Distillation of Vodka

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Determination of Alcohol in Antonov Through Simple Distillation

*Lee, Sharmine Margaret Cruz

AbstractVodka is composed principally of two ingredients, water and ethanol, with traces of few impurities and additives giving

it 80 as its proof and 40 as its percent ethanol. The experimentation aimed to separate its major constituents, and to

determine the percent concentration of ethanol by using simple distillation method.A calibrated volume of 20 mLvodka was placed in the distillation set-up and was heated constantly. A calibrated volume (0.5 mL or 10 gtt) of

distillate was collected in every test tube pending the temperature until it reached close to 100o

C. The volume odistillate collected by the end of the distillation was 11.0mL at 98 oC, giving a percent alcohol of 55%.

Introduction

Distillation is a method where in a mixture

of liquids with sufficiently different boiling points

can often be separated into its components. Thisis a purifying technique where it can be simply

explained as a process of converting liquid to avapour, condensing the vapour, and then

collecting the distillate into a separate container.

Vodka is colourless liquid, usually distilled from

fermented grains such as sorghum, corn, rye orwheat. Water on the other hand is known to usas the universal solvent. The objective of the

experiment is to

(1) Separate the components of an alcoholic

beverage (vodka) by using simple distillation,

(2) Calculate the percentage of ethanol and

percentage loss in vodka, and

(3) Examine and observe simple distillation

carefully and at a better perspective.

Methodology

All the needed materials were equipped

and cautiously set-up for the simple distillation

procedures. The joints on each end were securelywrapped with masking tape to inhibit vapour lossand for the safety of these glass apparatus.

Boiling stones were placed in the quick-fit

distilling flask (3 pieces of boiling stones). Acertain volume (20mL) of the sample beverage

(vodka) was also added here. Subsequently, the

flask was heated with an alcohol lamp which wascontinuously being rotated underneath the flask.A certain volume (0.5mL) of distillate was

collected in calibrated test tubes until the set-upreached an approximate temperature of 98oC.Afterwards, the set-up was cooled and the

volume of the residue was recorded. The first and

the last distillate were collected for a flammabilitytest. The temperature readings and the volumeof the distillate gathered were plotted in a graph.

The percent alcohol and percent loss were alsoconsidered in the experiment.

Results & Discussion

The quick-fit apparatus was used. Thecomponents of a quick-fit apparatus are (1) a

pear-shaped flask, where the residue is placed

(2) a distilling head, which holds thethermometer to allow the temperature of vapours

to be observed during the distillation process, (3)

a liebig condenser which is a tube surrounded bya water jacket to cool and condense vapours, (4)

a mercurial thermometer to measure thetemperature, and (5) a receiver adapter that

connects the condenser and receiver.

Fig.1. Simple Distillation Set-Up with a test tubeas its receiving flask.
http://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Water


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In the pear-shaped flask contained the20mL sample of vodka and 3 pieces of boiling

stones. The boiling stones were irregularly

shaped. They are added to liquid samples tomake them boil more smoothly. They provide

nucleation sites so that the liquid boils easily

without becoming superheated.

The heating of the flask should gradually

be rotated. However, if heating is too rapid andthe condensate is pushed too rapidly, equilibriumbetween liquid and vapour will not occur and

separation of the components will be

substandard. If the flask is heated too stronglybefore the distilling head has been warmed byhot vapours and condensate, the still head may

overflow, or show an unnecessary amount of

liquid in one or more portions. The following table

shows the result from the simple distillation:

Table 1 illustrates that as the volume ofdistillate increases, the temperature also

increases until the temperature closes to 100oC

It is observed that they are directly proportionato each other. In this experiment, two distinct

conclusions are obtained. The first corresponds to

the component with the least boiling point whichis separated first, and the second correspondswith the highest boiling point that is drawn off

last. The component with the highest boilingpoint can be distilled and redistilled until itbecomes pure.

Daltons Law of Partial Pressure provesthis theory stating that a mixture will only boil ifthe sum of the two partial pressures is equal to

the atmospheric pressure. According to Raoults

Law, the partial vapour pressure of a mixture in

an ideal solution is equal to the vapour pressureof that pure mixture times its mole fraction in the

liquid. The theory of Daltons and Raoults law isthat the vapour composition above a mixture is

dependent both on the vapour pressures of thepure compound and on their mole fraction in the

mixture.

The first test tube produced a blue flame

which means that ethanol is present in the firstdistillate, while the drops collected in the fina

distillate did not produce any flame becausealcohol has already been separated. It shows that

as the distillation of the sample continues, there

is a decreasing amount of alcohol being gatheredin the separate test tubes. The first test tube

contains the most alcohol compared to the

succeeding test tubes used which contain adecreasing amount of ethanol.

Figure 2 (found on the next page) shows

that as the volume of temperature increases

the amount of distillate also increases. When the

temperature reached close to 100oC, at about

98oC, the temperature stopped escalating and is

constant as depicted by the straight lines in the

graph.

Test

Tube

Volume

(mL)Temperature oC

Flame

Test1 0.50 78 Blue

2 1.00 79

3 1.50 80

4 2.00 81

5 2.50 82

6 3.00 82

7 3.50 82

8 4.00 82

9 4.50 82

10 5.00 8311 5.50 84

12 6.00 84

13 6.50 84

14 7.00 84

15 7.50 89

16 8.00 91

17 8.50 92

18 9.00 93

19 9.50 96

20 10.00 9621 10.50 97

22 11 98 Negative

Table 1. Volume, Temperature and FlammabilityTest of the distillate


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Using the formulas above, we will obtain the

results:

Therefore, the percent alcohol of the

sample is 55%. The percent loss of 10%, on the

other hand, is the percentage loss. Simpledistillation is used in separating components of

liquid mixtures, which have boiling point more

than 25C from each other at one atmosphericpressure. Fractional distillation separates liquidmuch better than simple distillation because of

the glass beads present in the fractionatingcolumn. Simple distillation gives inferiorseparation than fractional distillation for it

provides theoretical plates on which the refluxing

liquid can condense, re-evaporate and condenseagain, essentially distilling the compound all overagain.

References

[1] Mayo, D.W., Pike, R.M. & Trumper, P. K

(2000).Microscale Organic Laboratory. 4th ed

New York: John Wiley & Sons, Inc. pp. 617-651.

[2] Whitten,K.W.,(2010). Chemistry. 9th ed. CA

Mary Finch. P.493

[3] Vodka.http://www.associatepublisher

.com/e/v/vo/vodka.htm. June 29,2012


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Distillation of Vodka