Functional Groups in Organic Compounds:
We have seen that alkanes, alkenes and alkynes are defined by the type of carbon-carbon bonds present in them.
We can distinguish classes of organic molecules by "functional groups", which largely determine how they react with other compounds and some general properties
functional group - a specific arrangement of atoms in an organic compound that is capable of characteristic chemical reactions.
The carbon-carbon double bond is the functional group defines an alkene
The carbon-carbon triple bond is the functional group that defines an alkyne
If we move away from pure hydrocarbons, there are many more functional groups common to organic chemistry
Note: -R is commonly used to represent a general alkyl substituent (e.g. methyl, ethyl, propyl, etc...)
1. Alcohols - contains the OH group (frequently used as antiseptics), general structure R-OH
General formula: . For example with ethanol R = CH3CH2-
2. Ethers: General structure R-O-R'
Name alkyl groups on both sides in alphabetical order - follow with ether
There are many more: Here is a list of some additional functional groups, you should know the functional group characteristic of each type of organic compound and be able to recognize by the name of an organic compound (just look at the ending suffix) what group it belongs to.
Again, remember, functional groups play a major role in determining the physical and especially the chemical properties of organic molecules.
Demo: Salicylic acid (aspirin) to oil of wintergreen:
Some examples of different fragrances mainly esters:
Let's look again at the ingredients list for the mango. You should be able to recognize molecules from many of the above classes.
a-Terpinolene, Ethyl butanoate, 3-Carene, Ethyl acetate, Ethyl 2-butenoate, a-Terpinene, a-Thujene, Dimethyl sulfide, Limonene, b-Phellandrene, Myrcene, p-Cymen-8-ol, b-Caryophyllene, cis-3-Hexene-1-ol, hexadecyl acetate, 5-Butyldihydro-3H-2-furanone, trans-2-hexenal, Ethyl tetradeconaoate, a-Humulene, Ssabinene, 2-Carene, Camphene, Ethyl octanoate, 4-Isopropenyl-1-methylbenzene 1-Hexanol, g-terpinene, hexanal, Ethyl hexadecanoate, a-Copaene, Hexadecanal, Ethanol, Ethyl propionate, Dihydro-5-hexyl-3H-2-furanone, Carveol, Geranial, Ethyl decanoate, Furfural, Butyl acetate, Methyl butanoate, 2,3, Pentanedione, 1,1, diethoxyethane, pentadecanal, Butyl formate, 1-Butanol, 5-Methylfurfural, Ethyl dodecanoate, 2-Acetylfuran, 2 Methyl-1-butanol, 4-Methylacetophenoen, Acetaldehyde, Cyclohexane
Many organic compounds belong to more than one class:
amino acids - contain a carboxylic acid functionality and an amine functionality. Amino acids are used by the body to make proteins. Below is a structural formula for glycine, the simplest amino acid.
Simple sugars such as glucose are polyhydroxyaldehydes. The hydroxy indicates the OH group of the alcohol. Below is a structural formula for glucose.