12-Tungstophosphoric acid anchored to SBA-15: An efficient, environmentally benign reusable catalysts for biodiesel production by esterification of free fatty acids

Preparation, Characterization and Catalytic Properties of SBA-15-SO3H Supported Tungstophosphoric Acid for Esterification Reaction

“…In addition, narrow pore size distribution was observed (Fig. 4b) for all samples, indicating long range order [5].…”

“…In addition, as the TPA loading increases, the peaks at 1637 and 3450 cm −1 become broader. These bands are ascribed to the bending and stretching vibrations of bridging hydroxyl, because of the interaction of TPA and surface silanol groups of SBA-15-SO 3 H [5]. All N 2 adsorption/desorption isotherms (Fig.…”

“…Due to its structural features, TPA has been frequently used as an efficient catalyst for various organic reactions [2][3][4][5][6]. However, TPA has such deficiencies, as extremely low surface area (< 10 m 2 g −1 ), porous structure and thermal stability, which result in the limited usage of it in various acid catalyzed reactions [7].…”

Characterizations and Catalytic Activities Investigation of Synthesized Solid-Based Heterogeneous Catalysts in the Esterification Reaction

“…Heteropoly acid (HPA) compounds are known for their strong Bronsted acidity and high proton mobility and hence being used in a variety of reactions [15][16][17][18][19][20][21]. These compounds show high activity in reactions, nevertheless, their low surface areas [19] and solubility in the presence of polar solvents [17,19] limit their use as catalysts. The investigations in the use of these compounds focused clearly on the chemical interactions of the compound with certain support materials.…”

“…Among these, aluminum was incorporated to the mesoporous structure to create Bronsted acid sites and the synthesized catalysts were successfully used in degradation of polymers [7,13,14]. Heteropoly acid (HPA) compounds are known for their strong Bronsted acidity and high proton mobility and hence being used in a variety of reactions [15][16][17][18][19][20][21]. These compounds show high activity in reactions, nevertheless, their low surface areas [19] and solubility in the presence of polar solvents [17,19] limit their use as catalysts.…”