Question

In reference to cloth or fiber, the term acetate usually means cellulose acetate, a semisynthetic polymer made by treating cellulose with acetic anhydride. Cellulose acetate is spun into yarn by dissolving it in acetone or methylene chloride and forcing the solution through spinnerets into warm air, where the solvent evaporates.

(a) Draw the structure of cellulose acetate.

(b) Explain why cellulose acetate is soluble in organic solvents, even though cellulose is not.

(c) (A true story) An organic chemistry student wore a long-sleeved blouse to the laboratory. She was rinsing a warm separatory funnel with acetone when the pressure rose and blew out the stopper. Her right arm was drenched with acetone, but she was unconcerned because acetone is not very toxic. About ten minutes later, the right arm of the student’s blouse disintegrated into a pile of white fluff, leaving her with a ragged short sleeve and the tatters of a cuff remaining around her wrist. Explain how a substance as innocuous as acetone ruined the student’s blouse.

(d) Predict what usually happens when students wear polyvinyl chloride shoes to the organic laboratory.

Short answer

(b)In cellulose, the hydroxyl groups are protected as esters. As a result of it, they form weak hydrogen bonds and are soluble in organic solvents.

(c) Acetone dissolve student’s blouse.

(d) Poly vinyl chloride (PVC) is soluble in organic solvents.

Step-by-step solution

Formation of cellulose acetate

Cellulose when treated with acetic anhydride forms cellulose acetate.

Hydrogen bonds

Hydrogen bonding is a special type of dipole-dipole interactions which exists in molecules containing a hydrogen atom linked by a covalent bond to a highly electronegative atom (like N,O or F). It is of two types namely, intermolecular hydrogen bonding (formed between two molecules of the same or different compounds) and intramolecular hydrogen bonding (formed between hydrogen atom and N, O or F atom of the same molecule).

Poly vinyl chloride (PVC)

The monomer used in making PVC is vinyl chloride. Vinyl chloride polymerizes in the presence of peroxides to form poly vinyl chloride.

Explanation

(b) In cellulose, the hydroxyl groups are protected as esters. As a result of it, they form weak hydrogen bonds and are soluble in organic solvents.

(c)Acetone dissolve student’s blouse.

(d) Poly vinyl chloride (PVC) is soluble in organic solvents. Shoe soles are generally made of poly vinyl chloride.