Question

Using your roadmap as a guide, show how to convert butane into butanal. Show all reagents needed and all molecules synthesized along the way.

Short answer

Question: Describe the step-by-step process of converting butane to butanal. Answer: The conversion of butane to butanal involves two main steps. First, butane is converted to 1-butanol through the formation of 1-bromobutane via a free radical halogenation reaction with bromine and UV light, followed by a nucleophilic substitution reaction with sodium hydroxide. Second, 1-butanol is oxidized to form butanal using a mild oxidizing agent, pyridinium chlorochromate (PCC), to selectively oxidize the primary alcohol without forming carboxylic acids.

Step-by-step solution

Convert Butane to 1-Butanol

The first step in the conversion of butane to butanal is to transform butane into 1-butanol. This can be achieved by first converting butane into 1-bromobutane via a free radical halogenation reaction. In this reaction, butane reacts with bromine (Br2) under ultraviolet (UV) light to replace one of the hydrogen atoms with a bromine atom. The reaction proceeds as follows: C4H10 + Br2 -> C4H9Br + HBr Next, we will replace the bromine atom with an -OH group in a nucleophilic substitution reaction. To do this, 1-bromobutane is reacted with sodium hydroxide (NaOH) to form 1-butanol: C4H9Br + NaOH -> C4H9OH + NaBr

Oxidize 1-Butanol to Butanal

Having obtained 1-butanol, the final step is to oxidize it into butanal. To achieve this, we will use a specific mild oxidizing agent required for this oxidation—pyridinium chlorochromate (PCC). PCC allows selective oxidation of primary alcohols to aldehydes while avoiding the formation of carboxylic acids. The reaction is given by: C4H9OH + PCC -> C4H8O + HCl + Cr(OH)3 So, using the above two sequential reactions, we can convert butane into butanal.