Question

Using your roadmaps as a guide, show how to convert propane into propyl propanoate. You must use propane as the source of all carbon atoms in the target molecule. Show all reagents needed and all molecules synthesized along the way.

Short answer

Question: Provide a step-by-step reaction sequence to convert propane (C3H8) into propyl propanoate (C6H12O2) using propane as the source of all carbon atoms, and mention the reagents needed and products formed at each step. Answer: The conversion of propane to propyl propanoate can be achieved in the following steps: 1. Convert propane into propanol using hydration and reduction reactions with H2O and H2/Pd or Pt as reagents, forming propanol (C3H8O) as the product. 2. Convert propanol to propyl bromide by reacting with hydrobromic acid (HBr) through an SN2 reaction, resulting in propyl bromide (C3H7Br) and water (H2O). 3. Convert propyl bromide into propanoic acid by forming a Grignard reagent with magnesium (Mg) and then reacting with CO2 and water (H2O), producing propanoic acid (C3H6O2) and MgBr(OH). 4. Perform a Fischer esterification by reacting propanol (C3H8O) with propanoic acid (C3H6O2) in the presence of a strong acid catalyst such as sulfuric acid (H2SO4), resulting in the formation of propyl propanoate (C6H12O2) and water (H2O).

Step-by-step solution

Convert propane into propanol

Since the first step is to convert propane (C3H8) into an alcohol, we will use a two-step process: hydration followed by reduction. First, we hydrate propane using sulfuric acid (H2SO4) as a catalyst and water (H2O) to form a propene intermediate. Next, we reduce the propene by reacting it with H2 and a catalyst like Pd or Pt to form propanol (C3H8O). The overall reaction is as follows: C3H8 + H2O -> C3H6 + H2SO4 -> C3H8O

Convert propanol into propyl bromide

With propanol as our starting material, our next step is to convert it into an alkyl halide, specifically propyl bromide (C3H7Br). This can be achieved through the reaction with hydrobromic acid (HBr). The reaction is called an SN2 reaction and proceeds as follows: C3H8O + HBr -> C3H7Br + H2O

Convert propyl bromide into propanoic acid

Now, our goal is to convert propyl bromide into a carboxylic acid, which we will later use to form our target ester. We will achieve this by undergoing two sequential reactions. The first one is reacting it with magnesium (Mg) in a dry ether (usually diethyl ether) to form a Grignard reagent, and then followed by reacting the Grignard reagent with carbon dioxide (CO2) and acidifying the resulting salt with water (H2O) to form propanoic acid (C3H6O2). The overall reaction is as follows: C3H7Br + Mg -> C3H7MgBr C3H7MgBr + CO2 -> C3H6O2MgBr C3H6O2MgBr + H2O -> C3H6O2 + MgBr(OH)

Form propyl propanoate from propanol and propanoic acid

Finally, we will form our target ester, propyl propanoate, by reacting propanol (C3H8O) with propanoic acid (C3H6O2) in the presence of a catalyst such as sulfuric acid (H2SO4) or some other strong acid. This reaction is called a Fischer esterification and proceeds as follows: C3H8O + C3H6O2 -> C6H12O2 + H2O Now, we have successfully converted propane into propyl propanoate using propane as the source of all carbon atoms and showing all reagents needed and molecules synthesized along the way.