Acetone (C3H6O) – Structure, Properties, Preparation, Uses

What is Acetone?

Acetone is an organic compound that is highly flammable and has a chemical formula of C₃H₆O. The other name for acetone is propanone. It is produced in the exhaust of plants, vehicles, forest fires, and trees. It is also produced in the human body and found in blood and urine.

Acetone is a colorless volatile compound that is miscible in ethanol, water, and ether. It has a pungent or irritating odor and has wide applications as a solvent or an antiseptic. If you want to know more about what acetone is, please read on!

Acetone was first produced by alchemists by the dry distillation of metal acetates. Nowadays, It is prepared from propylene either directly or indirectly. Around 80% of acetone is prepared in a process called the cumene process. Also, some older methods of preparing cumene exist. 

Acetone Structure

Below is a representation of the acetone structure:

Acetone formula is C₃H₆O or CH3COCH3. It is the simplest known ketone with six atoms of hydrogen, three atoms of carbon, and one atom of oxygen. Two methyl groups are attached to the middle carbon atom in the atoms of the acetone compound. This carbon atom also forms a double bond with an atom of oxygen by forming a ketone or carbonyl functional group. In the structure of acetone, there are two available valencies, both of which are attached to carbon atoms. Thus, the keto group in the compound exists within a chain. 

Preparation of Acetone

Around 80% of acetone in industries is produced by a process known as the cumene process. Here, cumene is produced by alkylating benzene with propylene and then it is oxidized by air to give acetone and phenol. 

Production of Acetone

• In the industry, acetone can be produced from isopropanol by catalytic dehydrogenation by zinc oxide or copper. It can also be produced if the silver catalyst is oxidized catalytically. 
• It is obtained by passing an oxygen and propane mixture under pressure into an aqueous solution of cupric chlorides and palladium. 
• It is produced by the oxidation of natural gas. 
• Of all the processes, the most important one for producing 2-propanone and phenol is the cumene phenol process. It is executed by the oxidation of cumene to give it hydroperoxide. This hydroperoxide is then decomposed by dilute sulfuric acid to give 2-propanol and phenol. 

General Properties of Acetone – C₃H₆O

Physical Properties 

Acetone molar mass	Acetone molar mass is 58.08 g·mol−1
Appearance	A colorless liquid at room temperature
Odour	Pungent or irritating
Melting point	−94.6 °C (−138.5 °F; 178.5 K)
Density	0.7846 g/ ㎤
Boiling point	56.04 °C (132.89 °F; 329.20 K)
Magnetic susceptibility (χ)	−33.78·10−6 ㎤/mol
Solubility in water	Miscible
Solubility in other liquids	Miscible in diethyl ether, ethanol, benzene, methanol, and chloroform
Refractive index (nD)	1.3588
Viscosity	0.295 mPa·s (25 °C)
Acetone Formula	C3H6O

Chemical Properties of Acetone

Keto/enol Tautomerism:

Acetone shows keto-enol tautomerism, which is one of its most important chemical properties. Several molecules containing the -carbonyl group exhibit a proton-transfer equilibrium known as tautomerism due to the acidity of α-hydrogens. Tautomers are constitutional isomers easily interconvertible and are differentiated by a different location for an atom or a group. 

As there is a rearrangement of atoms in tautomers, they are quite different from resonance forms in which the only difference is in the position of lone pair electrons or bonds. In the term keto/enol tautomerism, “keto” indicates that the tautomer comprises a carbonyl bond, whereas “enol” indicates the presence of a hydroxyl group or a double bond.

The equilibrium point in keto-enol tautomerization depends on the stabilization factors of both the keto and enol tautomer. Under normal conditions for simple carbonyl compounds, the equilibrium usually strongly favors the keto tautomer. It is preferred because the keto tautomer is more stable than the enol tautomer by about 46-59 kJ/mol. The stability is also due to the fact that the C=O double bond is more stable and stronger than the C=C double bond. 

Also, ketones contain two alkyl groups that donate electrons to the carbon of the carbonyl group; therefore, their stability is high, and they are less likely to form the enol tautomer as compared to aldehydes. For instance, propanal is thousands of times more apt to be in its enol tautomer than acetone.

