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ORGANIC CHEMISTRY
Covalent bonds of carbon, multiple covalent bonds in carbon compounds.
Hydrocarbons: alkanes, cycloalkanes, alkenes and alkynes.
Aromatic and heteroaromatic compounds.
Alcohols, phenols and ethers.
Aldehydes and ketones.
Carboxylic acids and substituted carboxylic acids.
Carboxylic acid derivatives: esters, amides, anhydrides.
Nitrogen containing organic compounds.
Isomerism in organic chemistry: structural, geometrical and optical isomers.
Answer of the topics of organic chemistry:
Carbon atom charactericstic
Most atoms are only capable of forming small molecules. However one or two can form larger molecules.
By far and away the best atom for making large molecules with is Carbon. Carbon can make molecules that
have tens, hundreds, thousands even millions of atoms! The huge number of possible combinations means
that there are more Carbon compounds that those of all the other elements put together!
A single Carbon atom is capable of combining with up to four other atoms.
The unique thing about the Carbon atom is that it will combine with other Carbon atoms.
This means that Carbon atoms can form chains and rings onto which other atoms can be attached.
Carbon compounds are classified according to how the Carbon atoms are arranged and what other groups of
atoms are attached.
1- Carbon forms stable bonds with itself to make chains.
2- Carbon forms stable bonds with most other elements.
3- Carbon forms branched chains.
4- Carbon forms ring chains.
5- Carbon forms double bonds.
6- Carbon forms triple bonds.
7- Carbon forms cis-trans isomers.
8- Other elements may interrupt the chain.(SH, COOH..)
9- All of the above may occur together.
Alkanes
Alkanes are hydrocarbons that contain only single bonds. When carbons double back on one another to
form a ring, they are called cycloalkanes.
General formula: R–CH2–CH2–R, CnH2n+2
The symbol R is used to designate a generic (unspecified) alkyl group.
The formulas and structures of alkanes increase uniformally by a CH2 increment
Nomenclature of Alkanes:
For a base of one to four carbons, historical root names were chosen. For compounds of five carbons and up,
the greek name for the number of carbons is used. The ending of -ane is added to indicate that it is an alkane.
Name
Molecular
Formula
Structural
Formula
methane
CH4
CH4
ethane
C2H6
CH3CH3
propane
C3H8
CH3CH2CH3
butane
C4H10
CH3CH2CH2CH3
pentane
C5H12
CH3(CH2)3CH3
ALKANE REACTIONS & emdash; MOSTLY INERT
No reaction with strong acids, bases, & redox agents. ex. plastics.
HALOGEN SUBSTITUTION
With ultraviolet light to break strong covalent bonds. Then halogens can replace the hydrogens.
NITRATION
Nitric acid HO-NO2 replaces hydrogens with nitro groups -NO2. These are the nitro compounds.
COMBUSTION ("burn it")
Add oxygen and get CO2 and H2O
Alkenes:
Alkenes are hydrocarbons with carbon-carbon double bonds. Alkenes have three Sp2 hybridized orbitals
and a p orbital, and have bond angles of about 120 degrees. Unlike carbon-carbon single bonds, double
bonds do not have free bond rotation, and have shorter bond lengths. This is due to the rigidity of the double
bond.
General formula: R–CH=CH–R, CnH2n
The symbol R is used to designate a generic (unspecified) alkyl group.
Examining the bond dissociation energies, we find that the dissociation energy of a single bond is much
higher than that of a double bond, about 20kcal/mol more. This means that double bonds are significantly
more reactive than single bonds, classifying it as a functional group.
Nomenclature of Alkenes:
Naming of alkenes is very similar to the naming of alkanes, using the root name of the longest carbon chain.
The ending, however, is changed from -ane to -ene, and a number is given to show the location of the
double bond for molecules of more than three base carbons.
ethene (There is no need for a
number. A one is implied. )
Propene (one is implied)
2-Butene
PROPERTIES OF THE DOUBLE BOND
Highly reactive because &emdash; the carbons are closer together.
ALKENE REACTIONS & emdash; HALOGEN ADDITION
Halogens will break the second bond and add thereto and making an alkane.
TEST FOR THE DOUBLE BOND
Add bromine and the red colour disappears as the bromine is added to the double bond as in the above
reaction.
Alkynes
Alkynes, are hydrocarbons with carbon-carbon triple bonds. Alkynes two Sp hybridized orbitals and 2 p
orbitals, and have bond angles of 180 degrees.
unlike carbon-carbon single bonds, triple and double bonds do not have free bond rotation, and have shorter
bond lengths. This is due to the rigidity of the triple bond.
General formula: R–C≡C–R, CnH2n-2
The symbol R is used to designate a generic (unspecified) alkyl group.
Examining the bond dissociation energies, we find that the dissociation energy of a single bond is much
higher than that of a triple bond, about 20kcal/mol more. This means that double bonds are significantly
more reactive than single bonds, classifying it as a functional group.
Nomenclature of Alkynes:
Naming of alkynes is very similar to the naming of alkenes, using the root name of the longest carbon chain.
The ending, however, is changed from -ene to -yne, and a number is given to show the location of the triple
bond for molecules of more than three base carbons.
ethyne (There is no need for a
number. A one is implied. )
Alcohols
Propyne (one is
implied)
2-Butyne
Alcohols are an extremely important class of organic compounds that contain the hydroxyl (-OH) group.
Alcohols have high boiling points comparatively because of the existence of the hydrogen bonding .
When many people think of alcohol, they primarily think of ethanol, or the alcohol contained in beer and
wine. However, there are thousands of unique alcohols, and alcohols are some of the most common and
useful compounds in nature and industry. Alcohols can be synthesized by a host of different methods, and
are easily converted into other functional groups. For this reason they are often used as intermediates in a
larger scale synthesis.
Structure and Classification
Alcohols very closely resemble the structure of water. The only difference is that there is an R group in the
place of a water hydrogen. A very important way to classify alcohols is by the carbon that they are bonded
to. A primary alcohol is attatched to a primary carbon. A secondary alcohol is attatched to a secondary
carbon. A tertiary alcohol is attatched to a tertiary carbon.
General formula of Primary alcohol: ROH
General formula of Secondary alcohol: R2COH
General formula of Tertiary alcohol: R3COH
The symbol R is used to designate a generic (unspecified) alkyl group.
Example of Primary
Alcohol
Example of Secondary
Alcohol
Example of Tertiary
Alcohol
COMMON ALCOHOLS
methanol, CH3OH, "wood alcohol". ethanol, CH3CH2OH, "booze". 2-propanol, CH3CH2CH3,, "rubbing
alcohol". OH
DENATURED ALCOHOL
has government poisons added to discourage drinking it. This is done to industrial ethanol so that the liquor
tax is not charged for industrial usage.
ABSOLUTE ALCOHOL
is 100% pure ethanol. This can only be accomplished by a chemical process to remove the last 5% of water.
It is used for special chemical reactions where water must be absent. (At 95%, the water-ethanol mixture
becomes azeotropic which means that the common boiling points prevent further separation by distillation).
Ketones and Aldehydes:
Ketones are a class of functional groups that contain an internal carbonyl (C=O) group, and are connected to
two alkyl groups. Aldehydes are a class of functional groups that contain an external carbonyl group,
attatched to alkyl substituent and a Hydrogen.
Ketone General Form
Aldehyde General form
Common Names: Aldehydes
Common names for aldehydes are derived from the common names of carboxylic acids. They often reflect
the Latin or Greek term for the original source of the acid or the aldehyde.
Carboxylic Acids
Aldehyde
Formic Acid (ant bites)
Formaldehyde
Acetic Acid (vinegar)
Acetaldehyde
Benzoic Acid
Benzaldehyde (Oil in almonds
Physical Properties:


