22.4 – Functional Groups Organic compounds can be classified with respect to their functional groups. Functional groups: structural features comprised of specific arrangements of atoms.

Note: R is used to indicate carbon chains of any length.

Naming Halo-Hydrocarbons Halo-hydrocarbons contain –F, –Cl, –Br, and/or –I as substituents. Use the prefixes fluoro-, chloro-, bromo-, iodo- to represent these substituents. Indicate position with the number of the carbon it is attached to.

Name the following: Example: Parent name? pentane 2-bromo-5,5-dichloro-1,1-difluoro-3-iodo Substituents?

Naming Alcohols Alcohols contain an –OH group. Alcohols can be primary (1°), secondary (2°), or tertiary (3°) depending on whether the carbon attached to the –OH is attached to 1, 2, or 3 other carbons. To name alcohols use the name of the parent alkane, drop the “e” and add “-ol” at the end. Specify the position of the –OH group with the smallest number possible.

Name the following: Example: 2-butanol chloro-1-propanol bromo-2-methyl-2-pentanol Secondary alcohol Primary alcohol Tertiary alcohol

Naming Aldehydes Aldehydes contain a carbonyl group C=O. This functional group will always be at the end of the chain and therefore there is no need to indicate the position of the functional group. To name aldehydes use the name of the parent alkane, drop “e” and add “-al” at the end.

Name the following: Example: butanal4-iodohexanal

Naming Ketones Ketones also contain a carbonyl group C=O. However, they have R groups on both sides of the carbon. To name ketones use the name of the parent alkane, drop “e” and add “-one” at the end. Where the carbonyl group on the chain is indicated with a number. Alternatively, each R group can be named as if it were a substituent and listed alphabetically followed by the word “ketone.” If the two R groups are identical, use the prefix “di.”

Name the following: Example: 2-butanone (ethylmethylketone) 3-pentanone (diethylketone)

Naming Ethers Ethers contain an –O– single bonded to an R group on either side. To name ethers, name each R group as a substituent and list them alphabetically followed by the word “ether.” If two R groups are identical use the prefix “di.”

Name the following: Example: dipropyl ether methylpentylether

Naming Carboxylic Acids Carboxylic acids contain a carbon double bonded to an oxygen and single bonded to an –OH. This functional group will always be at the end of the chain and therefore,there is no need to indicate the position of the functional group. These are also known as organic acids and will always be weak acids. To name carboxylic acids use the name of the parent alkane, drop the “e” and add “-oic acid” at the end.

Name the following: Example: butanoic acid 7,9-dichlorodecanoic acid

Naming Esters Esters contain a C double bonded to an O and single bonded to another O with R groups on either side. To name esters, treat the R group attached to the O as a substituent (with the –yl ending). Use the name of the parent alkane for the R group attached to the =O, 'drop the “e” and add “-oate”. So the name will be “____yl ____oate”

Name the following: Example: ethylbutanoate methylethanoate