Chapter 25 Keywords

Question 1

Hydrogenation

Answer 1

The addition of Hydrogen to an unsaturated molecule

Question 2

Aromatic compound

Answer 2

Contains a benzene ring

Question 3

Mono Substitution

Answer 3

Aromatic compounds with one substituent group and benzene is the parent chain

Eg alkyl
-ethylbenzene

Halogens
-chlorobenzene

Nitro
-nitrobenzene

Question 4

Disubstituted

Answer 4

Aromatic compound with two substituent groups

Now you number the C in the ring

Question 5

Halogen carrier

Answer 5

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

Question 6

Friedel-Crafts Alkylation

Answer 6

-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

Question 7

Acylation

Answer 7

• An electrophillic Substitution whereby benzene reacts with Acyl Chloride in the presence of AlCl3 catalyst to make an aromatic ketone
• it’s electrophillic Substitution

Question 8

Electrophile

Answer 8

Electron pair acceptor

Positively charged

Question 9

Substitution

Answer 9

When one atom or group of atoms is replaced by another atom or group of atoms

Question 10

Phenols

Answer 10

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

Question 11

Phenols vs Alcohol

Answer 11

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

Question 12

Phenols vs Carboxylic Acid

Answer 12

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

Question 13

How to distinguish between Phenol and CA?

Answer 13

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

Question 14

Activating groups

Answer 14

Activates the aromatic ring therefore the ring reacts more readily with e philes.
All 2,4- directing (ortho para) are activating, except halogens.

Question 15

Deactivating groups

Answer 15

Deactivates the aromatic ring and makes it react less readily with electrophiles
3- directing (meta)

Question 16

2,4- directing groups

Answer 16

NH2 or NH
OH
OR
R or C6H5
halogens
CH3

Question 17

3 directing

Answer 17

RCOR acyl groups
COOR esters
SO3H
CHO
COOH
CN
NO2
NR3+

Question 18

Steric effect

Answer 18

Large substituted groups getting in the way which affects the proportions of different Substituted isomers