The polar nature of the C=O (due to the electronegativity difference of the atoms) means dipoledipole interactions will occur.
Though C=O can not hydrogen-bond to each other, the C=O can accept hydrogen bonds from
hydrogen bond donors (e.g. water, alcohols).
The implications of these effects are:
o
o
o
higher melting and boiling points compared to analogous alkanes
lower boiling points than analogous alcohols
more soluble than alkanes but less soluble than alcohols in aqueous media
To name ketones using the IUPAC system, you find the largest carbon chain containing the ketone. Use
numbers to give the position of the ketone and chain the -ane ending to -anone.
Propanone
2-Butanone
Ethers:
General formula: ROR
Structure:


The ether functional group consists of an O atom bonded to two C atoms via  bonds.
Both the C-O bonds are polar due to the high electronegativity of the O atom.

The O atom in an ether chain behaves much like a -CH2- in an alkane
Physical Properties:




The polar nature of the C-O bond (due to the electronegativity difference of the atoms ) results in
intermolecular dipole-dipole interactions.
An ether cannot form hydrogen bonds with other ether molecules since there is no H to be donated
(no -OH group)
Ethers can be involved in H-bonding with systems able to donate H (e.g. water).
The implications of these effects are:
o lower melting and boiling points compared to analogous alcohols
o solubility in aqueous media similar to analogous alcohols.
It is a volatile, highly flammable liquid that was used as an anesthetic in the past. It is currently used as an
industrial and laboratory solvent
Eszters
General formula:
where R and R' are any alkyl groups. Most esters have pleasant odors. Esters are responsible for the
fragrances of many flowers and the pleasant tastes of ripened fruits. Bananas contain the ester amyl acetate,
and oranges the ester octyl acetate. Wintergreen mints contain the ester methyl salicylate, called oil of
wintergreen.
Beeswax and other waxes are composed of esters
Esthers are compounds derived from the reaction of a organic acid with an alcohol. Acid + alcohol --> ester
+ water
R--C=O + R'--OH ----> R--C=O + H2O | | C-OH C-O-R'
Esters are the compounds that give fruits their characteristic flavors and odours. ie. methyl salycilate is "Oil
of Wintergreen".
Physical Properties:




