Organic ChemistryThe Chemistry of

Carbon Compounds

CarbonCarbon

““Organic” ChemistryOrganic” 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)

AgOCN + NH4Cl CNH2 NH2

O

Friederich WohlerFriederich Wohler

Organic ChemistryOrganic 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 The Secret to Organic Compounds: the unique Compounds: the unique

carbon atomcarbon 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 Common organic compound families 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

ExamplesExamples

C

CH

CH

CH

CH

CH

CH

O

C

CH

C

CH

CH

CH

OH

CO

O

CH3 CHO

C

C

C

OH OH

OCHCH2

OH

OH

benzaldehyde m ethyl salicylate ascorbic acid

C

CH3

CH3

O C

CH3

OH

OCH3

CH2CH3

Cl C Cl

F

Facetone acetic acid propane Freon 12

Classification of Hydrocarbons

HydrocarbonsHydrocarbons

Hydrocarbons: AlkanesHydrocarbons: 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 AlkanesExamples of Alkanes

Structures of AlkanesStructures of AlkanesC H

H

H

H= CH4

C C

H

H

H

C

H

H

H

H

H

=

C C

H

H

H

C

H

H

C

H

H

H

H

H

=

CH3CH2CH3

CH3CH2CH2CH3

C C

H

H

H

C

H

CH3

H

H

H

CH3 CH CH3

CH3

=

m ethane

propane

butane

isobutane

Structural IsomersStructural Isomers

Structural IsomersStructural Isomers

CycloalkanesCycloalkanes• Alkanes that form rings are called cycloalkanes

CH2

CH2

CH2

CH2

CH2

CH2

CH2CH2

CH2

CH2

CH2

CH2

CH2CH2

CH2

CH2

CH2

CH2

=

=

=

=

cyclopropane

cyclobutane

cyclopentane

cyclohexane

HaloalkanesHaloalkanes• Alkanes with halogens

Cl C Cl

F

F

Cl C Cl

Cl

F

F C C

Cl

F F

F

Cl

Freon 11Freon 11 Freon 12Freon 12 Freon 14Freon 14

ChlorofluorocarbonsChlorofluorocarbons• Insoluble in water and are unreactive

towards substances• Unreactiveness lets them reach the

stratosphere and react with the ozone layer

AlkenesAlkenes

AlkynesAlkynes• Contains a C≡C bonds

August Kekule and the August Kekule and the DreamDream

• C6H6

• "...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."

• "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."

24.3

Aromatic Hydrocarbons

C

CC

CC

C

H

H

H

H

H

H

C

CC

CC

C

H

H

H

H

H

H

Aromatic HydrocarbonsAromatic Hydrocarbons• Cyclic structures with alternating C–C

and C=C bonds

24.3

Polycyclic Aromatic Hydrocarbons

Functional GroupsFunctional 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

AlcoholsAlcohols• has the general structure R–OH

– derived from hydrocarbons and contain -OH groups

• Polar molecules and are soluble in water (Why?)

Some Common AlcoholsSome 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 AlcoholsSome Common Alcohols• Isopropyl Alcohol

– Also known as rubbing alcohol– Used as a disinfectant

• Ethylene glycol– Also known as antifreeze– Has multiple –OH groups

CH3

CHCH3

OH

C C

H

OH

H H

OH

H

AlcoholsAlcohols

Sterols, ethylene glycol

C6H12O6 (aq) 2CH3CH2OH (aq) + 2CO2 (g)enzyme

CH2 CH2 (g) + H2O (g) CH3CH2OH (g)H2SO4

Biological production of ethanol

Commercial production of ethanol

Metabolic oxidation of ethanol

CH3CH2OH CH3CHO + H2alcohol dehydrogenase

DRINKABLE vs. DENATURED Alcohol

EthersEthers• 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

EthersEthers

CH3

OCH2

CH2CH3

CH C O

CH3F

F

Cl

Clmethyl propyl ether methoxy flurane

CH3 O C CH3

CH3

CH3

methyl tert-butyl ether

Compounds with a Carbonyl Compounds with a Carbonyl GroupGroup

• Carbonyl functional group is C=O• Types of different carbonyl

compounds– Aldehydes– Ketones– Carboxylic Acids– Esters– Amides

Aldehydes and KetonesAldehydes and Ketones• Aldehydes must have at least one H

atom attached to the carbonyl group:

• Ketones must have two C atoms attached to the carbonyl group:

RCH

O

RCR'

O

Functional Group Chemistry

H C H

O

H C

O

CH3 C

O

CH3H3C

formaldehyde acetaldehyde acetone

ALMONDS, FORMALIN

Carboxylic AcidsCarboxylic Acids• Carboxylic acids contain a carbonyl

group with an -OH attached.• The carboxyl functional group is -

COOH

• Carboxylic acids are weak acids.

