Derivatives of Hydrocarbons A functional group is a reactive portion of a molecule that undergoes predictable reactions. All other organic compounds can be considered as derivatives of hydrocarbons (i.e., they are derived from hydrocarbons). Organic Compounds Containing Oxygen Many of the important functional groups contain oxygen. Alcohols An alcohol is a compound obtained by substituting a hydoxyl group ( OH) for an H atom on a carbon atom of a hydrocarbon group. General formula: the OH is attached to a C with at most other C attached to it. e.g., methyl alcohol (aka methanol) or ethanol OR ethyl alcohol or 1-butanol OR 1-butyl alcohol the OH is attached to a C with other C attached to it. e.g. 2-propanol OR isopropanol OR isopropyl alcohol e.g. 2-butanol OR 2 butyl alcohol 21-13
the OH is attached to a C with other C attached to it. e.g. 2 methyl 2 propanol OR tertiary butyl alcohol OR t-butyl alcohol Ethers An ether is a compound with an oxygen bridge between two alkyl groups. General formula: An example is: CH3 CH2 O CH2 CH2 CH3 CH3 CH2 O CH2 CH3 This is the most common ether, often called simply It can be used as an Aldehydes An aldehyde is a compound containing a carbonyl group with at least one H atom attached to it. General formula: A carbonyl group looks like: Examples are: ethanal a.k.a. acetaldehyde methanal a.k.a. Formaldehyde is used in the manufacture of plastics and resins. Formaldehyde is actually a gas, which is very soluble in water. An aqueous solution of 35% formaldehyde is sold as Formalin for use in disinfection and the preservation of biological specimens. 21-14
Aldehydes can also be derived from aromatic hydrocarbons. At low molecular weights, aldehydes have sharp, penetrating odors (e.g. formaldehyde). At higher molecular weights, they become more fragrant. Ketones A ketone is a compound containing a carbonyl group with two hydrocarbon groups. General Formula: Examples are: dimethyl ketone 2-butanone Carboxylic Acids A carboxylic acid is a compound containing the carboxyl group, COOH. General Formula: An Example is: ethanoic acid 21-15
The following table lists some common carboxylic acids Esters An ester is a compound formed from a carboxylic acid, RCOOH, and an alcohol, R OH. General Formula for an ester: For example: acetone acetic acid This is an example of a reaction. Another example reaction: Acetylsalicylic acid is 21-16
A condensation polymer is a polymer formed by linking together many molecules through condensation reactions. Dacron is formed by: A water molecule is formed for every connection made. Organic Compounds Containing Nitrogen Amines Most organic bases are amines. Amines are compounds that are structurally derived by replacing one of the H atoms on ammonia with hydrocarbon groups. The general formulas are: These are all bases because the nitrogen atom has a lone pair of electrons with which to act as a Just like We can replace the ammonia with an amine. 21-17
Amides Amides are compounds derived from the reaction of ammonia, a primary, or a secondary amine with a carboxylic acid. General formulas are: primary amide secondary amide tertiary amide A sample formation reaction is: Also: ammonia acetic acid 21-18
Polyamides When a compound containing two amine groups reacts with a compound containing two carboxalic acid groups, a condensation polymer called a polyamide is formed. Nylon 66 is an example of a polyamide. Amine: hexamethylene diamene (a.k.a. 1,6-diaminohexane) Carboxylic acid: adipic acid (a.k.a. hexanoic acid) Vinyl Polymers Many simple alkenes, called vinyl monomers, undergo polymerization reactions. Typical Lengths: a few hundred to many thousand units. 21-19
Formation Reaction The process requires an initiator (In ) (This is known as a free radical.) In first adds to the double bond yielding a reactive intermediate. The intermediate then adds to a second alkene molecule. This reaction can then happen multiple times until the chain is terminated.. 21-20
Summary of Common Functional Groups 21-21