Ethanol (dilute)

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Legality: Production of alcohol in the US

In 1978 the US federal government passed laws regarding the home production of undistilled spirits.[1]

27 C.F.R. §25.206 & §24.75

  • Part 25 asserts: With additional limitation set by individual states, it is permissible for an individual to produce up to 100 gallons of beer per year for "home consumption", and this production shall not be subject to tax. A household with two or more adults may produce 200 gallons per year, likewise.
  • Part 24 asserts: With additional limitations set by individual states, it is permissible for an individual to produce up to 100 gallons of wine (including mead, etc) for "home consumption", and this production shall not be subject to tax. A household with two or more adults may produce 200 gallons per year, likewise.

Bottom line: Do not produce this chemical without checking to make sure that you may do so legally.

 

Dilute ethanol is an aqueous solution of 5-10% ethanol.

Uses

Primary

  • Feedstock for ethanol
  • It is frequently consumed as a foodstuff by humans, who find its effects on their nervous system pleasant.

Hazards

  • Consumption of alcohol can have negative effects on the human nervous system in both the short and long term.

Character

The ethanol/water azeotrope

Ethanol forms an azeotrope with water at 190 proof, which is

  • 95% by volume
  • 93.75 by mass
  • 16.269 Molar

These measurements give a useful additional result as well:

  • From [1]: at the azeotrope, there would be 50g of water in a liter.
  • From [2]: at the azeotrope, there would be 750g of ethanol in a liter.
  • Therefore the density of the azeotrope is 800g/L

The boiling point for the azeotrope is substantially lower than water, and slightly lower than for pure ethanol.

Production

Bioproduction

  • Dilute ethanol is primarily produced by fermentation of natural sugars, or bacterial production via the ABE Process followed by purification detailed below.

Purification

Filter

  1. Filter through a paper filter
  2. Filter through a carbon filter
  3. Filter through a paper filter

First distillation

  1. Estimate concentration (C)
  2. Calculate Fore (F) = 0.05 * C
  3. Place ethanol in alembic
  4. Heat double boiler to just below a boil
  5. Place alembic in double boiler
  6. When you have received F units of fluid in the receiver, switch to a second receiver
  7. Discard the contents of the first receiver (the Fore, which may contain impurities)
  8. Wait until the receiver and alembic contain equal amounts of fluid
  9. Discard the contents of the alembic
  10. In the receiver is your purified dilute ethanol
  11. Estimate concentration again
    Check: It should be higher

Triple azeotrope

The ethanol-water system forms a minimum-boiling azeotropic mixture at 89.4 mole% ethanol at 78.15°C. As noted earlier, starting with a mixture containing lower proportion of ethanol, it is not possible to obtain a product richer than 89.4 mole% ethanol using conventional distillation.
 Adding benzene (bp 80.2°C) serves as the entrainer that forms a new minimum-boiling azeotrope with 22.8 mole% ethanol, 23.3 mole% water and 53.9 mole% benzene. This mixture boils at 64.86°C which leaves as the overhead product from the first column. Relatively pure ethanol leaves the column as bottoms product.
The distillate can be gravitically separated into ethanol-water and ethanol-benzene fractions which can be fed back into the system.

Testing

Calculation of percent ethanol
1 - (density of solution)
=========================
0.211
  • Take a spoonful of material and put it on a cool non-flammable surface. Try to light it with a flame. If it does not burn, the mixture is <10% ethanol. If it burns and burns away completely, it's nearly 100% ethanol. If it burns but leaves a puddle of water, the amount of water left will give an indication of how much ethanol there is.

Storage

  • Out of reach of children

Disposal

  • Evaporate

See Also

References

  1. "Home Manufacture of Alcoholic Beverages"
    National Conference of State Legislatures
    link last accessed 11 July 2015.