Lesson 3.2. Extraction/Isolation Techniques

Liquid-liquid extraction

one of the most common methods for removing an organic compound from a mixture

purification

Liquid-Liquid Extraction is used by chemists not only in the isolation of natural products but also in the isolation and _________ of products from most chemical reactions.

greater solubility

Liquid-Liquid Extraction using a Separatory Funnel involves transferring a solute from one solvent into another, because of its a._________________ in the second. The two solvents must be b._____________ and form two distinct layers, and in general one layer is aqueous and the other is an organic solvent such as diethyl ether, hexane, or dichloromethane.

a = ?

immiscible

Liquid-Liquid Extraction using a Separatory Funnel involves transferring a solute from one solvent into another, because of its a._________________ in the second. The two solvents must be b._____________ and form two distinct layers, and in general one layer is aqueous and the other is an organic solvent.

b = ?

diethyl ether, hexane, or dichloromethane.

non-polar organic solvents usually used in Liquid-Liquid Extraction

Fill Separatory Funnels not more than ¾ full

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 1: ?

• The a.________________________________________________________ before any liquids are added to the funnel in case the stopcock leaks or is not completely closed.

stopcock should be closed and a clean beaker placed under the funnel

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 1:

• The a.________________________________________________________ before any liquids are added to the funnel in case the stopcock leaks or is not completely closed.

a = ?

so that when you shake it, the separation process would be more efficient

Why should separatory funnels be only filled ¾ full?

Holding and Using Separatory Funnels

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 2: ?

• If the contents of the funnel are to be shaken, it is held in a specific manner, use a.______________________________________________________.

swirling (gentle shaking)

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 2:

• If the contents of the funnel are to be shaken, it is held in a specific manner, a._________________, use one hand to hold the upper portion (near the stopcock) and the other on the funnel.

a = ?

Shaking the Separatory Funnel

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 3: ?

a. A separatory funnel and its contents should be shaken to mix the immiscible liquids as ____________ as possible.

b. The funnel must be vented every few seconds to avoid the b._______________ within the funnel.

c. ____________ is accomplished by inverting the funnel with the stopcock pointing upward and away from you and your neighbors and slowly opening it to release any pressure.

d. At the end of the period of shaking (___________ are usually sufficient if the shaking is vigorous), the funnel is vented a final time.

e. It is then supported on an ____________, and the layers are allowed to separate.

intimately

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 3: ?

a. A separatory funnel and its contents should be shaken to mix the immiscible liquids as ____________ as possible.

b. The funnel must be vented every few seconds to avoid the b._______________ within the funnel.

c. ____________ is accomplished by inverting the funnel with the stopcock pointing upward and away from you and your neighbors and slowly opening it to release any pressure.

d. At the end of the period of shaking (___________ are usually sufficient if the shaking is vigorous), the funnel is vented a final time.

e. It is then supported on an ____________, and the layers are allowed to separate.

a = ?

buildup of pressure

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 3: ?

a. A separatory funnel and its contents should be shaken to mix the immiscible liquids as ____________ as possible.

b. The funnel must be vented every few seconds to avoid the b._______________ within the funnel.

c. ____________ is accomplished by inverting the funnel with the stopcock pointing upward and away from you and your neighbors and slowly opening it to release any pressure.

d. At the end of the period of shaking (___________ are usually sufficient if the shaking is vigorous), the funnel is vented a final time.

e. It is then supported on an ____________, and the layers are allowed to separate.

b = ?

Venting

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 3: ?

a. A separatory funnel and its contents should be shaken to mix the immiscible liquids as ____________ as possible.

b. The funnel must be vented every few seconds to avoid the b._______________ within the funnel.

c. ____________ is accomplished by inverting the funnel with the stopcock pointing upward and away from you and your neighbors and slowly opening it to release any pressure.

d. At the end of the period of shaking (___________ are usually sufficient if the shaking is vigorous), the funnel is vented a final time.

e. It is then supported on an ____________, and the layers are allowed to separate.

c = ?

