Organic Chemistry Essentials

• Chemistry of carbon compounds

• Carbon can form 4 covalent bonds with other atoms. This allows it to make millions of different compounds.

• Carbon can form single, double, and triple bonds.

Hydrocarbon

• compound containing only hydrogen and carbon

• Ex. CH4 C2H6

Hydrocarbon derivative

• compound with some hydrogen atoms replaced by other elements (O, N, F, Cl, Br, I)

• ex. CH3Br

Straight chained hydrocarbon

Ex. CH3CH2CH2CH2CH2CH3

or C6H14

Branched hydrocarbon

CH3

CH3CH2CHCH2CH3

or C6H14

Saturated hydrocarbon

• no double or triple bonds

Unsaturated hydrocarbon

• contains double and/or triple bonds

• not “saturated” with hydrogen

Structural formulas

Condensed Structural formulas

CH3-CH3

Alkanes

• hydrocarbons with only single bonds

• General formula: CnH2n+2

• names end in -ane

• boiling pt. increases with # of carbons

Name # carbons Structural Formula

Methane 1 CH4

Ethane 2 CH3CH3

Propane 3 CH3CH2CH3

Butane 4 CH3CH2CH2CH3

Pentane 5 CH3CH2CH2CH2CH3

IUPAC Names

Name # carbons Structural Formula

Hexane 6 CH3CH2CH2CH2CH2CH3

Heptane 7 CH3CH2CH2CH2CH2CH2CH3

Octane 8 CH3CH2CH2CH2CH2CH2CH2CH3

Nonane 9 CH3 CH2 CH2CH2CH2CH2CH2CH2CH3

Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

Alkenes

• contain at least one double bond

• name ends in -ene

• general formula: CnH2n

Alkynes

• contain at least one triple bond

• name ends in -yne

• general formula: CnH2n-2

Nomenclature

• naming system

• IUPAC (International Union of Pure and Applied Chemistry)

Rules for naming alkanes

1. Name the longest carbon chain in the structure. If the chain is cyclic, include the prefix cyclo.

2. Name, in alphabetical order, the kinds of groups which are attached to the chain you named in step 1. Use the appropriate prefix, such as di-, tri-, tetra-, etc., to indicate how many of each group are present.

3. Number the carbon atoms in the longest chain consecutively from the end of the chain which allows the attached groups to have the lowest numbers possible. Assign to each group you named in step 2 the number(s) indicating its position(s) on the main chain.

Rules for naming alkenes and alkynes

1. Name the longest carbon chain containing the carbon-carbon double or triple bond. The name of the longest chain ends in –ene for an alkene; in –yne for an alkyne. The position of the double or triple bond in the carbon chain is indicated by a number before the name of the chain.

2. Name the groups attached as in alkanes.

3. When assigning numbers to atoms in the chain, start numbering from the end of the chain closest to the double or triple bond.

Naming branched chain alkanes

• substituent- atom or group of atoms that takes the place of hydrogen on a hydrocarbon molecule

• ex. C, O, N, S, P, Cl, F, I, Br

Alkyl Group

• hydrocarbon substituent

• alkane with one H removed

• drop the -ane ending and add -yl H

H C CH3 methyl H H H H C C CH3CH2 ethyl H H

Name the following:

3,3-diethylhexane

4-ethyl-4,6-dimethyl-5-propylnonane

6-ethyl-4,5-dipropylnonane

Draw the following:

2,2,4-trimethylpentane

Draw the following:

3-ethyl-2-hexene

Draw the following:

4-bromo-2,2-dichloro-3,5-diethyl-6-fluorooctane

Properties of Hydrocarbons

• nonpolar

• not attracted to water

Structural Isomers

• compounds that have the same molecular formula but different molecular structures.

• physical and chemical properties differ

Butane 2-methylpropane or isobutane

CH3-CH2-CH2-CH3 CH3

CH3-CH-CH3

Geometric Isomers

• Each of the carbons of the double bond must have at least one substituent.

• Ex. CH3CH=CHCH3 has 2 geometric isomers because the double bond is not free to rotate. Bond angle (sp2) is 120o.

cis-2-butene trans-2-butene

Stereoisomers

• Stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in space is different in each isomer.

• The two main types of stereoisomerism are:

• cis-trans isomerism

• optical isomerism

Optical isomerism is a form of isomerism where the two different isomers are the same in every way except being non-superimposable mirror images of each other. Optical isomers are known as chiral molecules.A compound is chiral when it cannot be superimposed on its mirror image. The pair of mirror imaged non-superimposable compounds are known as enantiomers. Even though very similar still, different enantiomers of the same chiral drug can have very different pharmological effects, mainly because the proteins they bind to are also chiral.

