Butanone structure, properties and uses

5010
Charles McCarthy

The butanone is an organic compound, specifically a ketone, whose chemical formula is CH3CHtwoCar3. Its appearance is that of a colorless liquid used primarily as a solvent. Has properties similar to acetone, but boils at a higher temperature and evaporates more slowly.

It is produced by the catalytic dehydrogenation of 2-butanol (chiral compound). However, it is found in its natural state in the composition of some fruits. It is part of the fumes from the exhaust pipes of vehicles, and is a component of tobacco smoke.

Butanone molecule. Source: Pixabay.

It is after acetone the simplest of this family of organic compounds. Butanone causes irritation to the eyes and nose. At unusually high doses it can cause irritation of the lung mucosa. On the other hand, this liquid is considered a precursor agent for narcotics..

Butanone has great solubility in water; but it is also very soluble in organic solvents such as ethanol, ether, acetone, benzene, and chloroform. This could be explained because your log of P (0.29) value for the octane / water partition coefficient is low.

Article index

  • 1 Structure of butanone
  • 2 Properties
    • 2.1 Molecular formula
    • 2.2 Names
    • 2.3 Molar mass
    • 2.4 Physical description
    • 2.5 Odor
    • 2.6 Boiling point
    • 2.7 Melting point
    • 2.8 Flash point
    • 2.9 Solubility in water
    • 2.10 Solubility in organic solvents
    • 2.11 Density
    • 2.12 Vapor density
    • 2.13 Vapor pressure
    • 2.14 Octanol / water partition coefficient
    • 2.15 Auto ignition temperature
    • 2.16 Decomposition
    • 2.17 Viscosity
    • 2.18 Heat of combustion
    • 2.19 Heat of vaporization
    • 2.20 Surface tension
    • 2.21 Ionization potential
    • 2.22 Odor threshold
    • 2.23 Refractive index
    • 2.24 Dissociation constant
    • 2.25 Stability
  • 3 Uses
    • 3.1 Solvent
    • 3.2 Reagent
    • 3.3 Plastic cement
    • 3.4 Other uses
  • 4 References

Structure of butanone

The image above shows the butanone molecule with a spheres and bars model. The oxygen atom of the carbonyl group can be seen on the second carbon (red sphere). This group, C = O, is responsible for giving the molecule a permanent dipole moment.

Butanone, structurally seen, is nothing more than an acetone to which has been added a methylene group, CHtwo. As there are more carbons, the dipole moment is smaller compared to acetone; but its higher molecular mass makes it boil at a higher temperature.

This molecule, like other ketones, lacks the ability to form hydrogen bonds; and therefore their dipole-dipole interactions are not as strong.

That is why it is a volatile liquid. As the temperature drops (-86.6 ° C), its weak dipoles are the ones that orient its molecules in an orderly fashion to form a crystal. In addition to this, it can also be commented that butanone is structurally asymmetric.

Properties

Molecular formula

C4H8O or CH3CartwoCH3

Names

- Butanone.

- 2-butanone.

- Butan-2-one.

- Methyl ethyl ketone.

Molar mass

72.107 g / mol.

Physical description

Colorless liquid.

Odor

Mint fragrant, moderately strong.

Boiling point

79.59 ° C at 760 mmHg.

Melting point

-86.6 ºC.

ignition point

-9 ºC (closed cup).

Water solubility

29 g / 100 mL at 20 ° C. Although its dipole moment is less than that of acetone, it can still interact to an excellent degree with water molecules. From them it receives hydrogen bonds: (CH3) (CHtwoCH3) C = O-HOH. Due to this it is very soluble in water.

Solubility in organic solvents

Soluble in benzene, alcohol and ether; Miscible with oils, ethanol, ether, acetone, benzene and chloroform. Note that butanone is soluble in a wide variety of solvents.

Density

0.7997 g / cm3 at 25 ºC.

Vapor density

2.41 (relative to water = 1).

Vapor pressure

90.6 mmHg at 25 ºC.

Octanol / water partition coefficient

Log P = 0.29

Auto ignition temperature

505 ºC.

