Question

Using your roadmap as a guide, show reagents and conditions to bring about these conversions, which may require more than one step.

Short answer

Question: Identify the reagents and conditions necessary to convert benzene to phenol and alcohol to aldehyde. Discuss the mechanisms involved in the proposed transformations. Answer: In the conversion of benzene to phenol, the reagents and conditions are as follows: 1. Nitration of benzene: HNO3 and H2SO4 at 50-60°C, forming nitrobenzene via electrophilic substitution. 2. Reduction of nitrobenzene using Sn/HCl or Fe/HCl with heat, forming aniline. 3. Diazotization of aniline using NaNO2 and HCl at 0-5°C, forming a diazonium salt. 4. Hydrolysis of the diazonium salt with H2O and heat, resulting in the formation of phenol. For the conversion of alcohol to aldehyde, the reagents and conditions are as follows: 1. Oxidation of alcohol using pyridinium chlorochromate (PCC) in CH2Cl2, forming aldehyde. This mild oxidation prevents the formation of carboxylic acid.

Step-by-step solution

Identify the reactants and products

First, let's find out what reactants and products are involved in the conversion. Since the specific examples of conversions are not given in the exercise, let's consider two examples: Example 1: Conversion of benzene to phenol. Example 2: Conversion of alcohol to aldehyde.

Break down the reactions

In this step, let's break down the reactions into their individual steps, citing the reagents and conditions at each step. Example 1: Conversion of benzene to phenol Step 1: Nitration of benzene Reagents and conditions: HNO3, H2SO4, and benzene, 50-60 °C. Reaction: Benzene + HNO3 -> Nitrobenzene (Electrophilic substitution) Step 2: Reduction of nitrobenzene Reagents and conditions: Sn/HCl or Fe/HCl, heat. Reaction: Nitrobenzene + 6[H] -> Aniline (Reduction) Step 3: Diazotization of aniline Reagents and conditions: NaNO2, HCl, and aniline, 0-5 °C. Reaction: Aniline + NaNO2 + HCl -> Diazonium salt (Diazotization) Step 4: Hydrolysis of diazonium salt Reagents and conditions: H2O, heating. Reaction: Diazonium salt + H2O -> Phenol (Hydrolysis) Example 2: Conversion of alcohol to aldehyde Step 1: Oxidation of alcohol Reagents and conditions: Pyridinium chlorochromate (PCC), CH2Cl2. Reaction: Alcohol + PCC -> Aldehyde (Oxidation)

Verify the steps for correctness

After breaking down the reactions, analyze them for correctness, and ensure that the reagents and conditions used are appropriate for each conversion step. Example 1: The conversion of benzene to phenol includes nitration of benzene, reduction of nitrobenzene to aniline, diazotization of aniline, and hydrolysis of diazonium salt. All the reagents and conditions mentioned in each step are appropriate for the desired transformation. Example 2: The conversion of alcohol to aldehyde involves oxidation. The reagents and conditions mentioned, using PCC in CH2Cl2, are appropriate for a mild oxidation, preventing the formation of carboxylic acid. In conclusion, the student should now understand how to identify the reactants and products, break down the reactions into individual steps, and apply the correct reagents and conditions for each step to achieve the desired chemical transformations.