@article {CASTANHEIRO201716,
	title = {Tungstophosphoric acid immobilised in SBA-15 as an efficient heterogeneous acid catalyst for the conversion of terpenes and free fatty acids},
	journal = {Microporous and Mesoporous Materials},
	volume = {249},
	year = {2017},
	note = {n/a},
	pages = {16 - 24},
	abstract = {<p>Alkoxylation of α-pinene, β-pinene and limonene was performed in the presence of SBA-15-occluded tungstophosphoric acid (HPW). The HPW was immobilised in SBA-15 using the sol-gel method. The catalysts were characterised by N2 adsorption, FT-IR, Raman spectroscopy, X-Ray diffraction, ICP-AES and TEM. A series of catalysts with different heteropolyacid loadings ranging from 1.8 to 19.3~wt. \% were prepared. PW4-SBA-15 (with 10.8~wt. \%) exhibited the highest catalytic activity for the alkoxylation of α-pinene with ethanol. An approximately 53\% selectivity to α-terpinyl ethyl ether was observed over the PW-SBA-15 catalysts. PW4-SBA-15 was also used as a catalyst for the alkoxylation of other terpenes, including β-pinene and limonene. The PW4-SBA-15 catalyst exhibited high catalytic stability for the alkoxylation of α-pinene with ethanol. PW4-SBA-15 was also used as a catalyst for the esterification of free fatty acids (i.e., palmitic, stearic and oleic acids) with ethanol. Good catalytic activity was observed for the PW4-SBA-15 catalyst with the different substrates used in the esterifications.</p>
},
	keywords = {Fatty acids, Heteropolyacids, SBA-15, Terpenes},
	issn = {1387-1811},
	doi = {https://doi.org/10.1016/j.micromeso.2017.04.047},
	url = {http://www.sciencedirect.com/science/article/pii/S1387181117302962},
	author = {Castanheiro, J. E. and I. M. Fonseca and A. M. Ramos and Vital, J.}
}
