Aldehydes and Ketones and Optical isomerism Flashcards
What is structural isomerism?
Same molecular formula but different structural formula
What is stereoisomerism?
Same structural formula but different arrangement of atoms in space
What are the three types of structural isomerism?
Chain, Positional and Functional
What are the two types of stereoisomerism?
Geometrical isomerism (E/Z)
Optical isomerism
What are optical isomers?
Non-super imposable mirror images
When can optical isomerism occur?
When a carbon atom bonds to 4 different groups
Definition of optical isomers
Rotate the plane of polarised light. One isomer will rotate it clockwise, the other isomer will rotate it anti-clockwise
What is an enantiomer?
Each optical isomer can be called enantiomer
What does enantiomerically pure mean?
If a sample contains only one optical isomer it is said to be enantiomerically pure
What does optically active mean?
An enantiomerically pure compound is optically active as it will rotate the plane of polarised light
What does racemic mixture mean?
A mixture which contains equal quantities of enantiomers
List the similar properties of optical isomers
same melting and boiling point
same solubility in a range of solvents
same Mr
same peaks in their NMR spectrum, IR spectrum and mass spectrum
What is the mechanism for the reduction of aldehydes and ketones?
Nucleophilic addition
What is the reagent of nucleophilic addition when forming an alcohol?
NaBH4
What is the condition of nucleophilic addition when forming an alcohol?
Acidic solvent
