIR spectroscopies. As compared to the parent AIMMSH materials, the incorporation of excessive amount of calcium tends to result in an overall increase in acid amount while at the expense of strong acid sites. The CaAlMMSH materials were found to have Superior catalytic activities than AIMMSH in the amidation of palmitic acid with N-hexadecylamine. However, no significant enhancement in catalytic activity for the esterification of palmitic acid with cetyl alcohol was observed upon introducing calcium onto the AIMMSH materials. Such discrepancies were ascribed to variations in available acid sties and coking in the two different condensations reaction over the CaAlMMSH materials as catalysts.