Transcript Organic Chemistry

Organic Chemistry
The Chemistry of Carbon
Compounds
Carbon
“Organic” Chemistry
• Historically, organic compounds are defined as
compounds extracted or isolated from plants and
animals.
– VITALISM: Scientists believed that organic
compounds contained a vital force that was only
found in living systems
• Disproved by Friederich Wohler in 1828 by
synthesizing urea using inorganic materials (silver
cyanate and ammonium chloride)
O
AgOCN + NH4Cl
C
H2N
NH2
Friederich Wohler
Organic Chemistry
• Study of carbon compounds
– Composed of carbon, hydrogen, oxygen,
nitrogen, sulfur, phosphorus, and the halogens
• More than 95% of known compounds are organic
compounds (Carbon-containing)
• Recall
– Carbons can have 4 bonds
– Nitrogen can have 3 bonds
– Oxygen can have 2 bonds
– Hydrogen can have 1 bond
Common Elements in Organic Compounds
C, H, O, (N, S)
The Secret to Organic Compounds:
the unique carbon atom
• CATENATION
– Ability of C-atoms to bond to each other so
strongly, they can form long chains.
Eg. Thousands of C-atoms bonded.
– Each carbon can have four bonds, maximum
Common organic compound families
• HYDROCARBONS: Only C and H
– Alkanes, alkenes, alkynes, arenes, aromatic
compounds
• OXYGEN-CONTAINING
– Alcohols, ethers, aldehydes, ketones, carboxylic
acids, esters, acid anhydrides
• NITROGEN-CONTAINING
– Amines, Amides
Examples
CH
HC
C
HC
CH
O
OH
O
C
C
C
H
CH
HC
C
HC
CH
O
CH3
HO
CH2
O
H3C
acetone
C
HC
OH
ascorbic acid
F
C
O
HO
acetic acid
H3C
Cl
CH2
CH3
propane
C
O
C
HO
H3C
C
O
CH
C
CH
methyl salicylate
benzaldehyde
H3C
HO
Cl
F
Freon 12
Classification of Hydrocarbons
Hydrocarbons
Hydrocarbons: Alkanes
•
•
•
•
Simplest hydrocarbons
Contains only C–C and C–H bonds
Usually used as fuels
Three types
– Straight chain alkanes
– Branched alkanes
– Cyclic alkanes
Examples of Alkanes
Structures of Alkanes
H
H
C
H
CH4
=
methane
H
H
H
H
H
H
H
C
C
C
H
H
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
CH3 H
C
C
C H
H
H
H
CH3CH2CH3
=
H
=
propane
CH3CH2CH2CH3 butane
CH3
=
H3 C
CH CH3
isobutane
Structural Isomers
Structural Isomers
Cycloalkanes
• Alkanes that form rings are called cycloalkanes
CH2
H2C
CH2
H2C
CH2
H2C
CH2
H2C
=
cyclopropane
=
cyclobutane
=
cyclopentane
CH2
CH2
CH2 CH
2
CH2
H2C
CH2
H2C
CH2
CH2
=
cyclohexane
Haloalkanes
• Alkanes with halogens
F
Cl
C
F
Freon 11
Cl F
Cl
Cl
C
C
F
F
Freon 12
Cl
F Cl
C
F
Freon 14
Cl
Chlorofluorocarbons
• Insoluble in water and are unreactive towards
substances
• Unreactiveness lets them reach the stratosphere
and react with the ozone layer
Alkenes
Alkynes
• Contains a C≡C bonds
August Kekule and the Dream
• C6H6
•
•
"I fell into a reverie, and lo, the atoms were gamboling before my eyes!
Whenever, hitherto, these diminutive beings had appeared to me, they had
always been in motion; but up to that time, I had never been able to discern the
nature of their motion. Now, however, I saw how, frequently, two smaller atoms
united to form a pair; how a larger one embraced the two smaller ones; how
still larger ones kept hold of three or even four of the smaller; whilst the whole
kept whirling in a giddy dance. I saw how the larger ones formed a chain,
dragging the smaller ones after them, but only at the ends of the chain. . . The
cry of the conductor: “Clapham Road,” awakened me from my dreaming; but I
spent part of the night in putting on paper at least sketches of these dream
forms. This was the origin of the Structural Theory."
