Transcript Organic Reactions

Organic Reactions
Hydrogenation
Addition
Substitution
Combustion
Esterification
Fermentation
Saponification
Polymerization
Hydrogenation
• Unsaturated hydrocarbons undergo addition
when H2 (g) is added:
Note that hydrogenation produces a single product from two reactants:
A+BC
Addition
• Halogens (F2, Cl2, Br2, and I2) will combine with
unsaturated hydrocarbons:
Note that addition creates a single product from two reactants:
A+BC
Substitution
• Saturated hydrocarbons (alkanes) lose a
hydrogen and gain a halogen:
• Note that there are two products in
substitution reactions – addition only has one!
Distinguishing Between Addition and
Substitution
• Table Q can help you with the identity of the
hydrocarbon, which is usually representated
as a chemical formula.
Substitution
Addition
Addition
Esterification
• Acid + Alcohol  Ester + Water
• Look for the functional groups to identify the
reaction!
R-OH + R-COOH  R-COOR + H2O
• A product or a reactant can be missing in a
question
Combustion
• Organic Molecule + O2  CO2 + H2O
• Usually saturated hydrocarbons are used
• Balancing these equations is fun!
Fermentation
• Look for sugar reactant and alcohol and CO2
products:
Saponification
• Fat + OH-  Soap + Glycerol
+ NaOH(aq) 
• Only need to recognize the reaction!
Addition Polymerization
• Unsaturated hydrocarbon molecules are
induced to add to each other, breaking double
bonds.
Condensation Polymerization
• Esterification is the most common type of condensation reaction on
the regents exam.
• Protein synthesis is a commonly cited example of condensation.
Review for Functional Group Test
• Organic compounds contain carbon atoms
that are bonded to one another in chains,
rings, and networks to form a variety of
structures (polymers, oils, and other large
molecules).
• Carbon has four valence electrons and always
makes four covalent bonds with other atoms.
Functional groups impart distinctive
physical and chemical properties to
organic compounds.
• The functional groups contain electronegative
elements (halogens, O, and N). The more polar
compounds have higher melting and boiling
points than their hydrocarbon counterparts.
Hydrogen “bonds”
• When the electronegative element is bonded
to hydrogen, it is capable of making hydrogen
bonds.
• These strong intermolecular forces lead to
higher MP and BP, and lower vapor pressures
than other functional groups that are bonded
to carbon only.
Hydrocarbons, organic
acids, alcohols, esters,
amines, amides, and
amino acids are
categories of organic
molecules that differ in
their structural formulas
as a result of different
functional groups.
What you need to be able to do…
• You need to be able to use Tables P, Q and R
with ease to get the organic questions.
• Identifying functional groups, naming
compounds, recognizing saturated and
unsaturated hydrocarbons, especially in
reactions; these are skills you need to have.
What You Will See
• Note that you will see full structural formulas
and condensed structural formulas.
• Table R has partially condensed formulas. You
need to be able to discern between these
different ways of describing molecules.
IUPAC Organic Nomenclature System
• Hydrocarbons, organic acids, alcohols, and
esters are names using the IUPAC system.
• The IUPAC system provides a method of
distinguishing among isomers of organic
compounds.
Isomers
• Isomers have the same molecular formula,
empirical formula, and % composition. They
test this definition a lot.
• If you’re not sure about an isomer, count the
carbons, hydrogens, and oxygens; make sure
they’re the same as the molecule in question.
Unsaturated organic compounds
contain at least one double or triple
bond.
• Each bond is a pair of shared electrons.
• How many electrons (or pairs) in double and
triple bonds?
Recognizing Hydrocarbons
• You need to be able to recognize a alkane,
alkene, or an alkyne by its chemical formula
(Table Q).
• Know how to use the general formulas, and
know. They often ask this question as part of a
substitution or addition reaction question.
Addition, hydrogenation, substitution,
polymerization, esterification,
fermentation, saponification,
oxidation, and combustion are
examples of organic reactions.
• Addition is probably the most popular
reaction they test with, followed by
esterification.
List of Organic Reactions
• substitution (by halogens) of saturated hydrocarbons
• addition (by hydrogen and halogens) of unsaturated
hydrocarbons
• esterification (condensation):
alcohol + organic acid  ester + H2O
• combustion: organic compound + O2  CO2 + H2O
• fermentation:
C6H12O6 (glucose)  2CH3CH2OH (ethanol) + 2 CO2
• saponification: fatty acids + base  soap + glycerol
• addition polymerization: usually polyethylene (ethene)
• condensation polymerization: esters, proteins,
polysaccharides, fats, synthetics