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Uses of Aldehydes and Ketones
- 40% aqueous solution of formaldehyde is called formalin. It is used for preserving biological specimens.
- Formalin has hardening effct, hence it is used for tanning.
- Formalin is used in the production of thermo setting plastic known as bakelite, which is obtained by heating phenol with formalin.
- Acetaldehyde is used for silvering of mirrors
- Paraldehyde is used in medicine as a hypnotic.
- Acetaldehyde is used in the commercial preparation of number of organic compounds like acetic acid, ethyl acetate etc.,
- Acetone is used as a solvent, in the manufacture of smokeless gun powder (cordite)
- It is used as a nail polish remover.
- It is used in the preparation of sulphonal, a hypnotic.
- It is used in the manufacture of thermosoftning plastic Perspex.
Benzaldehyde is Used
- As a flavouring agent
- In perfumes
- In dye intermediates
- As starting material for the synthesis of several other organic compounds like cinnamaldehyde, cinnamic acid, benzoyl chloride etc.
- Acetophenone has been used in perfumery and as a hypnotic under the name hypnone.
- Benzophenone is used in perfumery and in the preparation of benzhydrol eye drop.
Carbon compounds containing a carboxyl function group, -COOH are called carboxylic acids. The Carboxyl group is the combination of carbonyl group and the hydroxyl group (-OH).
However, carboxyl group has its own characteristic reaction. Carboxylic acids may be aliphatic (R – COOH) or aromatic (Ar – COOH) depending on the alkyl or aryl group attached to carboxylic carbon. Some higher members of aliphatic carboxylic acids (C12 to C18) known as fatty acids occur in natural fats as esters of glycerol.
Aldehydes are currently used in the production of resins and plastics. The simplest ketone, propanone, is commonly called acetone. Acetone is a common organic solvent that was one used in most nail polish removers, but has largely been replaced by other solvents.
It is used in tanning, preserving, and embalming and as a germicide, fungicide, and insecticide for plants and vegetables, but its largest application is in the production of certain polymeric materials.
- Ketone behaves as an excellent solvent for certain types of plastics and synthetic fibres.
- Acetone act as a paint thinner and a nail paint remover.
- It also is used for medicinal purposes such as chemical peeling procedure as well as acne treatments.
Example of Ketone
Ketones contain a carbonyl group (a carbon-oxygen double bond). The simplest ketone is acetone (R = R’ = methyl), with the formula CH3C(O)CH3. Many ketones are of great importance in biology and in industry. Examples include many sugars (ketoses), many steroids (e.g., testosterone), and the solvent acetone.
Example of Aldehyde
Aldehydes are given the same name but with the suffix – ic acid replaced by – aldehyde. Two examples are formaldehyde and benzaldehyde. As another example, the common name of CH2 = CHCHO, for which the IUPAC name is 2-propenal, is acrolein, a name derived from that of acrylic acid, the parent carboxylic acid.
Generally, the common names of ketones consist of the names of the groups attached to the carbonyl group, followed by the word ketone. (Note the similarity to the naming of ethers). Another name for acetone, then, is dimethyl ketone. The ketone with four carbon atoms is ethyl methyl ketone.
Common Ketones are Acetone and Methyl Ethyl Ketone. They have different uses. Acetone is known as fingernail polish remover but is also commonly used as lacquer and varnish solvent.
Aldehydes are made by oxidising primary alcohols. The aldehyde produced can be oxidised further to a carboxylic acid by the acidified potassium dichromate (VI) solution used as the oxidising agent. In order to stop at the aldehyde, you have to prevent this from happening.