Chapter 25 Keywords Flashcards
Hydrogenation
The addition of Hydrogen to an unsaturated molecule
Aromatic compound
Contains a benzene ring
Mono Substitution
Aromatic compounds with one substituent group and benzene is the parent chain
Eg alkyl
-ethylbenzene
Halogens
-chlorobenzene
Nitro
-nitrobenzene
Disubstituted
Aromatic compound with two substituent groups
Now you number the C in the ring
Halogen carrier
Needed for the halogenation of benzene
Benzene won’t react with halogens without them
Allows reaction to happen at room temperature
*they can be made in situ in the reaction vessel by the reaction of metal + halogen
Friedel-Crafts Alkylation
-The Substitution of a H in the benzene ring by an alkyl group
-Requires a Halogen carrier to make the electrophile
Eg if adding chloroethane your Halogen carrier is AlCl3/FeCl3
-a way of increasing chain length
-electrophillic Substitution
Acylation
- An electrophillic Substitution whereby benzene reacts with Acyl Chloride in the presence of AlCl3 catalyst to make an aromatic ketone
- it’s electrophillic Substitution
Electrophile
Electron pair acceptor
Positively charged
Substitution
When one atom or group of atoms is replaced by another atom or group of atoms
Phenols
An organic chemical contains a hydroxyl group directly attached to the aromatic ring. The simplest member being phenol.
Reacts more readily and under milder conditions than benzene
It’s a weak acid
Proximity of the OH group to benzene ring influences the OH group
*any compound with an OH DIRECTLY attached to the carbon ring reacts in a similar way to phenol
Phenols vs Alcohol
Phenol
- Less soluble in water than alcohol because of the non polar benzene ring
- more acidic than alcohols
- reacts with solutions of strong bases
Alcohol ethanol
- Nah react with Strong base or weak base
- more soluble in h20 than phenols
Phenols vs Carboxylic Acid
Phenol
- react with strong bases but not weak bases
- weaker acid than CA
CA
- strong enough to react with strong bases and weak bases
- more acidic than phenols and have a higher Ka value
How to distinguish between Phenol and CA?
React both with sodium carbonate. The phenol won’t react but the CA solution with sodium carbonate with make sodium carboxylate water and CO2 which causes effervescence
Activating groups
Activates the aromatic ring therefore the ring reacts more readily with e philes.
All 2,4- directing (ortho para) are activating, except halogens.
Deactivating groups
Deactivates the aromatic ring and makes it react less readily with electrophiles
3- directing (meta)