Organic Mechanisms Flashcards
What is a substitution reaction?
An atom or group of atoms on the organic molecule are directly replaced by another
Why can alkanes not undergo addition reaction?
Because every C atoms is bonded to 4 other atoms ie saturated
What is a free radical?
A species which contains an unpaired electron
What is homolytic fission?
Breaking a covalent bond in such a way that 1 electron goes to each atom
What happens in the initiation step of free radical substitution?
Making free radicals by homolytic fission of a covalent bond using UV light
What happens in the propagation step of free radical substitution?
The reaction of a free radical with a molecule to produce another free radical
What happens in the termination step of free radical substitution?
The combination of 2 free radicals to form a single molecule
What is the main factor that governs the production of alternate products?
The excess of chlorine
What are the 2 mechanisms involving alkenes?
1) Free radical addition
2) Electrophilic addition
What is an electrophile?
A species which can accept a pair of electrons from a species with a high electron density
What kind of reaction produces electrophiles?
Heterolytic fission
What are the steps of electrophilic addition?
1) Hydrogen in the H-X is attached by a pair of electrons on the C=C
2) Heterolytic fission of the H-X forming :X-
3) :X- attacks the carbocation to form the haloalkane
What are the conditions for electrophilic addition with H2SO4 and how do you get a product to become an alcohol?
1) Cold conc H2SO4
2) Heat + Add water to the product
What do the carbocation intermediates tell us about the reaction?
Which route is most favoured
What is a nucleophile?
A species with a lone pair of electrons which can be used to bond with an electropositive carbon atom
