functional groups
Common Functionality
It is important to be able to identify functional groups in organic molecules since they are the entities that have function and undergo chemical change. There are around 15 important functions that must be memorized over the two semesters, many of them being used later in Biochemistry and Polymer Chemistry. Examples of groups from the first semester are given below and both semesters are summarized in the video.
Alkyl Halides
Alkyl halides, in which sp3 carbon is bonded to fluorine, chlorine, bromine, or iodine are generally quite dangerous compounds to work with, however they find many uses in organic synthesis and polymer chemistry. Simple alkyl halides are used in substitution and elimination reactions, in which the polarized C-X bond makes them electrophilic, and the halogen serves as a leaving group. Alkyl halide polymers include polyvinyl chloride (PVC) used in house siding and plumbing pipes, as well as the perfluorinated teflon that is used as a non-stick coating on cooking equipment and water-sealed plumbing tape. An example of a simple alkyl halide is shown here.
1-Chlorobutane (1o alkyl halide)
Alkenes
Alkenes are organic molecules with a double bond betwen two adjacent carbons. They will be trigonal planar in shape around the functional group and serve as important nucleophiles in organic synthesis. They are typically made by elimination reactions in the first semester, and then by methods such as the Wittig reaction later on. The substitution pattern of the alkene plays a role in its stability and reactivity, with more attached alkyl groups stabilizing the alkene carbons through electron donation. Examples of simple alkenes are given below.
Cyclohexene (disubstituted)
Alkynes
Alkynes are unsaturated organic molecules with a triple bond betwen two adjacent carbons. The sp hybrid carbons make attached protons on terminal alkynes slightly acidic, and the linear shape makes them suitable for directing attached groups into opposite directions in space. Alkynes are typically produced by sequential elimination reactions from dihalides. Examples of simple alkynes are given below.
2-Pentyne (internal)
Di-t-butylacetylene (internal)
Cyclononyne (internal)
1-Hexyne (terminal)
Alcohols
Alkynes are unsaturated organic molecules with a triple bond betwen two adjacent carbons. The sp hybrid carbons make attached protons on terminal alkynes slightly acidic, and the linear shape makes them suitable for directing attached groups into opposite directions in space. Alkynes are typically produced by sequential elimination reactions from dihalides. Examples of simple alkynes are given below.
1-Octanol (primary)
Isopropanol (secondary)
Glycerol (primary & secondary)
Cyclopentanol (secondary)
Ethers
Alkynes are unsaturated organic molecules with a triple bond betwen two adjacent carbons. The sp hybrid carbons make attached protons on terminal alkynes slightly acidic, and the linear shape makes them suitable for directing attached groups into opposite directions in space. Alkynes are typically produced by sequential elimination reactions from dihalides. Examples of simple alkynes are given below.
Tetrahydrofuran
Methylphenyl ether
Furan
Diethyl ether