Transcript Intro to Organic Reactions

Intro to Organic
Reactions
Reactions of Alkanes
• They burn!
• Hydrocarbon
and Oxygen
yields Carbon
Dioxide and
Water
Reactions of Alkanes
Substitution Rxn
H
H
+ Cl2
C
H
H
UV
lite
Cl
H
+ HCl
C
H
H
Reactions of Alkenes
Addition Reactions
• Alkenes are unsaturated —
more single bonds can form to
the C atoms
• Molecules such as Br2, H2, HCl,
HBr, and H2O add to the double
bond
Addition Rxn
Halogenation
| |
C = C + X2
| |
X = Cl2, Br2, I2
| |
-C-C| |
X X
An Addition Reaction
Fat
placed
in Br2
vapor
Unsaturated Fats
An Addition Reaction
The fat in bacon is
partially unsaturated.
The fat adds Br2 to
the C=C bonds.
Addition Rxn
| |
C = C + H2
| |
Pt
cat
| |
-C-C| |
H H
An Addition Reaction
• Fats can be “hydrogenated” with H2.
Saturated Fats
Peanut butter has partially hydrogenated
vegetable oil.
Addition Rxn
| |
C = C + HX
| |
H+
| |
-C-C| |
H X
Addition Rxn
| |
C = C + HOH
| |
H+
| |
-C-C| |
H OH
Reactions of Aromatics
• Substitutions — not additions
— are typical.
CH3
+ CH3Cl
AlCl3
+ HCl
AlCl3 is a catalyst. Catalysts typically
used in aromatic substitutions.
Alcohol Reactions
Screen 11.6
Substitution
Elimination—the
reverse of addition
TYPES OF ALCOHOLS
H
Primary
R
C
OH
CH3 CH2 OH, ethanol
H
CH3
R
Secondary
R
C
OH
R
R
C
R
H3 C
C
H
H
Tertiary
rubbing alcohol
OH
OH
More Alcohol Reactions
H
H
C
H
C
OH ( )
+ Oxidizin g agent
H
H H
Eth anol
H
O
C
C
H ( )
H
Acetaldehyde
+ Oxidizin g agent
Ethanol is a PRIMARY
ALCOHOL. It is oxidized
to an ALDEHYDE and
then to an ACID.
H
H
O
C
C
OH ( )
H
Acetic acid
More Alcohol Reactions
OH
R—C—R'
H
Secondary alcohol
oxidizing
agent
O
R—C—R'
Ketone
(–R and –R' are organic groups. They may be the
same or different.)
SECONDARY ALCOHOLS are oxidized to
KETONES — and reaction stops there.
Reduction of the
Carbonyl Group
H
O
H2
cat
C
R
R
H
C
OH
H
aldehyde  primary alcohol
OH
O
LiAlH4
R
C
R'
C
R
R'
H
ketone  secondary alcohol
Acid-Base Reaction
O
O
R
+ NaOH
C
OH
R
C
+ HOH
O-Na+
Acids + Alcohols  ESTERS
O
O
R
HO
C
OH
R'
H+
R
+ HOH
C
O
R'
Condensation Reaction
Esters have generally pleasant odors
Acids + Alcohols  ESTERS
O
O
CH 3 COH + CH 3 CH 2 OH
Acetic acid
Ethanol
H+
CH 3 COCH 2 CH 3 + H 2O
Ethyl acetate
H
O
Aspirin,
acetylsalicylic acid,
Acid and Ester
C
O
O
C
O
CH3
Acids + Amines  AMIDES
O
O
R
H+
N
H
C
OH
H
R'
R
C
N
O
H
Condensation Reaction
+ HOH
R'
Acids + Amines  AMIDES
N-methylacetamide
Acids + Amines  AMIDES
H
C
H
H
H
O
H
O
C
C
C
C
C
C
N
C
H
H
H
H
Amide link
Acetoaminophen
Tylenol, Datril, Momentum, ...
Amino Acid + Amino Acid  Peptide
O
O
H2N
Alanine
CH
C
OH
+
H2N
CH
C
Serine
CH2
CH3
OH
OH
O
H
C
N
O
-H2O
H2N
CH
CH3
Peptide Bond
CH
CH2
OH
C
OH
Polymers
• Giant molecules made by joining many
small molecules called monomers
• Average production is 150 kg per
person annually in the U.S.
Polymer Classifications
• Thermoplastics (polyethylene) soften
and flow when heated
• Thermosetting plastics — soft initially
but set to solid when heated. Cannot
be resoftened.
• Other classification: plastics, fibers,
elastomers, coatings, adhesives
Polymer Preparation
• Addition polymers — directly
adding monomer units together
• Condensation polymers —
combining monomer units and
splitting out a small water (water)
Polyethylene: Addition Polymer
n H2 C
CH2
Ethylene
H
H
C
C
H
H
n
Polyethylene
A polymer with a molar mass of
1 x 106 has about 360,000 units.
Mechanism of Addition
Polymerization
Types of Polyethylene
Linear, high density
PE (HDPE)
Branched, low
density PE, LDPE
Cross-linked PE, CLPE
Types of Polyethylene
Polymers based on Substituted Ethylenes, CH2=CHX
CH2CH
OH
CH2CH
n
polyvinyl alcohol
CH2CH
OCCH3 n
O
polyvinyl acetate
n
polystyrene
Table 11.12: others are PVC, acrylonitrile,
polypropylene, polymethyl methacrylate
H
H
C
C
H
Cl
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
H
Cl
H
Cl
H
Cl
H
Cl
H
Cl
H
H
H
H
H
Cl
H
H
H
Cl
C
C
C
C
C
C
C
C
C
C
H
Cl
Cl
H
H
H
Cl
H
H
H
Polystyrene
• Polystyrene is nonpolar material and
dissolves in organic solvents.
• PS foam is mostly air, and when it dissolves
it collapses to a much smaller volume.
Slime!
Slime is
polyvinylalcohol
cross-linked
with boric acid
Bubble Gum!
A copolymer
Styrene + butadiene
Condensation Polymers
O
n HOC
O
COH + n HOCH2CH2OH
terephthalic acid
O
C
ethylene glycol
O
COCH2CH2O
+ H2 O
n
Polyethylene terephthalate (PET), a polyester
Polyesters, PET
Jackets made from
recycled PET soda bottles
Soda bottles,
mylar film.
Polyesters: Mechanism
Polymer Recycling Symbols
LDPE =
HDPE =
PP =
V=
Low density PE = 0.910-0.925 g/cm3
High density PE = 0.941-0.965
Polypropylene = 0.90
PVC (Vinyl chloride) = 1.30-1.58
a POLYAMIDE
O
O
C
C
OH R
O
+
OH
O
H-N
H
R’
H
N-H
H H
- C - R - C - N - R’ - N -
Polyamides: Nylon
•Each monomer has 6 C atoms in its chain.
•A polyamide link forms on elmination of HCl
•Result = nylon 66
Proteins are Polyamides
H
N
CH
CH3
O
H
C
N
O
CH
CH2
OH
C
*
Fats and Oils: Saponification
Glyceryl stearate, a fat + NaOH
O
CH2 O CR
O
+ 3 NaOH
CH O CR
O
CH2 O CR
R = —(CH2 )16CH3
OH
0
OH
OH
Glycerol
+ 3
R
C
O- Na+
sodium stearate (a soap)