Experiment 1: Macroscale Extraction

[TRUE/FALSE] solute is MORE SOLUBLE in the second solvent than the first

TRUE. That is the reason why the solute is EXTRACTED from one solvent into the other

[TRUE/FALSE] The difference in POLARITIES of solvents involved in extraction are important to be considered

TRUE

[TRUE/FALSE] During extraction, the solute and solvent must be MISCIBLE to mix freely

FALSE. The solvents must be IMMISCIBLE to freely mix.

[TRUE/FALSE] The two solvents muist also be able to create separate layers for the extraction to work

TRUE.

[TRUE/FALSE] Extraction is included in the most important techniques for isolating and purifying organic substances

TRUE

CAFFEINE may be extracted from tea using what solvent?

DICHLOROMETHANE (DCM)

VANILLIN may be extracted frm vanilla using what solvent?

ETHANOL

[TRUE/FALSE] Natural products in animal and plants have LOW WATER CONTENT making it easy for extraction

FALSE. They have HIGH water content

Since natural oroducts are water-soluble substances, what must be the characteristic of your solvent?

Water Immiscible Organic Solvent.. They are particularly useful for isolating the matural products

THREE COMMONLY USED ORGANIC SOLVENTS

1.Diethyl ether, 2. Hexane, 3. Dichloromethane

The APPARATUS used for extraction

Separatory Funnel

[TRUE/FALSE] Organic Solvents are slightly polar solvents.

TRUE. They should be nonpolar or slightly polar in order to properly extract the organic compound frm the solution

what are the two layers that will form during extraction in a separatory funnel

- aqueous layer

- organic layer

[TRUE/FALSE] shaking the funnel will allow the layers to separate

TRUE

[TRUE/FALSE] A water wash removes highly polar and water-soluble materials from the organic layer

TRUE

[TRUE/FALSE] Emulsion may form during shaking

TRUE

What do you add to the solution to prevent emulsion?

Add a SATURATED SODIUM CHLORIDE SOLUTION

What can YOU DO to prevent emulsion from forming?

Gently stir ussing the glass rod

What SHOULD YOU DO while shaking, to prevent the breaking of the funnel?

After 3 shakes, slowly open the lever to release the gas

[TRUE/FALSE] You can add a drop of water to the sample and the solution it dissolves with is the ORGANIC LAYER

FALSE. The layer where the water will combine with is the WATER-SOLUBLE LAYER/AQUEOUS LAYER

caffein is extracted using what solvent?

dichloromethane

Is dichloromethane denser than water?

Yes

If dichloromethane is denser than water, where will its layer most likely be? [upper/lower]

Lower. The aqueous solution is the upper layer

Can you repeat the extraction using DCM several times?

Yes, you can.

What is the next step after you get the organic layer?

Dehydrate the solution

What do you add to the DCM extract to remove the excess water?

Add anhydrous sodium sulfate

[TRUE/FALSE] Water is used to wash water-soluble impurities

TRUE

[TRUE/FALSE] Add all of the anhydrous sulfate before dehydrating the DCM extract

FALSE. You need to add the anhydrous sulfate PORTION BY PORTION

If the extract after dehydration is too small, what is the alternative to filtration?

Decantation

Technically, What should be done after you dehydrate the extract?

Filter it.

Where should you put the filtrated extract?

In an empty evaporating dish

[TRUE/FALSE] The empty evaporating dish should be pre-weighed

TRUE

Why do you need to pre-weigh the evap dish?

For the calculation of percent yield

After filtration of the extract, what is the next step?

A. Proceed to Murexide Test

B. Proceed to Steam Bath

C. Proceed to adding Potassium chlorate

B. Proceed to steam bath.

This is to get the caffeine in preparation of the murexide test

What will happen to the caffeine if you let the filtered extract too long in the steam bath?

A. Caffeine will turn yellow

B. Caffeine will turn white

C. Caffeine will sublime

D. Nothing will happen to caffeine

C. Caffeine will sublime

At what temperature will the caffeine start to sublime?

A. 168 deg

B. 127 deg

C. 178 deg

C. 178 deg

After the dryong of caffeine, what is the next step?

Weigh it with the evaporating dish

What do you need to compute for the extraction of caffeine?

Its percentage yield

[TRUE/FALSE] You need 0.4 g of the caffeine powder for the murexide test

FALSE. You only need a PINCH of it

Formula of Percentage yield

% yield = [Weight of the caffeine / weight of the solution] x 100

From what value will you get the weight if the solution?

galing sa weight ng coffee na ginamit niyo para sa solution. Sa case ng experiment natin, ang wt. of solution is 1.9 g

A 1.5 g of caffeine was extracted from a 1.9% coffee solution. COMPUTE for the % yield.

78.95%

What are the two reagents that you will put to the caffeine for the murexide test?

Concentrated HCl and KClO3

What color will the outcome be after adding the wo reagents and outting them to a steam bath?

yellow

What reagent will be used to moisten the mixture?

Ammonia (NH3)

[TRUE/FALSE] Any purine will react to HCl and KClO3 even without ammonia

FALSE. A purine will react to HCl and KClO3 when exposed to ammonia

What is the name of the solution formed when the dehydrated base mixture is exposed/moistened with ammonia?

Murexide

What color will be evident when a purine is exposed to ammonia?

Purple Color

[TRUE/FALSE] When an unknown substance produces a purple color upon exposure to ammonia, it is automatically ruled out as caffeine

FALSE. Caffeine is a purine. All purines react with ammonia to produce a purple color. So you still cannot guarantee if it is caffeine but you are sure that it is a purine compound

Do Xanthines produce a positive result with murexide test as well?

Yes

Which is the correct IUPAC name of Caffeine?

A. 2,4,8-triethylpurine-2,6-dione

B. 1,3,7-triethylpurine-2,6-dione

C. 1,3,7-trimethylpurine-2,6-dione

D. 2,4.8-trimethylpurine-2,6-dione

C. 1,3,7-trimethylpurine-2,6-dione

give the synonym of Caffeine

1,3,7-trimethylxanthine

Which is the correct formula of caffeine?

A. C6-H10-N4-O2

B. C8-H10-N4-O2

C. C8-H12-N4-O2

B. C8-H10-N4-O2

Color of caffeine?

White

Odor of caffeine?

Odorless

Taste of caffeine?

Bitter

[kaya nga bitter ka eh, eme, yung kape pala]

Boiling point of caffeine?

178 deg

Melting point of caffeine?

235 deg

Density of caffeine?

1.23 g/cm3

What is its primary use?

Stimulant

Chemical safety of caffeine?

Irritant

What are the two groups seen in caffeine’s structure?

A. 3 methyl groups

B. 1 purine ring