Transcript Organic Chemistry rubax

Organic Chemistry
1) Hydrocarbons
2) Substituted Hydrocarbons
3) Organic Families
4) Organic Reactions
(c) 2006, Mark Rosengarten
Hydrocarbons
 Molecules made of Hydrogen and Carbon
 Carbon forms four bonds, hydrogen forms one bond
 Hydrocarbons come in three different homologous series:
– Alkanes (single bond between C’s, saturated)
– Alkenes (1 double bond between 2 C’s, unsaturated)
– Alkynes (1 triple bond between 2 C’s, unsaturated)
 These are called aliphatic, or open-chain, hydrocarbons.
 Count the number of carbons and add the appropriate suffix!
(c) 2006, Mark Rosengarten
Alkanes
 CH4 = methane
 C2H6 = ethane
 C3H8 = propane
 C4H10 = butane
 C5H12 = pentane
 To find the number of hydrogens,
double the number of carbons and add
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Methane
Meth-: one carbon
-ane: alkane
The simplest organic
molecule, also known as
natural gas!
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Ethane
Eth-: two carbons
-ane: alkane
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Propane
Prop-: three carbons
-ane: alkane
Also known as “cylinder gas”, usually stored under pressure
and used for gas grills and stoves. It’s also very handy as a
fuel for Bunsen burners!
(c) 2006, Mark Rosengarten
Butane
But-: four carbons
-ane: alkane
Liquefies with moderate pressure, useful for gas lighters. You
have probably lit your gas grill with a grill lighter fueled with
butane!
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Pentane
Pent-: five carbons
-ane: alkane
Your Turn!!!
Draw Hexane:
Draw Heptane:
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Alkenes
 C2H4 = Ethene
 C3H6 = Propene
 C4H8 = Butene
 C5H10 = Pentene
 To find the number of hydrogens, double
the number of carbons.
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Ethene
Two carbons, double bonded.
Notice how each carbon has
four bonds? Two to the other
carbon and two to hydrogen
atoms.
Also called “ethylene”, is used for the production of
polyethylene, which is an extensively used plastic. Look for
the “PE”, “HDPE” (#2 recycling) or “LDPE” (#4 recycling)
on your plastic bags and containers!
(c) 2006, Mark Rosengarten
Propene
Three carbons, two of them
double bonded. Notice how
each carbon has four bonds?
If you flipped this molecule so that the double bond was on
the right side of the molecule instead of the left, it would still
be the same molecule. This is true of all alkenes.
Used to make polypropylene (PP, recycling #5), used for
dishwasher safe containers and indoor/outdoor carpeting!
(c) 2006, Mark Rosengarten
Butene
This is 1-butene, because the double
bond is between the 1st and 2nd
carbon from the end. The number 1
represents the lowest numbered
carbon the double bond is touching.
This is 2-butene. The double bond
is between the 2nd and 3rd carbon
from the end. Always count from
the end the double bond is closest
to.
ISOMERS: Molecules that share the same molecular
formula, but have
different structural formulas.
(c) 2006, Mark Rosengarten
Pentene
This is 1-pentene. The double bond is
on the first carbon from the end.
This is 2-pentene. The double bond is
on the second carbon from the end.
This is not another isomer of pentene.
This is also 2-pentene, just that the
double bond is closer to the right end.
(c) 2006, Mark Rosengarten
Alkynes
 C2H2 = Ethyne
 C3H4 = Propyne
 C4H6 = Butyne
 C5H8 = Pentyne
 To find the number of hydrogens, double
the number of carbons and subtract 2.
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Ethyne
Now, try to draw propyne! Any isomers? Let’s see!
Also known as “acetylene”, used by miners by dripping
water on CaC2 to light up mining helmets. The “carbide
lamps” were attached to miner’s helmets by a clip and had
a large reflective mirror that magnified the acetylene
flame.
Used for welding and cutting applications, as ethyne
oC!
burns at temperatures
over
3000
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Propyne
This is propyne! Nope! No
isomers.
OK, now draw butyne. If there are any isomers, draw
them too.
(c) 2006, Mark Rosengarten
Butyne
Well, here’s 1-butyne!
And here’s 2-butyne!
Is there a 3-butyne? Nope! That would be 1-butyne. With
four carbons, the double bond can only be between the 1st
and 2nd carbon, or between the 2nd and 3rd carbons.
Now, try pentyne!
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Pentyne
1-pentyne
2-pentyne
Now, draw all of the possible isomers for hexyne!
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Substituted Hydrocarbons
 Hydrocarbon chains can have three kinds of “dingly-
danglies” attached to the chain. If the dingly-dangly is
made of anything other than hydrogen and carbon, the
molecule ceases to be a hydrocarbon and becomes another
type of organic molecule.
– Alkyl groups
– Halide groups
– Other functional groups
 To name a hydrocarbon with an attached group, determine
which carbon (use lowest possible number value) the
group is attached to. Use di- for 2 groups, tri- for three.
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Alkyl Groups
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Halide Groups
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Organic Families
 Each family has a functional group to identify it.
– Alcohol (R-OH, hydroxyl group)
– Organic Acid (R-COOH, primary carboxyl group)
– Aldehyde (R-CHO, primary carbonyl group)
– Ketone (R1-CO-R2, secondary carbonyl group)
– Ether (R1-O-R2)
– Ester (R1-COO-R2, carboxyl group in the middle)
– Amine (R-NH2, amine group)
– Amide (R-CONH2, amide group)
 These molecules are alkanes with functional groups attached. The name is
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based on the alkane name.
Alcohol
On to DI and TRIHYDROXY
ALCOHOLS
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Di and Trihydroxy Alcohols
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Positioning of
Functional Group
PRIMARY (1o): the functional group is
