Reactions

Polymers

• A compound of a high molecular mass made up of a series of monomer units

• Important compounds• Used for multitude applications

– Any you can think of?– Natural Polymers

• DNA, RNA, Starches, Proteins, Enzymes – Synthetic

• Polystyrene, Polyvinyl Chloride

Chain Growth Polymers

• Compounds formed by the addition of identical monomer units

• Monomer is often an alkene

• A radical initiator is usually present

General Example

• N is in the hundreds or thousands

• L is a substituent that determines the type of monomer

Monomer Examples

• Ethene (ethylene)– Polyethylene

• Propene (propylene)– Polypropylene

Monomer Examples

• Styrene– Polystyrene

• Chloroethene (vinyl chloride)– Polyvinyl Chloride

Types of Plastic

• Plastic containers have numbers that tell you the type of plastic (1-7)

• #1 PET Polyethylene terephthalate (Soda)• #2 HDPE High-density polyethylene (Milk) • #3 PVC Polyvinyl chloride (Pipes) • #4 LDPE Low-density polyethylene (Bags) • #5 PP Polypropylene (Butter Containers)• #6 PS Polystyrene (Styrofoam)

Mechanism

• An radical initiator is present. Written In.

Step-Growth Polymers

• Reaction between two different monomers

A-A + B-B [-A-A-B-B-A-A-B-B-]n

Example

Carboxylic Acids

• Contain a carboxyl group -COOH

• Polar molecules, Exhibit H bonding

• Smaller acids are water soluble

• Fairly high BP

• Much more acidic than alcohols– The two Oxygens make the H easily ionizable

• Low pH

Ester Synthesis

• Esters are prepared by reacting an alcohol and a carboxylic acid with an acid catalyst

RCOOH + R’OH RCOOR’ + H2O

• The OH from the acid and the H from the alcohol form the water

• Don’t need to worry about the mechanism

• Propanol is reacted with butanoic acid. Determine the products of the reaction.

Reaction Consideration

• Product purification

– The ester is a liquid and must be removed

– The will be react and water in the flask too

– Separate by distillation

• By BP

• Salicylic acid reacts with acetic anhydride