PAG 6.3: Preparation of benzoic acid
Analysis
1) a) Balanced symbol equation is:
C6H5COOCH3 +NaOH -> CH6H5COONa + CH3OH
Methyl benzoate (C6H5COOCH3) and sodium hydroxide (NaOH) are in a 1:1
ratio in the balanced symbol equation and 0.03 moles of NaOH reacted 1.25
X 10^-3 mol of methyl benzoate. 0.03 is greater than 1.25 X 10^-3 so NaOH
was in excess in the alkaline hydrolysis of methyl benzoate.
b) percentage yield =
2)
Obtained Melting Point (°C) Expected Melting Point (°C)
Recrystallised Benzoic Acid 101-111 121-127
Crude Benzoic Acid 117-122 118-122
Expected recrystallised benzoic acid melting point
Expected crude benzoic acid melting point
DePaul University. (September 2002). Recrystallization and Melting Points.
[online] Last accessed 29th December 2022:
https://condor.depaul.edu/mdintzne/171-02*sample%20lab.pdf
Analysis
1) a) Balanced symbol equation is:
C6H5COOCH3 +NaOH -> CH6H5COONa + CH3OH
Methyl benzoate (C6H5COOCH3) and sodium hydroxide (NaOH) are in a 1:1
ratio in the balanced symbol equation and 0.03 moles of NaOH reacted 1.25
X 10^-3 mol of methyl benzoate. 0.03 is greater than 1.25 X 10^-3 so NaOH
was in excess in the alkaline hydrolysis of methyl benzoate.
b) percentage yield =
2)
Obtained Melting Point (°C) Expected Melting Point (°C)
Recrystallised Benzoic Acid 101-111 121-127
Crude Benzoic Acid 117-122 118-122
Expected recrystallised benzoic acid melting point
Expected crude benzoic acid melting point
DePaul University. (September 2002). Recrystallization and Melting Points.
[online] Last accessed 29th December 2022:
https://condor.depaul.edu/mdintzne/171-02*sample%20lab.pdf
