Selective production of green solvent (isoamyl acetate) from fusel oil using a sulfonic acid-functionalized KIT-6 catalyst

Isoamyl acetate production from fusel oil was demonstrated in a heterogeneous system using sulfonated mesoporous silica KIT-6 catalysts. These were prepared by co-condensation at different 3-mercaptopropyl(methyl) dimethoxysilane (MPMDS):tetraethoxysilane (TEOS) ratios and subsequent oxidation (x-SO3H-KIT-6, where x is the molar ratio of MPMDS). Isoamyl acetate production was performed via esterification of fusel oil with acetic acid in a batch reactor at different reaction temperatures and reaction times. The optimal conditions were: 80 degrees C, 3h, catalyst loading of 5 wt.%, and a 2:1 (v/v) acetic acid:fusel oil ratio. Under these conditions, a 95% yield of isoamyl acetate was achieved. The efficiency in terms of turnover frequency (TOF) was strongly affected by the number and accessibility of the acid sites, and therefore by the MPMDS:TEOS ratio. The highest yield was found for 0.3-SO3H-KIT-6, while 0.1-SO3H-KIT-6 had the highest TOF. The 0.3-SO3H-KIT-6 catalyst also exhibited excellent reusability over four cycles, with only a small reduction in isoamyl acetate yield in each cycle. Overall, the 0.3-SO3H-KIT-6 catalyst exhibited catalytic activity comparable to that of a commercial esterification catalyst. This novel catalyst has potential practical applications in selective production of isoamyl acetate.