1–2 min

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 3: ?

a. A separatory funnel and its contents should be shaken to mix the immiscible liquids as ____________ as possible.

b. The funnel must be vented every few seconds to avoid the b._______________ within the funnel.

c. ____________ is accomplished by inverting the funnel with the stopcock pointing upward and away from you and your neighbors and slowly opening it to release any pressure.

d. At the end of the period of shaking (___________ are usually sufficient if the shaking is vigorous), the funnel is vented a final time.

e. It is then supported on an ____________, and the layers are allowed to separate.

d = ?

iron ring

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 3: ?

a. A separatory funnel and its contents should be shaken to mix the immiscible liquids as ____________ as possible.

b. The funnel must be vented every few seconds to avoid the b._______________ within the funnel.

c. ____________ is accomplished by inverting the funnel with the stopcock pointing upward and away from you and your neighbors and slowly opening it to release any pressure.

d. At the end of the period of shaking (___________ are usually sufficient if the shaking is vigorous), the funnel is vented a final time.

e. It is then supported on an ____________, and the layers are allowed to separate.

e = ?

Layer Identification

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 4: ?

It is important to ascertain which of the two layers in a separatory is the aqueous layer and which is the organic by searching their a.__________ wherein the lighter solvents are at the top.

density

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 4:

It is important to ascertain which of the two layers in a separatory is the aqueous layer and which is the organic by searching their a.__________ wherein the lighter solvents are at the top.

a = ?

Emulsion (Main Problem)

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 5: ?

Occasionally the two immiscible liquids will not separate cleanly into two distinct layers after shaking, because an emulsion may form that results from a a.______________ of the two layers.

• Remedies

I. Add a few milliliters of a _________________________________________ because it increases the ionic strength of the aqueous layer.

II. Mechanical/Filter Method: Filter the heterogeneous mixture by ______________ through a thin pad of a filter-aid which removes gums and mucilage.

III. Add a small quantity of _____________________ like surfactants to the mixture and re-shake the mixture.

colloidal mixture

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 5:

Occasionally the two immiscible liquids will not separate cleanly into two distinct layers after shaking, because an emulsion may form that results from a a.______________ of the two layers.

• Remedies

I. Add a few milliliters of a _________________________________________ because it increases the ionic strength of the aqueous layer.

II. Mechanical/Filter Method: Filter the heterogeneous mixture by ______________ through a thin pad of a filter-aid which removes gums and mucilage.

III. Add a small quantity of _____________________ like surfactants to the mixture and re-shake the mixture.

a = ?

saturated solution of aqueous sodium chloride (brine)

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 5:

Occasionally the two immiscible liquids will not separate cleanly into two distinct layers after shaking, because an emulsion may form that results from a a.______________ of the two layers.

• Remedies

I. Add a few milliliters of a _________________________________________ because it increases the ionic strength of the aqueous layer.

II. Mechanical/Filter Method: Filter the heterogeneous mixture by ______________ through a thin pad of a filter-aid which removes gums and mucilage.

III. Add a small quantity of _____________________ like surfactants to the mixture and re-shake the mixture.

I = ?

vacuum filtration

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 5:

Occasionally the two immiscible liquids will not separate cleanly into two distinct layers after shaking, because an emulsion may form that results from a a.______________ of the two layers.

• Remedies

I. Add a few milliliters of a _________________________________________ because it increases the ionic strength of the aqueous layer.

II. Mechanical/Filter Method: Filter the heterogeneous mixture by ______________ through a thin pad of a filter-aid which removes gums and mucilage.

III. Add a small quantity of _____________________ like surfactants to the mixture and re-shake the mixture.

II = ?

water-soluble detergent

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 5:

Occasionally the two immiscible liquids will not separate cleanly into two distinct layers after shaking, because an emulsion may form that results from a a.______________ of the two layers.

• Remedies

I. Add a few milliliters of a _________________________________________ because it increases the ionic strength of the aqueous layer.

II. Mechanical/Filter Method: Filter the heterogeneous mixture by ______________ through a thin pad of a filter-aid which removes gums and mucilage.

III. Add a small quantity of _____________________ like surfactants to the mixture and re-shake the mixture.

III = ?

