Chemical Mechanisms Flashcards
What is the mechanism for the reaction of a halogen and an alkane?
Free radical substitution
What are the steps of free radical substitution?
- Initiation
- Propagation
- Termination
Draw the mechanism for the reaction between chlorine and methane.
What are the conditions for free radical substitution?
UV light or very high temperatures
Describe two limitations of radical substitution reactions in the synthesis of organic molecules.
- Further substitution is possible, and can be prevented by using an excess of alkane
- A mixture of products is formed, instead of the desired product
What is homolytic fission?
When one atom gains both bonding electrons from the broken covalent bond, forming ions
What is heterolytic fission?
when both atoms keep a bonding electron, forming radicals
What is a radical?
A species with an unpaired electron
What is a nucleophile?
An electron pair donor e.g. a double bond
What is an electrophile?
An electron pair acceptor, attracted to a region of negative charge
What is the mechanism for the reaction between alkenes and hydrogen halides?
Electrophilic addition
Draw the mechanism for the reaction between hydrogen bromide and ethene.
What is the mechanism for the reaction between halogens and alkenes?
Electrophilic addition
