Flashcards
A2 Organic Chemistry - Reactions
Cards in this deck (11)
- 1Describe the delocalised model of benzene- Cyclic hydrocarbon (C6H6)
- The p-orbitals on the carbon atoms overlap sideways to produce a pi-cloud of electron density above and below the plane of the carbon atoms containing 6 electrons.
- Delocalised pi-cloud spread over whole molecule
- Therefore stable molecule - 2Nitration of benzene: Type of reaction and essential conditions and reagents- Electrophilic substitution
- Nitrating mixture of conc. H2SO4 and HNO3
- 50 degrees C
- Conc. sulphuric acid = catalyst - 3Halogenation of benzene: Type of reaction and conditions and reagents- Electrophilic substitution
- Room temp. and pressure
- Halogen carrier (e.g. FeCl3) - 4Equation for formation of NO2+ ion (nitryl cation) for nitration of benzeneHNO3 + H2SO4 --> NO2+ + HSO4- + H2O
- 5Equation for formation of Br+ electrophile in halogenation of benzene - Equation for reformation of FeBr3 (catalyst)Br2 + FeBr3 --> Br+ + FeBr4-
H+ + FeBr4- --> FeBr3 + HBr - 6Why does bromine react more readily with cyclohexene than with benzene?- The electrons in the pi-bond of cyclohexene are localised between two carbon atoms and therefore have a region of high electron density. This can polarise the halogen.
-Benzene has a delocalised pi-cloud spread over whole ring, which has a low electron density. Cannot polarise non-polar molecule so a halogen carrier is required to generate powerful electrophile. - 7-Equation for phenol + sodium hydroxide -Name the salt produced salt6H5OH + NaOH --> C6H5O-Na+ + H2O
Salt produced: Sodium Phenoxide - 8- Equation for phenol + sodium - Name organic product2C6H5OH + 2Na --> 2C6H5O-Na+ + H2
-Sodium phenoxide - 9Phenol + 3Br2 =2,4,6-tribromophenol + 3HBr
- 10Explain why bromine reacts more readily with phenol that with benzene- In phenol: There is a lone pair of electrons (in p-orbital) on the oxygen atom in the phenol group, which is drawn into the benzene ring
- This creates a higher electron density and activates ring
-Increased electron density can polarise a bromine molecule - 11Write the equation for the oxidation of ethanol and conditionsCH3CH2OH + [O] --> CH3CHO + H2O
(forms an aldehyde- distilled immediately)
CH3CH2OH + 2[O] --> CH3COOH + H2O
(oxidation further to a carboxylic acid)
- oxidising agent: H+/Cr2O7(2-) from potassium dichromate
Orange to Green
Information
- Description
- A2 Organic Chemistry reactions for OCR
- Created by
- Deleted user · Nov 2016
- Updated
- Dec 25, 2016
- Views
- 32
- Tags
- History
-
- Created by yannycollins · Dec 21, 2015
- Copied by Said Arab · Dec 21, 2015
- Copied by Tariq hudda · Nov 30, 2016
- Rating