Post on 17-Jan-2023
Chem 108: Lab Simula1on
Aspirin Synthesis
https://www.youtube.com/watch?v=6lFQaxiRAmI
(Video includes recrystallization of crude aspirin with ethyl acetate, which is not part of the Lab Manual’s procedure, and
sulfuric acid is used in place of phosphoric acid)
https://forms.gle/XdLVP45QAtdP8RX18 _______________________
Experiment: Synthesis of an NSAID (Non-steroid anti-inflammatory drug)
Aspirin
http://chemconnections.org/general/movies/Representations.MOV
NSAIDs are used primarily to treat inflammation, mild to moderate pain, and fever.
C9H8O4
Synthesis of Aspirin (an NSAID)
Aspirin & Pain
Used primarily to treat inflammation, mild to moderate pain, and fever.
Representing Organic Molecules Common Formulas & Drawings
Molecular formula: Empirical Formula:
Bond-Line Structure:
C7H16O C7H16O
O
H
Condensed Structure:
Review: Lewis Structures & Molecular Modeling molview experiment (http://molview.org/)
Common Functional Groups
Name General Formula
Alcohols R-ΟΗ
Ethers R-Ο-Rʹ′
Amines R-ΝΗ2
Carboxylic Acids
R-C-OH
O
REACTANT: Salicylic Acid
Common Functional Groups
Name General Formula
Aldehydes
Ketones
Carboxylic Acids
Esters
Amides
R-C-OH
O
R-C-OR'
O
R-C-N
O
R
"
R
'
PRODUCT: Acetyl salicylic acid (Aspirin)
Synthesis of Aspirin
OOCCH3
COOH
CH3COCCH
3
O O
CH3COOH
OH
COOH
acetyl ester
acid
aspirin
++
alcohol (phenol)
acid
salicylic acidacetic
anhydride
ethanoic anhydride
acetic acid H3PO4
C7H6O3 C9H8O4
Synthesis of Aspirin
1. Get equipment from stockroom with your group.
2. Follow instructions in lab manual pg.88 carefully. Be mindful of your safety. WEAR eye protection.
3. Store in lab drawer as instructed in Part A.3 of the instructions of the lab procedure.
4. Part A-4. Next Week
H3PO4
(Pre-Covid-19): Lab Manual Procedure pp. 87-91; Data form (pg. 90 )
C7H6O3 C9H8O4
Vacuum Filtration
https://www.youtube.com/watch?v=uJO_frXdNsU
Part A.3 pg. 88 of the instructions of the lab procedure.
How many grams of aspirin can be produced from 5.0 g of salicylic acid reacting with an excess of acetic anhydride, C4H6O3 if everything is done perfectly in the experimental procedure?
QUESTION
OOCCH3
COOH
CH3COCCH
3
O O
CH3COOH
OH
COOH
acetyl ester
acid
aspirin
++
alcohol (phenol)
acid
salicylic acidacetic anhydride" acetic acid"
!grams (Reactant) grams (Product)
grams (R)"
grams (R)" (Divide)""
Mass (R) by Molar"
1 mol (R)" grams (P)"
? grams (P)"
1 mol (P)"
Moles Molar Mass
? mol (P)"
? mol (R) "
"Gatekeepers”!from!Balanced reaction
Theoretical (Yield) Mass Calculations Reactant Product
(Multiply)""" Mass (P)"
by Molar"
Stoichiometry
!
5.0 grams (SA)"
grams (SA)" (Molecular Weight SA)"
1 mol (SA)"
grams (A)"
? (A)"
1 mol (A)"
(Molecular Weight A)"
Stoichiometry
1 mol A"
1 mol SA "
"Gatekeeper"
Mass Calculations:
C9H8O4 MW = 180.15
C7H6O3
MW = 138.12
grams (Aspirin) grams (Salicylic Acid) Moles Molar Mass
SA A
6.5 g aspirin
Answer
Percent Yield
In synthesis as in any experiment, it is very difficult and at most times impossible to be perfect. Therefore the actual yield (g) is measured and compared to the theoretical calculated yield (g). This is the percent yield:
% Yield = actual (g) / theoretical (g) x 100
1
QUESTION
Kate’s synthesis of aspirin, C9H8O3, using acetic anhydride produced 5.90g. The calculated theoretical yield was 6.50g; what is her % yield?
A) 47.5% B) 80.3% C) 90.8% D) 110%
1
ANSWER
Kate’s synthesis of aspirin, C9H8O3, produced 5.90g. The calculated theoretical yield was 6.50g; what is her % yield?
A) 47.5% B) 80.3% C) 90.8% D) 110%
1
5.90g / 6.50g X 100 =
Comparing Synthetic Procedures
In synthesis as in any experiment, there are many different possible ways to produce the same product such as aspirin.
