Organic Chemistry Notes



Organic Chemistry Notes

I. Organic Chemistry

A. The study of carbon and its compounds.

B. Carbon is special because it has four electrons in its outside energy level. This makes it hard for carbon to gain or lose four electrons to get a full outside energy level. Instead, carbon shares its electrons forming covalent bonds. These covalent bonds are stronger than normal because carbon is small and its nucleus is close to the shared electrons creating a strong force of attraction.

C. Carbon has several allotropes. An allotrope is a form of an element that has an arrangement different from other forms of the same element. Graphite is very soft, pencil lead. Diamonds are the hardest substance known to man.

II. Hydrocarbons

A. Compounds composed of only carbon and hydrogen.

B. The structural formula shows how elements bond to form a compound. Structural formulas are used in organic chemistry because several different compounds may have the same molecular formula. Isomers are compounds that have the same molecular formula but have different structural formulas.

C4H8

l l

- C—C-

l l l l l l

- C—C- - C—C—C=C -

l l l l

C. Alkanes

1. Saturated, each carbon is bonded to four other atoms. Only single bonds found between the carbon atoms.

2. General formula Cn H2n+2 C6H14

3. Alkanes are named by using a prefix based on number of carbon atoms in the main chain (longest chain of carbons without back-tracking on a connecting line) and then adding the suffix “ane.”

Meth 1 Carbon Atom

Eth 2 Carbon Atoms

Prop 3 Carbon Atoms

But 4 Carbon Atoms

Pent 5 Carbon Atoms

Hex 6 Carbon Atoms

Hept 7 Carbon Atoms

Oct 8 Carbon Atoms

Non 9 Carbon Atoms

Dec 10 Carbon Atoms

l l l l

-C—C—C—C- Butane

l l l l

l l l l l l

-C—C—C—C—C—C- Hexane

l l l l l l

l l l l l l l l

-C—C—C—C—C—C—C—C- Octane

l l l l l l l l

4. In many cases you may have carbon atom(s) that are not part of the main chain. Name the group, based on the number of carbon atoms present, using the preceding chart. Use a “yl” ending to identify it as a group.

l l l l

-C—C—C—C- 2 Methyl Butane

l l l l

-C-

l

l

-C-

l l l l l l l

-C—C—C—C—C—C—C- 3 Methyl, 4 Ethyl Heptane

l l l l l l l

-C-

l

-C-

l

D. Alkenes

1. Unsaturated hydrocarbons, they contain a double bond in the main chain.

2. General formula Cn H2n C3H6

3. To name alkenes, determine the number of carbon atoms in the main chain and use the appropriate prefix. Use the suffix “ene” to indicate the compound is an alkene. Write the number of the lowest carbon atom in the main chain that the double bond is attached to before the name of the alkene. Double bonds take priority over carbon groups in numbering carbons in the main chain.

l l l l

-C—C—C==C- 1 – Butene

l l

l

-C-

l l l l l l

-C—C==C—C—C—C- 4 Methyl 2-Hexene

l l l l

E. Alkynes

1. Unsaturated hydrocarbons, they contain a triple bond in the main chain.

2. General formula Cn H2n - 2 C7H12

3. To name alkynes, determine the number of carbon atoms in the main chain and use the appropriate prefix. Use the suffix “yne” to indicate the compound is an alkyne. Write the number of the lowest carbon atom in the main chain that the triple bond is attached to before the name of the alkyne. Triple bonds take priority over carbon groups in numbering carbons in the main chain.

l l

-C—C—C=C- 1 – Butyne

l l

l l

-C- -C-

l l l l

-C—C=C—C—C—C- 4,5 Dimethyl 2-Hexyne

l l l l

F. Cycloalkanes

1. Saturated hydrocarbons arranged in a ring.

2. Name the compound based on the number of carbons in the ring and add the suffix “ane.” Write the prefix “cyclo” in front of the compound name.

l l l

-C—C—C-

l l Cyclohexane

-C—C—C-

l l l

l l

-C—C- Cyclobutane

l l

-C—C-

l l

G. Aromatic Hydrocarbons

1. Compounds with distinctive odors.

2. Used in plastics, solvents, paints, and explosives.

3. All aromatics contain the benzene ring.

l

-C==C—C-

l ll

-C==C—C-

l

Read in Prentice Hall Chemistry pages 693 through 717.

