Question

Describe the theory for the purification techniques used including IMFs involved in this step:

Acetaminophen was synthesized from p-aminophenol and the crude product was recrystallized using a 50:50 solution of hot methanol:water. Describe the purification in terms of reactions, IMFs, or other important factors.

Answer 1

Acetaminophen synthsized with the treatment of p-aminophenol and acetic anhydride in water.

PURIFICATION TECHNIQUES

The acetaminophen was mostly purified by the crystallization technique, the synthesis from p-aminophenol, also its common impurities present.

In order to remove the same we can use water as p-aminophenol is very soluble in water. the reaction works via Nucleophilic substitution and amine reacts as nucleophile.

Recrystallization can be done using hot methanol:water (1:1 ratio), in order to obtain crystals first we have to dissolved properly in the calculated ratio of methanol and water, then settled at room temperature and may be lower temperature. Sometimes variation in ratio from 20-80% MeOH/H2O we can check whic ratio is providind product with higher purity and yield.

Important factors while recrystallization.

• use all time deionized water
• use polar solvent i.e methanol of high purity
• timing of crystallization
• temperature controls as the IMFs factors involved may increase or decrease the temperature.
• binary mixture should be correctly measured.
• all other reagent of high purity used.

IMFs fatcors

The acetaminophen structure containing free hydroxyl group, amide fuctional moiety and the alkyl group, their is higher chances or we can say it exhibit vanderwall force and hydrogen bonding.

the hydrogen bond present in the moiety is strongest bond between N-O, sometimes may increase the temperature or solubilty.

the stabilty and crstal growth determination also depend on the inermolecular forces such as dipole dipole interaction and other attractive forces.

the crystal shape orthprhombic shape depends on internaland external factors of boiling point , melting points and forces involved.