useful products from organic sources organic chemistry
TRANSCRIPT
Useful Products from Organic Sources
ORGANIC CHEMISTRY
How coal formed
Over millions of years, due to high temperatures and pressure…
…the trees became fossilized, forming coal.
Millions of years ago trees died and fell to the bottom of swamps.
Over time they became covered by mud and rock.
How oil and natural gas formed
Crude oil
• Crude oil is a mixturemixture. It contains hundreds of different compounds. Some are small but most are large.
• Nearly all of these compounds contain carbon and hydrogen only. only.
• They are called hydrocarbons.• Also some other compounds contain small amounts of Also some other compounds contain small amounts of
N and S. Why?N and S. Why?
Hydrocarbons are molecules that contain carbon and hydrogen onlyonly.
How oil and natural gas formed
Q1 Explain why oil contains carbon and hydrogen.
Q2 Explain where the energy in oil originated.
The importance of oil
• The hydrocarbons in crude oil are essential to our way of life
• We use them as fuels for most forms of transport.
• We also use them as raw materials from which a
HUGE range of useful everyday substances are made .. Such as…………..make a list!
• Crude oil is a mixture of hydrocarbons with a VERY wide range of sizes.
• Crude oil itself has no uses because its properties are
not definite. • To make crude oil into useful substances we have to
separate the mixture into molecules of similar size.• This is done in an oil refineryoil refinery in a process called
fractional distillation.• The physical property used to separate the fractions is
boiling point.
Making oil useful
Fractional Distillation
Can you predict and explain where the fractions are obtained from the fractionating tower?
Fraction Boiling Range
(oC)
Kerosene 150 - 240
Diesel 220 – 275
Petrol 40 - 175
Bitumen >350
Fuel gas Below 40
Lubricating oil 250-350
cool
hot
Fuel gas
Petroleum
Kerosene
Diesel
Lub. Oil
Bitumen
Fractional Distillation
Why do these fractions condense over a boiling range?
Fraction Boiling Range (oC)
Fuel gas Below 40
Petrol 40 - 175
Kerosene 150 - 240
Diesel 220 – 275
Lubricating oil 250-350
Bitumen >350
cool
hot
Fuel gas
Petroleum
Kerosene
Diesel
Lub. Oil
Bitumen
Fractional Distillation
Fuel gas
Petrol / gasoline
Naphtha
Paraffin / Kerosine
Diesel fuel
Fuel and lubricating oil
Bitumen
Burned in the refinery to fuel the distillation process, sold as LPG, purified and sold as bottled camping gas
Fuel for cars and motorcycles, also used to make chemicals.
Used to make chemicals used everwhere.
Fuel for greenhouse heaters and jet engines, manufacture of chemicals.
Fuel for lorries, trains.
Fuel for the heating systems of large buildings, fuel for ships, lubricating oil.
Roofing, and road surfaces.
Uses of each fraction
Why are the fractions useful?
Similarities between crude oil and its fractions:
Differences between crude oil and its fractions:
The boiling points of molecules
In general, the bigger the molecule the higher the boiling point.
0
50
100
150
200
250
300
350
0 5 10 15 20
No. Carbon atoms
B.Pt
(oC)
Here are the boiling ranges of some fractions obtained from distillation of petroleum.1. Using the previous graph, estimate the size range of the molecules present in each fraction.
Fraction Boiling Range
(oC)
Number of carbons
Fuel gas Below 40
Petrol 40 - 175
Kerosine 150 - 240
Diesel 220 - 275
1-5
5-10
9-14
13-17
What is crude oil?
• Crude oil is a mixture of different sized hydrocarbons. The exact composition depends upon where the oil comes from but typically it contains a lot of big molecules. (Why is this not good?)
Fuel gas PetrolNaphtha KerosineDiesel Fuel Oil and bitumen
Small molecules
Medium molecules
Big molecules
Which is a correct statement about crude oil?
A. A mixture of carbohydrates.
B. Formed by the decay of dead sea creatures.
C. Consist of a mixture of very large molecules.
D. Is purified in an oil rig.
Which is a correct statement about fractionaldistillation?
A. Oil is separated into fractions with the same size molecule.
B. Oil is separated into fractions with the same density.
C. Oil is separated into fractions with similar size molecules.
D. Oil is separated into alkanes and alkenes.
Which is a correct order for these fractions working down from the top of the column?
A. Fuel gas, kerosene, petrol, diesel, bitumen.
B. Fuel gas, diesel, kerosene, petrol, bitumen.
C. Fuel gas, petrol, diesel, kerosene, bitumen.
D. Fuel gas, petrol, kerosene, diesel, bitumen.