bonded to a carbon that is on the end of
the chain.
SECONDARY (2o): The functional
group is bonded to a carbon in the middle
of the chain.
TERTIARY (3o): The functional group
is bonded to a carbon that is itself
directly bonded to three other carbons.
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Organic Acid
These are weak acids. The H on the right side is the one
that ionized in water to form H3O+. The -COOH
(carboxyl) functional group is always on a PRIMARY
carbon.
Can be formed from the oxidation of primary alcohols
using a KMnO4(c)catalyst.
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Aldehyde
Aldehydes have the CO (carbonyl) groups ALWAYS on a
PRIMARY carbon. This is the only structural difference
between aldehydes and ketones.
Formed by the oxidation of primary alcohols with a catalyst.
Propanal is formed from the oxidation of 1-propanol using
pyridinium chlorochromate
(PCC) catalyst.*
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Ketone
Ketones have the CO (carbonyl) groups ALWAYS on a
SECONDARY carbon. This is the only structural difference
between ketones and aldehydes.
Can be formed from the dehydration of secondary alcohols
with a catalyst. Propanone is formed from the oxidation of 2propanol using KMnO4 or PCC catalyst.*
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Ether
Ethers are made of two alkyl groups surrounding one oxygen
atom. The ether is named for the alkyl groups on “ether” side
of the oxygen. If a three-carbon alkyl group and a fourcarbon alkyl group are on either side, the name would be
propyl butyl ether. Made with an etherfication reaction.
(c) 2006, Mark Rosengarten
Ester
Esters are named for the alcohol and organic acid that
reacted by esterification to form the ester. If the alcohol was
1-propanol and the acid was hexanoic acid, the name of the
ester would be propyl hexanoate. Esters contain a COO
(carboxyl) group in the middle of the molecule, which
differentiates them from organic acids.
(c) 2006, Mark Rosengarten
Amine
- Component of amino acids, and therefore proteins, RNA and
DNA…life itself!
- Essentially ammonia (NH3) with the hydrogens replaced by
one or more hydrocarbon chains, hence the name “amine”!
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Amide
Synthetic Polyamides: nylon, kevlar
Natural Polyamide: silk!
For more information on polymers, go here.
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Organic Reactions
 Combustion
 Fermentation
 Substitution
 Addition
 Dehydration Synthesis
– Etherification
– Esterification
 Saponification
 Polymerization
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Combustion
 Happens when an organic molecule reacts with oxygen gas
to form carbon dioxide and water vapor. Also known as
“burning”.
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Fermentation
 Process of making ethanol by having yeast digest simple
sugars anaerobically. CO2 is a byproduct of this reaction.
 The ethanol produced is toxic and it kills the yeast when
the percent by volume of ethanol gets to 14%.
(c) 2006, Mark Rosengarten
Substitution
 Alkane + Halogen  Alkyl Halide + Hydrogen Halide
 The halogen atoms substitute for any of the hydrogen
atoms in the alkane. This happens one atom at a time. The
halide generally replaces an H on the end of the molecule.
C2H6 + Cl2  C2H5Cl + HCl
The second Cl can then substitute for another H:
C2H5Cl + HCl  C2H4Cl2 + H2
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Addition
 Alkene + Halogen  Alkyl Halide
 The double bond is broken, and the halogen adds at either
side of where the double bond was. One isomer possible.
(c) 2006, Mark Rosengarten
Etherification*
 Alcohol + Alcohol  Ether + Water
 A dehydrating agent (H2SO4) removes H from one
alcohol’s OH and removes the OH from the other. The two
molecules join where there H and OH were removed.
Note: dimethyl ether and diethyl ether are also produced from
this reaction, but can be separated out.
(c) 2006, Mark Rosengarten
Esterification
 Organic Acid + Alcohol  Ester + Water
 A dehydrating agent (H2SO4) removes H from the organic
acid and removes the OH from the alcohol. The two
molecules join where there H and OH were removed.
(c) 2006, Mark Rosengarten
Saponification
The process of making soap from glycerol esters (fats).
Glycerol ester + 3 NaOH  soap + glycerol
Glyceryl stearate + 3 NaOH  sodium stearate + glycerol
The sodium stearate is the soap! It emulsifies
grease…surrounds globules with its nonpolar ends, creating
micelles with - charge that water can then wash away. Hard
water replaces Na+ with Ca+2 and/or other low solubility ions,
which forms a precipitate called “soap scum”.
Water softeners remove these hardening ions from your tap
water, allowing the soap to dissolve normally.
(c) 2006, Mark Rosengarten
Polymerization
 A polymer is a very long-chain molecule made up of many monomers (unit




molecules) joined together.
The polymer is named for the monomer that made it.
– Polystyrene is made of styrene monomer
– Polybutadiene is made of butadiene monomer
Addition Polymers
Condensation Polymers
Rubber
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Addition Polymers
Joining monomers together by breaking double
bonds
Polyvinyl chloride (PVC): vinyl siding, PVC pipes, etc.
Vinyl chloride
polyvinyl chloride

n C2H3Cl
-(-C2H3Cl-)-n
Polytetrafluoroethene (PTFE, teflon):
TFE
n C2F4
PTFE

-(-C2F4-)-n
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Condensation Polymers
Condensation polymerization is just dehydration synthesis,
except instead of making one molecule of ether or ester, you
make a monster molecule of polyether or polyester.
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Rubber
The process of toughing rubber by cross-linking the polymer
strands with sulfur is called...
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VULCANIZATION!!!
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THE END
(c) 2006, Mark Rosengarten