The polar nature of the C-O bond (due to the electronegativity difference of the atoms ) results in
intermolecular dipole-dipole interactions.
An ether cannot form hydrogen bonds with other ether molecules since there is no H to be donated
(no -OH group)
Ethers can be involved in H-bonding with systems able to donate H (e.g. water).
The implications of these effects are:
o lower melting and boiling points compared to analogous alcohols
o solubility in aqueous media similar to analogous alcohols.
Amines:
General formulas:
Primary amide:RNH2,
Secondary amide: R2NH
Tertiary amide: R3N
Quaternary amide: R4N+
Amines are ammonia derivatives with one or more alkyl substituents attatched to it. They can be classified
as primary, secondary, tertiary, or quaternary ammonium salts.
Primary Amine
Secondary Amine
Tertiary Amine
Quaternary
Ammonium Salt
Nomenclature of Amines:
Common Names:
Common names for amines are formed from the alkyl groups bonded to the nitrogen, followed by the word
amine. Di-, tri-, and tetra are used to describe identical substituents.
Methyl amine
Dimethyl amine
Trimethyl amine
IUPAC Names:
Naming of amines is very similar to the naming of alcohols. The longest chain containing the amine is used
as the root name. The -e ending in the naming of alkanes is changed to -amine, and a number gives the
position of the amino group along the chain. Other substituents on the carbon chain are given numbers, and
the prefix N- is used for each substituent on nitrogen.
2-butanamine
N-methyl
butanamine
3, N,N-trimethyl-2-butanamine
Amines are basic compounds with strong odors. The odor of amines is often described as "fishy" since the
odor of raw fish comes from the amines contained. Sometimes even "foul smelling" is an understatement,
and two of the amines produced in decaying flesh have suggestive names (cadaverine and putresine).
Despite this foul reputation, the amines are essential to life as constituents of amino acids. They occur in
drugs and vitamins, and are essential starting materials for many synthetic processes. The aromatic amine
aniline is the basis for the synthesis of a whole class of synthetic dyes. Synthetic amines such as benzedrine
have medical applications.
Carboxylic acids
General formula
Carboxylic acids (RCO2H) are a common and important functional group (e.g. amino acids, fatty acids etc.)
and providethe point of access to the carboxylic acids derivatives (acyl chlorides,acid anhydrides, esters,
amides etc.).
Carboxylic acids are the most acidic of the common organic functionalgroups
Nomenclature:
Functional group suffix = -oic acid (review)
If the acid is substituted onto a ring the suffix -carboxylic acid is used
The anion dervived by deprotonation of a carboxylic acids is the carboxylate.
Physical Properties:

The polar nature of both the O-H and C=O bonds (due to the electonegativity difference of the
atoms) results in the formation of strong hydrogen bonds with other carboxylic acid molecules or
other H-bonding systems (e.g. water). The implications are:
o higher melting and boiling points compared to analogous alcohols
o high solubility in aqueous media
o hydrogen bonded dimers in gas phase and dimers or aggregates in pure liquid
Structure:

The CO2H unit is planar and consistant with sp2 hydridisation and a resonance interaction of the lone
pairs of the hydroxyl oxygen with the  system of the carbonyl.
Acidity:




Carboxylic acids are the most acidic simple organic compounds (pKa ~ 5).
But they are only weak acids compared to acids like HCl or H2SO4. (Remember the lower the pKa,
the stronger the acid)
Resonance stabilisation of the carboxylate ion allows the negative charge to be delocalised between
the two electronegative oxygen atoms (compare with alcohols, pKa ~ 16).
Adjacent electron withdrawing substituents increase the acidity by further stabilising the carboxylate.
Carboxylic Acid
Structure
pKa
Ethanoic acid
CH3CO2H
4.7
Propanoic acid
CH3CH2CO2H 4.9
Fluoroethanoic acid CH2FCO2H
Reactions of alcohol
http://pages.towson.edu/ladon/orgrxs/alcohol/alcohorx.htm,
2.6
Reactions of ethers
http://pages.towson.edu/ladon/orgrxs/ether/etherrx.htm
Reactions of esters
http://pages.towson.edu/ladon/orgrxs/carbox/esterrx.htm,
Reactions of aldehyde and ketones
http://science.marshall.edu/castella/chm204/chap14.pdf,
Prosperities and reactions of Carboxylic acids,Esters, Amines and Amides
http://www.vvc.edu/academic/chemistry/Unit%2009%20Lecture%20Fourth%20Edition%20Colored.pdf,
Aromatic compound
http://www.chemguide.co.uk/basicorg/conventions/names3.html
Heteraromatic compound
http://www.biologie.uni-hamburg.de/bonline/library/newton/Chy251_253/Lectures/Heteroaromatics/HeteroaromaticsFS.html
Isomerism in organic chemistry: structural, geometrical and optical isomers.
http://faculty.lacitycollege.edu/boanta/LAB102/Organic%20Isomers.htm