Organic Reactions Flashcards
What is an electrophile?
- Electron pair acceptor
- Has low electron density / positively charged
- Likes electrons
What is a nucleophile?
- Electron pair donor
- Has high electron density / negatively charged
- Likes the nucleus
What are the 4 types of reactions?
- Addition
- Substitution
- Elimination
- Rearrangement
What is an addition reaction?
Two reactants added to form one product
A + B -> C
What is an elimination reaction?
One reactant splits into into two products
A -> B + C
What is a substitution reaction?
Two reactants exchange atoms to form two new products
A-B + C-D -> A-C + B-D
What is a rearrangement reaction?
One reactant rearranges to form an isomeric product
A -> B
What is it called when covalent bonds break unsymmetrically?
Heterolytic cleavage - unsymmetrical - forms radicals
What is it called when covalent bonds break symmetrically?
Homolytic cleavage - symmetrical - forms ions
What does a curly arrow look like when only one electron is being transferred?
Half an arrow head
What reactions undergo Electrophilic addition?
Double bond in alkenes act as nucleophile
- Alkene + HX -> Halogenoalkane
X = Halogen - Alkene + H₂ -> Alkane
- Alkene + H₂O -> Alcohol
- Alkene + X₂ -> Halogenoalkane
NOT WITH F₂ (too reactive) OR I₂ (too unreactive)
How are alcohols broken down?
Oxidation
C-O and C-H to form C=O
What is soft oxidation?
Primary alcohol -> Aldehyde
OR
Secondary alcohol -> Ketone
What is hard oxidation?
Primary alcohol -> Aldehyde -> Carboxylic acid
What is esterification?
Primary / Secondary alcohol + Carboxylic acid -> Ester + Water
What is electrophilic substitution?
Benzene acts as nucleophile (Because it has 3 double bonds so is high in electron density)
1. Electrophile formed with X₂
E.g. Br-Br + AlBr₃ -> Br ⁺ + Br-AlBr₃ ⁻
2. Benzene attacks the electrophile Br ⁺
3. Br from Br-AlBr₃ ⁻attacks the H on the benzene and the H attacks the carbon cation
4. Forms Bromobenzene + H-Br + AlBr₃
What can alkenes react with?
- HX
- H₂
- H₂O
- XX
X being a halogen
