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FRIDAY 16 TH MARCH 2012. 12:01 PM GMT. 4 SUBSTANCES…. PROPAN-1-OL PROPANONE PROPANAL PROPANOIC ACID. THE FATE OF THE FREE WORLD RESTS UPON THEIR IDENTIFICATION. Armed with a mass and infrared spectrometer, the government desperately tries to identify the 4 substances. Time is running out….
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FRIDAY 16TH MARCH 2012 12:01 PM GMT
4 SUBSTANCES… PROPAN-1-OL PROPANONE PROPANAL PROPANOIC ACID
Armed with a mass and infrared spectrometer, the government desperately tries to identify the 4 substances. Time is running out…
In a last ditch attempt they call in their analytical expert… …Relatively atomic Matt
Initially he identifies the compounds displayed formulae, using their systematic names to identify their functional groups
His first analysis… • Propan-1-ol: 1-ol suffix is indicative of a hydroxyl functional group attached to carbon 1, present in primary alcohols. • Propanone: -one suffix indicates compound is a ketone, having a C=O bond to a secondary or tertiary carbon atom. • Propanal: name suggests three carbon aldehyde,therefore C=O bond on a primary carbon atom. • Propanoic acid: -anoic acid suffix indicates COOH functional group, present in carboxylic acids.
-OH group on carbon 1 alcohol Propan-1-ol Propanone Propanal Propanoic acid C=O bond on secondary carbon ketone C=O bond on primary carbon aldehyde C=O bond on primary carbon OH group on same carbon (COOH group) carboxylic acid
Now that the compounds structures are known, RAM can match the infrared spectra to the sample molecules. He first requires an OCR datasheet…
Peak in 1640-1750 region indicates C=O bond. • Could be propanone or propanal • Most likely propanal due to peaks in 2850-3100 region.
Peak in 1640-1750 region indicates C=O bond. • Could be propanone or propanal • Most likely propanone as little absorptions after 3000
Peak in 1640-1750 region indicates C=O bond. • Peak in 1000-1300 region indicates C-O bond. • Very broad peak in 2500-3300 region indicates O-H bond in carboxyl group. • Identified as propanoic acid
Peaks in 1000-1300 region indicate C-O bond. • Peak in 2850-3100 region indicates C-H bond, in organic compounds. • Broad peak in 3200-3550 region indicates O-H bond in alcohols or phenols. • Identified as propan-1-ol
IR SPECTRA RESULTS PROPAN-1-OL PROPANONE PROPANAL PROPANOIC ACID
FINALLY RAM MUST CONDUCT A MASS SPECTROMETRY TEST. IN THIS TEST THE SAMPLES ARE BOMBARDED WITH AN ELECTRON GUN THEN SMASHED INTO AN ION DETECTOR
TO HELP WITH IDENTIFICATION ON THE MASS SPECTRA, RAM CALCULATES THE MOLECULAR MASSES OF EACH COMPOUND, TO ENABLE THE M+ ION TO BE IDENTIFIED PROPAN-1-OL: PROPANONE: PROPANAL: PROPANOIC ACID:
THE LARGEST MASS TO CHARGE RATIO WITH A PEAK IS 60. This must be the M+ ion. PROPAN-1-OL has an of 60. • PEAK At 31 DUE TO FRAGMENT ION, PRESENT IN PROPAN-1-OL. • PEAK AT 14 DUE TO + ion • PEAK AT 15 DUE TO + or Carbon-13+ ion • Identified as PROPAN-1-OL
THE LARGEST MASS TO CHARGE RATIO WITH A PEAK IS 74. This must be the M+ ion. Propanoic acid has an of 74. • PEAK At 57 DUE TO FRAGMENT ION, PRESENT IN PrOPANOIC ACID. • PEAK AT 45 DUE TO + ion • PEAK AT 43 DUE TO + ion • Identified as PROPANOIC ACID
THE LARGEST MASS TO CHARGE RATIO WITH A PEAK IS 58. This must be the M+ ion. PROPANONE AND PROPANAL HAVE AN of 58. • PEAK AT 43 DUE TO + OR + FRAGMENT ion • PEAK At 29 DUE TO + ION, PRESENT IN PROPANAL NOT PROPANONE. • Identified as PROPANAL
THE LARGEST MASS TO CHARGE RATIO WITH A PEAK IS 58. This must be the M+ ion. PROPANONE AND PROPANAL HAVE AN of 58. • PEAK AT 57 DUE TO + or + ion – present in Propanal or propanone • PEAK At 43 DUE TO +ION PRESENT IN PROPANone NOT PROPANal. • Identified as PROPANONE
THANKS TO THE FAST IDENTIFICATION OF THE 4 SUBSTANCES BY RELATIVELY ATOMIC MATT, THE FREE WORLD REMAINS FREE… …UNTIL NEXT TIME…