AS ORGANIC CHEMISTRY REASCTIONS Flashcards
Number of ways to convert an alkene to halogenoalkane
- Addition of a hydrogen Halide
2. Addition of halogen
Addition of hydrogen halides to alkenes
- Electrophilic additio
- Bubble through a concentrated solution
- Room temperature
- Major an minor products
Addition of Halogen
- Addition reactions
- Free Radical substitution
- Room temperature
- Decolorisation -> good test for C=C
What is the way that a halogenoalkane can be converted to an alkene?
Elimination reactions
Describe the elimination reaction of a halogenoalkane to alkene
- Done under ethanolic NaOH
- involves the loss of an HX group
How can an alkene be converted to an alkane?
By the addition of Hydrogen
Addition of Hydrogen to an alkene
- Addition reaction
- Nickel Catalyst
2 ways that an alkene can be converted to an alcohol
- Addition of Steam
2. Cold dilute acidified manganate solution (VII)
Describe the addition of steam in making an alcohol from an alkene.
- Addition reaction
- Catalyst: Conc Phosphoric acid
- 330 Degrees Celsius
- 6 MPa pressure
Cold Acidified Manganate reaction of Alkenes
- Makes Diols
- Dilute solution fo KMnO4
- Goes from purple to colourless
- Room temperature/Pressure
How can an alcohol be made into an alkene?
- Dehydration reaction
Dehydration of Alcohol
- Makes Alkene
- Elimination reaction
- Loss of water
- Catalyst: Hot Aluminium Oxide Powder
Aldehyde from Alkene
Oxidation with KMnO4
Oxidation of Alkenes under distillation
- Produces Aldehyde
- Hot Concentrated KMnO4
Carboxylic acid from aldehyde
Oxidation with concentrated KMnO4 under reflux
Aldehyde to Alcohol
Reduction.
Oxidation of Alcohol to Aldehyde
- Acidified (H2SO4) K2Cr2O7
- Orange -> Green
- warming required
- primary alcohol
- Distill to prevent carboxylic acid formation
Alcohol to Aldehyde
Oxidation
Reduction of Aldehyde to Alcohol
- Reducing agent: LiAlH4 / NaBH4
- if LiAlH4, then under dry ether
- if NaBH4, then (NaOH)aq + warm
- Primary alcohol
Halogenoalkane to nitriles
Substitution with Cyanide, CN-
Halogenoalkanes substitution with Cyanide
- Ethanolic solution of KCN
- heated under reflux with the halogenoalkane
Halogenoalkane to hydrolysis
- Substitution with Aqueous alkali, OH-
2. Hydrolysis
Halogenoalkane substitution with aqueous alkali
- Produce halogenoalkane
- warmed NaOH
- SN1 Mechanism
- Nucleophilic substitution
Hydrolysis of alcohol
- Produces Halogenoalkane
- carried out under reflux
- slower than NaOH
- rate can be investigated with AgNo3
- SN2 Mechanism
Alcohol to Halogenoalkane
- Substitution
2. Halogenation
Halogenation of alcohols
- Alcohol is heated under reflux
- halogenoalkane produced then distilled
4 ways of substituting an alcohol to halogenoalkane
- HX (Hydrogen halide) made insitu
- SOCl2 (sulfur dichloride)
- Phosphorus (V) Chloride
- PI3 or PBr3
Hydrogen halide made insitu
NaCl + H2SO4 -> NaHSO4 + HCl
Used in substitution of alcohol to halogenoalkane
Alcohol substitution with Sulfur dichloride
- No distillation
- halhhogenolkane, HCl and SO2 produced
Alcohol substitution with solid PCl5
- used as a test for OH group
- For chloroalkanes
- steamy fumes of HCl produced
- halogenoalkane, HCl and POCl3 produced
Alcohol substitution with PI3/ PBr3
- To make bromo/iodoalkanes
- made insitu with red phosphorus and bromine or iodine
- Warmed with alcohol
Amines from Halogenoalkanes
- Substitution with ammonia, NH3 in ethanol
Halogenoalkane substitution with ammonia
- makes amines
- Excess ammonia in ethanol under pressure
- Nucleophilic addition
- Ammonia is a nucleophile
- can go onto form secondary and tertiary amines
Amines from nitriles
Reduction
Reduction of nitriles
- Produces amines
- using sodium and ethanol
Aldehyde to nitriles
Addition of HCN-
Addition of HCN- to aldehydes
- Produces Nitriles
- Nucleophilic addition
- HCN insitu: NaCN + H2SO4
Alkenes to Ketones
- Oxidation
Oxidation of Alkenes
- Produces Ketones
- Hot Conc. KMnO4
Nitrile to Carboxylic acid
- Reflux with dilute HCl
Secondary Alcohol to Ketone
- K2Cr2O7 + H2SO4 (Acidified potassium dichromate)
- Orange to Green
- Warming required
- Secondary Alcohols
Ketone to Secondary Alcohol
Reduction
Reduction of a Ketone
- Produces a secondary Alcohol
- NaBH4/LiAlH4 used as reducing agents
- LiAlH4 used in dry ether at rtp
- NaBH4 warm in aqueous alkaline
Carboxylic acid to alcohol
Reduction
Reduction fo carboxylic acid
- Reducing agent: LiAlH4 in dry ether at rtp
- Produces Alcohol
Esterification
- H2SO4 (Acid Catalyst)
- Heated under reflux
- Sweet fruity smelling substance
Hydrolysis of esters
- heat under reflux with acid/base -> Equilibrium
2. heat under reflux with NaOH -> Full hydrolysis
Reaction of Alcohol with Sodium metal
- Breakage of the OH bond
- Longer hydrocarbons are less vigrous