"...I was sitting writing on my textbook, but the work did not progress; my
thoughts were elsewhere. I turned my chair to the fire and dozed. Again the
atoms were gamboling before my eyes. This time the smaller groups kept
modestly in the background. My mental eye, rendered more acute by the
repeated visions of the kind, could now distinguish larger structures of
manifold conformation; long rows sometimes more closely fitted together all
twining and twisting in snake-like motion. But look! What was that? One of the
snakes had seized hold of its own tail, and the form whirled mockingly before
my eyes. As if by a flash of lightning I awoke; and this time also I spent the
rest of the night in working out the consequences of the hypothesis."
Aromatic Hydrocarbons
H
H
H
H
C
C
C
C
C
C
H
H
H
H
H
C
C
C
C
C
C
H
H
H
24.3
Aromatic Hydrocarbons
• Cyclic structures with alternating C–C and C=C
bonds
Polycyclic Aromatic Hydrocarbons
24.3
Functional Groups
• Determines the properties of the organic
compound
– Compounds with the same functional group will
react similarly
• Alkenes: –C=C– bond
• Alkynes: –C≡C– bond
• Aromatic hydrocarbons: cyclic structure with
alternating –C–C– and –C=C– bonds
Alcohols
• has the general structure R–OH
– derived from hydrocarbons and contain OH groups
• Polar molecules and are soluble in water
(Why?)
Some Common Alcohols
• CH3OH (methanol)
– Used as an industrial solvent
– Possible replacement for gasoline in
automobiles
• CH3CH2OH (ethanol)
– Made from fermentation of grain or other sugar
materials
– Made by reaction of ethylene with water
(denatured alcohol)
– Used for beverages and fuels
Some Common Alcohols
• Isopropyl Alcohol
– Also known as rubbing alcohol
– Used as a disinfectant
• Ethylene glycol
– Also known as antifreeze
– Has multiple –OH groups
OH
CH
H3C
H
CH3
H
H
C
C
OH OH
H
Alcohols
Sterols, ethylene glycol
Biological production of ethanol
C6H12O6 (aq)
enzyme
2CH3CH2OH (aq) + 2CO2 (g)
Commercial production of ethanol
CH2 CH2 (g) + H2O (g)
H2SO4
CH3CH2OH (g)
Metabolic oxidation of ethanol
CH3CH2OH
alcohol dehydrogenase
CH3CHO + H2
DRINKABLE vs. DENATURED
Alcohol
Ethers
• Has the R-O-R’ general structure
• Compounds in which two hydrocarbons
linked by an oxygen are called ethers.
• Used as general anesthetic
• Used as solvents
• Less soluble in water than alcohols
Ethers
F
Cl
O
H3C
CH
CH2
CH2
CH3
Cl
methyl propyl ether
O
C
O
F
methoxy flurane
CH3
H3C
C
CH3
CH3
CH3
methyl tert-butyl ether
Compounds with a Carbonyl Group
• Carbonyl functional group is C=O
• Types of different carbonyl compounds
– Aldehydes
– Ketones
– Carboxylic Acids
– Esters
– Amides
Aldehydes and Ketones
• Aldehydes must have at least one H atom attached
to the carbonyl group:
O
R
C
H
• Ketones must have two C atoms attached to the
carbonyl group:
O
R
C
R'
Functional Group Chemistry
O
O
O
H C H
H C CH3
H3C C CH3
formaldehyde
acetaldehyde
acetone
ALMONDS, FORMALIN
Carboxylic Acids
• Carboxylic acids contain a carbonyl group with an
-OH attached.
• The carboxyl functional group is -COOH
O
R
C
OH
• Carboxylic acids are weak acids.
