por The butanone is an organic compound, specifically a ketone, whose chemical formula is CH3CH2COCH3. Its appearance is that of a colorless liquid used primarily as a solvent. It has similar properties 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 emissions from the exhaust pipes of vehicles, and is a component of tobacco smoke.
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 pulmonary mucosa. On the other hand, this liquid is considered a narcotic precursor agent.
Butanone presents 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 its value of the log of P (0.29) for the octane/water partition coefficient is low.
[toc]
butanone structure
The image above shows the butanone molecule in a ball-and-stick 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, seen structurally, is nothing more than an acetone to which a methylene group, CH2, has been added. As there are more carbons, the dipole moment is smaller compared to that of acetone; but its greater 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 what 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
C4H8O or CH3COCH2CH3
Names
– Butanone.
– 2-butanone.
– Butan-2-one.
– Methyl ethyl ketone.
molar mass
72.107 g/mol.
Physical description
colorless liquid
Smell
Fragrant minty, moderately strong.
Boiling point
79.59ºC at 760 mmHg.
Melting point
-86.6ºC.
ignition point
-9 ºC (closed cup).
Water solubility
29 g /100 mL at 20ºC. 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)(CH2CH3)C=O—HOH. Because of 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 25ºC.
Vapor density
2.41 (relative to water = 1).
Vapor pressure
90.6 mmHg at 25ºC.
Octanol/water partition coefficient
log P = 0.29
auto ignition temperature
505ºC
Decomposition
It decomposes by photochemical processes through oxidation by free hydroxyl radicals, as well as by direct photolysis decomposition. When heated to decomposition it emits an acrid smoke.
Goo
0.40 cPoise at 25ºC.
heat of combustion
2,444.1 kJ/mol at 25ºC.
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 25ºC.
ionization potential
0.54 eV.
odor threshold
Low odor: 0.735 mg/m3.
High odor: 147.5 mg/m3.
Refractive index
1.788 at 20ºC.
dissociation constant
pKa = 14.70.
Stability
Stable, but highly flammable. Incompatible with oxidizing agents, bases, and strong reducing agents. Moisture should be avoided.
Applications
Solvent
Butanone is used as a solvent in the preparation of surface coatings, the manufacture of smokeless powder, the preparation of colored resins, and in the removal of grease accumulation produced by lubricants.
In addition, it is used in the preparation 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 hard wood 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 coffee decaffeination process. 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.
– Undergoes self-codensation for the production of ethyl amyl ketone.
– Reacts with citral to obtain perfume components such as methylpseudoionone.
– It is involved 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 applications as a plastic welding agent, with use in the assembly of polystyrene scale models. The butanone gradually dissolves the polystyrene, allowing the edges to come together as a new polymerization occurs. This behavior is from a cement and not from a glue.
Other uses
Butanone is used as a sterilizer for bacterial spores in surgical instruments, needles, hypodermic injectors, and dental instruments.
It is used as a flavoring agent for foods in very low concentrations; for example, in alcoholic beverages the concentration is 20 ppm; in baked goods, 12.7 ppm; meats are 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 hemoproteins.
References
Morrison, RT and Boyd, R, N. (1987). Organic Chemistry. 5th 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. (10thedition.). WileyPlus. National Center for Biotechnology Information. (2019). Methyl ethyl ketone PubChem Database. CID=6569. Retrieved from: pubchem.ncbi.nlm.nih.gov Wikipedia. (2019). Butanone. Retrieved from: en.wikipedia.org Royal Society of Chemistry. (2015). Butanone. Chemspider. Retrieved from: chemspider.com Arlem Cheprasov. (2019). What is butanone? Formula & uses. Study. Retrieved from: study.com Vasler Ben. (May 17, 2017). Butanone. Chemistry World. Recovered from: chemistryworld.com