H. Halocarbons

1. Compounds where a halogen (F, Cl, Br, I) is substituted for hydrogen.

2. Halogens usually increase the reactivity of the compound.

3. Halogens are treated like a carbon group in naming the compound. Give the number of the carbon in the main chain the halogen is attached to. Drop the “ine” at the end of the halogen name and add “o.”

l l 1 l l

-C—C—C—C—C- 2 Bromo Pentane

l l l l l

Br

l l l l l l

-C—C—C—C==C—C- 1 Fluoro, 5 Chloro, 2-Hexene

l l l l

Cl F

III. Functional Groups

A. Alcohols

1. Used as an organic solvent, antiseptic, and beverage.

2. General formula ROH R is a symbol for a hydrocarbon.

3. The hydroxyl group (OH) attached to the benzene ring is phenol, the standard in bacterial control.

4. To name an alcohol, name the hydrocarbon, drop the “e” and add the suffix “ol.” Write the number of the carbon the OH is attached to in front of the compound name.

l l l l

-C—C—C—C—OH 1 Butanol

l l l l

5. Diols have two OH groups in the compound. Triols are alcohols with three OH groups.

l l

-C------C- 1,2 Ethanediol (Ethylene Glycol)

l l

OH OH

l l l

-C--------C--------C- 1,2,3 Propanetriol (Glycerol)

l l l

OH OH OH

B. Aldehydes

1. Aldehydes are used as solvents (formaldehyde), fragrances, flavorings (cinnamon, vanilla), and many sugars are aldehydes.

2. General formula R—C—H

ll

O

3. To name aldehydes, name the hydrocarbon, drop the “e,” and add the suffix “al.”

l l l

-C—C—C—C—H Butanal

l l l ll

O

C. Ketones

1. Ketones are used as solvents (acetone), fragances, flavorings, and many sugars are ketones.

2. General formula R—C—R’

ll

O

3. To name a ketone, count the number of carbons in the chain and name the alkane with that number of carbons. Drop the “e” at the end of the alkane and add the suffix “one.” Write the number of the carbon where the oxygen is double bonded.

l l l l

-C—C—C—C—C- 2 – Pentanone

l l l ll

O

D. Ethers

1. Ethers are used as solvents, starting fluid, and were used as anesthetics for surgery.

2. General formula R—O—R’

3. To name an ether, identify the smaller hydrocarbon and write the prefix for the number of carbons present and add the “oxy” ending. Next, name the larger hydrocarbon.

l l l l l

-C—C—O—C—C—C- Ethoxypropane

l l l l l

E. Organic Acids

1. Weak acids, found in foods with a sour taste.

2. General formula R—C—OH

ll

O

3. To name organic acids, count the number of carbons present and identify the alkane with the same number of carbons. Drop the “e” from the alkane name and add the suffix “oic” and the word acid.

O

l l l ll

-C—C—C—C—OH Butanoic Acid

l l l

F. Esters

1. Used as flavorings and fragrances (pineapple, apple, orange).

2. General formula R—C—O—R’

ll

O

3. Esters are the combination of an organic acid and an alcohol.

4. To name an ester, name the alcohol and drop its normal ending and add the suffix “yl.” Name the organic acid and change the “oic” to “oate.”

l l l l

-C—C—C—O—C—C- Ethyl Propanoate

l l ll l l

O

G. Amines

1. Amines are found in amino acids, DNA, vitamins, and in addictive compounds like nicotine, cocaine, amphetamines.

2. General formula R—NH2

3. To name an amine, name the hydrocarbon and drop the “e.” Add the suffix amine.

H

l l l l l

-C—C—C—C—N—H Butanamine

l l l l

Read in Prentice Hall Chemistry pages 725 to 755.

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