Organic reactions Flashcards
Conditions to turn primary alcohol into an aldehyde
Distillation and use of oxidising agent like Acidified potassium dichromate (vii)
How to turn primary alcohol into a carboxylic acid?
Heat under reflux and add oxidising agent of acidified potassium dichromate (vii)
How to turn secondary alcohols into ketones?
Heat under reflux with oxidising agent like acidified potassium dichromate (vii)
Colour change for reduction of dichromate (vii) ions?
orange to green
Conditions of oxidising for tertiary alcohols?
They do not oxidise under normal conditions
How to dehydrate alcohols to alkenes?
Heat under reflux and add concentrated phosphoric acid
How to go from alcohols to haloalkanes?
Heat under reflux with concentrated sulphuric acid
How to go from alkenes to alcohols?
Steam and phosphoric acid (electrophilic addition)
How to go from an alkene to a haloalkane?
Room temp
Hydrogen halides in a gaseous state
(Electrophilic addition)
How to go from alkene to an alkane?
Nickel catalyst
423 Kelvin
(Electrophilic addition)
How to go from alkane to haloalkane?
UV Light
(Free radical substitution)
Conditions of the nitration of Benzene?
Electrophilic substitution
Conc. HNO₃ and Conc. H₂SO₄ catalyst
50°C for mono nitration
Conditions of halogenation of benzene?
Electrophilic substitution (Cl ⁺ or Br ⁺ )
Halogen (e.g.Cl₂) + Halogen Carrier catalyst (e.g. AlCl₃/FeCl₃)
Benzene reacting with haloalkanes conditions
Electrophilic substitution ( CH₃⁺) = alkylation
Halogen carrier catalyst + reflux +anhydrous conditions
Friedel-Crafts reaction
Benzene reacting with acyl chlorides conditions
Electrophilic substitution (CH₃C⁺O) = acylation
Halogen carrier catalyst + reflux + anhydrous conditions
Friedel-Crafts reactions
Phenol reacting with Nitric acid conditions
Electrophilic substitution
dilute HNO₃, no catalyst (reacts much more readily than benzene)
forms 2 isomers: 2-nitrophenol and 4-nitrophenol
Phenol reacting with bromine conditions
Electrophilic substitution
no catalyst + decolourises orange bromine
product = 2,4,6-tribromophenol =antiseptic
Reactions of phenol and NaOH
Neutralisation reaction
Phenol = weak acid: not acidic enough to react with carbonates :(
How to go from aldehydes to primary alcohols?
Nucleophilic addition (H⁻ Hydride ions)
Reducing agent = NaBH₄ (supplies hydride ions)
Add water)
How to go from a ketone to a secondary alcohol?
Nucleophilic addition (H⁻ hydride ions)
Reducing agent = NaBH₄ (supplies hydride ions)
Then add water)
Reactions of carbonyls and hydrogen cyanide (description, benefit)
Nucleophilic addition (:CN⁻⁻⁻)
HCN = weak acid, partially dissociates in water ⟶ CN⁻⁻⁻
CN⁻⁻⁻ attacks δ+ carbon on carbonyl group
Extends carbon chain
H⁺ (from H₂O or HCN) bonds to oxygen = hydroxyl group
How to go from carboxylic acid to acyl chloride?
React with SOCl₂ = thionyl chloride
OH group replaced by Cl group
How to go from acyl chloride to an ester?
React with an alcohol, faster and easier than by using a carboxylic acid and an alcohol
How to go from a carboxylic acid to an ester?
Add alcohol
Heat with acid catalysts (H₂SO₄)
Reversible reaction: separate product as it forms using fractional distillation
N.B Oxygen in ester bonds comes from alcohol
How to go from an ester back to a carboxylic acid?
Add water
Acid hydrolysis
Reflux ester with hot quests acid e.g. HCl, H₂SO₄ (dilute)
How to get an alcohol and a salt from an ester?
react with an alkali
Base hydrolysis
reflux ester with a hot aqueous alkali e.g. NaOH (dilute)
How to get phenylamine from nitrobenzene?
Heating under reflux with tin catalysts + conc. HCl
if 2 substitutions: 12[H] and 4H₂O !!
Must add NaOH (phenyl amine +HCl ⟶ salt :( )
Reduction
Amino Acid + Acid ⟶
Amino Acid + Acid ⟶ Salt
If pH is lower than isoelectric point, amino acid behaves as a base: amino group reacts
NH₂ ⟶ NH₃⁺ = cation
Amino Acid + Base ⟶
Amino Acid + Base ⟶ Salt + Water
If pH is higher than isoelectric point, amino acid behaves as an acid: COOH group reacts
COOH ⟶ COO⁻⁻⁻ = anion
Amino acid + Alcohol ⟶
Amino acid + Alcohol ⟶ Ester + water
Strong acid catalyst (H₂SO₄)
Amino Acid + Amino Acid ⟶
Amino Acid + Amino Acid ⟶ Amide (dipeptide)
Condensation reaction: elimination of H₂O
Forms a dipeptide = secondary amide
Dicarboxylic acid + Diamine ⟶
Dicarboxylic acid + Diamine ⟶ Polyamide + water
Condensation polymer (loses H₂O)
Dicarboxylic acid + Diol ⟶
Dicarboxylic acid + Diol ⟶ Polyester + water
Condensation polymer (loses H₂O)
H⁺
Polyamide + 2H₂O ⟶
H⁺
Polyamide + 2H₂O ⟶ Dicarboxylix acid + diamine
Polyamide hydrolyses more easily with an acid than a base = acid hydrolysis
Polyester + 2NaOH ⟶
Polyester + 2NaOH ⟶ Dicarboxylix acid salt + Diol
Polyesters hydrolysis more easily with a base than an acid = base hydrolysis
Haloalkane + CN⁻⁻⁻ ⟶
Haloalkane + CN⁻⁻⁻ ⟶ Nitrile + X⁻⁻⁻
Nucleophilic substitution
Reflux haloalkane with potassium cyanide in ETHANOL SOLVENT
Nitrile + 4[H] ⟶
Nitrile + 4[H] ⟶ Primary amine
Reduction (method 1)
Use Lithium Aluminium Hydride: LiAlH₄, which is a strong reducing agent, and dilute acid
Nitrile + 2H₂ (g) ⟶
Nitrile + 2H₂ (g) ⟶ Primary amine
Reduction (method 2 - used in industry)
Hydrogen gas, metal catalyst (e.g. Platinum or Nickel)
High temp + pressure
N.B Nitriles can also be reduced with sodium metal and ethanol !!
Nitrile + 2H₂O + HCl ⟶
Nitrile + 2H₂O + HCl ⟶ Carboxylic acid + NH₄Cl
Acid hydrolysis
reflux nitrile in dilute HCl (with heat)
Haber Process
N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g)
Forward reaction = exothermic
High pressure favours forward reaction
BUT
low temp decreases yield so compromise @ 450°C
High pressure = dangerous & expensive compromise of 200 atm.
Finely divided porous iron catalyst
Acyl chloride + alcohol =
ester + HCl
Acyl chloride + Phenol
ester +HCl
Acyl chloride + Water
Carboxylic acid + HCl
Acyl chloride + Ammonia/amines
Amide + NH4Cl (ammonia chloride)
