Organic II Flashcards
Definition of NMR spec
analytical technique that allows the structure of a molecule to be determined by analysing bond & atom environments.
What is the environment of an atom
an atom depends on the surrounding atoms and bonds in the molecule.
Whats a chiral carbon
a carbon with four different groups bonded to it. (sometimes referred to as a ‘chiral centre’ or an ‘asymmetric carbon’). It will rotate plane polarised light in equal, opposite amounts.
What are stereoisomers?
molecules that have the same structural formula but a different arrangement of atoms in space. (The two types of stereoisomerism are E-Z and optical)
What are optical isomers
- non-superimposable mirror images which rotate the plane of plane-polarised light in an equal amount but opposite directions.
What is plane polising light
light that oscillates in one plane.
What is a polarimeter used for?
can be used to measure the rotation of plane-polarised light (by enantiomers).
What are enantiomers?
optical isomers of the same molecule are referred to as enantiomers. - mirror images of each other
What is a racemic mixture?
(“racemate”) is a 50-50 mixture of the two enantiomers of an optical isomer. (Does not rotate the plane of plane-polarised light as the rotations cancel)
Whats a carbonyl compound?
aldehydes or ketones. The carbonyl group is C=O.
NOT CARBOXYLIC ACIDS
What is hydrolysis?
a reaction in which a compound is split apart in a reaction involving water.
Whats a condensation reaction?
the joining two molecules together via the removal of a small molecule (often water but not always).
How do we synthesis acyl chlorides from carboxylic acids
- add PCl5 to carboxylic acid
- in dry ether
reaction between acyl chloride and water
carboxylic acid and HCl
reaction between acyl chloride and alcohol
ester + HCl
reaction between acyl chloride and conc ammonia
amide and HCl
reaction between acyl chloride and amine
N amide and HCl
Explain why ethanoic acid has a higher boiling point
than ethanol 3 marks
can form intermolecular bonds with itself due to its dipoles
so pd-pd interactions and hydrogen bonding
greater london forces as its basically like a two in one acid
Explain why octadecanoic acid (C17H35COOH) is
insoluble in water while ethanoic acid is soluble.
What does a amino acid look like in acidic solutions look like
with groups lookings like -COOH and -N+H3
What does an amino acid look like in basic solutions
with groups looking like -COO- and -NH2
what does an amino acid look in methanol
an ester forms, so sweet smells, and a molecule of water (usually) forms
what are some differences during esterification if we use an acyl chloride rather than alcohol
the reaction is irreversible when using acyl chlorides
hydrogen chloride is produced as a by product rather than water (misty fumes are produced rather than water)
the reaction with the acyl chloride is much faster so an acid catalyst isn;t needed when using acyl chlorides
