Introduction:

Fusel oil is an impurity in the ethanol production process, from which high value-added products such as esters can be obtained.

Objective:

To experimentally obtain isoamyl acetate by taking advantage of the heavy fraction (>132 oC) separated in the distillation of fusel oil.

Materials and Methods:

The experimental study was carried out in four stages: dehydration of the fusel oil by liquid-liquid extraction with a saturated sodium chloride solution, using anhydrous sodium sulfate as a drying agent; separation of the alcohols present by distillation, esterification and purification of the final product. In the esterification, a Plackett-Burman design of experiments was performed analyzing the effect, on the yield, of the variables: feed ratio, reaction time and amount of catalyst.

Results and Discussion:

The water removed represented 24 % of the initial fusel oil sample and upon distillation and characterization by gas chromatography, the working fraction (>132 oC) was found to contain 95.09 % w/w isoamyl alcohol. The highest yield of isoamyl acetate was achieved in experiment IV, when using an acid/alcohol feed ratio of 1.2, 60 min of reaction and 0.5 % w/w catalyst, obtaining in the purification the ester at 98.01 % w/w.

Conclusions:

The fusel oil used contained ethanol, n-propanol, isobutanol and isoamyl alcohol. The esterification of the heavy fraction, with greater presence of isoamyl alcohol, allowed obtaining its corresponding ester with high levels of purity.

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