Organic Reactions Flashcards
Ethanoyl Chloride + water
Describe the reaction and give the products
Ethanoic acid + HCl
Vigorous
Acyl chloride + alcohol
Give the products and describe the reaction
Ester + HCl
Goes to completion unlike COOH + OH
Propanoyl chloride + conc. ammonia solution
Give the products and describe the reaction
Propanamide + HCl
Room temperature, violent
How would you form a chloroalkane from an alcohol?
PCl5
Reaction of acyl chloride + amine
N-substituted amide + HCl
Violent reaction
Amine + acid —>
Ammonium salt
CH3CH2NH2 + HCl –>
CH3CH2NH3+Cl- (salt)
How would you form a secondary amine?
Primary amine + halogenoalkane
Ethanoyl chloride + phenylamine –>
Two reactions:
N-phenylethanamide + HCl
then:
Phenylamine + HCl –> Phenylammonium chloride
Equation for the combustion of ethanol
C2H5OH + 3O2 –> 2CO2 + 3H2O
Why does the reaction between PCl5 and an alcohol not need heating?
The reaction is very vigorous at room temperature
What are the two inorganic products formed from the reaction of PCl5 and an alcohol?
Phosphorus oxychloride (POCl3) and Hydrogen chloride (HCl)
Give the equation for the reaction between PCl5 and propan-1-ol
CH3CH2CH2OH + PCl5 –> CH3CH2CH2Cl +
POCl3 + HCl
How would you chlorinate a tertiary alcohol?
Add conc. HCl at room temperature, shake
How would you brominate an alcohol?
Warm with a mixture of potassium bromide and 50% concentrated sulfuric acid
Give the three equations for the bromination of butan-1-ol
KBr + H2SO4 –> KHSO4 + HBr
2KBr + H2SO4 –> K2SO4 + 2HBr
CH3CH2CH2CH2OH + HBr –>
CH3CH2CH2CH2Br +H2O
Write the equation for the formation of the reactant that reacts with an alcohol to form an iodoalkane
2P + 3I2 –> 2PI3
What would you use in the iodination of an alcohol?
A mixture of red phosphorus and iodine, heat under reflux
Give the equation for the reaction between ethanol and phosphorus(III) iodide
3C2H5OH + PCl3 –> 3C2H5I + H3PO3
What is H3PO3?
Phosphonic acid (or phosphorous acid)
What is formed in the dehydration of an alcohol?
An alkene
What is the inorganic product of a dehydration reaction of an alcohol?
H2O
What do you react alcohols with to dehydrate them?
Conc. phosphoric acid
What are the two possible products of the dehydration of butan-1-ol?
But-1-ene and But-2-ene
When butan-2-ol is dehydrated, there is more than one organic product. Explain why there is only one pair of E/Z isomers when pentan-3-ol is dehydrated
It is symmetrical so the double bond can only form between the second and third carbon whereas in butan-2-ol the double bond could form between the first and second carbon or the second and third carbon
What type of solution do small amines form when dissolved in water?
An alkaline solution
-the amine takes a H+ ion from water forming alkyl ammonium ions and OH- ions
RCOOH + PCl5 –>
RCOCl + POCl3 + HCl
RCOOH —-> RCH2OH
LiAlH4 in dry ether
CH3COOH + NaOH –>
CH3COONa + H2O
2CH3COOH + Na2CO3 —>
How could you test for a reaction?
2CH3COONa + H2O + CO2
Use limewater
CH3COOH + NaHCO3 –>
CH3COONa + H2O + CO2
Are carboxylic acids soluble in water?
- Shorter chained ones are as they are very polar and form hydrogen bonds with the water molecules
- solubility decreases as the length of the chain increases as they have stronger intermolecular forces between
- if these stronger intermolecular forces are stronger than hydrogen bonding with water would be then the carboxylic acid won’t dissolve
a) Explain why propanoic acid behaves as an acid but propanol does not
b) Describe a simple test to distinguish between propanol and propanoic acid
a) Propanoic acid partially dissociates in water to release H+ ions. Propanol doesn’t
b) Add sodium carbonate. Propanoic acid will cause fizzing of bubbles of CO2. Propanol will show no reaction
What is needed in the reaction of a carboxylic acid and an alcohol?
What is formed?
Heat, acid catalyst
An ester
How would you retrieve the ester formed from the reaction between a carboxylic acid and an alcohol?
Why would you have to do it this way?
- The reaction is reversible
- Product must be separated as it forms
- Use distillation as the apparatus for the reaction
- Add sodium carbonate to react with any acid still present in the mixture
- The ester will form on top of the aqueous layer and can be separated using a separating funnel
What type of reaction is the reaction between amine and ethanoyl chloride?
Addition-elimination
-Two molecules join together, a small molecule is then eliminated
Amine + halogenoalkane –>
Secondary amine + hydrogen halide
CH3CH2CH2CH2NH2 + CH3CH2Cl –>
CH3CH2CH2CH2NHCH2CH3 + HCl
What are the problems of reacting an amine with a halogenoalkane?
Forms a secondary amine that then can react with more halogenoalkane to produce a tertiary amine which will then react to form a quaternary salt
What is the solubility of amines like?
Very soluble but solubility decreases as the chain length increases
Form hydrogen bonds with the water
Functional group of an amide
RCONH2
Why would there be two reactions when an acyl chloride is reacted with conc. aqueous ammonia?
CH3CH2COCl + NH3 –> CH3CH2CONH2 + HCl
NH3 will react with HCl to form NH4Cl
How would you form a primary amine from a nitrile?
Use LiAlH4 in dry ether
CH3CN + 4[H] –> CH3CH2NH2
