Skip to main content
Ch. 14 - Structural Identification 1: Infrared Spectroscopy and Mass Spectrometry
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Non è quello che usi tu?Cambia libro di testo
Capitolo 13, Problema 43b

Identify the peaks in the mass spectrum of octan-4-one that correspond to (b) the McLafferty rearrangement.
<IMAGE>

Guida verificata passo dopo passo
1
Understand the McLafferty rearrangement: This is a reaction in mass spectrometry where a molecule undergoes a rearrangement involving the transfer of a hydrogen atom and the cleavage of a bond, typically resulting in a neutral molecule and a radical cation.
Identify the structure of octan-4-one: Octan-4-one is a ketone with the formula C8H16O. The carbonyl group is located at the fourth carbon in the chain.
Locate the gamma hydrogen: In the McLafferty rearrangement, a hydrogen atom three carbons away from the carbonyl group (gamma position) is involved. For octan-4-one, identify the gamma hydrogen relative to the carbonyl group.
Illustrate the rearrangement: Draw the mechanism showing the transfer of the gamma hydrogen to the carbonyl oxygen, resulting in the cleavage of the bond between the alpha and beta carbons, forming a double bond and a neutral alkene molecule.
Determine the mass of the resulting fragments: Calculate the mass of the radical cation and the neutral alkene formed from the McLafferty rearrangement. These masses correspond to the peaks you would observe in the mass spectrum.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Mass Spectrometry

Mass spectrometry is an analytical technique used to measure the mass-to-charge ratio of ions. It helps identify the composition of a sample by generating a mass spectrum, which displays the masses of fragments. Understanding how molecules break apart and form ions is crucial for interpreting these spectra.
Video consigliato:
01:25
How to Read a Mass Spectrum

McLafferty Rearrangement

The McLafferty rearrangement is a specific fragmentation pattern observed in mass spectrometry, particularly in carbonyl compounds. It involves a hydrogen atom transfer from a gamma-carbon (three carbons away from the carbonyl group) to the carbonyl oxygen, followed by cleavage of the bond between the alpha and beta carbons, resulting in a stable enol and a neutral alkene.
Video consigliato:
06:08
Definition of Claisen Rearrangement

Fragmentation Patterns

Fragmentation patterns in mass spectrometry refer to the specific ways in which a molecule breaks apart into smaller ions. These patterns are influenced by the structure of the molecule and the stability of the resulting fragments. Recognizing these patterns, such as the McLafferty rearrangement, is essential for deducing the structure of the original compound from its mass spectrum.
Video consigliato:
08:06
Common Splitting Patterns