Transcript organic chem ppt notes

Organic Chemistry
Essentials
• Chemistry of carbon compounds
• Carbon can form 4 covalent bonds with
other atoms. This allows it to make
millions of different compounds.
• Carbon can form single, double, and triple
bonds.
Hydrocarbon
• compound containing only hydrogen and
carbon
• Ex. CH4
C2H6
Hydrocarbon derivative
• compound with some hydrogen atoms replaced
by other elements (O, N, F, Cl, Br, I)
• ex. CH3Br
Straight chained hydrocarbon
Ex. CH3CH2CH2CH2CH2CH3
or C6H14
Branched hydrocarbon
CH3
CH3CH2CHCH2CH3
or C6H14
Saturated hydrocarbon
• no double or triple bonds
Unsaturated hydrocarbon
• contains double and/or triple bonds
• not “saturated” with hydrogen
Structural formulas
Condensed Structural formulas
CH3-CH3
Alkanes
•
•
•
•
hydrocarbons with only single bonds
General formula: CnH2n+2
names end in -ane
boiling pt. increases with # of carbons
IUPAC Names
Name
# carbons
Structural Formula
Methane 1
CH4
Ethane 2
CH3CH3
Propane 3
CH3CH2CH3
Butane 4
CH3CH2CH2CH3
Pentane 5
CH3CH2CH2CH2CH3
Name # carbons
Structural Formula
Hexane 6
CH3CH2CH2CH2CH2CH3
Heptane 7
CH3CH2CH2CH2CH2CH2CH3
Octane 8
CH3CH2CH2CH2CH2CH2CH2CH3
Nonane 9
CH3 CH2 CH2CH2CH2CH2CH2CH2CH3
Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
Alkenes
• contain at least one double bond
• name ends in -ene
• general formula: CnH2n
Alkynes
• contain at least one triple bond
• name ends in -yne
• general formula: CnH2n-2
Nomenclature
• naming system
• IUPAC (International Union of Pure and
Applied Chemistry)
Rules for naming alkanes
1. Name the longest carbon chain in the
structure. If the chain is cyclic, include the
prefix cyclo.
2. Name, in alphabetical order, the kinds of
groups which are attached to the chain you
named in step 1. Use the appropriate prefix,
such as di-, tri-, tetra-, etc., to indicate how
many of each group are present.
3. Number the carbon atoms in the longest
chain consecutively from the end of the chain
which allows the attached groups to have the
lowest numbers possible. Assign to each
group you named in step 2 the number(s)
indicating its position(s) on the main chain.
Rules for naming alkenes and
alkynes
1. Name the longest carbon chain containing
the carbon-carbon double or triple bond.
The name of the longest chain ends in –
ene for an alkene; in –yne for an alkyne.
The position of the double or triple bond
in the carbon chain is indicated by a
number before the name of the chain.
2. Name the groups attached as in alkanes.
3. When assigning numbers to atoms in the
chain, start numbering from the end of the
chain closest to the double or triple bond.
Naming branched chain alkanes
• substituent- atom or group of atoms that
takes the place of hydrogen on a
hydrocarbon molecule
• ex. C, O, N, S, P, Cl, F, I, Br
Alkyl Group
• hydrocarbon substituent
• alkane with one H removed
• drop the -ane ending and add -yl
H
H
C
CH3
methyl
H
H
H
H
C
C
H
H
CH3CH2
ethyl
Name the following:
3,3-diethylhexane
4-ethyl-4,6-dimethyl-5-propylnonane
6-ethyl-4,5-dipropylnonane
Draw the following:
2,2,4-trimethylpentane
Draw the following:
3-ethyl-2-hexene
Draw the following:
4-bromo-2,2-dichloro-3,5diethyl-6-fluorooctane
Properties of Hydrocarbons
• nonpolar
• not attracted to water
Structural Isomers
• compounds that have the same molecular formula
but different molecular structures.
• physical and chemical properties differ
Butane
CH3-CH2-CH2-CH3
2-methylpropane or
isobutane
CH3
CH3-CH-CH3
Geometric Isomers
• Each of the carbons of the double bond
must have at least one substituent.
• Ex. CH3CH=CHCH3 has 2 geometric
isomers because the double bond is not free
to rotate. Bond angle (sp2) is 120o.
cis-2-butene
trans-2-butene
Stereoisomers
• Stereoisomerism is the arrangement of
atoms in molecules whose connectivity
remains the same but their arrangement in
space is different in each isomer.
• The two main types of stereoisomerism are:
• cis-trans isomerism
• optical isomerism
Optical isomerism is a form of isomerism where the two
different isomers are the same in every way except being nonsuperimposable mirror images of each other. Optical isomers are
known as chiral molecules.