RCOH

O

VINEGAR, ASPIRIN, FACIAL WASH, ANTS, CITRUS FRUITS, PROTEINS, PRESERVATIVES

Common Carboxylic Common Carboxylic AcidsAcids

EstersEsters• Esters contain -COOR groups:

• Usually have fruity odors and tastes

R'COR

O

Ester Flavors and Ester Flavors and FragrancesFragrances

CH3

CH2CH2

CO

O

CH3

CH3

CH2CH2

CO

O

CH2

CH3

CH3

CO

O

CH2

CH2

CH2CH2

CH3

CH3

CO

O

C

CH

C

CH

CH

CH

OH

CO

O

CH3

m ethyl salicylate(w intergreen)

m ethyl butyrate (apple)

ethyl butyrate(pineapple)

pentyl acetate (banana)

benzyl acetate(jasm ine)

Functional Group Chemistry

Esters have the general formula R’COOR, where R is a hydrocarbon group.

CH3COOH + HOCH2CH3 CH3 C O CH2CH3 + H2O

O

ethyl acetate

Banana: isopentyl acetatePineapple: ethyl butanoateApple: methyl butanoatePear: propyl ethanoateOrange: Octyl ethanoateRaspberry: 2-Methylpropyl ethanoateOil of Wintergreen: methyl salycilate

Esters Galore!Esters Galore!    allyl caproate     pineapple

        amyl acetate         apple, banana         amyl butyrate      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         grape         geranyl acetate                 geranium         geranyl butyrate                 cherry         geranyl valerate                 apple         linalyl acetate                 lavender,sage         linalyl butyrate                 peach         linalyl formate                 apple, peach         menthyl acetate                 peppermint         methyl benzyl acetate         cherry         methyl cinnamate               strawberry         methyl phenyl acetate        honey         methyl salicylate               wintergreen         methyl anthranilate             grape,jasmine         nonyl caprylate                 orange         octyl butyrate                   parsnip         terpenyl butyrate               cherry

HOW TO MIMIC NATURE: HOW TO MIMIC NATURE: Making synthetic Making synthetic

flavoringflavoring• 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 %

AminesAmines• Organic bases• Contain carbon, hydrogen, and nitrogen

CH2

CH2CH2

CH2

CH2

NH2NH2

CH2

CH2CH2

CH2

NH2

NH2

cadaverine putresine

CH2

CH

CH2

NH

CH2

CH2

CH2

CH2

CH3

coniine

C

CH

CH

CH

CH

CH

CH2

CHNH

CH3

CH3

m etham phetam ine

AmidesAmides• composites of carbonyl and amine functionalities• proteins

RCN

O

R'

H

Name the functional Name the functional groupgroup

C

CH

CH

CH

CH

CH

CH

O

C

CH

C

CH

CH

CH

OH

CO

O

CH3 CHO

C

C

C

OH OH

OCHCH2

OH

OH

benzaldehyde m ethyl salicylate ascorbic acid

C

CH3

CH3

O C

CH3

OH

OCH3

CH2CH3

Cl C Cl

F

Facetone acetic acid propane Freon 12

Compounds with multiple Compounds with multiple functional groupsfunctional groups

CCCH

CCH2

O

ONHCH2

OH

OH

CH2

CH3

CH3

OH CCCH

CCH2

O

ONHCH2

OH

OH

CH2

CH3

CH3

OH CCCH

CCH2

O

ONHCH2

OH

OH

CH2

CH3

CH3

OH CCCH

CCH2

O

ONHCH2

OH

OH

CH2

CH3

CH3

OH

Vitamin B5

Pantothenic acid

MangMangoo

Would you eat this?Would you eat this?-Terpinolene, Ethyl butanoate, 3-Carene, Ethyl

acetate, Ethyl 2-butenoate, -Terpinene, -Thujene, Dimethyl sulfide, Limonene, -Phellandrene, Myrcene, p-Cymen-8-ol, -Caryophyllene, cis-3-Hexene-1-ol, hexadecyl acetate, 5-Butyldihydro-3H-2-furanone, trans-2-hexenal, Ethyl tetradeconaoate, -Humulene, sabinene, 2-Carene, Camphene, Ethyl octanoate, 4-Isopropenyl-1-methylbenzene 1-Hexanol, -terpinene, hexanal, Ethyl hexadecanoate, -Copaene, Hexadecanal, Ethanol, Ethyl propionate, Dihydro-5-hexyl-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, 4-Methylacetophenoen, Acetaldehyde, Cyclohexane

FOSSIL FUELSFOSSIL FUELS• Coal, Petroleum, Natural Gas• From decayed organic matter• Makes up 90% of energy used

CoalCoal• Main element is carbon, but contains

small% of other elements• Complete combustion:

– C(s) + O2(g) CO2(g)• Limited supply, strip mining

Natural GasNatural 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 SpillThe Guimaras Oil Spill

Gasoline: C5-C12 alkanesGasoline: 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

DieselDiesel• 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

POLYMERSPOLYMERS• Poly: Many Meros: Parts• Made up of repeating monomers

• Copolymer is a polymer made up of two or more monomers

• Common biopolymers: Proteins, DNA, RNA, starch, cellulose

( CH CH2 CH2 CH CH CH2 )n

Some commercial Some commercial polymerspolymers

• 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: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)