Question

Propose reagents and experimental conditions for the conversion of butadiene to adipic acid.

Short answer

Question: Outline the process of converting butadiene into adipic acid, including the main stages and reagents involved. Answer: The conversion of butadiene into adipic acid involves two main stages: (1) extending the carbon chain via ozonolysis with ozone (O₃) to yield glyoxal and then reductive amination with ammonia (NH₃) and sodium cyanoborohydride (NaBH₃CN) to form 1,6-diaminohexane, and (2) oxidation of terminal amines to carboxyl groups using either nitric acid (HNO₃) or a mixture of hydrogen peroxide (H₂O₂) and sulfuric acid (H₂SO₄) to obtain adipic acid.

Step-by-step solution

1. Carbon chain extension via an ozonolysis/reductive amination sequence

To accomplish the carbon chain extension, we can start by reacting butadiene with ozone (O₃) in the process called ozonolysis. This reaction will yield glyoxal (CHOCHO). Afterward, the glyoxal must undergo reductive amination with ammonia (NH₃) and a reducing agent, such as sodium cyanoborohydride (NaBH₃CN), to yield 1,6-diaminohexane (H₂N(CH₂)₆NH₂).

2. Oxidation of the diamine to adipic acid

To further oxidize the terminal amines to carboxylic acids, the diamine can be treated with nitric acid (HNO₃) or a mixture of hydrogen peroxide (H₂O₂) and a stronger acid like sulfuric acid (H₂SO₄) to obtain adipic acid (HOOC(CH₂)₄COOH). Overall, the conversion of butadiene to adipic acid can be achieved in two primary steps: extending the carbon chain via ozonolysis and reductive amination, followed by oxidation of terminal amines to carboxyl groups.