With the derivatives of carboxylic acid, the carbonyl is stabilized by the group that is leaving through the donation of electrons, making the generation of enol tautomer much less possible. Generally, ketones have a 100,000,000 times higher chance of being in an enoltautomer form than esters. Below is a representation of the keto-tautomerism shown by acetone:

Haloform Reaction

As acetone contains the CH₃-C=O group, it exhibits a haloform reaction, which means that it reacts with halogens to give acid salt and haloform in the presence of alkali. 

Haloform Reaction Mechanism

Below is a step-by-step explanation of the haloform reaction:

Step 1

The alpha hydrogen is taken out by the base (hydroxide ion) to produce an enolate. After this, the reaction between halogen and enolate occurs, which leads to the formation of a halogenated ketone in addition to an anion corresponding to the halogen. 

Step 2

There is a repetition of step 1 two times to give a tri-halogenated ketone.

Step 3

The hydroxide ion functions as a nucleophile and attacks the doubly bonded electrophilic carbon. The double bond is between carbon and oxygen. After the reaction, it changes into a single bond, rendering the oxygen atom anionic.

This favors the reformation of the carbon-oxygen double bond, and there is a displacement of the carbon attached to three halogens, and the carboxylic group is left. After this, an acid-base reaction occurs, there is a donation of a proton by the carboxylic acid to the tri-halomethyl anion, and the required haloform product is obtained. 

Uses of Acetone

Acetone has wide applications in the textile and pharmaceutical industries, laboratories, and in the manufacture of domestic products of daily use. It is also employed in the manufacture of methyl methacrylate and methyl isobutyl ketone. It also has wide applications in the fields of chemical research and the analytical industry.

Uses as a solvent: Acetone is employed as a solvent for cellulose, lacquers, acetylene, and cellulose acetate. It acts as an excellent solvent for some plastics and synthetic fibers used in the making of polyester resin. It is also used in the manufacture of varnishes and paints.

Uses in medicine: It is employed as a solvent in the manufacture of medicines to ensure their accurate dosage. It is also employed in the disinfection and sterilization of medical instruments and equipment. Dermatologists use acetone to deal with acne present on the peeling skin. 

Domestic uses of acetone: Acetone has many domestic applications. It is employed as an additive in skin creams and makeup, is the main ingredient in super glue and nail paint remover, and is used for printing artifacts on ABC plastic and three-dimensional printed models. It is used in cleaning products targeted for cleaning electronic appliances and gadgets. 

Hazards of Acetone 

• It is highly flammable but has low acute and chronic toxicity.
• This may cause a sore throat or cough if inhaled. 

Acetone Safety 

Keep everything away from your skin, eyes, and clothing. When not in use, keep the container’s tight seal intact. Storage should be kept cool and away from heat and ignition sources. Prevent the buildup of static charges.

Conclusion

We hope that this article helps you gain a fundamental understanding of acetone structure, acetone formula, acetone molar mass, what acetone is, what its physical and chemical properties are, what its applications are, and how it is prepared in the laboratory. We hope that by the end, you will be able to answer most of the questions regarding this topic.

Frequently Asked Questions

1. Where is Acetone Found?

A. It can be found in plants, trees, volcanic gas, and forest fires. This is also produced by your body when it breaks down fat.

2. How Can People be Exposed to Acetone?

A. Breathing acetone from the environment could expose you to acetone. This can happen if the outside air contains low levels of acetone. It may be present in the air where you work.

3. What is Pure Acetone?

A. Pure acetone is made up of only molecules or ions.

4. Can Acetone Be Used as a Nail Polish Remover?

A. It is a powerful solvent, it is used as a nail paint remover. Additionally, it can also be used as a super glue remover. It is also effectively employed for preparing nail paints and removing different types of oils. 

5. Is Acetone Toxic?

A. Inhalation of acetone in moderate to high amounts for a time period can lead to nose, lung, throat, and eye irritation. It can also result in dizziness, headaches, rapid pulse, confusion, vomiting, nausea, unconsciousness, effects on the blood, changes in menstrual cycles in females, and in a worst-case scenario, coma.