MASS SPECTROSCOPY

Identify possible Groups that fit the fragment size in the table. Group that is suggested 15 17 28 29 43 45 77

Mass spec. fragments Fragment size Group that is suggested 15 CH3 17 OH 28 C=O or C2H4 29 C2H5 43 COCH3 45 COOH 77 C6H5 Capital Tutor

Determine the Mr and assign possible group to each fragment.

2. Determine the Mr, assign possible groups to each group and sketch a possible Structural Formula for the Compound analysed. (Remember the structure must contain the possible fragment patterns to be valid) Alkane

Alcohol

INFRA RED SPECTROSCOPY

1500-4000 Is called the Functional Group Range. Each Functional Group in an Organic Compound Absorbs IR Radiation of specific Wavelengths. So if we shine Infra-Red Radiation at a sample of the Compound and note which Wavelengths are absorbed we can identify the functional group present. Where is the finger print region found on an Infra-Red Spectra and how can we use this information? 1500-4000 Is called the Functional Group Range. 0-1500 is called the “Fingerprint” Area and the Spectra is unique to each compound. This area can be matched using a computer to a database of known IR’s to identify the compound.

ALKANES CONTAIN JUST THE C-H BOND Cyclohexane C–H

ALKENES CONTAIN a C-H and a C=C cyclohexene C=C C–H

butanal C–H C=O

ethanol O–H

propanone C=O

ethanoic acid O-H C=O Capital Tutor

methyl ethanoate C=O Capital Tutor

Match the following eight compounds to the following eight IR spectra. hex-2-ene pentane methylpropan-1-ol 2-methylpentan-3-one butanal butanoic acid propyl ethanoate nitrobenzene Capital Tutor

                 Capital Tutor

 propyl ethanoate C=O C-O                 Capital Tutor

                 Capital Tutor

 2-methylpentan-3-one C=O                 Capital Tutor

                 Capital Tutor

 methylpropan-1-ol O-H                 Capital Tutor

                 Capital Tutor

 nitrobenzene C-H                 Capital Tutor

                

 pentane C-H                 Capital Tutor

                 Capital Tutor

 butanal C-H C=O                 Capital Tutor

                 Capital Tutor

 butanoic acid O-H                 Capital Tutor

                 Capital Tutor

 hex-2-ene C-H C-H C=C                 Capital Tutor

2 Hydroxy-propanoic Acid   Sketch possible Mass Spectrums (minimum 3 fragments) and Infra Red Spectrums for the following Organic Compounds showing the main Identifying Functional Groups.   Propan-2-ol Octanoic Acid 2 Methyl 3 Ethyl Decanal Methyl Decanoate 2 Hydroxy-butanal 2 Hydroxy-propanoic Acid Capital Tutor