Given those possible procedures & reactions, there are many things to consider in selecting which reaction and method is best, such as their relative safety, cost and yield compared to the other possible choices.
% Yield = actual (g) / theoretical (g) x 100
1
!
5.0 grams (SA)"
grams (SA)" (Molecular Weight SA)"
1 mol (SA)"
grams (A)"
? (A)"
1 mol (A)"
(Molecular Weight A)"
Stoichiometry
1 mol A"
1 mol SA "
"Gatekeeper"
Different Synthetic Procedure:
C9H8O4 MW = 180.15
C7H6O3
MW = 138.12
grams (Aspirin) grams (Salicylic Acid) Moles Molar Mass
SA A
Acetyl chloride"
6.5 g aspirin
Same theoretical amount, but different
reactant
QUESTION
Gabe’s synthesis of aspirin, C9H8O3, using acetyl chloride produced 5.40g. The calculated theoretical yield was 6.50g; what is his % yield?
A) 47.5% B) 83.1% C) 90.8% D) 110%
1
Different Synthetic Procedure:
Answer
Gabe’s synthesis of aspirin, C9H8O3, using acetyl chloride produced 5.40g. The calculated theoretical yield was 6.50g; what is his % yield?
A) 47.5% B) 83.1% C) 90.8% D) 110%
1
Different Synthetic Procedure:
5.40g / 6.50g X 100 =
QUESTION
Gabe’s synthesis of aspirin, C9H8O3, using acetyl chloride produced a different yield than Kate’s using acetic anhydride. If all other factors were equal, except for the difference in these two reactants, which would be the better choice Kate’s or Gabe’s? Briefly explain the reason for your choice, and provide one additional factor to consider such as by-products and waste beside percent yield.
1
Different Synthetic Procedures:
!
Aspirin Lab Manual Data Example:
OOCCH3
COOH
CH3COCCH
3
O O
CH3COOH
OH
COOH
acetyl ester
acid
aspirin
++
alcohol (phenol)
acid
salicylic acid
C9H8O4 C7H6O3
grams (Aspirin)"Theoretical grams (Salicylic Acid)
6.00 g 84.60 g
77.69g
acetic anhydride" acetic acid"
!
6.00 grams (SA)"
grams (SA)" (Molecular Weight SA)"
1 mol (SA)"
grams (A)"
? (A)"
1 mol (A)"
(Molecular Weight A)"
Stoichiometry
1 mol A"
1 mol SA "
"Gatekeeper"
Theoretical Yield Calculation:
C9H8O4 MW = 180.15
C7H6O3
MW = 138.12
grams (Aspirin) grams (Salicylic Acid) Moles Molar Mass
SA A
7.83 g aspirin
!
Aspirin Lab Manual Data Example:
OOCCH3
COOH
CH3COCCH
3
O O
CH3COOH
OH
COOH
acetyl ester
acid
aspirin
++
alcohol (phenol)
acid
salicylic acid
C9H8O4 C7H6O3
grams (Aspirin)"Theoretical grams (Salicylic Acid) 7.83 g
7.83 g
6.00 g 84.60 g
% Yield = actual (g) / theoretical (g) x 100
% Yield = (6.91g) / (7.83 g) x 100 = 88.3%
77.69g
6.91 g
88.3 %
acetic anhydride" acetic acid"
Chem 108 Synthesis of Aspirin
Use pg. 90 as a working page for your individual data
Get individual data using your DVC ID & complete the table: http://chemconnections.org/general/chem108/Lab/RSC%20Aspirin/Aspirin-sim.codes.htm
http://www.rsc.org/learn-chemistry/resources/screen-experiment/aspirin/experiment/1
Optional Bonus
NOTE: Due to popularity & high web site traffic, access may be highly limited, very
difficult, & sporadic.
http://www.rsc.org/learn-chemistry/resources/screen-experiment/aspirin/experiment/1
http://chemconnections.org/general/chem108/Lab/RSC%20Aspirin/RSC-aspirin-login.html Same user name & number for login as Titration, find here:
Only Aspirin level 1 is to be completed; the lab book then downloaded and submitted as an e-mail attachment.
Only Aspirin level 1 is to be completed; the lab book then downloaded and submitted as an e-mail attachment.
http://www.rsc.org/learn-chemistry/resources/screen-experiment/aspirin/experiment/1
http://www.rsc.org/learn-chemistry/resources/screen-experiment/aspirin/experiment/1
Same user name & number for login as Titration, find here:
http://chemconnections.org/general/chem108/Lab/RSC%20Aspirin/RSC-aspirin-login.html
Download log book and send as an e-mail attachment