Dealkylation is defined as the removal of alkyl groups from a compound, and is used to alter chemical reactions in organic chemistry. Usually performed using various oxides in a process known as oxidative dealkylation, dealkylation has been used in a number of clinical and commercial applications. Through oxidative dealkylation chemists are able to repair DNA and RNA, and create commercial products from hydrocarbons. This is only a small sample of its practical application.

Before dealkylation can be performed, it is first necessary to identify the alkyl group in the compound. An alkane is an organic molecule made up of straight or branched chains of carbon and hydrogen atoms, where the carbon-carbon atoms are joined exclusively by single bonds. The alkyl group is a functional group on an organic molecule which is derived from an alkane that has lost a hydrogen atom. In general, alkyl groups are represented by the formula CnH2n+1.

There are two primary forms of dealkylation studied in the organic chemistry lab: O-dealkylation and N-dealkylation. Most dealkylation reactions in organic chemistry are seen as a result of oxidative dealkylation, called O-dealkylation. Oxidative dealkylation uses an oxide, a compound containing an oxygen atom and at least one other element, to draw away the alkyl group of an organic molecule through some form of reduction-oxidation, or redox, reaction. Through a change in carbon's oxidative state, the alkyl group breaks off and dealkylation is complete.

Aside from its commercial application, oxidative dealkylation has become an important part of research into mammalian metabolism. Specifically, this research involves the human metabolism of pharmaceuticals and other foreign and chemical substances and the role that dealkylation plays in that process. Dealkylation and the use of various oxidizing agents also plays a significant role in the clinical laboratory, where it can be used to change the ability of a particular solution to donate electrons in a laboratory setting.

Dealkylation is an important part of the process that turns crude oil into more usable products. Benzene and methylbenzene, for example, are both hydrocarbons found in crude oil, but benzene is more commercially valuable. When methylbenzene is mixed with hydrogen and a catalyst, and heated to a particular temperature and under a specific amount of pressure, the methyl group is removed through dealkylation, producing benzene.