Lecture: Organic Chemistry

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Announcements General Info
Lecture Organic Chemistry Organic Analysis Lab
Part 1 Density, IR, GC qualitative Friday
take-home quiz (worksheet) complete organic
lecture
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Alkanes are a class (family) of organic compounds
that contain only carbon and hydrogen atoms and
only single bonds. Alkanes are saturated (NO
double bonds). General formula
CnH2n2 Cycloalkanes are cyclic hydrocarbons.
They form rings!
Unsaturated Hydrocarbons are compounds composed
of carbon and hydrogen in which the carbon chain
contains at least one double or triple
carbon-carbon bond
An alkene contains at least one C-C double bond
General formula CnH2n In alkenes, there is
NO rotation around the carbons in the double
bond. It is rigid (fixed!). An alkyne contains
at least one C-C triple bond General formula
CnH2n-2 Triply bonded carbons can only have
one other bond, so geometry is linear.
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Functional Groups

• Functional groups have been substituted for
  hydrogen atoms in hydrocarbons.
• Still talking about organic (carbon-containing)
  molecules
• A functional group is a group of atoms that show
  a characteristic influence on the properties of
  the molecule
• generally, the reactions that a compound will
  perform are determined by what functional groups
  it has
• since the kind of hydrocarbon chain is irrelevant
  to the reactions, it may be indicated by the
  general symbol R

CH3OH
R group
functional group
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Environmental Note Functional Groups in
Familiar Compounds Flavors and odors of foods
and household products may often be attributed to
functional groups
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Functional Groups Alkenes, Alkynes, Aromatics,
Alcohols and Ethers alkene
alkyne aromatic alcohol
ether functional group condensed structural
formula
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Functional Groups Aldehydes, Ketones, Carboxylic
Acids, Esters, Amines, Amides aldehyde
ketone carboxylic acid ester
amine amide functional
group or or
or or
or or
or
-CONH2
-C(O)-
-CHO
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Alcohols

• R-OH
• Ethanol CH3CH2OH
• Grain alcohol fermentation of sugars
• Alcoholic beverages
• proof number 2X percentage of alcohol
• Isopropyl alcohol (CH3)2CHOH
• 2-propanol
• Rubbing alcohol
• Poisonous
• Methanol CH3OH
• Wood alcohol thermolysis of wood
• Paint solvent
• Poisonous

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Ethers

• R O R
• Ether diethyl ether CH3CH2OCH2CH3
• Anesthetic

Another important ether is methyl tertiary butyl
ether, MTBE. It was used until recently as a
gasoline additive to help in the combustion
process. It was phased out in favor of ethanol,
due to environmental concerns.
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Aldehydes and Ketones

• Contain the carbonyl group
• Aldehydes at least 1 side H
• Ketones both sides R groups
• Many aldehydes and ketones have pleasant tastes
  and aromas
• Some are pheromones
• Formaldehyde H2CO
• pungent gas
• formalin a preservative
• wood smoke, carcinogenic
• Acetone CH3C(O)CH3
• nail-polish remover

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Aldehydes and Ketones
ALDEHYDES KETONES

• acetophenone pistachio
• carvone spearmint
• ionone raspberries
• muscone musk

• butanal butter
• vanillin vanilla
• benzaldehyde almonds
• cinnamaldehyde cinnamon

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Carboxylic Acids

• RCOOH
• sour tasting
• weak acids
• citric acid
• found in citrus fruit
• ethanoic acid acetic acid
• vinegar
• methanoic acid formic acid
• insect bites and stings
• made by the oxidation of aldehydes and alcohols
• OH on the end of the chain
• always on main chain
• has highest precedence
• C of group always C1
• position not indicated in name

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Esters

• RCOOR
• sweet odor
• made by reacting carboxylic acid with an alcohol
• RaCOOH RbOH ? RaCOORb H2O
• name alkyl group from alcohol (B), then acid name
  (A) with ate ending
• precedence over carbonyls, but not carboxylic
  acid
• number from end with ester group

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Amines

• N containing organic molecules
• very bad smelling
• form when proteins decompose
• organic bases
• many amines are biologically active
• dopamine a neurotransmitter
• epinephrine an adrenal hormone
• pyridoxine vitamin B6

Dopamine
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Sample Problem Classify the following organic
compounds according to their functional
groups a. b. CH3CO2CH2CH3 c.
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Nomenclature
Substituents.. Alkyl group a carbon branch in
an alkane, which is missing one hydrogen atom.
Drop ane and add yl. Halogens a halogen
substituent is named according to its element.
Drop the ine and add o.

• RULES FOR NAMING ORGANIC COMPOUNDS
• Write the name of the longest continuous chain of
  carbon atoms
• Number the carbon atoms starting from the end
  nearest a substituent
• Give each branch a name and location (by the
  carbon number of the main chain to which it is
  attached

Combining steps 1 4 here because not being
tested on 4!
pentane
1 2 3 4 5
2-methyl pentane
2
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P3
Sample Problem Give the IUPAC name for the
following molecules
1
3
2
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SAMPLE PROBLEM 15.2
Naming Alkanes, Alkenes, and Alkynes