E8 Synthesis of Aspirin

January 101 Mass Relationship to Chem Rxn

E8 Synthesis of Aspirin

Dr. Fred O. Garces Chemistry 152 Miramar College

Quantitative Calculation from a Chemical Reaction


Safety

2

Safety glasses at all times

Use acetic anhydride in hood.

Do not place anything in your mouth

Be cautious when working with H2SO4.

In case of spill, immediately wash with water and notify instructor.

Use care when handling salicylic acid as it is toxic and an irritant.

Dispose of filtrate and aspirin in proper waste container.


Mapping out Solving Technique

(g)

( )Volume L

( )Temperature K

Pressure atm( )

R (.0821 atm • L

mol • K)

Density (g / cc)

Molar Mass (g / mol)

MolesABalance equation

← → # # # # # # # # # Stoic. coefficient .

MolesB

Mass (g)

L# of molecules / atoms

Conc. (mol / L)

Vol (L)

Volume (L)

Temperature (K)

Pressure (atm)

N Av (6.02 •1023)

R (.0821 atm • L

mol • K)

Vol (L)

)Conc. (mol / L

Density (g / cc)

Mass (g)Molar Mass (g / mol)

Gas phase

Aqueous phase

Solid phase

Liquidphase

particle(atomic) phase

Vol ( )

Gas phase

Aqueous phase

Solid phase

Vol (L)(l)Liquid

phase(atomic) phase

N Av (6.02 •1023) particle

# of molecules / atoms

A

B

C

D 4

2

1 3


A

B

C

D

E

F

1

2

3

4

5

6

The Same Problem with Different Faces

Type of Stoichiometry Questions Consider: aA + bB ! cC + dD

Questions:

Products: Given X grams of A, how much C or D is produced

Given X grams of B, how much C or D is produced Given X grams of C, how much D is produced Given X grams of D, how much C is produced

Reactants: Producing X grams of C, how much A or B is required Producing X grams of D, how much A or B is required

Co-product: Producing X grams of C, how much D is also produced Producing X grams of D, how much C is also produced

Also problem can ask what is the limiting and excess reagents ?


Mapping out Solving Technique A

B

C 1

3

D

2

W

Y

X

B

D

C

2

4

3

7

9

8


The History of 2-(acetyloxy)-benzoic acid or salicylic acid • 4BC Hippocrates- The precursor of aspirin was first documented by Hippocrates. He wrote

that the “tea” from willow bark had medicinal use. • Edmund Stone - Discovered that the yellow crystals from willow bark, (Salix abla, Salicin) were

the active ingredient to cure headaches. • Clinical test of Salicin showed upset stomach and nausea side effects. • Salicin + NaOH yields salt which was more mild but was still acidic. • Felix Hoffman - In the next evolution of the drug known as aspirin, Hoffman explored

structurally modifying Salicin to help his father’s upset stomach side effect. In the discovery of the synthesis, the drug could not be patented, but the synthetic method was. Hoffman worked for the German company Bayer.

• Toxicity of aspirin show lethal levels of 20-30 g at one time. It is recommended that patients take about 325-360 mg /4 hours.

• Some side effect include nausea, abdominal pain, heartburn, ringing in the ears, increase blood clotting- time and ulcers.

• Benefits: Nonaddicting, antipyretic (fever), analgesic (pain), anti-inflammation.

Aspirin is produced by the reaction of salicylic acid and acetic anhydride. C7H6O3(s) + C4H6O3 (l) " C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride acetylsalicylic acid acetic acid

O OH

H3C

O

O

O

CH3

OH +

O OH

O

O

CH3

H3C

O

OH

+


Why you get headaches Prostaglandin - hormone produced in your tissues and body fluids.

Responsible for: Sensation of pain Fever Inflammation Swelling

Acetylsalicylic acid (aspirin) Anti-inflammatory Analgesic Antipyretic

Tylenol Acetaminophen ...hospitals recommend most.

Advil ibuprofen

C

OHO

O CCH3

O

CH

CH3C

OHO

CH2

CH

H3C CH3

NH

CCH3

O

OH

Structural representation of these chemicals will be explain in Organic Chemistry chapter later in the semester


Stoichiometry Calculations Aspirin is produced by the reaction of salicylic acid and acetic anhydride.

