Mass Of Crude During Synthesis Lab Report

Part 1
Table 10: Mass of crude acetaminophen produce during synthesis.
Substance Mass
Crude acetaminophen 2.0222

Table 11: Mole calculation of 4-aminophenol and acetic anhydride.
Compound 4-aminophenol Acetic anhydride Acetaminophen
Mass/ volume used 2.0126 g (1.08 g)/mol x 2.2 ml=2.376 g -
Molecular weight 109.13 g/mol 102.09 g/mol 151.63 g/mol
Mole (2.0126 g)/(109.13 g/mol)
=0.018 mol (2.376 g)/(102.09 g/mol)
= 0.023 mol

4-aminophenol acts as limiting reagent during the synthesis of acetaminophen. Thus, the theoretical mole of acetaminophen same as the mole of 4-aminophenol present in the starting of reaction. Since, there from the chemical equation, it showed that 1 mole of 4-aminophenol produces 1 mole of acetaminophen.
Percentage

The melting point on the USP monograph is 168 ℃ to 172 ℃15. The melting point of these two acetaminophen was lower compared to the standard specification it may contain water molecule. The range of melting point for both acetaminophen was wide as well, this should that these two acetaminophen contain not pure enough. It contained two or more compounds in it. The USP grade acetaminophen may contaminated as it used for a period of time.
Table 13: Maximum wavelength of synthesised and USP grade acetaminophen
Compound Maximum wavelength (nm)
Synthesised acetaminophen 244.0
USP grade acetaminophen 246.0

In visualise, maximum wavelength of USP grade acetaminophen should be around 247 nm instead of 246 nm. However, the spectrometer failed to form a peak in the USP grade acetaminophen spectrum at 247 nm. The maximum wavelength of synthesised acetaminophen was 244 nm. This was close to the USP grade acetaminophen. The peak in synthesised acetaminophen does not form a sharp peak as USP grade acetaminophen. This may because the solution was too diluted. This affect the concentration of synthesised acetaminophen in the solution. Refer to appendixes 3 and 4 on page

Diagram 4: TLC of synthsised and USP grade acetaminophen
Rf of synthesised acetaminophen= (5.50 cm)/(5.90 cm ) =

The percentage of crude acetaminophen was 77.78%. The infrared spectrum of synthesised acetaminophen was similar to the USP grade acetaminophen. The functional groups and type of bonds in acetaminophen were identified. The NH bond stretching at wavenumber 3325.81 cm-1 and 3325.44 cm-1 in USP grade acetaminophen and synthesised acetaminophen. The bending of NH bond formed a band around 1610 cm-1. The presence of carbonyl group in both synthesised and USP grade acetaminophen gave a peak at wavenumber 1663.50 cm-1 and 1664.71 cm-1. Acetaminophen is para-disubstitution, it formed a peak around wavenumber 837cm-1. There were two small broad peaks found in both spectrum around wavenumber 3160 cm-1 to 3210 cm-1, this indicated the presence of OH group in the solutions. The melting point of synthesised and USP grade acetaminophen were 160 ℃-170 ℃ and 160 ℃-173 ℃. Both of these acetaminophen do not comply with the USP monograph melting point which is 168 ℃ to 172 ℃. This indicated there are some impurity presence in both of the synthesised and USP grade acetaminophen. The maximum wavelength of synthesised acetaminophen was 244.0 nm which was close to the wavelength of USP grade acetaminophen. The retention factor of synthesised and USP grade acetaminophen were 0.93 and 0.94. This showed that the purity of synthesised acetaminophen was similar to the USP grade acetaminophen. The absorbance value of synthesised and USP grade