Clove Oil

Question 1

Name given to this method of isolation?

Answer 1

Steam distillation

Question 2

Why is steam distillation used?

Answer 2

Some components of clove oil have high boiling points and high temperatures would damage the molecules in oil

Question 3

Why can’t cloves be heated directly? And at what temp is it at

Answer 3

It would cause cloves to char and oil would be destroyed therefore steam is used and temp is kept slightly above 100 Celsius

Question 4

Where is the steam produced?

Answer 4

Steam generator

Question 5

What is the function of the safety tube?

Answer 5

Ensures there is no build up of pressure in steam generator

Question 6

What would occur if there was no safety tube?

Answer 6

The pressure in steam generator would increase and therefore water would be pushed up safety tube

Question 7

What is the purpose of the steam trap?

Answer 7

It traps the steam that has condensed to water

Question 8

What would occur if steam trap was no present?

Answer 8

Flask with cloves would fill up with water from condensed steam

Question 9

Why are whole cloves used in this experiment?

Answer 9

They contain the bud of the clove which is part with most oil

Question 10

Name and chemical formula of oil found in cloves?

Answer 10

Eugenol, C10H12O2

Question 11

What’s the boiling point of eugenol?

Answer 11

254 degrees celsius

Question 12

Why are the cloves harvested/picked before they flower?

Answer 12

Stage in which its richest in oil

Question 13

Give a safety precaution

Answer 13

Wear gloves during exp - eugenol can burn skin

Question 14

Describe steps used in extraction?

Answer 14

Set up apparatus as shown
Add whole cloves and warm water in pear shaped flask
Connect steam generator to rest of apparatus and heat to boiling point. Regulate heat so there is a constant supply of steam to pear shaped flask
Add anti bumping granules in steam generator
Leave for a few minutes
Collect distillate - pale milky appearance

Question 15

What is the distillate of the experiment?

Answer 15

Emulsion [product of experiment]

Question 16

What’s an emulsion?

Answer 16

Mixture of immiscible liquids where tiny particles of one liquid are dispersed throughout the other, but not dissolved

Question 17

Common emulsion found in everyday life?

Answer 17

Mayonnaise - em of oil in water

Question 18

Appearance of emulsion?

Answer 18

Pale and milky

Question 19

How do you remove the oil from the emulsion?

Answer 19

Solvent extraction

Question 20

Name a suitable solvent for solvent extraction?

Answer 20

Cyclohexane

Question 21

Why is cyclohexane suitable for solvent extraction

Answer 21

It will dissolve clove tuenoil but no other substances

Question 22

Describe steps in solvent extraction

Answer 22

Add cyclohexane to emulsion in a sep funnel, where two liquids are “washed” - shaken for few minutes in stoppered funnel
Two liquids are separated into layers and water layer is discarded
Magnesium sulphate is added to organic solution and acts a drying agent and swirl conical flask
Pour into fluted paper in funnel which separated mg sulphate from oil and cyclohexane into clean dry flask
Evaporate cyclohexane in evaporating dish

Question 23

What is meant by washing?

Answer 23

Extract the maximum amount of clove oil from emulsion

Question 24

When the emulsion is “washed” what is observed?

Answer 24

Less milky, more clear solution

Question 25

What is the purpose of adding anhydrous magnesium sulfate to organic solution?

Answer 25

Acts as a drying agent

Question 26

How do you know enough magnesium sulphate is added?

Answer 26

Until powder settles at the bottom without forming clumps

Question 27

Why is it necessary to remove magnesium sulphate from cyclohexane solution?

Answer 27

To remove any traces of oil from magnesium sulphate

Question 28

How is magnesium sulphate removed?

Answer 28

By filtration and washing with cyclohexane

Question 29

How is cyclohexane removed from clove oil?

Answer 29

Evaporation in evaporating dish/over water bath

Question 30

Give two reasons why cannot heat directly with Bunsen burner to remove cyclohexane

Answer 30

Cyclohexane is flammable | Oil and cyclohexane could be evaporated together

Question 31

Give two uses of clove oil

Answer 31

Flavouring foods | Pain relief

Question 32

Name another substance that can be extracted with steam distillation

Answer 32

Orange oil from skin of oranges

Question 33

Give a brief note explaining how steam distillation is used to extract oils from plant materials

Answer 33

Steam passes through plant material which forms a gaseous emulsion with oil in plant material. Hot emulsion is forced under pressure into Liebig condenser and converts gaseous emulsion into liquid and is extracted with organic solvent

Question 34

What substance distilled across along with natural product?

Answer 34

Steam/h20

Question 35

Identify safety feature of apparatus

Answer 35

Safety tube - ensures there's no pressure build up in safety generator Air tight seals - no steam escapes

Question 36

What is meant by Imiscible liquids

Answer 36

Do not dissolve in each other

Question 37

How to calculate percentage yield?

Answer 37

pure mass organic liquid / plant material x100/1

Question 38

What natural product did you extract in the school lab using steam distillation?

Answer 38

Eugenol

Question 39

What substance distilled alongside the Eugenol?

Answer 39

Water

Question 40

Name a technique that could be used to seperate the organic substance from the water

Answer 40

Solvent Extraction

Question 41

Calculate percentage yield - which is actual yield and which is theoretical yield

Answer 41

actual yield - what was actually obtained | theoretical yield - you either work out, or its the other grams

Question 42

What is the difference between a seperating funnel and and a dropping funnel?

Answer 42

S funnel - has a stopper | Dropping funnel - has no stopper

Question 43

Why is a beaker always placed below seperating funnel

Answer 43

In case tap is left open, to collect solution

Question 44

During solvent extraction, washing occurs and the tap is opened, why?

Answer 44

To release pressure of vaporised liquid inside the funnel

Question 45

In solvent extraction, why is washing repeated?

Answer 45

In order to extract the maximum amount of oil from the emulsion

Question 46

What is the purpose of adding the anhydrous magnesium sulphate during solvent extraction

Answer 46

To absorb the water from solution (oil of cloves - eugenol)

Question 47

What is the purpose of fluted filter paper?

Answer 47

Speeds up filtration - the surface area of the filter paper in contact with the liquid is greater

Question 48

What remains in filtered paper after filtration of magnesium sulfate from oil of cloves solution

Answer 48

Magensium sulphate

Question 49

What is the structure of eugenol?

Answer 49

Benzene + 3 carbons with one double bond on second carbon. on top - OH, and then beside, OCH3

Question 50

Why shouldn't you allow eugenol to come in contact with skin?

Answer 50

It has a burning effect on skin

Question 51

Name a spectroscopic technique that could help confirm the identity of a sample of Eugenol

Answer 51

IR infrared