- Structure of butanone
- Properties
- Molecular formula
- Names
- Molar mass
- Physical description
- Odor
- Boiling point
- Melting point
- ignition point
- Water solubility
- Solubility in organic solvents
- Density
- Vapor density
- Vapor pressure
- Octanol / water partition coefficient
- Auto ignition temperature
- Decomposition
- Viscosity
- Heat of combustion
- Heat of vaporization
- Surface tension
- Ionization potential
- Odor threshold
- Refractive index
- Dissociation constant
- Stability
- Applications
- Solvent
- Reagent
- Plastic cement
- Other uses
- References
The butanone is an organic compound, specifically a ketone, having the chemical formula CH 3 CH 2 COCH 3. Its appearance is that of a colorless liquid used primarily as a solvent. It has properties similar to acetone, but it 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 vehicle exhaust pipes, and it 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 exhibits 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.
Structure of butanone
The upper image shows the butanone molecule with a ball-and-stick model. The oxygen atom of the carbonyl group (red sphere) can be seen on the second carbon. 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 a methylene group, CH 2, has been added. As there are more carbons, the dipole moment is smaller compared to acetone; but its higher molecular mass causes it to 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 that 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 be further commented that butanone is structurally asymmetric.
Properties
Molecular formula
C 4 H 8 O or CH 3 COCH 2 CH 3
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 ° C.
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: (CH 3) (CH 2 CH 3) 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 / cm 3 at 25 ° C.
Vapor density
2.41 (relative to water = 1).
Vapor pressure
90.6 mmHg at 25 ° C.
Octanol / water partition coefficient
Log P = 0.29
Auto ignition temperature
505 ° C.
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 ° C.
Heat of combustion
2,444.1 kJ / mol at 25 ° C.
Heat of vaporization
31.30 kJ / mol at boiling point; and 34.79 kJ / mol at 25 ° C.
Surface tension
23.97 mN / m at 25 ° C.
Ionization potential
0.54 eV.
Odor threshold
Low odor: 0.735 mg / m 3.
High odor: 147.5 mg / m 3.
Refractive index
1,788 at 20 ° C.
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.
- Rubber bands.
- Lacquers.
- Varnishes.
- Glues.
- Solvents.
- Paint removers.
- Adhesives.
- Plastic cements.
- Sealants.
- Magnetic tapes.
- Transparent paper.
- Printing inks.
- Cosmetics and pharmaceutical products.
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 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. It is also used as a solvent in markers used on whiteboards.
Reagent
- Butanone is used as a water-soluble photoinitiator for the photopolymerization of methacrylic acid.
- It condenses with formaldehyde to produce isopropenyl ketone.
- It experiences auto-condensation for the production of ethyl amyl ketone.
- Reacts with citral to obtain perfume components such as methylpseudoionone.
- It intervenes as a catalyst in the production of hydrazine.
- Additionally, it is a precursor of 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 the hemeproteins.
References
- Morrison, RT and Boyd, R, N. (1987). Organic Chemistry. 5 ta Edition. Editorial Addison-Wesley Interamericana.
- Carey F. (2008). Organic Chemistry. (Sixth edition). Mc Graw Hill.
- Graham Solomons TW, Craig B. Fryhle. (2011). Organic Chemistry. Amines. (10 th edition.). Wiley Plus.
- National Center for Biotechnology Information. (2019). Methyl ethyl ketone PubChem Database. CID = 6569. Recovered from: pubchem.ncbi.nlm.nih.gov
- Wikipedia. (2019). Butanone. Recovered from: en.wikipedia.org
- Royal Society of Chemistry. (2015). Butanone. Chemspider. Recovered from: chemspider.com
- Arlem Cheprasov. (2019). What is butanone? Formula & uses. Study. Recovered from: study.com
- Vasler Ben. (May 17, 2017). Butanone. Chemistry World. Recovered from: chemistryworld.com