A compound is chiral when it cannot be superimposed on its
mirror image. The pair of mirror imaged non-superimposable
compounds are known as enantiomers. Even though very similar
still, different enantiomers of the same chiral drug can have very
different pharmological effects, mainly because the proteins they
bind to are also chiral.
4 different
groups
attached to
the carbon
The two enantiomers of bromochlorofluoromethane
Cyclic hydrocarbons
• compounds that contain a hydrocarbon ring
• general formula is: CnH2n
Cyclopropane
Cyclobutane
Aliphatic compounds
• hydrocarbon compounds which do not
contain rings
Arenes
• unsaturated cyclic hydrocarbons
• Benzene, C6H6, is an arene.
• Benzene is a flat molecule with resonance.
Shorthand ways to draw benzene:
Aromatic compound
• any substance in which the bonding is like
benzene
• A benzene ring used as a substituent on a
hydrocarbon chain is called a phenyl group.
• Ex.
methylbenzene
(toluene)
Nomenclature:
Natural gas- 80% methane, 10% ethane,
4% propane, 2 % butane
Petroleum = complex mixture of hydrocarbons
Cracking= a controlled process by which
hydrocarbons are broken down or rearranged into
smaller, more useful molecules
Functional Group
• Chemically reactive part of an organic
molecule
• Learn these functional groups
• R means the rest of the molecule (usually
hydrocarbon
The Common Functional Groups
Class
Halohydrocarbons
Alcohols
Ethers
Aldehydes
General Formula
RX
ROH
ROR
O
R C H
The Common Functional Groups
Class
Ketones
Carboxylic Acids
Esters
Amines
General Formula
O
R C R'
O
R C OH
O
R C O R'
RNH2
Halocarbons
• Organic compounds containing F,Cl, Br, or I
• Halogen groups are named as substituents
just as alkyl groups are.
chloromethane
Cl
I I
Cl-C-Cl CH3-CH-CH-CH3 bromobenzene
2,3-diiodobutane
H
Cl-CH2-CH3CH3
Trichloromethane
(chloroform)
1-chloropropane
Alcohols
Organic compounds with a hydroxyl group (-OH)
Naming: drop “e”, add “-ol”
Methanol
Ethanol
Methyl alcohol
Ethyl alcohol
“wood alcohol”
“drinking alcohol”
propanol
propyl alcohol
n-propanol
1-propanol
2-propanol
isopropanol
isopropyl alcohol
“rubbing alcohol”
Alcohols can be classified as
primary, secondary or tertiary.
antifreeze
Glycerine
1,2,3-propantriol
Phenol
Properties of Alcohols
• Hydrogen bonding
• Short-chained alcohols are soluble in water
Fermentation- production of ethanol from sugars by
the action of yeast or bacteria
C6H12O6  2CH3CH2OH + 2CO2
Denatured Alcohol- ethanol with an added substance
to make it toxic
Ethers
• Compounds in which oxygen is bonded to two
carbon groups
• R-O-R’
• Name the R groups in alphabetical order and add
the word ether.
ethyl methyl ether
dimethyl ether
ethyl phenyl ether
diethyl ether
1st reliable general anesthetic, 1842
Aldehydes
• Organic compounds in which the carbon of
the carbonyl group ( C=O ) is always
joined to at least one H.
• Naming: drop “e”, add “-al”, carbonyl
carbon is #1
methanal
(formaldehyde)
ethanal
CH3
H
CH3CH2CHCH2C=O
3-methylpentanal
Ketones
• Organic compounds in which the carbon of the
carbonyl group is joined to 2 other carbons. The
carbonyl group is in the middle of the chain
instead of the end of a chain as in an aldehyde.
• Naming: drop “e”, and “one”. If carbonyl can be
in more than one position, give it a #
3-hexanone
Propanone
(acetone)
Naming: drop “e”, add “oic acid”
The carboxyl carbon is always #1.
butanoic acid
methanoic acid
“formic acid”
propanoic Acid
“propionic acid”
Esters
• Derivatives of carboxylic acids in which the
–OH of the carboxyl group has been replaced
by an –OR from an alcohol
• Formed by combination of a carboxylic acid
with an alcohol in a dehydration reaction
• Often common flavors and odors
Naming: Name alkyl group, then acid with –ate
ending
ethyl ethanoate or
ethyl acetate
(apple scent)
methyl ethanoate
methyl methanoate
or methyl acetate
or methyl formate
Amines
-NH2
• the suffix amine is added to the alkyl
substituent
• can also be named as an amino group
3-aminopropanoic acid
ethylamine
cyclohexylamine
POLYMERS
• made of repeating units called monomers