VINEGAR, ASPIRIN, FACIAL WASH, ANTS, CITRUS FRUITS, PROTEINS,
PRESERVATIVES
Common Carboxylic Acids
Esters
• Esters contain -COOR groups:
O
R'
C
OR
• Usually have fruity odors and tastes
Ester Flavors and Fragrances
O
O
CH2
H3C
C
CH2
C
CH3
H3C
O
methyl butyrate
(apple)
benzyl acetate
(jasmine)
O
CH2
H3C
C
CH2
CH2
O
CH3
ethyl butyrate
(pineapple)
OH
O
C
C
HC
C
HC
CH
O
CH3
CH
O
C
H3C
O
CH2
O
CH2
pentyl acetate
(banana)
CH2
CH3
CH2
methyl salicylate
(wintergreen)
Functional Group Chemistry
Esters have the general formula R’COOR, where R is a
hydrocarbon group.
O
CH3COOH + HOCH2CH3
CH3 C O CH2CH3 + H2O
ethyl acetate
Banana: isopentyl acetate
Pineapple: ethyl butanoate
Apple: methyl butanoate
Pear: propyl ethanoate
Orange: Octyl ethanoate
Raspberry: 2-Methylpropyl ethanoate
Oil of Wintergreen: methyl salycilate
Esters Galore!
allyl caproate
amyl acetate
amyl butyrate
pineapple
apple, banana
apricot, pear,
pineapple
amyl caproate
apple, pineapple
amyl valerate
apple
benzyl acetate
pear, strawberry
bornyl acetate
pine tree flavor
iso-butyl acetate cherry, raspberry,
strawberry
ethyl acetate
peach, pineapple,
raspberry
ethyl butyrate
banana, pineapple, strawberry
ethyl caproate
strawberry
ethyl cinnamate cinnamon
ethyl formate
lemon, strawberry
ethyl heptoate
grape, pineapple
ethyl isovalerate apple
ethyl heptanoate apricot, cherry, grape, raspberry
ethyl lactate
grape
ethyl pelargonate
geranyl acetate
geranyl butyrate
geranyl valerate
linalyl acetate
linalyl butyrate
linalyl formate
menthyl acetate
methyl benzyl acetate
methyl cinnamate
methyl phenyl acetate
methyl salicylate
methyl anthranilate
nonyl caprylate
octyl butyrate
terpenyl butyrate
apple
grape
geranium
cherry
lavender,sage
peach
apple, peach
peppermint
cherry
strawberry
honey
wintergreen
grape,jasmine
orange
parsnip
cherry
HOW TO MIMIC NATURE:
Making synthetic flavoring
•
•
A good cherry is supposed to be tough to
formulate. Here
is an example of a *minimum* synthetic cherry
flavoring:
ethyl methyl p-tolyl glycidate
16.0 %
iso-amyl acetate
12.0 %
iso-butyl acetate
12.0 %
p-methyl benzyl acetate
11.0 %
benzaldehyde
8.0 %
vanillin
7.0 %
benzyl alkcohol
5.5 %
piperonal
5.0 %
ethyl caprate
4.0 %
cinnamic aldehyde dimethyl acetal
3.0 %
p-tolyl aldehyde
3.0 %
cinnamyl anthranilate
3.0 %
ethyl caproate
2.0 %
geranyl butyrate
2.0 %
terpenyl butyrate
0.5 %
Amines
• Organic bases
• Contain carbon, hydrogen, and nitrogen
H2N
CH2
CH2
CH2
CH2
NH2
CH2
CH2
H2N
CH2
cadaverine
CH
CH2
H2C
CH
N
H
CH2
CH2
coniine
NH2
CH2
putresine
CH2
H2C
CH2
CH3
CH2
NH
HC
C
CH
HC
CH
CH3
CH
methamphetamine
CH3
Amides
• composites of carbonyl and amine functionalities
• proteins
O
R
C
N R'
H
Name the functional group
CH
HC
C
HC
CH
O
OH
O
C
C
C
H
CH
HC
C
HC
CH
O
CH3
HO
CH2
O
H3C
acetone
C
HC
OH
ascorbic acid
F
C
O
HO
acetic acid
H3C
Cl
CH2
CH3
propane
C
O
C
HO
H3C
C
O
CH
C
CH
methyl salicylate
benzaldehyde
H3C
HO
Cl
F
Freon 12
Compounds with multiple functional
groups
OH
H3C
HO
CH
C
CH2
NH
C
CH2 O
CH2 C
CH3 O
Vitamin B5
Pantothenic acid
OH
Mango
Would you eat this?
