MOTOR FREIGHT RULES CIRCULAR Naming RULES AND REGULATIONS ...
Organic Naming Rules Chemistry 332 For complete Rules go to:
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Transcript of Organic Naming Rules Chemistry 332 For complete Rules go to:
Organic Naming Rules
Chemistry 332
For complete Rules go to:
http://www.acdlabs.com/iupac/nomenclature/
Organic Compounds
• Consist of mainly four elements
• Carbon
• Hydrogen
• Oxygen
• Nitrogen
Why Do We Need a Separate Set of Rules?
• Examine some typical organic compounds
• CH4
• C2H6
• Name these using typical covalent rules
Carbon tetrahydride
Dicarbon hexahydride
So?
• That wasn’t so bad, right?
• How about these:
• C4H10
• C5H12
• See my point?
Tetracarbon decahydride
Pentacarbon ??? hydride
Isomers
• If that’s not enough, how about this one:
C
H
H
C
H
H
C
H
H
C
H
H
H H
Formula?
C4H10
C
H
H
C
H
HC
H
HCH
H
H
H
Formula?
C4H10
Different Structure
Same Formula
Overall Problems
• Memorizing too many prefixes for large numbers
• Different chemicals having the same formulas
• Keep in mind that thus far we’ve only dealt with TWO different elements!
So what to do?
• Number of hydrogens is going to be the same, regardless of isomerism
C
H
H
C
H
H
C
H
H
C
H
H
H HC
H
H
C
H
H
C
H
H
C
H H
C
H
H
H H
C
H
H C HH
C
H
H
C
H H
C
H
H
H
H
C
H
H
C5H12C5H12
C5H12
Solution
• Since number of hydrogens don’t change
with isomerism, why bother naming them?
• Name the molecule simply based on number of
CARBONS
• We can always add prefixes or suffixes later
for differentiation
Name based on number of Carbons
• 1• 2• 3• 4• 5• 6• 7• 8• 9• 10
• Meth• Eth• Prop• But• Pent• Hex• Hept• Oct• Non• Dec
Did that Really Help?
C
H
H
C
H
H
HH
C
H
H
HH Carbon tetrahydride becomes: Methane
Dicarbon hexahydride becomes: Ethane
C
H
H
C
H
H
C
H
H
C
H
H
H HC
H
H
C
H
H
C
H
H
C
H
H
CH4
C2H6
Octacarbon ???hydride becomes:Octane
C8H18
Alkanes• Alkanes are hydrocarbons
that contain only single bonds.
• The general formula for alkanes is: CnH2n+2
• n represents the number of carbon atoms in the molecule
Some Practice• What is the formula for an alkane that has 6
carbon atoms?
• Use the general formula to figure this out.
• Draw out the dot structure for this molecule.
• Do all carbon atoms share 4 times?
• Do all hydrogen atoms share 1 time?
Hmm, not too bad!If there are 6 carbon atoms,
then the H atoms must equal 14
Formula = C6H14 Hexane
Dot Structure
C – C – C – C – C – C
Multiple Bonds
• Carbon can make multiple bonds with another carbon
• This changes the name.
• Why?
Examine Structures
C
H
H
C
H
H
H H C2H6Ethane- notice that each carbon has four bonds
What will happen to the structure if we double bond the two carbons?
C
H
C
H
H HC2H4
Each carbon still has four bonds BUT now the hydrogens have changed!!
Naming molecules with multiple bonds
• Name the molecule as normal
• Change the suffix of the longest chain name
• Double bonds = ene
• Triple bonds = yne
• Use numbering and prefixes for positioning and multiple multiple bonds.
So….
C
H
H
C
H
H
H H C
H
C
H
H H C CH H
C2H6 C2H4 C2H2
ethane ethene ethyne
Alkenes
• Alkenes contain a double bond in the molecule.
• The general formula for alkenes is
CnH2n
A little practiceA little practice..
• What is the formula for an alkene with 4 carbons?
• Draw the dot structure.
• You can place the double bond between any two carbons since it wasn’t specified.
Wow, I can do this!Wow, I can do this!
• The formula is C4H8 Butene
• The dot structure is
C – C = C – C
Alkynes
• Alkynes contain a triple bond in the molecule.
• The general formula for alkynes is
CnH2n-2
Some more practice.
• What is the formula for an alkyne with 7 carbons?
• Draw the dot structure.
• You can place the triple bond between any two carbons since it wasn’t specified.
I am so smart!
• The formula is C7H12 Heptyne
• The dot structure is
C – C ≡ C – C – C – C – C
Practice
C C C CH H
H H H
H
H
CH H
H
CH
H 3 methyl-1-pentene
H
H
C C C C CH H H H
H H H
H CH
H
CH
H
2-heptene
H
H
C CH
H
H CH
CH
H
1-butene
Functional Groups
• Nature has done us a favor.
• There are many common groups that we can organize or file into different categories.
• Then we can name them based on these categories.
