# Step-by-Step Solution: Toluene + Butan--ol +₃ ## . **Understanding the Reactants** - **Toluene**: \( C_6H_5CH_3 \), an aromatic ring with a methyl group (activating, ortho/para-directing). - **Butan-1-ol**: \( CH_3CH_2CH_2CH_2OH \), a primary alcohol. - **BF₃ (Boron Trifluoride)**: A Lewis acid catalyst. ## 2. **Type of Reaction** This is a **Friedel–Crafts alkylation** using an alcohol as the alkyl source. BF₃ acts as a Lewis acid, generating a carbocation (or similar reactive intermediate) from the alcohol, which then alkylates the aromatic ring. ## 3. **Generation of the Alkylating Agent** - BF₃ interacts with the alcohol, enhancing the leaving ability of water: \[ CH_3CH_2CH_2CH_2OH + BF_3 \rightarrow CH_3CH_2CH_2CH_2^+ + BF_3OH^- \] - Forms a **butyl carbocation** (\( CH_3CH_2CH_2CH_2^+ \)). ## 4. **Friedel–Crafts Alkylation Step** - **Toluene** is in excess, so multiple alkylations are possible. - The butyl carbocation attacks the benzene ring of toluene, most favorably at the ortho and para positions (due to methyl group activation). ## 5. **Major Products** ### **Product 1:** *Monobutylated Toluene* - The butyl group is added **para** to the methyl due to steric reasons (para is preferred over ortho when possible): - **4-butyl toluene** (\( p \)-butyl toluene), or systematically **1-methyl-4-butylbenzene**. ### **Product 2:** *Dibutylated Toluene* - Since toluene is in excess, after monoalkylation, further alkylation can occur: - **Di(butyl)toluene** at both ortho and para positions (e.g., 2,4-dibutyl toluene). - However, with excess toluene and only one equivalent of butan-1-ol, **monobutylation** is the dominant product. If excess butan-1-ol is used, further substitution is possible. ## 6. **Final Answers** ### **Step-by-Step Summary** 1. **BF₃** activates butan-1-ol, generating a butyl carbocation. 2. **Toluene** undergoes electrophilic aromatic substitution (EAS) with the carbocation. 3. **Major product**: Para-butyl toluene. 4. **Minor product**: Ortho-butyl toluene (some ortho substitution always occurs). 5. If enough butan-1-ol is present, **diallylated toluenes** can form, but with excess toluene, these are minor. --- ## **Summary Table** | Product Name | Structure | Notes | |-------------------|-----------|--------------------------------| | 4-butyl toluene |  | Para alkylation (major) | | 2-butyl toluene |  | Ortho alkylation (minor) | *Images: Para and ortho butyl toluene (source: chemsynthesis.com, chemblink.com)* --- ## **Final Answer** > **The two main products are:** > > 1. **4-butyl toluene** (para-butylation, major product) > 2. **2-butyl toluene** (ortho-butylation, minor product) **Reaction equation:** \[ \text{Toluene (excess)} + \text{butan-1-ol} \xrightarrow{BF_3} \text{4-butyl toluene} + \text{2-butyl toluene} \]