2025 CHEM 221 Experiment 7: Recrystallization &
Melting Point Measurement: Identifying a Constituent of
“Panacetin” Concordia University
Lab Report
Experiment 7: Recrystallization & Melting Point
Measurement: Identifying a Constituent of “Panacetin”[1]
CHEM 221 Lab Section 53L
, 1. Introduction:
Recrystallization is an important purification method in organic chemistry by using
solubility differences to remove impurities. The crude mixture is first dissolved at a high
temperature in a carefully selected solvent. The target compound will dissolve effectively in the
appropriate solvent at high temperatures but poorly at room temperature or lower, while the
impurities remain soluble or insoluble throughout. After the compound has completely dissolved,
the hot solvent is typically filtered to remove any insoluble impurities. As the solution cools, the
pure substance starts to crystallize because its solubility decreases with temperature. Slow
cooling, as opposed to quick cooling, encourages the formation of well-ordered crystals, which
are generally better at excluding contaminants. After crystallization is finished, the pure crystals
are filtered out of the remaining solution (sometimes known as the "mother liquor"), cleaned of
any remaining residues using a cold solvent, and then dried.[2][3]
2. Experimental:
The process of recrystallizing a crude phenacetin/acetanilide sample can be performed following
this outline:
3. Discussions:
After performing a couple of experiments, there are three common techniques used in
organic chemistry to extract and purify the compound: liquid-liquid extraction, recrystallization
Melting Point Measurement: Identifying a Constituent of
“Panacetin” Concordia University
Lab Report
Experiment 7: Recrystallization & Melting Point
Measurement: Identifying a Constituent of “Panacetin”[1]
CHEM 221 Lab Section 53L
, 1. Introduction:
Recrystallization is an important purification method in organic chemistry by using
solubility differences to remove impurities. The crude mixture is first dissolved at a high
temperature in a carefully selected solvent. The target compound will dissolve effectively in the
appropriate solvent at high temperatures but poorly at room temperature or lower, while the
impurities remain soluble or insoluble throughout. After the compound has completely dissolved,
the hot solvent is typically filtered to remove any insoluble impurities. As the solution cools, the
pure substance starts to crystallize because its solubility decreases with temperature. Slow
cooling, as opposed to quick cooling, encourages the formation of well-ordered crystals, which
are generally better at excluding contaminants. After crystallization is finished, the pure crystals
are filtered out of the remaining solution (sometimes known as the "mother liquor"), cleaned of
any remaining residues using a cold solvent, and then dried.[2][3]
2. Experimental:
The process of recrystallizing a crude phenacetin/acetanilide sample can be performed following
this outline:
3. Discussions:
After performing a couple of experiments, there are three common techniques used in
organic chemistry to extract and purify the compound: liquid-liquid extraction, recrystallization