a-Terpinolene, Ethyl butanoate, 3-Carene, Ethyl acetate,
Ethyl 2-butenoate, a-Terpinene, a-Thujene, Dimethyl
sulfide, Limonene, b-Phellandrene, Myrcene, pCymen-8-ol, b-Caryophyllene, cis-3-Hexene-1-ol,
hexadecyl acetate, 5-Butyldihydro-3H-2-furanone,
trans-2-hexenal, Ethyl tetradeconaoate, a-Humulene,
sabinene, 2-Carene, Camphene, Ethyl octanoate, 4Isopropenyl-1-methylbenzene 1-Hexanol, a-terpinene,
hexanal, Ethyl hexadecanoate, a-Copaene,
Hexadecanal, Ethanol, Ethyl propionate, Dihydro-5hexyl-3H-2-furanone, Carveol, Geranial, Ethyl
decanoate, Furfural, Butyl acetate, Methyl butanoate,
2,3, Pentanedione, 1,1, diethoxyethane, pentadecanal,
Butyl formate, 1-Butanol, 5-Methylfurfural, Ethyl
dodecanoate, 2-Acetylfuran, 2 Methyl-1-butanol, 4Methylacetophenoen, Acetaldehyde, Cyclohexane
FOSSIL FUELS
• Coal, Petroleum, Natural Gas
• From decayed organic matter
• Makes up 90% of energy used
Coal
• Main element is carbon, but contains small% of
other elements
• Complete combustion:
– C(s) + O2(g)  CO2(g)
• Limited supply, strip mining
Natural Gas
• Principally methane
• Formed ages ago probably by heat, pressure, and
action of bacteria on organic matter.
Chemistry In Action: The Petroleum Industry
Crude Oil
The Guimaras Oil Spill
Gasoline: C5-C12 alkanes
• C5-C12 alkanes, some sulfur and nitrogen-containing hydrocarbons
• >C15, difficult to combust, causes knock
• OCTANE Rating:
Isooctane (CH3)3CCH2CH(CH3)2 = 100
Heptane = 0
• Some cpds improving octane rating: tetraethyllead
Diesel
• Runs on engine designed by Engineer Rudolf Diesel
• Petrodiesel: It is a hydrocarbon mixture, (C10-C15) obtained in the fractional
distillation of crude oil between 250 °C and 350 °C.
• Biodiesel: Methyl esters of fats from natural oils
POLYMERS
• Poly: Many Meros: Parts
• Made up of repeating monomers
• Copolymer is a polymer made up of two or more monomers
(
CH
CH2
CH2
CH
CH
CH2 )n
• Common biopolymers: Proteins, DNA, RNA, starch, cellulose
Some commercial polymers
• PET: Polyethylene
terephthalate
– Plastic bottles
• Polytetrafluoroethylene
– Teflon™
• Polypropylene
• Polystyrene
• Polyvinyl chloride
• Nylon (synthetic polyamide,
similar to bonds in proteins)
http://www.nationalgeographic.com/education/plastics/index.html
References:
 Hill, JW and Kolb DK. Chemistry for the Changing Times, 7th
ed. Prentice Hall International. 1992.
 Brown, TL. Le May, Jr., HE, and Bursten, BE. Chemistry: The
Central Science. 1997.
 Schmid, G. Organic Chemistry. Mosby-Year Book, Inc. 1996.
 http://chemed.chem.purdue.edu/genchem/ (accessed on July
28, 2003)
 Partial list of ingredients for the mango from Snyder, C.H. “The
Extraordinary Chemistry of Ordinary Things”, J. Wiley & Sons,
1998. p. 54
 Picture of Mango from
http://www.globalgourmet.com/ggt/ggt0598/art/mango.jpg
(accessed on June 6, 2003)