Transcript Organic Chemistry

Organic Chemistry
Is the study of the
chemistry of carbon
compounds containing
hydrogen:hydrocarbons
Origin
• Originally defined as the chemistry of living materials
or originating from living sources.
• Wohler synthesized urea from non organic sources
(1800 – 1882)
• Now generally defined as the chemistry of carbon
and its compounds.
• Organic foods are foods that are produced
using methods that do not involve modern
synthetic inputs such as synthetic pesticides and
chemical fertilizers.
This is different from the scientific use of the term
"organic," to refer to a class of molecules that
contain carbon, especially those involved in the
chemistry of life.
HOW DO ORGANIC COMPOUNDS LOOK LIKE?
• Ethanol
• Caffeine
• Aspirin
CHOCOLATE
• Theobromine is the
primary alkaloid found
in cocoa and
chocolate
• Its presence is one of
the causes for
chocolate's moodelevating effects.
Vitamin C
Natural
Ascorbic Acid
• Unlike most mammals and
other animals, humans do not
have the ability to make their
own vitamin C. Therefore, we
must obtain vitamin C through
our diet
Synthetic
Synthetic vitamins are made in
a laboratory setting from coal
tar derivatives.
Uses of hydrocarbons
• Gasoline is a mixture of hydrocarbons
(C8H18 for example) that contain no atoms
of oxygen.
• Gasohol contains ethyl alcohol, C2H5OH,
which does contain oxygen. The addition
of alcohol to gasoline, therefore, adds
oxygen to the fuel.
Petroleum: http://science.howstuffworks.com/environmental/energy/oilrefining2.htm
Libra Oil Field
• Xvsdzc
Why is carbon so special?
Carbon can form single, double and triple
bonds with itself
•
The bond length is defined as the distance between the nuclei of the
atoms involved in the bond.
•
The strength of the C-C bond indicates it is quite thermally stable in
comparison to other elements in the same group.
• Si-Si 226
• Ge-Ge 188
Carbon can catenate
One of the remarkable property of carbon atom is its unique
capacity to link with other carbon atoms. It can form chains and
rings.
Carbon cannot expand its octet of
valence electrons
• CCl4 is immiscible in water and does not
react.
• SiCl4 reacts vigorously in water to
produce HCl because a njon bonding pair
of electrons in water is able to expand the
octet of silicon.
• The silicon atom is bigger, and so there is
more room around it for the water
molecule to attack.
• But silicon has the additional advantage
that there are empty 3d orbitals available
to accept a lone pair from the water
molecule. Carbon doesn't have 2d orbitals.
Hydrocarbons
Saturated: CONTAIN
Unsaturated:
ONLY SINGLE BONDS
CAN CONTAIN A DOUBLE OR A
TRIPLE BOND
Alkanes
Alkenes, Alkynes &
Aromatics
H
C-C
H
C
C
H
C
C
CC
= CC
H
C
H
H
C
Homologous Series
• One in which all the members have the
same general formula.
• The neighbouring members differ by CH2
, show similar chemical properties and a
gradation in their physical properties.
Alkanes
a homologous series
Alkanes are saturated hydrocarbons that
contain only single carbon-carbon bonds.
The simplest alkane is CH4
The general formula of an alkane is
CnH2n+2
The first 4 members are gases at standard conditions,
and are good fuels
Prefixes for # of Carbons
1
Meth
6
Hex
2
Eth
7
Hept
3
Prop
8
Oct
4
But
9
Non
5
Pent
10
Dec
Homologous Series:
CH4
Methane
C2H6
Ethane
C3H8
Propane
C4H10
Butane
C5H12
Pentane
A homologous series
of alkanes
Each compound in
this series differs
from the previous
compound by a
–CH2 –
Propane
Butane
Structural Isomers
• Structural isomers are compounds with
the same molecular formula but different
structural formula.
• As the number of carbon atoms in an
alkane molecule increases, so do the
possibilities for isomerism of this kind.
General Properties of Alkanes
• The boiling points of alkanes are very low for their
molecular mass. This is because the molecule is
completely nonpolar( inertness)
• It increases with an increase in mass.
Boiling Points of Alkanes
http://wiki.chemeddl.org/index.php/8.2_Organic_Compounds:_Hydrocarbons
• The more spherical the isomer, the lower boiling point( less
dispersion forces) due to less surface area to form
intermolecular bonds.
Naming Alkanes
a)Attached carbon groups (substituents) end in –yl
– Methyl
– Ethyl
– Propyl
3-ethylpentane
CH3 CH3CH2CH3CH2CH2 –
Types of Formulas
1. Chemical Formula (Sum)
C3H8
2. Structural Formula
3. Condensed Formula
4. Line Formula
CH3 CH2 CH3
Naming Alkanes
b) Other substituents
-chloro
-bromo
-iodo
-ol
Cl
Br
I
OH
Cl
CH3


