To synthesize propanone (acetone) and monohydroxybenzene (phenol) from benzene and propylene, we can use a combination of different chemical reactions, primarily alkylation and oxidation processes. Here are the steps for each compound:
Preparation of Propanone (Acetone):
-
Alkylation of Benzene:
Benzene can be alkylated using propylene (which is a branched alkene) in the presence of a catalyst. This process is called Friedel-Crafts alkylation. Here’s how it works:- Benzene reacts with propylene in the presence of a Lewis acid catalyst (like AlCl3) to form isopropylbenzene (cumene).
- The reaction can be represented as: \[ \text{C}_6\text{H}_6 + \text{C}_3\text{H}_6 \xrightarrow{\text{AlCl}_3} \text{C}_6\text{H}_5\text{C(CH}_3)_2 \]
-
Oxidation of Isopropylbenzene (Cumene):
Next, the isopropylbenzene can be oxidized to form propanone. This can be done through air oxidation or the use of oxidizing agents:- Isopropylbenzene undergoes oxidation, first forming cumene hydroperoxide, which can then be rearranged and cleaved to yield acetone (propanone).
- The overall reaction can be simplified as: \[ \text{C}_6\text{H}_5\text{C(CH}_3)_2 \rightarrow \text{C}_3\text{H}_6\text{O} + \text{by-products} \]
Preparation of Monohydroxybenzene (Phenol):
-
Friedel-Crafts Acylation of Benzene:
To prepare phenol, we can utilize a different route from the alkylation of propylene. Instead, we can start with phenol’s industrial production known as the cumene process, which is indirectly related to our starting materials:- Here, we start with benzene and acylate it using an acyl chloride derived from propylene or propanoyl chloride.
- The reaction forms a ketone, but in the context of preparing phenol, we consider a transformation involving the hydrolysis of isopropylbenzene as an intermediate.
-
Hydrolysis and Rearrangement:
The ketone formed can be further processed to yield phenol:- From isopropylbenzene/Cumene produced earlier, it gets converted to phenol through catalytic oxidation or hydrolytic cleavage reactions.
-
Direct Hydrolysis of Cumene Hydroperoxide:
Alternatively, the hydroperoxide of cumene can be acidic or basic hydrolyzed to yield phenol directly: \[ \text{C}_6\text{H}_5\text{C(CH}_3)_2\text{O}_2\text{H} \rightarrow \text{C}_6\text{H}_5\text{OH} + \text{Acetone} \]
Summary:
- Propanone (Acetone): Prepared by alkylating benzene with propylene to form isopropylbenzene, which is then oxidized.
- Monohydroxybenzene (Phenol): Prepared from the hydrolysis of cumene formed during the same processes or from the direct acylation and rearrangements.
Each of these reactions needs specific conditions, such as catalysts and reagents, to proceed efficiently and would typically be performed in a laboratory or industrial setting.