Reactions Dr. M. Abd-Elhakeem Faculty of Biotechnology Organic Chemistry Chapter 3

Is a Chemical reaction in which two molecules or (functional groups) combine to form one single molecule, together with the loss of a small molecule. Usually water molecule. Condensation

Most common condensation reaction occurs between Carbonyl group and amino group such as condensation between two amino acids to form peptide.

Condensation between hydrazine hydrate or phenyl hydrazine with aldehydes and ketones to form characteristic hydrazones and with di carbonyl compound to form heterocyclic ring.

Also reaction of alcohols and acids which known as esterification is considered a condensation process because it involves a production of water molecule

is a chemical process in which a certain molecule is split into two parts by the addition of a Molecule of water. Hydrolysis

Esters and amides shows hydrolysis reactions as illustrated below OH H

Hydrolysis reactions are very important for our life, where many process in our body involve hydrolysis step such as 1- Hydrolysis of ATP (energy source of human cell) to form ADP and phosphate group that cause releasing energy

+ H2O- H2O

2- Hydrolysis of proteins, fats, oils, and carbohydrates during metabolism to form simple molecules suitable for absorption.

is a process of reacting Monomers together in a chemical reaction to form three-dimensional networks or chains. Polymers are molecules which consist of a long, repeating chain of smaller units called monomers. Polymers have the highest molecular weight among any molecules, and may consist of billions of atoms. Polymerization

Polymer: High molecular weight molecule made up of a small repeat unit (monomer). A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A- A-A-A-A-A Monomer: Low molecular weight compound that can be connected together to give a polymer Oligomer: Short polymer chain Copolymer: polymer made up of 2 or more monomers A-B-B-A-A-B-A-B-A-B-B-B-A-A-B

Polymer Synthesis There are two major classes of polymer formation mechanisms 1- Addition polymerization: The polymer grows by sequential addition of monomers to a reactive site

Addition Polymerization A

Propagation A

Addition Polymerization Propagation A

Addition Polymerization Termination

200 °C 2000 atm O 2 peroxidespolyethylene H2CH2CH2CH2C CH 2 Free-Radical AdditionPolymerization of Ethylene

20 2- Condensation polymerization Condensation polymerization: the polymer grows from monomers by splitting off a small molecule such as water or carbon dioxide. Example: formation of amide links and loss of water Monomers First unit of polymer + H 2 O

Types of Polymers 1- Polyolefins: made from olefin (alkene) monomers 2- Polyesters, Amides, Urethanes, etc.: monomers linked by ester, amide, urethane 3- Natural Polymers: Polysaccharides, DNA, proteins

Common Polyolefins

Polyesters, Amides, and Urethanes

Natural Polymers

Type Abbreviation Major Uses Low-density polyethylene High-density Polyethylene Polypropylene Poly(vinyl chloride) Polystyrene LDPE HDPE PP PVC PS Packaging film, wire and cable insulation, toys, flexible bottles housewares, coatings Bottles, drums, pipe, conduit, sheet, film, wire and cable insulation Automobile and appliance parts, furniture, cordage, webbing, carpeting, film packaging Construction, rigid pipe, flooring, wire and cable insulation, film and sheet Packaging (foam and film), foam insulation appliances, housewares, toys

Phenol-formaldehyde Urea-formaldehyde Unsaturated polyester Epoxy Melamine-formaldehyde Electrical and electronic equipment, automobile parts, utensil handles, plywood adhesives, particle board binder Similar to PF polymer; also treatment of textiles, coatings Construction, automobile parts, boat hulls, marine accessories, corrosion-resistant ducting, pipe, tanks, etc., business equipment Protective coatings, adhesives, electrical and electronics applications, industrial flooring highway paving materials, composites Similar to UF polymers; decorative panels, counter and table tops, dinnerware TypeAbbreviation Typical Uses PF UF UP - MF

END OF Chapter 3