CH3─CH2─CH─CH─CH3
STEP 1
Longest chain is ______________.
STEP 2
Number chain from end nearest substituent.
Cl CH3


CH3─CH2─CH─CH─CH3
STEP 3 Locate substituents and name alphabetically.
Line Formula:
http://elchem.kaist.ac.kr/jhkwak/OkanaganPdb97/nomenclature/ane-100.htm
Types of Formulas
STRUCTURAL
CHEMICAL
CONDENSED
LINE
NAMING
Aspirin: ASA
Alkenes
“Unsaturated” hydrocarbons, contain one double bond
between carbon atoms.
General Formula:
CnH2n
Alkynes
“Unsaturated” hydrocarbons, contain one triple bond
between carbon atoms.
General Formula:
CnH2n-2
• Alkene names change the end to –ene
Naming Alkenes & Alkynes
CH2= CH ─ CH2─ CH3
1
3
2
4
CH3─ CH=CH─ CH3
1
2
3
1
2
3
2-butene
4
CH3
|
CH3─ CH=C─CH3
CH
─ CC
─ CH
4 3
2 3
3
1-butene
2-methyl-2-butene
1
4
2-butyne
Alkynes
“Unsaturated” hydrocarbons, contain one triple bond
between carbon atoms.
General Formula:
CnH2n-2
Functional Groups
• functional groups are certain atoms or groups
of atoms that give compounds characteristic
properties.
CH3CH2OH
alcohol
Class of
Compound
1. Alcohol
2. Carboxylic
Acid
3. Aldehyde
4. Ketone
5. Ester
6. Ether
7. Amine
Functional
Group
Example
Name
Uses
Problems
• http://seacoast.sunderland.ac.uk/~hs0dad/
qm/ctinew/v2bprops.htm
• Sites:http://www.pkwy.k12.mo.us/west/tea
chers/anderson/pack10/pack10.html
• Assignments:
• http://www.pkwy.k12.mo.us/west/teachers/
anderson/pack10/pack10.html
• Chemistry of petroleum:
http://www.sciencenetlinks.com/Esheet.php?DocID=181
Aspirin
•
The origins of the aspirin date back to about 400 BC, when Hippocrates prescribed
an extract from the bark of the willow tree as a remedy for fever and pain..
•
Felix Hoffmann, a young chemist working for the German pharmaceutical giant Bayer
AG, was looking for a new painkiller to treat his father's rheumatism.
•
He prepared acetylsalicylic acid in 1897, and according to the literature, Henrich
Dreser, head of Bayer laboratories, started its clinical use shortly thereafter. Bayer
registered Aspirin trademark and began selling it in 1899.
•
In the name of "aspirin" (as suggested by Hoffmann) "a" stand for "acetyl" and "spir"
for spireic acid (a different name of salicylic acid). Some prefer to believe that the
compound was named after Saint Aspirinius, patron saint of headaches.
Aspirin, ASA
a)How much ASA will be produced when 15g of salycilic acid is being
used ?
b) What will be the percent yield if you were able to produce 17g of
ASA?
Conclusion and Evaluation
• 1. What is the percent yield?
• 2. List at least thgree sources of errors
• 3. What realistic suggestions in terms of
materials and procedure can you make in
order to get better results?