Decomposition

It is decomposed by photochemical processes through oxidation by free hydroxyl radicals, as well as by direct photolysis decomposition. When heated to decomposition it emits acrid smoke.

Viscosity

0.40 cPoise at 25 ºC.

Heat of combustion

2,444.1 kJ / mol at 25 ºC.

Heat of vaporization

31.30 kJ / mol at boiling point; and 34.79 kJ / mol at 25 ºC.

Surface tension

23.97 mN / m at 25 ºC.

Ionization potential

0.54 eV.

Odor threshold

Low odor: 0.735 mg / m3.

High odor: 147.5 mg / m3.

Refractive index

1,788 at 20 ºC.

Dissociation constant

pKa = 14.70.

Stability

Stable, but highly flammable. Incompatible with strong oxidizing agents, bases, and reducing agents. Moisture should be avoided.

Applications

Solvent

Butanone is used as a solvent in the manufacture of surface coatings, manufacture of smokeless powders, manufacture of colored resins, and in the elimination of grease accumulation produced by lubricants..

In addition, it is used in the elaboration of:

- Artificial leather.

- Rubbers.

- Lacquers.

- Varnishes.

- Glues.

- Solvents.

- Paint removers.

- Adhesives.

- Plastic cements.

- Sealants.

- Magnetic tapes.

- Transparent paper.

- Printing inks.

- Cosmetics and pharmaceuticals.

It is also used as a solvent for degreasing metal surfaces, electronic equipment cleaners, and grease extraction. It is used for the extraction of hardwood and vegetable oil.

It is an inert ingredient in the manufacture of pesticides, and in the manufacture of cellulose acetate and cellulose nitrate.

It is used as an extraction solvent in food and food ingredient processing; for example, in the fractionation of fats and oils, as well as in the decaffeination process of coffee. Also used as a solvent in whiteboard markers.

Reagent

- Butanone is used as a water-soluble photoinitiator for the photopolymerization of methacrylic acid..

- Condenses with formaldehyde to produce isopropenyl ketone.

- Experiences self-condensation for the production of ethyl amyl ketone.

- Reacts with citral to obtain perfume components such as methylpseudoionone.

- Intervenes as a catalyst in the production of hydrazine.

- Additionally, it is a precursor to methyl ethyl ketone peroxide, which is a catalyst for some polymerization reactions..

Plastic cement

Butanone has application as a plastic welding agent, with use in the assembly of polystyrene scale models. The butanone dissolves the polystyrene, allowing the edges to come together when a new polymerization occurs. This behavior is of a cement and not of a glue.

Other uses

Butanone is used as a bacterial spore sterilizer in surgical instruments, needles, hypodermic injectors, and dental instruments..

It is used as a food flavoring agent in very low concentrations; for example, in alcoholic beverages the concentration is 20 ppm; in baked goods, 12.7 ppm; meats have around 26.5 ppm; chewing gum, 0.63 ppm; and in fats and oils, 1.0 ppm.

And finally, butanone is used in the separation of the apoprotein from the heme group in hemeproteins..

References

  1. Morrison, R. T. and Boyd, R, N. (1987). Organic Chemistry. 5ta Edition. Editorial Addison-Wesley Interamericana.
  2. Carey F. (2008). Organic Chemistry. (Sixth edition). Mc Graw Hill.
  3. Graham Solomons T.W., Craig B. Fryhle. (2011). Organic Chemistry. Amines. (10thedition.). Wiley plus.
  4. National Center for Biotechnology Information. (2019). Methyl ethyl ketone PubChem Database. CID = 6569. Recovered from: pubchem.ncbi.nlm.nih.gov
  5. Wikipedia. (2019). Butanone. Recovered from: en.wikipedia.org
  6. Royal Society of Chemistry. (2015). Butanone. Chemspider. Recovered from: chemspider.com
  7. Arlem Cheprasov. (2019). What is butanone? Formula & uses. Study. Recovered from: study.com
  8. Vasler Ben. (May 17, 2017). Butanone. Chemistry World. Recovered from: chemistryworld.com

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