Drying Agents

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 6: ?

a. In order to remove these small traces of water, drying agents, sometimes called ___________, are used.

b. Commonly used drying agent: __________________

There are two general requirements for a drying agent:

(1) neither it nor its hydrolysis product may react ____________ with the organic liquid being dried

(2) it must be _______________________ from the dry liquid. A drying agent should also be efficient so that the water is removed in a reasonably short period of time.

desiccants

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 6:

a. In order to remove these small traces of water, drying agents, sometimes called ___________, are used.

b. Commonly used drying agent: __________________

There are two general requirements for a drying agent:

(1) neither it nor its hydrolysis product may react ____________ with the organic liquid being dried

(2) it must be _______________________ from the dry liquid. A drying agent should also be efficient so that the water is removed in a reasonably short period of time.

a = ?

CaCl2, Na2SO4, MgSO4

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 6:

a. In order to remove these small traces of water, drying agents, sometimes called ___________, are used.

b. Commonly used drying agent: __________________

There are two general requirements for a drying agent:

(1) neither it nor its hydrolysis product may react ____________ with the organic liquid being dried

(2) it must be _______________________ from the dry liquid. A drying agent should also be efficient so that the water is removed in a reasonably short period of time.

b = ?

chemically

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 6:

a. In order to remove these small traces of water, drying agents, sometimes called ___________, are used.

b. Commonly used drying agent: __________________

There are two general requirements for a drying agent:

(1) neither it nor its hydrolysis product may react ____________ with the organic liquid being dried

(2) it must be _______________________ from the dry liquid. A drying agent should also be efficient so that the water is removed in a reasonably short period of time.

1 = ?

completely and easily removed

Liquid-Liquid Extraction using a Separatory Funnel:

STEP 6:

a. In order to remove these small traces of water, drying agents, sometimes called ___________, are used.

b. Commonly used drying agent: __________________

There are two general requirements for a drying agent:

(1) neither it nor its hydrolysis product may react ____________ with the organic liquid being dried

(2) it must be _______________________ from the dry liquid. A drying agent should also be efficient so that the water is removed in a reasonably short period of time.

2 = ?

acid-base extraction

If one or more of the compounds in the mixture to be separated is acidic or basic, the solubilities of these acidic and basic components can be manipulated.

insoluble

Since benzoic acid and phenol are organic compounds, both are a._________ in water and b.______ in ether.

a = ?

Soluble

Since benzoic acid and phenol are organic compounds, both are a._________ in water and b.______ in ether.

b = ?

ether

Separation of Benzoic Acid and Phenol using acid-base extraction (FIRST EXTRACTION):

1. Dissolve the sample (Benzoic acid + Phenol) in _________.

2. Extract with _____________________ which will interact with the acid, ionizing it.

3. It will form 2 layers:

a. Upper (Organic Layer)/Ether contains _______

b. Lower (Aqueous Layer) contains ______________________

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Benzoic Acid.

1 = ?

NaHCO3/H2O

Separation of Benzoic Acid and Phenol using acid-base extraction (FIRST EXTRACTION):

1. Dissolve the sample (Benzoic acid + Phenol) in _________.

2. Extract with _____________________ which will interact with the acid, ionizing it.

3. It will form 2 layers:

a. Upper (Organic Layer)/Ether contains _______

b. Lower (Aqueous Layer) contains ______________________

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Benzoic Acid.

2 = ?

phenol + neutral compound

Separation of Benzoic Acid and Phenol using acid-base extraction (FIRST EXTRACTION):

1. Dissolve the sample (Benzoic acid + Phenol) in _________.

2. Extract with _____________________ which will interact with the acid, ionizing it.

3. It will form 2 layers:

a. Upper (Organic Layer)/Ether contains _______

b. Lower (Aqueous Layer) contains ______________________

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Benzoic Acid.

3.a. = ?

Sodium Benzoate (Na + Benzoic Acid)

Separation of Benzoic Acid and Phenol using acid-base extraction (FIRST EXTRACTION):

1. Dissolve the sample (Benzoic acid + Phenol) in _________.

2. Extract with _____________________ which will interact with the acid, ionizing it.

3. It will form 2 layers:

a. Upper (Organic Layer)/Ether contains _______

b. Lower (Aqueous Layer) contains ______________________

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Benzoic Acid.

