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Chemistry
Dr. May Notes – Organic Chemistry
Introducing Carbon Compounds
There are over 6,000,000 carbon compounds known. 300,000 new ones are
synthesized each year. Dr. May has contributed over 1000 new compounds to this list.
Where do carbon compounds come from?
Plant material fell to the forest floor and pressure and heat turned it into coal.
Destructive (anaerobic) distillation can turn coal into a variety of organic
compounds.
Small plant organisms settled into prehistoric ooz, formed methane gas, modified
itself and formed petroleum and natural gas.
Living organisms synthesize a variety of Organic Chemicals. These include:
proteins, sugars, cellulose, starches, vitamins, oils, waxes, and fats.
Sorting out organic compounds
The properties of a compound depend on both the composition and the structure.
This gives us a variety of different compounds from the same composition depending on
the structure forming a different isomer. A hydrogen in a hydrocarbon can be replaced
with a different nonmetal element to form a derivative.
Carbon can bond with itself (covalent bond using the four valence electrons) to
form a carbon backbone. This carbon backbone can be a straight chain (unbranched) or
branched.
Carbon can be connected to itself by a single bond (saturated) or by a double bond
or triple bond (unsaturated).
The structure of many hydrocarbons are condensed when two or more groups
occur together as in n-octane below:
CH3CH2CH2CH2CH2CH2CH2CH3
=
CH3(CH2)6CH3
Alkanes
Alkanes are saturated hydrocarbons. That means that they have all the hydrogens
they can hold and there are no double or triple bonds.
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Naming hydrocarbons
Alkanes are named according to the longest string of carbons as shown below for
straight-chain (unbranched) hydrocarbons.
Chemical Formula
Longest Carbon Chain
CH4
CH3CH3
CH3CH2CH3
CH3(CH2)2CH3
CH3(CH2)3CH3
CH3(CH2)4CH3
CH3(CH2)5CH3
CH3(CH2)6CH3
CH3(CH2)7CH3
CH3(CH2)8CH3
1
2
3
4
5
6
7
8
9
10
Name
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
Alkenes
Alkenes have one or more double bond between two or more of the carbons. The
carbons are sharing two pairs of electrons. Alkenes are unsaturated meaning that they can
hold more hydrogens or that all the carbons do not have as much hydrogen around it as it
could have. If hydrogen gas (plus a catalyst) is shaken up with an alkene, it will become
an alkane.
Alkenes are named like alkanes, but we need to tell where the double bond is by
designating the number of the carbon where it is located. For example the structure below
is
1 2 3 4 5 6
CH3CH2CH=CHCH2CH3
3-hexene
CH3CH=CHCH2CH2CH3
2-hexene
CH2=CHCH2CH2CH2CH3
6 5 4 3 2
1
CH3CH2CH2CH2CH=CH2
1-hexene
1-hexene
The same but numbered the opposite
direction to make the smaller #
(not 5-hexene)
Alkynes
Alkynes have a triple bond. Two or more of the carbons are sharing three pairs of
electrons. Like the alkenes, the position of the triple bond needs to be designated by
giving the number of the carbon that the triple bond is associated with.
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Aromatic hydrocarbons
Benzene is the classic aromatic compound. It is composed of six carbons in a
hexane ring. Each carbon has one hydrogen attached to it. The bonds between the carbons
are half-single and half-double. The structure is half of the time (a), half the time (b),
represented as (c), and sometimes simply as the Greek letter phi ().
⇄
⇄
a
b
c
Functional groups
Group Name
General Structure
Example
Example Name
Alcohol
(Hydroxyl)
Ether
(Alkoxy)
Aldehyde
(Carbonyl)
ROH
CH3CH2OH
Ethanol
ROR
CH3CH2OCH2CH3
O
║
RCH
O
║
RCR
O
║
RCOH
O
║
RCOR
RNH2
RNR2
O
║
RCNH2
ROOR
RCN
RSR
RSH
RNO2
CH3CHO
Diethyl ether
(Ethoxy Ethane)
Acetaldehyde
(Ethanal)
Ketone
(Carbonyl)
Acid
(Carboxyl)
Ester
Amine
Amide
Peroxide
Nitrile
Sulfide
Mercaptan
Nitro
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CH3COCH3
Acetone
(Propanone)
CH3COOH
Acetic Acid
(Ethanoic Acid)
CH3COOCH2CH3
Ethyl Acetate
CH3CH2NH2
Ethyl Amine
CH3CONH2
Acetamide
CH3OOCH3
NCCH2COOH
CH3SCH3
CH3CH2SH
CH3NO2
Dimethyl Peroxide
Cyanoacetic acid
Dimethyl Sulfide
Ethyl Mercaptan
Nitromethane
Substitution and addition
CH4
+
methane
Cl2
CH2=CH2
Ethene
+
O
║
CH3COH
Acid


H2O
+
O
║
CH3COH
Acid
CH3Cl
+
chloromethane
CH3OH
alcohol
+
CH3CH2OH
ethanol
O
║
CH3COCH3
ester

CH3NH2
amine
HCl
O
║
CH3CNHCH3
amide

+
H2O
+
H2 O
Oxidation and reduction
[O] represents an oxidizing agent like copper oxide or potassium dichromate.
CH3CH2OH
Alcohol
OH
|
CH3CHCH3
Isopropyl
Alcohol
+
+
[O]
[O]


O
║
CH3CH
aldehyde
O
║
CH3CCH3
+
+
H2O
H2O
acetone
Polymerization
CH2=CH2

Ethene or
Ethylene
O
║
NH2CH2COH
+
Amino acid
glycine
[CH2CH2]n
polyethylene
O
║
NH2CH2COH

glycine
O
O
║
║
[NHCH2CNHCH2C]n
protein
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