C7H6O3(s) + C4H6O3 (l) ! C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride acetylsalicylic acid acetic acid aspirin

A B C D

1. Given X grams of A (salicylic acid) and B, how many moles of A and B is this? Strategy: grams-A g moles-A

One step [Conversion factor - MM ]

2. Given X grams of A (salicylic acid), how many moles of C is produced? Strategy: grams-A g moles-A g moles-B

Two steps [Conversion factor - MM , Bal equation]

3. Given X grams of A (salicylic acid), what mass of C is produced (in grams)? Strategy: grams-A g moles-A g moles-B g grams-B

Three step [Conversion factor - MM-A , Bal equation, MM-B ]


Stoichiometry Calculations

Aspirin is produced by the reaction of salicylic acid and acetic anhydride. C7H6O3(s) + C4H6O3 (l) ! C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride acetylsalicylic acid acetic acid aspirin

A (138 g/mol) B (102 g/mol) C (180-.0 g/mol) D

1. Given 100 grams of A (salicylic acid), how many moles of A (salicylic acid) is this? Strategy: grams-A g moles-A

One step [Conversion factor - MM ]

2. Given 100 grams of A (salicylic acid), how many moles of C (aspirin) is produced? Strategy: grams-A g moles-A g moles-C

Two steps [Conversion factor - MM , Bal equation]

3. Given 100 grams of A (salicylic acid), what mass of C is produced (in grams)? Strategy: grams-A g moles-A g moles-C g grams-C

Three step [Conversion factor - MM-A , Bal equation, MM-C ]


1.  Stoichiometry Calculations: Mass (Reactants) to Moles (Reactants)

Aspirin is produced by the reaction of salicylic acid and acetic anhydride. C7H6O3(s) + C4H6O3 (l) " C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride aspirin acetic acid If you mix 100. g of each of the salicylic acid and acetic acid (reactants), how many moles of each reactant (salicylic acid and acetic acid) does this represent ?

Strategy: Mass to Moles

€

Mass C7H6O3 → Moles C7H6O3 :

100g C7H6O3 • 1 mol138.0 g C7H6O3

= 0.725mol C7H6O3

€

M Wt. C7H6O3 = 7 • (12.0) + 6 • (1.0) + 3 • (16.0) = 138.0 g

mol

M Wt. C4H6O3 = 4 • (12.0) + 6 • (1.0) + 3 • (16.0) = 102.0 g

mol

€

Mass C4H6O3 → Moles C4H6O3 :

100g C4H6O3 • 1 mol102.0 g C4H6O3

= 0.980 mol C4H6O3

Extra Q: How many moles of product is produced from each.


€

One - line CalculationMass C7H6O3 → Moles C7H6O3 → MolesC9H8O4

100g C7H6O3 • 1 mol C7H6O3

138.0 g C7H6O3 • 1 moles C9H8O4

1 moles C7H6O3=

2. Stoichiometry Calculations: Mass (Reactants) to Mole (Products)

Aspirin is produced by the reaction of salicylic acid and acetic anhydride. C7H6O3(s) + C4H6O3 (l) " C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride aspirin acetic acid If you mix 100. g of salicylic acid (reactants), how many moles of aspirin can be theoretically obtain ?

From Previous problem MWt: C7H6O3 = 138.0 g/mol 100g C7H6O3 is 0.725 mol

€

ii) Moles C7H6O3 → Moles C9H8O4 :

0.725 mol C7H6O3 • 1 moles C9H8O4

1 moles C7H6O3= 0.725 mol C9H8O4

€

i) Mass C7H6O3 → Moles C7H6O3 :

100g C7H6O3 • 1 mol138.0 g C7H6O3

= 0.725 mol C7H6O3

€

moles aspirin = 0.725 mol C9H8O4


3. Stoichiometry Calculations: Mass (Reactants) to Mass (Products)

Aspirin is produced by the reaction of salicylic acid and acetic anhydride. C7H6O3(s) + C4H6O3 (l) " C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride aspirin acetic acid If you mix 100. g of salicylic acid (reactants), what mass of aspirin can be produced?

