Question

Polymerization of vinyl acetate gives poly(vinyl acetate). Hydrolysis of this polymer in aqueous sodium hydroxide gives the useful water-soluble polymer poly(vinyl alcohol). Draw the repeat units of both poly(vinyl acetate) and poly(vinyl alcohol).

Short answer

Question: Draw the repeat unit of poly(vinyl acetate) and explain the changes that occur during hydrolysis in the presence of aqueous sodium hydroxide to form poly(vinyl alcohol). Answer: The repeat unit of poly(vinyl acetate) can be represented as - [CH₂ - CH(OCOCH₃)] -. During the hydrolysis process in the presence of aqueous sodium hydroxide, the ester (COO) group in poly(vinyl acetate) is replaced by an alcohol (-OH) group, resulting in the formation of poly(vinyl alcohol). The repeat unit of poly(vinyl alcohol) after the hydrolysis reaction can be represented as - [CH₂ - CH(OH)] -.

Step-by-step solution

Understand the structure of vinyl acetate monomer

Vinyl acetate is an organic compound with the formula CH₃CO₂CH=CH₂. It is a colorless liquid that is the precursor to poly(vinyl acetate), an important polymer in industry. The structural formula of vinyl acetate can be represented as follows: CH₃ - C(=O) - O - CH=CH₂

Identify the repeat unit of poly(vinyl acetate)

When vinyl acetate undergoes polymerization, multiple vinyl acetate monomers are joined together, creating a long-chain molecule known as poly(vinyl acetate). During polymerization, the double bond in the vinyl group opens, and the monomers are connected with single bonds between the carbon atoms. The repeat unit in the polymer can be represented as follows: - [CH₂ - CH(OCOCH₃)] -

Understand the hydrolysis process and formation of poly(vinyl alcohol)

When poly(vinyl acetate) undergoes hydrolysis in the presence of aqueous sodium hydroxide, the ester (COO) group in the polymer is replaced by an alcohol (-OH) group to form poly(vinyl alcohol). The hydrolysis reaction can be represented as: Poly(vinyl acetate) + NaOH (aqueous) → Poly(vinyl alcohol) + Sodium Acetate

Identify the repeat unit of poly(vinyl alcohol)

Poly(vinyl alcohol) is a water-soluble polymer resulting from the hydrolysis of poly(vinyl acetate). After the hydrolysis reaction, the repeat unit in the poly(vinyl alcohol) can be represented as follows: - [CH₂ - CH(OH)] - Now that we have identified the repeat units of both poly(vinyl acetate) and poly(vinyl alcohol), their structures can be drawn as required.