Propionaldehyde
| |||
Names | |||
---|---|---|---|
IUPAC name
Propanal | |||
Systematic IUPAC name
Propionaldehyde | |||
Other names
Methylacetaldehyde; propionic aldehyde; propaldehyde | |||
Identifiers | |||
123-38-6 | |||
ChEBI | CHEBI:17153 | ||
ChEMBL | ChEMBL275626 | ||
ChemSpider | 512 | ||
| |||
Jmol-3D images | Image | ||
PubChem | 527 | ||
| |||
UNII | AMJ2B4M67V | ||
UN number | 1275 | ||
Properties | |||
C3H6O | |||
Molar mass | 58.08 g mol−1 | ||
Appearance | Colorless liquid Pungent, malty odor | ||
Density | 0.81 g cm−3 | ||
Melting point | −81 °C (−114 °F; 192 K) | ||
Boiling point | 46 °C (115 °F; 319 K) | ||
20 g/100 mL | |||
Viscosity | 0.6 cP at 20 °C | ||
Structure | |||
Molecular shape | C1, O: sp2
C2, C3: sp3 | ||
Dipole moment | 2.52 D | ||
Hazards | |||
EU classification | F+ Xi | ||
R-phrases | R11, R36/37/38 | ||
S-phrases | S9, S16, S29 | ||
NFPA 704 | |||
Flash point | −26 °C (−15 °F; 247 K) | ||
175 °C (347 °F; 448 K) | |||
Related compounds | |||
Related aldehydes |
Acetaldehyde Butyraldehyde | ||
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |||
verify (what is: / ?) | |||
Infobox references | |||
Propionaldehyde or propanal is the organic compound with the formula CH3CH2CHO. It is a saturated 3-carbon aldehyde and is a structural isomer of acetone. It is a colourless liquid with a slightly irritating, fruity odour.
Production
Propionaldehyde is mainly produced industrially through hydroformylation, by combining synthesis gas (carbon monoxide and hydrogen) with ethylene using a metal (typically rhodium) catalyst:
- CO + H2 + C2H4 → CH3CH2CHO
In this way, several hundred thousand tons are produced annually.[1]
Laboratory preparation
Propionaldehyde may also be prepared by oxidizing 1-propanol with a mixture of sulfuric acid and potassium dichromate. The reflux condenser contains water heated at 60 °C, which condenses unreacted propanol, but allows propionaldehyde to pass. The propionaldehyde vapor is immediately condensed into a suitable receiver. In this arrangement, any propionaldehyde formed is immediately removed from the reactor, thus it does not get over-oxidized to propionic acid.[2]
Uses
It is principally used as a precursor to trimethylolethane (CH3C(CH2OH)3) through a condensation reaction with formaldehyde; this triol is an important intermediate in the production of alkyd resins. Other applications include reduction to propanol and oxidation to propionic acid.[1]
Condensation of propionaldehyde with tert-butylamine gives CH3CH2CH=N-t-Bu, a three-carbon building block used in organic synthesis. Deprotonation of this imine with LDA produces CH3CHLiCH=N-t-Bu, which in turn condenses with aldehydes.[3]
Interstellar occurrence
Astronomers have detected propionaldehyde in the molecular cloud Sagittarius B2 near the center of the Milky Way Galaxy, about 26,000 light years from Earth.[4][5][6] Because molecules emit energy at specific frequencies, researchers were able to identify propionaldehyde and the related compound, acrolein, by measuring radio waves emitted by the cloud.
References
- ↑ 1.0 1.1 Anthony J. Papa "Propanal" In Ullmann's Encyclopedia of Industrial Chemistry, 2011, WIley-VCH, Weinheim. doi:10.1002/14356007.a22_157.pub2
- ↑ Charles D. Hurd and R. N. Meinert (1943). "Propionaldehyde". Org. Synth.; Coll. Vol. 2, p. 541
- ↑ Peralta, M. M. "Propionaldehyde t-Butylimine" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289.
- ↑ Scientists Discover Two New Interstellar Molecules: Point to Probable Pathways for Chemical Evolution in Space, National Radio Astronomy Observatory, June 21, 2004
- ↑ Two newly found space molecules. By: Goho, Alexandra, Science News, 00368423, 7/24/2004, Vol. 166, Issue 4
- ↑ Chemical Precursors to Life Found in Space Scientists say that a universal prebiotic chemistry may be at work