Why are organic compounds called organic compounds

Organic oxygen compounds

What are organic oxygen compounds?

The group of Oxygen compounds consists organic compoundswhich, like hydrocarbons, are also made up of carbon and hydrogen. With the oxygen compounds, however, is still at least an oxygen atom covalently bonded. Because of this oxygen, most of the oxygen compounds are reactive and play a role Redox reactions plays an important role not only in chemistry, but also in biology.


Alcohols contain at least one, if not more than one Hydroxyl groups (or also OH groups). Alcohols can form hydrogen bonds via this OH group. They are therefore readily soluble in water. A well-known example of an alcohol is Ethanolwhich is present in all alcoholic beverages and by which Alcoholic fermentation can be won. Another prominent example is Glycerin, this in dynamite Is used, but is also present in biomembranes.

Aldehydes and ketones

Aldehydes and ketones derive by oxidation of alcohols and have the Carbonyl group (or CO group) in common:

Unlike the alcohols, these do not form any hydrogen bonds with one another. Therefore, aldehydes and ketones have a lower boiling point. However, with water, aldehydes and ketones can form hydrogen bonds. They are therefore readily soluble in water. The simplest representative of the aldehydes is formaldehyde (or methanal). It is used in industry to make plastics. It is used in medicine as a disinfectant. Furthermore, formaldehyde can be used to fix tissue samples and make them durable, as it denatures and cross-links proteins. Has similar properties acetaldehyde (or ethanal), which is produced in the human body as a breakdown product of ethanol. acetone is the simplest representative of the ketones and is often used as a solvent in chemistry. Acetone is often found in special cleaners and nail polish removers in the home.

The carbonyl group of the aldehydes and ketones is very reactive. They react with water or other oxygen-containing compounds such as alcohols, with primary amines, with cyanes or ammonia. Furthermore, they can be used with the so-called Grignard-Reduction reduce to alcohol again.

Carboxylic acids

If aldehydes are oxidized further, the corresponding ones are obtained Carboxylic acids. These are characterized by a Carboxyl group (or COOH group). Many of these carboxylic acids are known by their common names, such as, for example acetic acid.

The carboxylic acids or the carboxyl groups of the carboxylic acids all meet the definition of a Brønsted acid. After neutralization with a base, carboxylic acids form salts. A well-known representative is the salt of pyruvic acid, viz Pyruvate.

Like the oxygen compounds presented above, the carboxylic acids are also very reactive. They form compounds with halides. Carboxylic acids react with themselves, splitting off water Carboxylic acid anhydrides. They also react with ammonia or other organic derivatives of ammonia, the amines Carboxamides. Another important reaction of the carboxylic acids is the Decarboxylation. Carbon dioxide is split off in the process. This reaction is known from metabolism: pyruvate is decarboxylated to acetyl before entering the citrate cycle. The reaction of carboxylic acids with alcohols is no less important. In the process, water is split off Ester. For example, the fatty acids in biomembranes are bound to glycerol via an ester bond and form the basis of the phospholipids.


Ester (or carboxylic acid esters) are replaced by a Condensation reaction of Carboxylic acids and alcohols educated. This reaction is a typical equilibrium reaction. The forward reaction will too Esterification called, the reverse reaction is one hydrolysis. If the hydrolysis takes place in the basic one, this is called Saponification. $ \ Text {NaOH} $ is often used for saponification, and then the alcohol is formed Carboxylic acid salt. In the case of a hydrocarbon chain of 12-18 carbon atoms, these salts also become Soap called.

In addition to soaps, the most famous representatives of the esters are those used as explosives Nitrocellulose and dynamite.


Ether contain a so-called Organyl group. You can think of this as an oxygen bridge in the molecule (or R-O-R '). Ethers are difficult to dissolve in water and they have a low boiling point.

Compared to the other oxygen compounds, ethers are rather inert and are therefore often referred to as inert solvents used. With strong acids form ethers Oxonium ions out. Ethers easily form with oxygen and when exposed to light Peroxides out. Peroxides are very explosive! Therefore, caution should always be exercised when handling ether in the laboratory.

You will know many of these oxygen compounds from everyday life, as they often have a pleasant scent.