Aromatic Compounds, Benzene, and Phenols

Flashcards on Aromatic Compounds, Benzene, and Phenols

The two major classes of organic chemicals are and .

aliphatic; aromatic

__ includes one or more rings of six carbon atoms with delocalised bonding.

Aromatic compounds

The simplest arene is with the molecular formula .

benzene; C6H6

In benzene, the six p electrons are __ in a ring structure above and below the plane of carbon atoms.

delocalised

The H-C-C bond angle is __ in Benzene.

120 degrees

__ means electrons are not attached to a particular atom.

Delocalised

The increase in stability connected to delocalisation is called the __.

delocalisation energy

Evidence for benzene having a delocalised structure includes bond length intermediate between short C=C and long C–C, hydrogenation less __ than expected, and only reacting with Br2 at high temp or in presence of a halogen carrier.

exothermic

The C6H5 - group is known as the __ group.

phenyl

Benzene does not generally undergo __ reactions because these would involve breaking up the delocalised system.

addition

Benzene's reactions are usually __ substitutions.

electrophilic

In benzene, electrons in -bond(s) are __.

delocalised

In alkenes, π- electrons are __ between two carbons.

localised

__ is a carcinogen and is banned for use in schools.

Benzene

Nitration of benzene uses conc nitric acid in the presence of concentrated __ acid (catalyst).

sulfuric

The electrophile in the nitration of benzene is __.

NO2+

In the halogenation of benzene, the catalyst can be or .

AlCl3; FeCl3

In Friedel Crafts Alkylation, the electrophile is the __.

R+

In Friedel Crafts Acylation, the electrophile is the __.

RCO+

In a __, the OH group is directly attached to the benzene ring.

phenol

Phenols are very weakly __ and are weaker acids than carboxylic acids.

acidic

Electron-donating groups such as and will force further substitutions to occur on the 2- and 4- positions of the ring.

OH; NH2

Electron-withdrawing groups (such as NO2) will have a __-directing effect of in electrophilic substitution of aromatic compounds.

3

If a –OH group, a Cl atom or an NH2 group is directly attached to a benzene ring the delocalisation in the benzene ring will extend to include the lone pairs on the __, __ and __.

N; O; Cl