f324 moduale 1 benzene
- Created by: rheabazzant
- Created on: 26-06-15 09:21
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- benzene
- faraday
- empirical formula= CH
- molecular formula= C6H6
- kekule
- structure of benzene
- cyclic
- 3 double bonds
- 1 hydrogen on each carbon
- problems with kekules structure
- low reactivity of benzene
- benzene compared to other alkenes is unreactive
- benzene doesn't undergo electrophilic addition which it should
- thermodynaic stanbilty
- the thermodynamic stability of benzene using kekules structure is lower than what it should be
- bond lenths
- double bonds are shorter than single bonds
- kekules structure should be a perfect hexagon but it cant be
- over come the problems
- suggested that there is a reversible reaction where the double bonds move place
- low reactivity of benzene
- structure of benzene
- delocalised structure
- pi- electrons delocalised around the ring, above and below the plane
- p- orbitals overlap to forma delocalised structure above and below the ring
- between each carbon is a sigma bond
- cyclic hydrocarbon with 6 carbons and 56 hydrogens
- pi- orbitals above and below the ring which form pi bonds
- bond angle- 120'
- ring is planer
- c-c bonds are equal lenth
- delocalised pi orbital system
- coulorless liquid
- sweet oder
- highly flammable
- component od petral and cigarette smoke
- formed naturally in forest fires and volcanoes
- reactions of benzene
- bromination
- nitration
- clorinattion
- electron dence ring attracts and electrophiel
- phenol
- one of the lone pairs on the oxygen overlap eith the delocalised electrons in the benzene ring and one of the lone pairs from the oxygen
- affect on both the propities of the benzene ring and the -oh
- interaction between the delocalised electrons in the benzene ring and 1 of the lone pairs on the oxygen atom
- -oh has to be directly attached to the benzene structure for it to be a phenol
- simplest phenol-
- there is a interaction between the delocalised electrons in the benzene ring and one of the lone pairs from the oxygen
- phenol reacts more rapidly with bromine than benzene because
- a lone pair of electrons ion the oxygen atom in the phenol group is drawn to the benzene ring
- this creates a high electron density in the ring structure and is activated
- the increase electron density polarises bromine molecules which are then attracted more strongly towards the ring in the benzene structure
- reactions of phenol with na
- C6H5OH+Aq -> C6H5O- + H+
- C6H5Oh is a pink solid at r.t.p
- phenols form a week acidic solution when dissolved in water
- C6H5OH + NAOH -> C6H5O-NA+ = H2O
- C6H5OH + NA -> C6H5O-NA+ + 1/2H2
- C6H5OH+Aq -> C6H5O- + H+
- reactions of phenol with BR
- CH5OH + 3BR -> C6H2BR3OH + 3HBR
- uses of phenol include: preparation of resins, dyes, explosives, lubricants, pesticides and plastics
- faraday
- phenol
- one of the lone pairs on the oxygen overlap eith the delocalised electrons in the benzene ring and one of the lone pairs from the oxygen
- affect on both the propities of the benzene ring and the -oh
- interaction between the delocalised electrons in the benzene ring and 1 of the lone pairs on the oxygen atom
- -oh has to be directly attached to the benzene structure for it to be a phenol
- simplest phenol-
- there is a interaction between the delocalised electrons in the benzene ring and one of the lone pairs from the oxygen
- phenol reacts more rapidly with bromine than benzene because
- a lone pair of electrons ion the oxygen atom in the phenol group is drawn to the benzene ring
- this creates a high electron density in the ring structure and is activated
- the increase electron density polarises bromine molecules which are then attracted more strongly towards the ring in the benzene structure
- reactions of phenol with na
- C6H5OH+Aq -> C6H5O- + H+
- C6H5Oh is a pink solid at r.t.p
- phenols form a week acidic solution when dissolved in water
- C6H5OH + NAOH -> C6H5O-NA+ = H2O
- C6H5OH + NA -> C6H5O-NA+ + 1/2H2
- C6H5OH+Aq -> C6H5O- + H+
- reactions of phenol with BR
- CH5OH + 3BR -> C6H2BR3OH + 3HBR
- uses of phenol include: preparation of resins, dyes, explosives, lubricants, pesticides and plastics
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