Aromatic Ketones

We are aware of the molecule’s carbonyl group and two ketones, which are molecules linked by hydrocarbons. It can be viewed as a mixed aromatic ketone if just one of them is an aromatic base, or as a simple Aromatic Ketone if both are. Examples of aromatic ketones are benzophenone and acetophenone. While simple aromatic ketones are solid, Alkyl Aromatic mixed ketones are liquid. Aromatic ketone is soluble in organic solvents but insoluble in water. The aromatic ketone is a significant industrial raw material in the chemical and medicinal fields.

Nomenclature Of Ketones

The elimination of the alcohol, which occurs as a result of the reduction of a cheap aldehyde or ketone utilised as the oxidant, addresses the issue that alcohol is less volatile than the comparable carbonyl molecule.

The International Union of Pure and Applied Chemistry (IUPAC) name of a ketone is derived by choosing the longest chain of carbon atoms containing the carbonyl group as the parent. The parent chain is counted from the end, therefore the carbonyl carbon has the lower number. To indicate that the molecule is a ketone, the parent alkane’s suffix -e is altered to -one. For instance, CH₃CH₂COCH₂CH(CH₃)₂ is known as 5-methyl-3-hexanone. The longest chain has six carbon atoms, thus carbon numbering must begin at the end, giving the carbonyl carbon the lower number. Carbon 3 has a carbonyl group, and carbon 5 has a methyl group. In cyclic ketones, the ring atoms are numbered beginning with the carbonyl carbon as number 1. Ketones are given common names by identifying each carbon group linked to carbon as a separate word, followed by the term “ketone.”

The most basic ketone, CH₃COCH₃, whose IUPAC name is 2-propanone, is almost always referred to by its common name, acetone, which is derived from the fact that it was initially synthesised by heating the calcium salt of calcium chloride.

Preparation Methods of Ketones

Ketones are a type of chemical molecule that contains carbonyl groups (C=O). A ketone has the generic formula R(C=O)R’, where R and R’ might be alkyl or aryl groups. Their substituents divide them into two categories: symmetrical ketones (where two identical groups are linked to the carbonyl group) and asymmetrical ketones (when two different groups are appended to the carbonyl group). There are numerous methods for producing ketones on a large scale and in laboratories. Oxidation of alcohol, hydrocarbons, and other substances is a common process. The following are some general procedures for preparing ketones:

1. Synthesis of Ketones from Acyl Chlorides

When acyl chlorides are treated with Grignard reagent and a metal halide, ketones are formed. Diakyl cadmium, for example, is generated when cadmium chloride reacts with the Grignard reagent. Dialkylcadmium is then generated by reacting with acyl chlorides to create ketones.

2. Ketone Synthesis from Nitriles

Further hydrolysis of nitriles with Grignard reagent gives ketones.

3. Ketone Synthesis from Benzenes or Substituted Benzenes

In the presence of a Lewis acid, such as AlCl₃, electrophilic aromatic substitution of a benzene ring with acid chlorides results in the creation of ketones. This is sometimes referred to as Friedel Craft’s acylation reaction.

4. Dehydrogenation of Alcohols for Ketone Production

Dehydrogenation of alcohol is the removal of two hydrogen molecules from an alcohol molecule during oxidation. During the oxidation of alcohol, both C-O and O-H bonds are broken, allowing C=O bonds to form. Secondary alcohols are dehydrogenated to form ketones in the presence of strong oxidising agents.

For example, when secondary alcohol vapours are passed over heated copper at 573 K, ketones are formed as a result of dehydrogenation. When tertiary alcohols are oxidised, they undergo dehydration rather than dehydrogenation. As a result, alkenes are produced in the case of tertiary alcohols.

Conclusion 

We conclude that Ketones are used as building blocks in the synthesis of many complex chemical molecules. They are most commonly employed as solvents, particularly in the production of explosives, lacquers, paints, and textiles. Ketones are also utilised as preservatives, tanning agents, and in hydraulic fluids.