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Other organic derivatives and polymers
NAME
SECTION.
DATE.
Other organic derivatives and polymers E X P E R I M E N T 12A OBJECTIVE:
To observe the chemical properties of amides.
EQUIPMENT:
50-ml and 125-ml Erlenmeyer flasks stopper for 50-ml Erlenmeyer flask ring stand 500-ml beaker
CHEMICALS:
benzoic anhydride ammonia (concentrated) acetamide sodium hydroxide solution (10%) urea
Amines
contain the functional group
and amides contain the functional group Ο — C—N<^ An amide can be prepared by the reaction of a carboxylic acid and an amine (or ammonia). Add 2 g of benzoic anhydride (formed from two molecules of benzoic acid) slowly to 5 ml of cold concentrated ammonia solution in a 50-ml Erlenmeyer flask. Shake vigorously after each portion is added. After all the solid has reacted, pour the solution into a 125-ml Erlenmeyer flask containing 50 ml of water. 109
UCKO /EXPERIMENTS
FOR LIVING
CHEMISTRY
/ 12
What is the solid that forms?
Draw its structural formula.
An amide can be hydrolyzed, broken down by water back into an acid and amine. Place about 0.5 g acetamide into a test tube containing 5 ml of 10% sodium hydroxide (NaOH) solution. Place the tube in a boiling water bath for several minutes. Note the resulting odor. What are the products of hydrolysis of acetamide?
Repeat the experiment using about 0.5 g urea in 3 ml of 10% sodium hydroxide. Describe the result.
E X P E R I M E N T 12B OBJECTIVE:
To prepare a polymer—nylon.
EQUIPMENT:
150-ml beaker tweezers or wire
CHEMICALS:
hexamethylenediamine (0.5 M in 0.5 M sodium hydroxide) adipoyl chloride (0.25 M in cyclohexane)
Polymers, which exist as plastics, fibers, and rubbers, are formed by chemically joining many smaller units together. Nylon is a condensation polymer prepared by reacting hexamethylenediamine with adipoyl chloride. Ο Ο II II -NH-CH2 - C H 2 - C H 2 - C H 2 - C H 2 - C H 2 - N H - C - C H 2 - C H 2 - C H 2 - C H 2 - C nylon 110
NAME
SECTION
DATE
In a 150-ml beaker, add 10 ml of a 0.5 M solution of hexamethylenediamine (in NaOH). Carefully pour down the side of the beaker so as to avoid mixing a 0.25 M solution of adipoyl chloride in cyclohexane. Why do two layers form?
Using a pair of tweezers or a piece of wire, free the walls of the beaker of polymer. Gently pull up polymer fiber from the center of the beaker between the two layers. A continuous " r o p e " of nylon should form. After removing the fiber, wash it, dry it, and look at it. Describe the polymer.
QUESTIONS E X P E R I M E N T 12A
1.
Write an equation for the reaction of benzoic acid with ammonia.
2.
Write an equation for the hydrolysis of acetamide.
3.
Draw the structure of urea.
111
UCKO/EXPERIMENTS
E X P E R I M E N T 12B
1.
What is a polymer?
2.
Why can nylon be called a polyamide?
FOR LIVING
CHEMISTRY
/ 12
SECTION.
DATE.
Other organic derivatives and polymers E X P E R I M E N T 12A OBJECTIVE:
To observe the chemical properties of amides.
EQUIPMENT:
50-ml and 125-ml Erlenmeyer flasks stopper for 50-ml Erlenmeyer flask ring stand 500-ml beaker
CHEMICALS:
benzoic anhydride ammonia (concentrated) acetamide sodium hydroxide solution (10%) urea
Amines
contain the functional group
and amides contain the functional group Ο — C—N<^ An amide can be prepared by the reaction of a carboxylic acid and an amine (or ammonia). Add 2 g of benzoic anhydride (formed from two molecules of benzoic acid) slowly to 5 ml of cold concentrated ammonia solution in a 50-ml Erlenmeyer flask. Shake vigorously after each portion is added. After all the solid has reacted, pour the solution into a 125-ml Erlenmeyer flask containing 50 ml of water. 109
UCKO /EXPERIMENTS
FOR LIVING
CHEMISTRY
/ 12
What is the solid that forms?
Draw its structural formula.
An amide can be hydrolyzed, broken down by water back into an acid and amine. Place about 0.5 g acetamide into a test tube containing 5 ml of 10% sodium hydroxide (NaOH) solution. Place the tube in a boiling water bath for several minutes. Note the resulting odor. What are the products of hydrolysis of acetamide?
Repeat the experiment using about 0.5 g urea in 3 ml of 10% sodium hydroxide. Describe the result.
E X P E R I M E N T 12B OBJECTIVE:
To prepare a polymer—nylon.
EQUIPMENT:
150-ml beaker tweezers or wire
CHEMICALS:
hexamethylenediamine (0.5 M in 0.5 M sodium hydroxide) adipoyl chloride (0.25 M in cyclohexane)
Polymers, which exist as plastics, fibers, and rubbers, are formed by chemically joining many smaller units together. Nylon is a condensation polymer prepared by reacting hexamethylenediamine with adipoyl chloride. Ο Ο II II -NH-CH2 - C H 2 - C H 2 - C H 2 - C H 2 - C H 2 - N H - C - C H 2 - C H 2 - C H 2 - C H 2 - C nylon 110
NAME
SECTION
DATE
In a 150-ml beaker, add 10 ml of a 0.5 M solution of hexamethylenediamine (in NaOH). Carefully pour down the side of the beaker so as to avoid mixing a 0.25 M solution of adipoyl chloride in cyclohexane. Why do two layers form?
Using a pair of tweezers or a piece of wire, free the walls of the beaker of polymer. Gently pull up polymer fiber from the center of the beaker between the two layers. A continuous " r o p e " of nylon should form. After removing the fiber, wash it, dry it, and look at it. Describe the polymer.
QUESTIONS E X P E R I M E N T 12A
1.
Write an equation for the reaction of benzoic acid with ammonia.
2.
Write an equation for the hydrolysis of acetamide.
3.
Draw the structure of urea.
111
UCKO/EXPERIMENTS
E X P E R I M E N T 12B
1.
What is a polymer?
2.
Why can nylon be called a polyamide?
FOR LIVING
CHEMISTRY
/ 12