Show how you would synthesize the following ethers in good yield from the indicated starting materials and any additional reagents needed.
(b) n-butyl phenyl ether from phenol and butan-1-ol

Verified step by step guidance

1. Step 1: Begin by recognizing that phenol (C₆H₅OH) is an aromatic alcohol and butan-1-ol (CH₃CH₂CH₂CH₂OH) is a primary alcohol. To synthesize n-butyl phenyl ether, you need to form an ether bond (C-O-C) between the phenol and butan-1-ol.
2. Step 2: Convert phenol into its phenoxide ion (C₆H₅O⁻) by treating it with a strong base such as sodium hydroxide (NaOH). This deprotonates the hydroxyl group of phenol, making it more nucleophilic.
3. Step 3: Prepare butan-1-ol for the reaction by converting it into a good electrophile. This can be achieved by reacting butan-1-ol with a strong acid like sulfuric acid (H₂SO₄) or phosphorus tribromide (PBr₃) to form butyl bromide (CH₃CH₂CH₂CH₂Br), a primary alkyl halide.
4. Step 4: Perform the Williamson ether synthesis, which involves reacting the phenoxide ion (C₆H₅O⁻) with butyl bromide (CH₃CH₂CH₂CH₂Br). The phenoxide ion acts as a nucleophile and attacks the electrophilic carbon in the butyl bromide, displacing the bromide ion (Br⁻) and forming n-butyl phenyl ether (C₆H₅OCH₂CH₂CH₂CH₃).
5. Step 5: Purify the product by distillation or recrystallization, depending on the physical properties of n-butyl phenyl ether, to ensure a good yield of the desired ether.

Key Concepts

Ethers and Their Synthesis

Ethers are organic compounds characterized by an oxygen atom connected to two alkyl or aryl groups. The synthesis of ethers can be achieved through various methods, including the Williamson ether synthesis, which involves the nucleophilic substitution of an alkoxide ion with a primary alkyl halide. Understanding the reactivity and properties of ethers is crucial for designing effective synthetic routes.

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions are fundamental in organic chemistry, where a nucleophile attacks an electrophile, resulting in the replacement of a leaving group. In the context of synthesizing n-butyl phenyl ether, the nucleophile is the alkoxide ion derived from butan-1-ol, which reacts with phenol. The mechanism can follow either an SN1 or SN2 pathway, depending on the structure of the reactants.

Reactivity of Alcohols and Phenols

Alcohols and phenols exhibit different reactivities due to their structural features. Alcohols can be converted into alkoxide ions, which are strong nucleophiles, while phenols can act as electrophiles in nucleophilic substitution reactions. The acidity of phenols allows for the formation of phenoxide ions, enhancing their reactivity in ether synthesis, particularly when reacting with alkyl halides.