Functional Groups
• A group of atoms that, when added to a hydrocarbon chain, alter the chemical properties of the chain.
• Just a few different functional groups to know…
Functional Groups
• Halogens• Alcohols
• Ethers• Aldehydes
• Ketones• Carboxylic Acids
• Esters• Amines
• R-F, R-Cl, R-Br • R-OH• R-O-R• R-COH• R-CO-R• R-COOH• R-COO-R
• R-NH2
What the heck is R?
• The R represents a chain of carbon atoms.
• The the length of the chain is not significant.
• It is important to understand where the functional group lies in relation to the chain of carbon atoms
Halides
• Fluorides, Chlorides, Bromides, and Iodides
• Simply name the molecule as normal but add the prefix Fluoro, Chloro, Bromo, or Iodo as necessary
Halides
Cl
Cl
2, 3 dichlorohexane
I
I
3, 3 diiodo-1-pentene
Alcohols
• R-OH• Name like normal
except add an –ol suffix
AlcoholsOH
OHC
H
H
C
H
H
H
OH
2 propanol
ethanol
1butenol
Ethers
• R-O-R• Name two “R” groups
with –yl endings• End name in ether
Uses of Ethers
Common solvents.
General anesthetic
Ethers are slightly soluble in water.
Ethers
ODimethyl ether
O Ethyl methyl ether
Aldehyde
• R-COH• This is a carbon to
oxygen double bond with a hydrogen at the end.
• Name as normal except use a “-al” suffix
Al Who?Al Who?
Aldehydes
C
H
H
C
H
H
C
H
H
CH H
Obutanal
C
H
H
C
Cl
Cl
C
H
H
C H
O
C
H
H
H 3,3 dichloropentanal
Uses ofUses of AldehydesAldehydes• Formaldehyde H2CO is used in the production of:
Dollar Bills
Ink used in books, magazines, and newspapers
Wrinkle-Free Clothing
Glues
Car bumpers
KetonesKetones
• R-CO-R• This is a carbon to
oxygen double bond but in the center of a hydrocarbon chain rather than the end
• Name as normal but give it a “-one” suffix
Uses of KetonesUses of Ketones
• Ketones are often used as stabilizers in paints and perfumes. They prevent the other chemicals from degrading or breaking down.
• Acetone is found in nail polish remover.
Ketones
propanone
2 hexanone
C
H
H
C
H
H
CH H
O
C
H
H
C
H
H
C
H
H
C
O
C
H
H
H C
H
H
H
Carboxylic Acids
• R-COOH or R-CO2H
• This is a carbon to oxygen double bond with the same carbon single-bonded to an OH group.
• Name as normal except give it the suffix “-anoic acid”.
HC
2 H3 O
2
Uses of Carboxylic AcidsUses of Carboxylic Acids
Carboxylic Acids are relatively weak acids.
Acetic Acid is the main ingredient in vinegar
Carboxylic Acids
C
H
H
C
H
H
C
H
H
CH OH
O
Butananoic acid
C
H
H
C
H
H
FC
O
HO 3-Fluoropropanoic acid
Esters
• R-COO-R
• This is a carbon to oxygen double bond with a carbon to oxygen single bonded to another single bonded carbon
• Name by given secondary branch “-yl” suffix and main branch “-anoate” suffix.
EstersEsters
Many esters have distinctive fruit-like odors, which has led to their common use in artificial flavorings and fragrances.
Esters
C
H
H
C
H
H
C
H
H
C
O
C
H
H
H C
H
H
HO
Secondary Branch
Main Branch
methylpentanoate
Methyl Pentanoate
Esters
C
H
H
H C
H
H
C
O
C
H
H
O C
H
H
HC
H
H
C
H
H
Butyl propanoate
C
H
H
H O
H
H
C
O
C
H
H
C C
H
H
HC
H
H
C
H
H
Methyl hexanoate
AminesAmines
• R-NH2
• Name the “R” group or groups with “-yl” endings
• Add the word “amine”
Uses of Amines
• Amines are found in many pharmaceuticals
Amines
C
H
H
N
H
H
H Methyl amine
C
H
H
N
C
H
H
HH
H Dimethyl amine
Summary
ClR
Halide
OHRAlcohol
RR OEther
HR CAldehyde
O
RR CKetone
O
OHR CCarboxylic
Acid
O
OR CEster
O
R NH2RAmine
• Alkanes• Alkenes• Alkynes• Halides
• Alcohols• Ethers
• Aldehydes• Ketones
• Carboxylic Acids• Esters
• Amines
Summary
• - “-ane”• = “-ene”• ≡ “-yne”• R-X “-o”• R-OH “-ol”• R-O-R “-yl ether”• R-COH “-al”• R-CO-R “-one”• R-COOH “-anoic acid”• R-COO-R “-yl” “-anoate”• R-NH2 “-yl amine”
Can You Do This?
• YES!
• It takes:
• Memorization
• Practice
• Practice
• Practice
• Practice
• And, oh yes…
• Practice!