Chemistry 1060 Laboratory Analysis Purity determination Thin Layer Chromatography TLC Separation and identification stationary phase silica gel mobile phase organic solvent Relative attraction to the two phases ID: 909323
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Slide1
Synthesis andAnalysis of Aspirin
Chemistry 1060 Laboratory
Slide2AnalysisPurity determination
Thin Layer Chromatography (TLC)
Separation and identification
stationary phase – silica gelmobile phase – organic solventRelative attraction to the two phasesPolarity
Slide3AnalysisThin Layer Chromatography (TLC)
Retention factor (
R
f) values
3 cm
5 cm
Solvent front
R
f
= 3/5 = 0.60
Origin
Slide4AnalysisThin Layer Chromatography (TLC)
Salicylic
acid (starting
material)Pure aspirinIsolated productUV detectionResultsIsolated product Rf
of pure
a
spirin
s
alicylic acid removed?
UV
Slide5AnalysisStructure confirmation
1
H nuclear
magnetic resonance (1H NMR) - or proton magnetic resonance (PMR)
Slide6Analysis1
H NMR
Slide7Analysis1
H NMR
radio-frequency region of the spectrum
Slide8Analysis1
H NMR – Shielding
Slide9Analysis1
H NMR – Chemical Shifts, Chemical Equivalency
tetramethylsilane
(TMS)
Slide10Analysis1
H NMR – Chemical Shifts,
Integration
3
1
Slide11Slide12Analysis1
H NMR – Chemical
Shifts, Complex Patterns
Slide13Analysis1
H NMR –
Characterizing starting material and product
salicylic acid
aspirin
Slide14SummaryGoals
Week 1:
To synthesize aspirin, from salicylic acid and acetic anhydride
To purify the product using recrystallizationWeek 2:To verify the purity and identity of the product using thin layer chromatography (TLC)
To further confirm the identity of the product by nuclear magnetic resonance (NMR) spectroscopy