organic compounds - compounds that contain carbon atoms

hydrocarbons - the simplest organic compounds, can be divided into four groups

Division of Hydrocarbons

• Hydrocarbons - aliphatic and aromatic

• Aliphatic - saturated and unsaturated

• Saturated aliphatic-alkanes

• Unsaturated aliphatic - alkenes, alkynes

Hydrocarbon Bonding

• four valence electrons allow four other atoms to bond with carbon

• alkanes - compounds that have only single bonds between the carbon atoms

• alkenes and alkynes - compounds that have double or triple bonds between the carbon atoms

• aromatic - carbon compounds in a ring structure

Nomenclature

• stem that is used for all aliphatic compounds, different endings that indicate if the compound is an alkane, alkene, or alkyne

Two things to determine when naming an organic compound

1. the number of carbon atoms in the compound

2. the family the compound belongs to

Rules for Naming ALKANES

1. select the longest continuous chain in the molecule and count the number of carbon atoms to determine the stem

2. Consider every branch of the main chain to be a substituent derived from another hydrocarbon. For each group that is a substituent, take the stem and add “yl” (ex. methyl, ethyl)

3. Number the carbon atoms so that the substituents have the lowest possible number

4. Name each substituent by finding the number of the carbon atoms it is attached to and using the name from step two

5. Separate numbers using commas and letters using dashes

6. Arrange substituents alphabetically

Rules for Naming ALKENES and ALKYNES

1. Identify the longest continuous carbon chain that contains the double or triple bond.

2. Number the carbon atoms in the chain, starting from the end closest to the double or triple bond.

3. Determine the position of the double or triple bond by assigning the lowest possible numbers to the carbon atoms involved.

4. Use the appropriate prefix to indicate the number of double or triple bonds: "ene" for alkenes and "yne" for alkynes.

5. Indicate the position of the double or triple bond by using the corresponding number before the prefix.

6. If there are multiple double or triple bonds, use the prefixes "di-" (two), "tri-" (three), etc.

7. Include the names of any substituents attached to the carbon chain, using appropriate prefixes.

8. Separate numbers and prefixes with hyphens and separate multiple numbers with commas.

9. If there are different substituents, list them in alphabetical order.

10. Use commas to separate numbers and dashes to separate numbers from letters.

Example: 2-butyne

Halogen Attachment

• Halogen attachments (F, Br, Cl, I) are very simple to include; they’re treated just as any other substituent

• ending of their name is dropped and an “o” is added

  • Ex. Br becomes “bromo”

Isomers and the Use of “n” and “iso” Prefixes

Isomers are compounds that have the same molecular formula, but different structural formulas

• the term “normal” is used to describe any STRAIGHT chain hydrocarbon above propane

  • abbreviation is the letter “n”

    • ex. n-butane, n-octane, n-decane

• the term “iso” is used on a straight-chain alkane with a hydrogen atom replaced by a methyl group on the SECOND carbon

  • ex. isopentane, isobutane, isohexane

Cycloalkanes and Aromatic Compounds

In many hydrocarbons, the ends of the carbon chain bend around to form a chain

• cyclic hydrocarbon - compounds that contain ring structures

• aliphatic compounds - hydrocarbon does NOT contain a ring structure

Two main types of ring structures: cycloalkanes and aromatic compounds

Cycloalkanes

• cycloalkanes are saturated ring compounds

• carbon to carbon bonds are all single bonds, alkanes

• their general molecular formula is the same for alkanes, CnH2n

• naming rules are similar to rules for alkanes

Aromatic Compounds

• aromatic compounds contain single or multiple rings

• the simplest aromatic compound is benzene, C6H6

  • this molecule is a six-carbon chain, each with one hydrogen atom attached to it

  • this leaves one electron from each carbon atom free to bond and form a double bond

Naming Aromatic Rings

• To name a compound attached to a benzene ring, follow similar rules to naming aliphatic compounds

• If there's only one attachment, the name is the same as if it were attached to an alkane, and there's no need for numbering

• If there are two attachments, number the compound, starting with the first attachment as one, and ensuring that the substituents have the lowest numbers

• The numbers can be placed to the right or left of the benzene ring, with only three possible combinations

• These combinations can be identified by numbers or prefixes.

• When two benzene rings are joined together, the name is naphthalene, three rings is anthracene

• if the benzene rings is attached to an aliphatic, the benzene radical is called “phenyl”

  • can be named as a benzene ring compound or aliphatic compound

Functional Groups

Functional Groups are structural fragments, or pieces, of different chemical compositions that are responsible for:

1. The classification of different substances into families, such as aliphatic and aromatic compounds

2. The reactivity of the family for chemical reactions

Examples of functional groups: alkanes, alkenes, alkynes, aromatic, cycloalkanes

• label the base chain of carbon atoms as R and R’

• R and R’ stand for any length of carbon atoms

  • alkyne: R-C-R’ or R-C-C-R’

Other Functional Groups

• Alcohols - hydroxyl group -OH attached, R-OH

• Ethers - two chains of carbon with an oxygen atom in the middle joining the atoms together R-O-R’

• Organic acids - the carboxyl group and often called carboxylic acids

• Esters - similar to organic acids but have a hydrocarbon group in place of the OH’s hydrogen atom on the carboxyl group

• Aldehydes - related to esters by having the O-R’=H atom

• Ketones - related to esters by having the O-R’ replaced with a R’

• Amines - based on ammonia where one or more of the hydrogen is replaced with an organic group

• Halocarbons - carbon chains that contain halogen atoms

Organic Compound - Functional Group Families