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Esterification of Acetic Acid with n-Butanol Using Heteropoly Acid Supported Modified Clay Catalyst

“…It is also used as a dehydrating agent [2]. Esterification reactions have been carried out extensively using homogenous as well as heterogeneous catalysts [3,4]. Though homogenous catalysts which include mineral acids such as H 2 SO 4 , HCl, HF, H 3 PO 4 , ClSO 2 OH etc.…”

“…Heteropoly acids (HPAs) have been widely used in numerous acid catalyzed reactions due to their strong Bronsted acidity [4,14] Dodecatungstophosphoric acid (DTP) is the most stable among all HPAs and is commonly used for acid catalysis since it possesses the highest Bronsted acidity [15,16]. In homogeneous liquid phase catalysis, the advantages of the HPAs are more distinctive due to their low volatility, low corrosiveness, high acidity, activity and flexibility.…”

“…A number of porous supports with high surface areas such as silica, ZrO 2 , active carbon, SBA-15, zeolite etc. [20][21][22][23][24][25], have been used for supporting HPAs. Acid modified clay minerals can also be used as an efficient support [26] because they exhibit higher surface area, pore volume, pore diameter and higher surface acidity [27] which results into its improved adsorption and catalytic properties.…”

Acilação de Friedel-Crafts do 2-metoxinaftaleno usando o ácido dodecafosfotúngstico suportado em sílica (HPW/SiO2) como catalisador e acetonitrila como solvente

“…Essas duas bandas são típicas da estrutura primária dos heteropoliácidos Keggin, variando de acordo com o metal constituinte do cluster óxido. [26][27][28][29] Desta forma, a espectroscopia UV-Vis tem se constituído numa técnica importante e simples para a caracterização, estudo de estrutura e quantificação dos heteropoliácidos Keggin.…”

Molybdenum Oxoanions as Dispersing Agents in the Preparation of Pd/C Catalysts for the Selective Oxidation of Glyoxal

“…A solid-state NMR study has shown that HPAs interact strongly with carbon [19]. The interaction of W-based HPAs and filamentous carbon has also been studied [20]. Another study demonstrated that HPAs interact more strongly with carbon than with silica [21].…”