Distilled alcoholic beverage production using reactive distillation techniques

The goal of this research was to couple industrial beverage distillation with a chemical reactionto create a flavored spirit without adding anything after the final distillation. Ethanol reacted withbutyric acid in the final distillation over Amberlyst® 15 to create ethyl butyrate, which gave thespirit a fruity smell comparable to Juicy Fruit® gum.It was shown that if a beverage ethanol fermentation having 63±3 g/L ethanol and 1 g/L butyricacid were distilled, the low wine will have 357 ± 32 g/L ethanol and 1:4 ± 0:1 g/L butyric acid.This sets up the low wine to be distilled over the catalyst to create the ethyl butyrate.For the study, low wine was obtained from a craft distillery. This gave the most accuraterepresentation of how this system would act in the beverage industry. Butyric acid was added tothis low wine and distilled on a glass vigreux column with copper wire on the inside to simulatean industrial copper distillation column. The distillations started with a pot ethanol concentrationof 30% ABV and varied: the butyric acid starting concentration from 0.5 g/L to 5 g/L, the catalystloading from 1 g dry / L to 100 g dry/L, and the catalyst position in the column from being in thepot, the bottom of the column, and the top of the column.All compounds, except butyric acid, followed the ethanol distillate concentration curve anddropped to zero as the ethanol ran out of the system. The butyric acid was not present in thedistillate until the ethanol concentration in the distillate started to decreased. As the butyric acidstarting concentration increased, the butyric acid in the distillate increased.The ethyl butyrate concentration was a function of all three variables mentioned above. Asstarting butyric acid concentration increased, so did the ethyl butyrate. As the catalyst loadingincreased, the ethyl butyrate concentration increased. When the catalyst was located in the pot, theethyl butyrate was shown to distill during the entire distillation only to drop with the ethanol. When the catalyst was in the bottom of the column, ethyl butyrate was present in the beginning but theconcentration increased to approximately doubling its starting concentration half way through thedistillation. When the catalyst was in the top of the column, the ethyl butyrate was severely delayedin the distillate, only to distill through the tails section and again fall with the ethanol.During distillation, lower boiling components vaporize and go up the column, making thebottom of the column a higher temperature than the top. Thus, there is more water and more butyricacid at the bottom of the column where the boiling point of the liquid is higher. As ethanol wasdepleted, the higher temperature water front rose past the catalyst and ultimately to the top of thecolumn where it came out as distillate, bringing butyric acid with it. When this front reached thecatalyst, the butyric acid reacted with ethanol to create the ethyl butyrate, which was carried up inthe vapor phase by the ethanol and out in the distillate. This unsteady-state system explains whyethyl butyrate presence in the distillate was largely controlled by the location of the catalyst, andbutyric acid was present only after ethanol had been depleted.As the catalyst loading was increased while holding the other variables constant, ethyl butyrateproduction increased. This show that the system did not reach chemical equilibrium during thedistillation.The reflux ratio in the glassware column was calculated to be 9.4. This value was used tocreate a simulation on AspenTech® Batch Modeler V10. The model has good agreement with theexperimental data.A provisional patent application has been filed for this process.