Extraction Practicum of Science Laboratory 2 - IPSE FPMIPA UPI Assignment

 Science Laboratory 2

Extraction Practicum

A.    Date           : October 9, 2017

      B.     Tittle          : Extraction

      C.    Objective   : To determine the solubility of solvent in extraction process

      D.    Basic Theory

Most chemical reactions show poor selectivity as the types of metal ions that take part. To improve the selectivity, it is common to resort to extraction methods. Solutes have different solubilises in different solvents, and the process of selectively removing a solute from a mixture with a solvent is called extraction. The solute to be extracted may be in a solid or in a liquid medium, and the solvent which is used for the extraction process may be water, a water-miscible solvent, or a water-immiscible solvent. The selection of the solvent to be used depends upon the solute and upon the requirements of the experimental procedure. An ideal extraction method should be rapid, simple, and inexpensive to perform; should yield quantitative recovery of target being analysed without loss or degradation; and should yield that is immediately ready for analysis without additional concentration or class fractionation steps. (Patnaik, 1995)

A simple extraction is often used in the work-up of an organic reaction mixture, but extraction can be used to separate and purify organic compounds. Extraction is particularly useful in the separation of acidic and basic components from an organic mixture by their reaction with dilute aqueous base or acid as appropriate. Since this relies on an acid-alkaline chemical reaction, the technique often called chemically active extraction. Whatever extraction protocol is being used, most extraction operations in the organic chemistry laboratory are carried out in separator funnels.

When an organic compound, X, is placed in a separator funnel with two immiscible liquids, such as water and chloroform, some of compound will dissolved in the water and some in the chloroform. In more technical language, the compound is said to partition or distribute itself between the two liquids, and the exact amount of X in each place phase clearly depends on its relative solubility in water and chloroform. The ratio of the concentration of X in each phase is known as the partition coefficient or distribution coefficient. (Cranwell, 2017) 

      E.     Materials and Equipments

1.    Materials :                                                

1.      Iodium (solid)

2.      Chloroform

3.      Distilled Water

4.    Equipments :                                            

1.         Balance (1 set)

2.         Watch glass (1)

3.         Iron ring (1)

4.         Beaker glass 250 mL (2)

5.         Graduated cylinder 200 mL (1)

6.         Stand (1)

7.         Spatula (1)

8.         Stirring rod (1)

9.         Separator funnel (1)

10.     Aquadest bottle (1)

11.     Pipette (1)

           F.     Observation Table

No	Procedure	Observation
1.	Separation of camphor ( C10H16O ) from contaminator Ø  Contaminated camphor powder is weighted by using balance and watch glass     Ø  The contaminated camphor powder is placed in 100 mL beaker glass by using spatula   Ø  50 mL of water are added into 100 mL round-bottom flask by using aquadest bottle   Ø  Beaker glass is placed on the wire gauze which already placed set up on the tripod   Ø  Bunsen burner is placed in the centre of tripod   Ø  100 mL round-bottom flask filled with 50 mL of water is placed on the surface of 100 mL beaker glass until the beaker glass’ surface is covered   Ø  The holes around the outer circle of beaker glass are plugged by aluminium foil   Ø   The bunsen burner is turned on by using matches and set up to be small fire             Ø  The fire is turned off and round-bottom flask is picked up by using tissue                   Ø  The crystals are collected by using spatula, placed on watch glass, and weighted by using balance	·         1 gram of contaminated camphor powder       ·         The initial colour of contaminated camphor powder is black         ·         Its colour is still black             ·         The temperature of water is in room temperature                                               ·         The contaminated camphor powder get burn       ·         The colour of powder slowly turn white       ·         By time, the bottom of the flask has visually something like dew       ·         The colour of substance in beaker glass turns black again           ·         There are some crystals on the bottom of the flask       ·         The colour of crystals is white       ·         The colour of substance in beaker glass is black burnt       ·         The colour of water is still colourless and the temperature is a bit warmer             ·         0.126 gram of crystal gotten       ·         The shape of crystals is star look alike

G.    Analysis Data and Discussion

Ø  Analysis data

At first, we do the calculation to determine mass of crystal and mass of the black substance:

Known:

Initial mass of contaminated powder: 1 gram

Mass of crystal: 0.216 gram

Question: Mass of the black substance?

Answer:

Initial mass of contaminated camphor powder = Mass of crystal + Mass of the black substance

1 gram = 0.216 gram + x

X = 1 gram – 0.216 gram

    = 0.784 gram = Mass of black substance

 

So, the mass of black substance left in beaker glass is 0.784 gram.

Ø  Discussion

            The black substance which had been mentioned above is carbon and mixed with the pure camphor that has original colour of crystal white. Carbon and camphor may have different vapour pressure which camphor has lower vapour pressure than carbon, so the camphor could sublimate and separate from the contaminator, carbon, or residue and becomes pure camphor (the crystal).

            After measurement, we got 0.216 gram of crystal or pure camphor. Because we don’t do the measurement for the residue to make sure the mass of it due to limited time and number of balance set, we just do the math to determine the mass of carbon or residue. It is quite confused and insecure at first because we don’t know the ratio of carbon and pure camphor before mixed. So, it is a bit hard to know if the result of crystal is in normal or expected mass of crystal after the experiment. But, at least, we can assume by the colour of initial powder which is visually almost completely black, so the carbon is much more than pure camphor and it can make the gotten result of crystal’s mass and the mass of residue just right and reliable.

            And also, not just because we didn’t actually do the real measurement using balance to determine the mass of residue, the less mass of crystal can be predicted occur because we picked up the flask three times to see if the sublimation had already started and checked the amount of crystal on the bottom of flask to see if the sublimation had stopped which could be known if there were no addition of crystal from the amount of crystal since the last checked up. The repeated pick up during the heating may influence the amount of crystal in the end. Because since the holes are covered by the aluminium to prevent any heat flowing out the system which can impact factors such as temperature, vapour pressure, and possibility of sublimation, the repeated pick up might also cause the heat flowing out and influence temperature which impact pressure which impact the possibility of sublimation. Because if we want higher possibility of sublimation, we should have high temperature to get high pressure. And the repeated pick up cause the substance couldn’t get maximum heat to do maximum sublimation and this analysis can be the fact of why we got few amount of crystal or pure camphor.

            And for the water in round-bottom flask, because we didn’t use thermometer, then we assumed that initial temperature of water followed the room temperature. And because we also didn’t use thermometer to measure the temperature of water after heating. It just can be known by touch. When picking up the flask which made of glass, the flask was felt warmer because of the heating and it can be assumed that so was the water.

      H.    Conclusion

After all, we can conclude that sublimation technique can be used as the method to separate impurity mixture and in the experiment, we get 0.216 gram of crystal or pure camphor and 0.784 gram of contaminator or residue or carbon. This technique is quite simple to applied and give good experimentally result of pure substances as expectation based on either theoretically or formulated calculation.

       I.       References

Furniss, B.S, Hannaford, A.J, Smith, PWG, and Tatchell, A.R. (1989). Vogel's textbook of Practical Organic Compound. Longman Group: UK

A.Holden, Claire, and Howard S. Bryant. (1968). Purification by Sublimation.    Taylor & Francis Group: England

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