3.b. = ?

Separate

Separation of Benzoic Acid and Phenol using acid-base extraction (FIRST EXTRACTION):

1. Dissolve the sample (Benzoic acid + Phenol) in _________.

2. Extract with _____________________ which will interact with the acid, ionizing it.

3. It will form 2 layers:

a. Upper (Organic Layer)/Ether contains _______

b. Lower (Aqueous Layer) contains ______________________

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Benzoic Acid.

4 = ?

HCl

Separation of Benzoic Acid and Phenol using acid-base extraction (FIRST EXTRACTION):

1. Dissolve the sample (Benzoic acid + Phenol) in _________.

2. Extract with _____________________ which will interact with the acid, ionizing it.

3. It will form 2 layers:

a. Upper (Organic Layer)/Ether contains _______

b. Lower (Aqueous Layer) contains ______________________

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Benzoic Acid.

5 = ?

organic layer (phenol + neutral compound)

Separation of Benzoic Acid and Phenol using acid-base extraction (SECOND EXTRACTION):

1. Get the _______________________________ from the 1st extraction.

2. Extract the compound with ______________, ionizing it.

3. It will separate into 2 layers:

a. Lower Layer (Aqueous) contains ___________________________.

b. Organic Layer contains a __________________________.

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Phenol.

1 = ?

NaOH/H2O

Separation of Benzoic Acid and Phenol using acid-base extraction (SECOND EXTRACTION):

1. Get the _______________________________ from the 1st extraction.

2. Extract the compound with ______________, ionizing it.

3. It will separate into 2 layers:

a. Lower Layer (Aqueous) contains ___________________________.

b. Organic Layer contains a __________________________.

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Phenol.

2 = ?

Na + Phenol

Separation of Benzoic Acid and Phenol using acid-base extraction (SECOND EXTRACTION):

1. Get the _______________________________ from the 1st extraction.

2. Extract the compound with ______________, ionizing it.

3. It will separate into 2 layers:

a. Lower Layer (Aqueous) contains ___________________________.

b. Organic Layer contains a __________________________.

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Phenol.

3.a. = ?

neutral compound

Separation of Benzoic Acid and Phenol using acid-base extraction (SECOND EXTRACTION):

1. Get the _______________________________ from the 1st extraction.

2. Extract the compound with ______________, ionizing it.

3. It will separate into 2 layers:

a. Lower Layer (Aqueous) contains ___________________________.

b. Organic Layer contains a __________________________.

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Phenol.

3.b. = ?

Separate

Separation of Benzoic Acid and Phenol using acid-base extraction (SECOND EXTRACTION):

1. Get the _______________________________ from the 1st extraction.

2. Extract the compound with ______________, ionizing it.

3. It will separate into 2 layers:

a. Lower Layer (Aqueous) contains ___________________________.

b. Organic Layer contains a __________________________.

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Phenol.

4 = ?

HCl

Separation of Benzoic Acid and Phenol using acid-base extraction (SECOND EXTRACTION):

1. Get the _______________________________ from the 1st extraction.

2. Extract the compound with ______________, ionizing it.

3. It will separate into 2 layers:

a. Lower Layer (Aqueous) contains ___________________________.

b. Organic Layer contains a __________________________.

4. _________________ the two layers.

5. Add _________ to the Aqueous Layer, to unionize the compound, leading to Phenol.

5 = ?

neutral RNH2 (amine)

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

1 = ?

5% HCl (aq)

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

2 = ?

Neutral Solution + Benzoic Acid

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

3.a. = ?

RNH3Cl (RNH2 + 5% HCl)

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

3.b. = ?

2M NaOH

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

4 = ?

Filter

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

5.a. = ?

evaporate

Separation of Carboxylic Acid and an Amine:

1. Add __________________ which is your organic solvent.

2. Add ________________.

3. 2 layers would be formed:

a. Organic Layer contains the __________________

b. Aqueous Layer contains _____________________.

4. Neutralize the aqueous layer with ____________ to give a pH 9-11.

5. To collect the sample:

   a. ________ if solid.

b. __________ if liquid

5.b. = ?