Saturated or Not?

Learning Objectives:

•Identify saturated & unsaturated compounds•Discuss the role of fats in the diet

•Explain how vegetable oils can be made into biodiesel

Ethane

Dodecene

Hexacosane

Hex-2-ene

C6H12

C6H14

Saturated

Unsaturated

Decolourises bromine

Brown solution with bromine

Burns with a sooty flame

Burns with a dull flame

Burns with a clean flame

Formed when fats are

hydrogenated

Used as monomers to

make polymers

Fats in the diet

Advantages• Both saturated and non saturated

fats are needed for a healthy balanced diet

• Foods rich in fats and oils are rich in vitamin E

• Omega 3 and 6 oils are good for the brain, heart, and joints

• Cholesterol is needed to make hormones and cell membranes

• Lipids are useful energy storage molecules (adipose tissue)

• Hydrogenated fats have longer shelf life

Disadvantages• Too many saturated fats can lead

to heart disease etc…• Hydrogenated trans fats raise LDL

levels lower HDL levels and inc risk of CHD. They cannot be metabolised so stay in blood longer

• Trans fatty acids are not kinky! Act like saturated fats

• Kosher/Halal/suitable for vegetarian/vegans

• Limited evidence suggested it may have a role in some cancers, liver disease, Alzheimer’s diabetes

Veggie Power• Vegetable oil contains a lot of energy it can be used as a

fuel – biodiesel.

• Biodiesel is a CLEAN fuel• It is RENEWABLE• It is CARBON NEUTRAL• Helps to reduce use of crude oil

• The vegetable oil is chemically digested to make it a better fuel

Bioethanol

• Produced from fermenting sugar from crops• RENEWABLE and CLEAN

• Glucose ethanol + carbon dioxide

• C6H12O6 2C2H5OH + 2CO2

• Ethanol is a good fuel, it burns easily in air to form CO2 and H2O

yeast

yeast

Non Renewable Ethanol

Ethene + steam Ethanol + hydrogen

Ethene comes from CRACKING crude oil products (Remember oil is heated to 800°C with a CATALYST – long chain ALKANE broken down to smaller alkene + alkane)

Ethanol produced chemically from crude oil is still cleaner as a fuel but it is NON RENEWABLE

catalyst

High pressure

• Workbook pages 85-88 to be completed for