Carbonyl Compounds and Carbonyl Groups

What are Carbonyl Compounds?

The compounds comprising of a carbonyl group -C=O are termed as Carbonyl Compounds. These compounds are a part of the organic chemistry with their primary members named as aldehydes and ketones.

Carbonyl Group

A carbonyl group is also called a functional group. It consists of a carbon atom which is linked to the oxygen atom through a double bond as shown below. This group is called the carbonyl group. The term Carbonyl also refers to carbon monoxide as the ligand within an organometallic or inorganic compound say a metal carbonyl for ex- nickel carbonyl.

Carbonyl Compounds

Again carbonyl compounds are divided into organic and inorganic carbonyl compounds, but in this article, we are dealing with the carbonyl compounds those of organic in nature.

Organic Carbonyl compounds

These include carbamates, urea and also the derivatives of phosgene, acyl chlorides chloroformates, carbonate esters, lactones, thioesters, lactams, isocyanates, and hydroxamates.

Carbonyl Compounds – Aldehydes and Ketones

In general, we come across the names aldehydes and ketones when we speak about the Carbonyl compounds. What is the role of these in the lists of carbonyl compounds? Aldehydes and ketones are the organic compounds which consist of the functional group as that of that of the carbonyl compounds. The main difference between these two compounds is the position of the carbonyl group. In aldehydes, the carbonyl group is placed at the ending of carbon chain whereas, in the ketones, it is located in the middle of the carbon ring. The examples of aldehydes include propanol, butanol, 4-chlorobutanol, etc. and some of the examples of ketones are propanone, acetone, 2-methyl-3-pentanone, etc.

Properties of Carbonyl Compounds

Some of the properties of carbonyl compounds are given below:

  • These are to be polar in nature. They exhibit both positive as well as negative charge in slight form. Hence these are said to be polar molecules.
  • These compounds are reported to be insoluble in water but sometimes they dissolve other forms of polar molecules.
  • These are known to be as chemically reactive compounds. It means that they control the reactions of a chemical reaction.

Carbonyl Compounds Reactions

The carbon atom of the carbonyl group is said to be electrophilic in nature as they tend to attract electron rich compounds. Some of the Examples of electrophiles include ions whereas the oxygen atoms are said to be nucleophiles as they do not have the rich density of electrons. They are said to be the lovers of nuclei such as the bases. The carbonyl compounds reactions are given below:

  1. Carbonyl Reduction: This reaction is a process in which the Carbonyl groups are reduced by the hydride reagents such as the LiAlH4 and NaBH4 with baker’s yeast, or by the process of catalytic hydrogenation.
  2. Carbonyl alkylation: This is a process in which the carbonyl compounds are alkylated with the use of organometallic compounds like Grignard reagents, organolithium reagents, acetylides, etc.
  3. Carbonyl Alpha-Substitution Reaction: This kind of substitution reaction involves the substitution of the atom of α hydrogen by an electrophile.

Applications of Carbonyl Compounds

  • The carbonyl compound propanone is used as a solvent since it gets dissolved in water as well as other organic solutions.
  • Formaldehyde is used in the manufacture of plastics and also it is used in the biological laboratories for preservation purposes.
  • Butanol is used to provide fragrance for keeping the bread fresh.
  • Acetaldehyde is used as a Synthesizer in many organic reactions.

Practise This Question

Doping of silicon (Si) with Arsenic (As) leads to