Needed information MWt: C7H6O3 = 138.0 g/mol MWt: C9H8O4 = 180.0 g/mol

€


100g C7H6O3 • 1 mol138.0 g C7H6O3

= 0.725 mol C7H6O3

€




€

iii) Moles C9H8O4 → Mass C9H8O4 :

0.725 mol C9H8O4 •180.0 g C9H8O4

1 moles C9H8O4= 130.5 g C9H8O4

€

mass aspirin = 130.5 g C9H8O4

€

One - line CalculationMass C7H6O3 → Moles C7H6O3 → MolesC9H8O4 → Mass C9H8O4

100g C7H6O3 • 1 mol C7H6O3

138.0 g C7H6O3•

1 moles C9H8O4

1 moles C7H6O3•

180.0 g C9H8O4

1 moles C9H8O4=


Stoichiometry Calculations: Mass (Reactants) to Molecules (Products)

Aspirin is produced by the reaction of salicylic acid and acetic anhydride. C7H6O3(s) + C4H6O3 (l) " C9H8O4 (s) + CH3CO2H (aq) salicylic acid acetic anhydride aspirin acetic acid If you mix 100. g of each of the reactants, how many molecules of aspirin are obtained?

€


100g C7H6O3 • 1 mol138.0 g C7H6O3

= 0.725 mol C7H6O3

€




€

iii) Moles C9H8O4 → Molecules C9H8O4 :

0.725 mol C9H8O4 • 6.02 • 1023 C9H8O4

1 moles C9H8O4= 4.36 • 1023 Molecules C9H8O4

€

One - line CalculationMass C7H6O3 → Moles C7H6O3 → MolesC9H8O4 → Mass C9H8O4

100g C7H6O3 • 1 mol C7H6O3

138.0 g C7H6O3

•1 moles C9H8O4

1 moles C7H6O3

• 6.02 • 1023 C9H8O4

1 moles C9H8O4

=

€

Molecules aspirin = 4.36 • 1023 Molecules C9H8O4


Percent Yield Revisited •The maximum mass of a product that can be obtained from a given amount of

reactant is the theoretical yield. •The mass of a product that is actually recovered is called the actual yield. •The actual yield (from experiment) expressed as a percentage of the theoretical

yield (from calculation) is called the percent yield. % Yield = Actual Yield Theod Yield

Car Production Revisited: Remember our Car analogy: Suppose a car manufacturing plant is capable of producing 123 cars per day. What is the efficiency of the company ( percent yield) if only 63 cars are produced each day? Actual Yield - 63 cars Theoretical Yield - 123 cars

% Yield = Actual Yield = 63 •100 = 51% Theod Yield 123

Aspirin Production Revisited: Suppose in our aspirin analogy, only 100.0 gram of aspirin is recovered during the experiment, what is the % yield ?

Actual Yield - 100.0 g Aspirin Theoretical Yield - 130.5 g Aspirin

% Yield = Actual Yield = 100.0 • 100 = 76.6 % Theod Yield 130.5

X 100

X 100

X 100


Procedure

Cool ~ 60mL of DI water in ice water bath


Data Table


Procedure


Summary • The key to success in stoichiometry is the stoic map and dimensional analysis

(g)

( )Volume L

( )Temperature K

Pressure atm( )

R (.0821 atm • L

mol • K)

Density (g / cc)

Molar Mass (g / mol)

MolesABalance equation

← → # # # # # # # # # Stoic. coefficient .

MolesB

Mass (g)

L# of molecules / atoms

Conc. (mol / L)

Vol (L)

Volume (L)

Temperature (K)

Pressure (atm)

N Av (6.02 •1023)

R (.0821 atm • L

mol • K)

Vol (L)

)Conc. (mol / L

Density (g / cc)

Mass (g)Molar Mass (g / mol)

Gas phase

Aqueous phase

Solid phase

Liquidphase

particle(atomic) phase

Vol ( )

Gas phase

Aqueous phase

Solid phase

Vol (L)(l)Liquid

phase(atomic) phase

N Av (6.02 •1023) particle

# of molecules / atoms

A

B

C

D 4

2

1 3

E8 Synthesis of Aspirin

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