Acetalization of ketones on K-10 clay and rare earth exchanged HFAU-Y zeolites: A mild and facile procedure for the synthesis of dimethylacetals

Abstract

Dimethylacetals of ketones; cyclohexanone, acetophenone, and benzophenone have been prepared by reacting ketones with methanol under mild reaction conditions. Large pore zeolites (H-Y and its rare earth metal, Ce 3+ , La 3+ , and RE 3+ modified forms), and mesoporous clay (K-10 montmorillonite and its cerium exchanged counterpart) with regular pore structure, silica and silica-alumina have been used as catalysts. Clay catalysts are found to be much more active than zeolites, thanks to slightly bigger pore size. The nature of the pores of the solid acid catalysts determine acetalization efficiency of a particular catalyst. As evidenced by the reaction time studies, the catalyst decay is greater over the zeolites than over the clays. Carrying out the reaction with ketones of different molecular sizes it is shown that K-10 clays and rare earth exchanged H-Y zeolites are promising environmentally friendly catalysts for their use in the production fine chemicals.

Zeolites as Catalysts for the Synthesis of Fine Chemicals

“…Acetalization of aldehydes can be performed in the presence of weak acids, while ketones generally need stronger ones such as sulfuric, hydrochloric, or p-toluenesulfonic acid. Acid zeolites and mesoporous aluminosilicates have been used as catalysts for the synthesis of dimethylacetals of different aldehydes and ketones using trimethylorthoformate or methanol as reactants, giving in general good yields [82][83][84][85][86][87][88].…”

Acid-activated clay as heterogeneous and reusable catalyst for the synthesis ofbioactive cyclic ketal derivatives

“…27 Furthermore, mesoporous aluminosilicate can effectively catalyze the reaction between carbonyl compounds and methanol. 28,29 The discovery of natural materials with high catalytic performance represents an alternative to pollutant and corrosive homogeneous catalysts. 30−33 Natural aluminosilicates such as zeolites and more particularly clays are economical, recyclable, nontoxic, noncorrosive, easy to handle, and effective catalysts in several chemical transformations.…”

Selective synthesis of dimethyl ether on eco-friendly K10 montmorillonite clay

“…As a solid acid catalyst, montmorillonite clay has a great potential to catalyze dehydration reactions [18][19][20]. Several studies revealed that the activity of montmorillonite clay in specific reactions such as acetalization and esterification is higher compared to zeolites in general, mainly because of the presence of mesopores in the montmorillonite clay structure [21][22][23]. Another catalytic dimension is added to clays, when used as support for redox-active metals in various reactions [6,24].…”