Halogenoalkanes reactions and mechanisms (6.3 3)

Question 1

Hydrolysis reaction

Answer 1

RX (H2O/warm) = ROH

Question 2

Making an alcohol

Answer 2

Heating a halogenalkanes with aqueous potassium hydroxide under reflux.The attacking nucleophile OH-.
RX (KOH/heating under reflux)=ROH
e.g. CH3CH2CH2CL+KOH=CH3CH2CH2OH +KCL
conversion of 1-chloropropane to propan-1-ol

Question 3

Advantage of an ionic equation

Answer 3

Nucleophile is clearly shown

Question 4

Making nitriles

Answer 4

heating with potassium cyanide dissolved in ethanol under reflux.
Attacking nucleophile is the CN-
e.g CH3CH2Br+KCN=CH3CH2CN+KBr
conversion of bromoethane into propanennitrile
Note organic product contains more then one carbon atom than starting material.Useful way of extending carbon chains

Question 5

Making primary amines 1 PART

Answer 5

Heating a halogenalkane with ammonia solution in a sealed tube makes primary amines. Sealed needed because ammonia is gs and would escape before could react. Attacking nucleophile of NH3 molecules
e.g.
CH3CH2CH2CH2I+NH3=CH3CH2CH2CH2NH2+HI

Question 6

Making primary amines 2 part

Answer 6

the organic product is a base would react with the inorganic product the acid HI to form a salt so better equation is .
CH3CH2CH2CH2I+NH3=CH3CH2CH2CH2NH3+ +I-
This is the first step. To produce high yield of the amine the amoonia is used in excess so reacts with second step to produce the amine.
CH3CH3CH3CH2NH3+I- +NH3=CH3CH2CH2CH2NH2 +NH4+I-

Question 7

Final step

Answer 7

Products are butylamine and ammonium iodide

CH3CH2CH2CH2I+2NH3=CH3CH2CH2CH2NH2+NH4+I-