Question

Show how you would synthesize butyl isopropyl sulfide using butan-1-ol, propan-2-ol, and any solvents and reagents you need.

Short answer

Butan-1-ol undergoes substitution reaction with phosphorous bromide and hydroxyl group gets substituted with bromine atom. Further, bromobutane on treatment with sodium hydrosulfide undergoes substitution reaction and bromo group gets substituted with “thiol” group and butan-1-thiol gets formed.

Step-by-step solution

Reaction of butan-1-ol with phosphorous bromide and sodium hydrosulfide:

Butan-1-ol undergoes substitution reaction with phosphorous bromide and hydroxyl group gets substituted with bromine atom. Further, bromobutane on treatment with sodium hydrosulfide undergoes substitution reaction and bromo group gets substituted with “thiol” group and butan-1-thiol gets formed.

Formation of butyl isopropyl sulfide:

Sodium hydroxide acts as base and abstracts the proton from butan-1-thiol and forms anion in which sulphur has negative charge, and propan-2-ol on reaction with tosyl chloride and pyridine forms the tosylate which on reaction with sulphur anion formed gives the required product, that is, butyl isopropyl sulfide.