The two enantiomers of bromochlorofluoromethane

4 different groups attached to the carbon

Cyclic hydrocarbons

• compounds that contain a hydrocarbon ring

• general formula is: CnH2n

Cyclopropane Cyclobutane

Aliphatic compounds

• hydrocarbon compounds which do not contain rings

Arenes

• unsaturated cyclic hydrocarbons

• Benzene, C6H6, is an arene.

• Benzene is a flat molecule with resonance.

Shorthand ways to draw benzene:

Aromatic compound

• any substance in which the bonding is like benzene

• A benzene ring used as a substituent on a hydrocarbon chain is called a phenyl group.

• Ex.

methylbenzene

(toluene)

Nomenclature:

Natural gas- 80% methane, 10% ethane,

4% propane, 2 % butane

Petroleum = complex mixture of hydrocarbons

Cracking= a controlled process by which hydrocarbons are broken down or rearranged into smaller, more useful molecules

Functional Group

• Chemically reactive part of an organic molecule

• Learn these functional groups

• R means the rest of the molecule (usually hydrocarbon

The Common Functional Groups

Class General Formula

Halohydrocarbons RX Alcohols ROH

Ethers ROR Aldehydes CR

OH

The Common Functional Groups

Class General Formula

Ketones

Carboxylic Acids

Esters

Amines RNH2

CRO

R'

CRO

OH

CRO

O R'

Halocarbons

• Organic compounds containing F,Cl, Br, or I• Halogen groups are named as substituents

just as alkyl groups are.

Cl I I

Cl-C-Cl CH3-CH-CH-CH3

H

Cl-CH2-CH3CH3chloromethane Trichloromethane (chloroform)

2,3-diiodobutane

1-chloropropane

bromobenzene

Alcohols

Methanol

Methyl alcohol

“wood alcohol”

Ethanol

Ethyl alcohol

“drinking alcohol”

Organic compounds with a hydroxyl group (-OH)

Naming: drop “e”, add “-ol”

propanol

propyl alcohol

n-propanol

1-propanol

2-propanol

isopropanol

isopropyl alcohol

“rubbing alcohol”

Alcohols can be classified as primary, secondary or tertiary.

antifreeze

Glycerine

1,2,3-propantriol

Phenol

Properties of Alcohols• Hydrogen bonding• Short-chained alcohols are soluble in water

Fermentation- production of ethanol from sugars by the action of yeast or bacteria

C6H12O6 2CH3CH2OH + 2CO2

Denatured Alcohol- ethanol with an added substance to make it toxic

Ethers• Compounds in which oxygen is bonded to two

carbon groups• R-O-R’• Name the R groups in alphabetical order and add

the word ether.

ethyl methyl etherdimethyl ether

ethyl phenyl ether

diethyl ether1st reliable general anesthetic, 1842

Aldehydes

• Organic compounds in which the carbon of the carbonyl group ( C=O ) is always joined to at least one H.

• Naming: drop “e”, add “-al”, carbonyl carbon is #1

methanal

(formaldehyde)

CH3 H

CH3CH2CHCH2C=O

3-methylpentanal

ethanal

Ketones• Organic compounds in which the carbon of the

carbonyl group is joined to 2 other carbons. The carbonyl group is in the middle of the chain instead of the end of a chain as in an aldehyde.

• Naming: drop “e”, and “one”. If carbonyl can be in more than one position, give it a #

Propanone

(acetone)

3-hexanone

Naming: drop “e”, add “oic acid”

The carboxyl carbon is always #1.

methanoic acid

“formic acid”propanoic Acid

“propionic acid”

butanoic acid

Esters

• Derivatives of carboxylic acids in which the –OH of the carboxyl group has been replaced

by an –OR from an alcohol• Formed by combination of a carboxylic acid

with an alcohol in a dehydration reaction• Often common flavors and odorsNaming: Name alkyl group, then acid with –ate

ending

methyl ethanoate

or methyl acetate

methyl methanoate

or methyl formate

ethyl ethanoate or ethyl acetate

(apple scent)

Amines-NH2

• the suffix amine is added to the alkyl substituent

• can also be named as an amino group

ethylamine

cyclohexylamine

3-aminopropanoic acid

POLYMERS

• made of repeating units called monomers