The butanal it is an open chain aldehyde, made up of four carbon atoms, and is analogous to butane; it is in fact the second most oxidized form of the hydrocarbon butane after butyric acid. Its molecular formula is CH3CHtwoCHtwoCHO, where -CHO is the formyl group.
This aldehyde, one of the lightest, consists of a transparent, flammable liquid that is less dense than water. In addition, it is soluble in water and miscible with most organic solvents; therefore it can be used to have single phase organic mixtures.
The presence of the carbonyl group (the one with the red sphere, upper image) gives chemical polarity to the butanal molecule, and therefore the ability to experience the dipole-dipole interaction between its molecules; although no hydrogen bonds are formed between them.
This results in butanal having higher boiling and melting points than butane, but lower than those presented by n-butyl alcohol..
Butanal is used as a solvent and is an intermediate to obtain numerous products; such as vulcanization accelerators for rubbers, resins, pharmaceuticals and agrochemicals.
Butanal is a toxic compound that by inhalation can cause inflammation of the upper respiratory tract, bronchi and pulmonary edema that can even have fatal consequences.
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It was just mentioned that the formyl group, -CHO, confers polarity to the butanal or butyraldehyde molecule due to the higher electronegativity of the oxygen atom. As a result of this, its molecules can interact with each other through dipole-dipole forces..
In the upper image it is shown, with a spheres and bars model, that the butanal molecule has a linear structure. The carbon of the -CHO group has sp hybridizationtwo, while the remaining carbons sp hybridization3.
Not only that, but it is also flexible, and its links can rotate on their own axes; and thus, different conformations or conformers are generated (same compound, but with their links rotated).
The following image better explains this point:
The first conformer (the upper one) corresponds to the molecule in the first image: the methyl group on the left, -CH3, and the group -CHO, are in positions anti parallel to each other; one points up, and the other down, respectively.
Meanwhile, the second conformer (the lower one) corresponds to the molecule with -CH3 and the -CHO in eclipsed positions; that is, they both point in the same direction.
Both conformers are rapidly interchangeable, and therefore the butanal molecule is constantly rotating and vibrating; and added the fact that it has a permanent dipole, this allows its interactions to be strong enough to boil at 74.8ºC..
-Butanal
-Butyraldehyde
-1-Butanal
-Butyral
-N-Butyraldehyde.
C4H8O or CH3CHtwoCHtwoCHO.
It is a clear, transparent liquid.
Characteristic, pungent, aldehyde odor.
167ºF to 760mmHg (74.8ºC).
-146 ºF (-96.86 ºC).
-8ºF (-22ºC) closed cup.
7 g / 100 mL at 25 ºC.
Miscible with ethanol, ether, ethyl acetate, acetone, toluene, and many other organic solvents.
0.803 g / cm3 at 68ºF.
2.5 (in relation to air taken equal to 1).
111 mmHg at 25 ºC.
446ºF. 425ºF (21.8ºC).
0.45 cPoise at 20 ° C.
2479.34 kJ / mol at 25 ºC.
33.68 kJ / mol at 25 ºC.
29.9 dyne / cm at 24 ºC.
0.009 ppm.
1.3843 at 20 ºC.
2.72 D.
225 nm and 282 nm (ultraviolet light).
Butanal can polymerize in contact with alkalis or acid, polymerization being dangerous.
When exposed to air it oxidizes, forming butyric acid. At a temperature of 230ºC, butanal ignites spontaneously with air.
Two molecules of butanal can react with each other, in the presence of KOH and a temperature of 6-8 ° C, to form the compound 2-ethyl-3-hydroxyhexanol. This type of compound is called aldol, since it has in its structure an aldehyde group and an alcoholic group.
Butanal can be produced by the catalytic dehydrogenation of n-butyl alcohol; the catalytic hydrogenation of crotonaldehyde; and the hydroformylation of propylene.
-Butanal is an industrial solvent, but it is also an intermediate in the synthesis of other solvents; for example 2-ethylhexanol, n-butanol and trimethylpropane.
-It is also used as an intermediate in the production of synthetic resins, including polyvinyl butyral; rubber vulcanization accelerators; manufacture of pharmaceutical products; crop protection products; pesticides; antioxidants; tanning aids.
-Butanal is used as a raw material for the production of synthetic aromas. In addition, it is used as a food flavoring agent.
-In man, butanal is used as a biomarker indicative of oxidative damage experienced by lipids, proteins and nucleic acids.
-It was used experimentally, together with formalin and glutardehyde, to try to reduce the softening experienced by the hoofs of cattle, due to exposure to water, urine and feces of the cattle themselves. The experimental results were positive.
Butanal is destructive to the membranes of the mucous tissue of the upper respiratory tract, as well as to the tissues of the skin and eyes..
By contact with the skin causes redness and burns. In the eyes, the same injuries occur, accompanied by pain and damage to the eye tissue.
Inhalation of butanal can have serious consequences, since it can cause inflammation and edema in the larynx and bronchi; while in the lungs, it produces chemical pneumonia and pulmonary edema.
Signs of overexposure include: burning sensations in the upper respiratory tract, coughing, wheezing, ie, wheezing when breathing; laryngitis, shortness of breath, headache, nausea and also vomiting.
Inhalation can be fatal as a result of respiratory tract spasm.
The ingestion of butanal causes a sensation of "burning" in the digestive tract: oral cavity, pharynx, esophagus and stomach.
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