Molybdenum oxide modified montmorillonite K10 clay as novel solid acid for flow synthesis of ionone isomers

Abstract

Molybdenum oxide modified montmorillonite K10 clay (Mt-K10) was developed to synthesize ionone isomers via cyclization of pseudoionone. A fixed bed flow reactor was used to convert the current homogenous batch process into a heterogeneous flow process. To increase the acidity, molybdenum oxide was loaded on Mt-K10. Since molybdenum oxide contains both Lewis and Bronsted acidity, the loading resulted in a higher acidity of 1% (w/w) MoO3/Mt-K10 catalyst compared to Mt-K10 alone. 1% (w/w) MoO3/Mt-K10 is new, green, and economical catalyst derived from ammonium heptamolybdate tetrahydrate as molybdenum precursor and using Mt-K10 as support. The support and catalyst were analyzed by various characterization techniques, including XRD, FTIR, NH3-TPD, BET, SEM, TEM, and XPS analysis. Thus, 100 % conversion of pseudoionone and 75 % selectivity of ionone isomers were obtained. 1% (w/w) MoO3/Mt-K10 catalyst could be easily prepared on a large scale and it is effective in the synthesis of isomers of ionone with higher selectivity in comparison with other solid acids.