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Fermentation and Distillation of Ethanol

Daryn J Toogood

Organic Chemistry 343-07 September 19th, 2019 !

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Objective ! This report entail the process to fermeuntate and distillate Ethanol. More so, Making moonshine the natural way by using the biocatalysts in yeast on a sucrose substrate. Pasteur salts are used to promote the fermentation process. The goal is to be employing Simple and Fractional distillation techniques to reach a 100% ethanol content."

" Fermentation Procedure -Place 20g sucrose in 250 mL round flask" ! -add 100 mL water" ! -add 1.5 yeast" -Swirl to dissolve "

Observation

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20.18 g sucrose " 1.508g yeast" 100 mL DI water" 19 mL pasteurs salts. "

Solution looks brown and cloudy."

-Add 17-18mL Pasteurs salt solution. " -Swirl to mix" -Cap with lightly greased Glass Vacuum adapter." -Place round flask in cushioned beaker " -Fill a medium sized test tube about halfway " with limewater " -Place tube in E. Flask. Submerge the free end " of the rubber tubing in the limewater. " ! *The limewater prevents atmospheric oxygen " from entering the fermentation solution and provides an " outlet for the CO2 formed during the reaction." Pre-Distillation Procedure " Solution smelt like wine" -Transfer the clear, supernatant liquid solution to another container by decanting" Solution was till brown with yellow tint even - if liquid is not clear, follow process" after filtrated, - Place 1 tbsp of Celite in a beaker with 100 mL of DI water. " - Shake" - Pour into Buchner Funnel (w/ Filter Paper) and apply vacuum " - A thin layer of Celite power will remind in funnel, discard that." - Filter Ethanol solution through B. Funnel. "

Simple Distillation

- Transfer 90 mL of solution from previous steps into a Round bottom flask. " - Add boiling chips and lightly grease all joint while setting up for Simple distillation. (Refer to Image 1 to ensure right set up." - Once everything set up properly, slowly heat RB flask. Gentle boiling will begin and liquid drops will start to drop in receiving las at a rate of 10 drops per minute. " - Continue distillation until temp. Has held 96-100°C (if it goes above 100°C stop distillation, at that point no more ethanol s coming through, only water.) If it maintains 96-100°C then Cole up to 20 mL of distillate. " - Record temperature as each 0.5-1.0 mL is collected. " - Create graph showing Temperature (y) vs. Volume of distillate (x). " - Pipet 1-2 mL of simple distillate into clear, TARED 10 mL flask/beaker. " Estimate ethanol content from density measurements. "

Fractional Distillation

- Transfer 90 mL of solution from previous steps into a Round bottom flask. "

- Add boiling chips and lightly grease all joint -

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while setting up for Fractional distillation. (Refer to image 2 to ensure right set up." Once everything set up properly, slowly heat RB flask. Gentle boiling will begin and liquid drops will start to drop in receiving las at a rate of 10 drops per minute." Collect 3 fractions in labeled e. flasks. Fraction 1 is distillate from 77°C-80°C, fraction 2 is from 80°C-96°C, and fraction 3 is anything above 96°C. Stop distilling once there are 2-3mL of fraction 3. Record the temperature from each .5-1mL collected." Record ethanol content from each fraction"

-once place in warmer, solution took 30-45 mins to increase temperature. " 25-64°C " Liquid began boiling around 64°C. And thermometer drastically jumped to 70°C, after a hours of being warmed temperature reached 95°C but not droplets had occurred yet "

First droplet dropped at 98°C" This is where error occurred, because I let distillation run for a very long time after temperature reached 100°C. " .9843g, density= .9843 g/mL" Approximately, 12.7% weight and 8.0 volume %.

Set-up Images " "

Image 1 - Simple distillation

Image 2- Fractional Distillation

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Image 3- Fermentation set up

Results Simple Distillation

Mass .9843g

Density .9843g/mL

% Volume

8.0%

Volume (mL)

Temp (°C)

0.5

98

1.0

100

% Weight

1.5

102

12.7%

2.0

102

2.5

102

3.0

103

3.5

103

4.0

104

Simple Distillation 104

Temperature (°C)

102.25

100.5

98.75

97 0.0

0.5

1.5

2

2.5

mL of Distillate

3.0

3.5

4.0

Fractional Distillation

???. Tara’s fractional distillation observations. "

Discussion ! To start the experiment, a solution of yeast, sucrose and Pasteur salts were combined connected to a bath of lime water. While being left alone over the week, the yeast in the solution went through cellular respiration. Sucrose was consumer as nutrient source and ethanol and carbon dioxide was produced. To separate the ethanol from the the carbon dioxide the techniques of simple distillation and fraction distillation was applied. Distillation becomes an option to separate two liquid when the liquids boil at two different temperatures. Simple distillation is used when there is a larger scale different between two liquid’s boiling points but difficult to create a pure sample. Factional distillation uses a packing of glass beads to pack the column and allows a separation of different liquids. The liquids will begin to boil and condense into packing at different concentrations (column hold up). The liquids are more pure when closer to the top, so they are vapored again and collected. With the boiling points of the liquids being different, they will move up column and packing at different paces. " ! The significance of % and density measurements with respect to separating power of distillation techniques is the key to getting a pure ethanol sample. If extended past a certain temperature, the other liquid present in the sample starts boiling and end up collecting traces of that liquid also. Which makes the distillation pointless. This error occurred during experiment. The temperature exceeded ethanol boiling point and the water started boiling and a lot of water was measured in ending sample. This also means the azeotrope formed by ethanol and water was present in the sample. The

azeotrope is better explained using fraction distillation but the partner of experiment didn’t provide adequate observation to provide an actual example of technique." The 1st fraction was to contain the azeotrope between water and ethanol, the second to contain pure ethanol and the third to contain solely water because its range of temperature was the closest boiling pint of water. "

Post Lab Questions 1.! An azeotrope is a mixture with a constant boiling point, making the two liquids hard to separate. Ethanol-water azeotrope with 95% alcohol- 4% water will boil to dryness at a constant temperature. The boiling point of solution is 78°C , pure ethanol boils at 78°C and water boils at 100°C. The azeotrope boiling point is closer to the pure substance than the substance with the higher boiling point. " 2. ! A liquid compound having a azeotrope present or potentially have the same boiling point is why having a constant boiling point doesn’t necessarily mean it is a pure substance. But pure liquids will always have a constant boiling point. " 3. ! The second fraction should contain the highest % volume of ethanol because the 1st contains the azeotrope and the third contains the pure water. " 4. ! A Maximum boiling point azeotrope is a azeotrope with a boiling point higher than the boiling point of the two pure liquids. The minimum boiling point azeotrope is a azeotrope with a whole boiling point lower than the boiling point of the two pure substances. Ethanol-water azeotrope falls under the minimum boiling point azeotrope because the boiling point of compound is lower than waters boiling point....