8-Hydroxy-2-methylquinoline-modified H₄SiW₁₂O₄₀: a reusable heterogeneous catalyst for acetal/ketal formation

Abstract

A heteropoly acid based organic hybrid heterogeneous catalyst, HMQ-STW, was prepared by combining 8-hydroxy-2-methylquinoline (HMQ) with Keggin-structured H4SiW12O40 (STW).

Facile synthesis of polyoxometalates tethered to post Fe-BTC frameworks for esterification of free fatty acids to biodiesel

“…The heteropolyacids (HPAs) were validated to be proper for esterication owing to the advantages of structural diversity, thermal stability, strong Brønsted acids and high oxidizing ability. 20,21 However, HPAs also have some drawbacks, such as very high solubility in polar solvents and low specic surface area, which limit their application of the catalytic eld. 22 In order to overcome these disadvantages, the exchange of protons of HPAs with different cations results in formation of insoluble salts and the immobilization of HPAs could be acted as efficient strategy for the catalytic reaction.…”