Method of preparing isopropyl alcohol

A method of preparing isopropyl alcohol, the method comprising:

• (S1) feeding a reaction product of a propylene monomer and water to a gas purification unit and separating gas components including an unreacted propylene monomer;
• (S2) feeding the reaction product from which the gas components are separated to a first organic material removal tower, and discharging an upper stream containing organic by-products and isopropyl alcohol and a lower stream containing isopropyl alcohol (IPA), an n-propyl alcohol (NPA) by-product, and water;
• (S3) feeding the upper discharge stream of the first organic material removal tower to a second organic material removal tower, introducing process circulating water, and discharging an upper stream containing organic by-products and a lower stream containing isopropyl alcohol and process circulating water;
• and
• (S4) feeding the lower discharge stream of the first organic material removal tower to an isopropyl alcohol (IPA) purification unit including a plurality of distillation towers and separating isopropyl alcohol.