Functional Groups Common Organic Chemicals

Methanol †CH 3 OH Wood alcohol. Indirectly poisonous; ingestion of 50 ml usually fatal

Ethanol † C 2 H 5 OH Alcohol, the socially acceptable intoxicating beverage. Acts as a depressant through interaction with chemicals in the brain responsible for transmission of information

Formaldehyde † CH 2 O Contains C=O group. The simplest aldehyde. Pungent colorless gas, used in solution as a preservative, formalin Contains C=O group. The simplest aldehyde. Pungent colorless gas, used in solution as a preservative, formalin

Acetaldehyde † C 2 H 4 O Pungent liquid, which is the primary metabolic product of alcohol during the process of becoming acetic acid; responsible for hangovers

Formic Acid † CH 2 O 2 The simplest carboxylic acid. Prime constituent of the venom produced by ants

Acetic acid † C 2 H 4 O 2 Colorless liquid with sharp odor; is the acid component of vinegar. Produced by oxidation of ethanol

Lactic Acid † C 3 H 6 O 3 Contains both –OH and -CO 2 H groups. Widespread in nature, produced by anaerobic fermentation of sugars, and the action of enzymes on glucose. Build-up in muscles during intense physical activity.

Glycerol † C 3 H 8 O 3 Propane with three – OH groups. Masses of H-bonds makes for a very viscous liquid. Several applications in cosmetics and foods. Foundation for a group of molecules called triglycerides.

Stearic Acid † C 18 H 36 O 2 A typical fatty acid: long hydrocarbon portion with a carboxylic acid group. Long chain allows for variety of secondary structure

Tristearin † C 57 H 110 O 6 A triglyceride – three fatty acid molecules condensed with one glycerol molecule. There are no H atoms attached to O atoms and hence no H-bonds. Hence fats do not dissolve in water. Important because they will not be washed out of the body.

Butanoic Acid † C 4 H 8 O 2 Fats and oils in cow’s milk have triglycerides made from short-chain acids like butanoic acid. This makes butter soft rather than waxy.

Butanedione † C 4 H 6 O 2 A double ketone (contains two C=O groups). Ketones are responsible for many flavours and smells. This one is cheese-like. Also contributes to the smell of perspiration.

Oxalic Acid † C 2 H 2 O 4 Oxalic acid occurs in many leafy green plants

Citric Acid † C 6 H 8 O 7 Common component in citrus fruits. Contains three carboxylic acid groups.

Benzaldehyde † C 7 H 6 O Colorless liquid that smells of bitter almonds. Benzene ring replaces the H atom in formaldehyde.

2-Heptanone † C 7 H 14 O Liquid with a clove- like odor. Responsible for the odor of many fruits and dairy products, e.g. blue cheese.

3-Methylbutane-1-thiol † C 5 H 12 S Like an alcohol, except the O is replaced by S (same group). Known collectively as thiols. Typically very pungent aromas. This molecule is squirted out in abundance by skunks.

Putrescine † C 4 H 12 N 2 Amines (contain NH 2 groups) commonly have vile smells and this one is no exception. Cadaverine is another closely related molecule with morbid associations. Interestingly, one of the constituents of nylon (hexamethylene diamine) is related to putrescine by the addition of two –CH 2 - groups.

Trimethylamine † C 3 H 9 N Derived from ammonia by the replacement of each H by –CH 3 A gas (boiling point 2°C), with the odor of rotten fish.