Propionaldehyde

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Propanal
Skeletal structure of propanal
Ball-and-stick model
Names
IUPAC name
Propanal
Systematic IUPAC name
Propanal
Other names
Propionaldehyde; Methylacetaldehyde; propionic aldehyde; propaldehyde
Identifiers
123-38-6 YesY
ChEBI CHEBI:17153 YesY
ChEMBL ChEMBL275626 YesY
ChemSpider 512 YesY
Jmol 3D model Interactive image
PubChem 527
UNII AMJ2B4M67V YesY
UN number 1275
  • InChI=1S/C3H6O/c1-2-3-4/h3H,2H2,1H3 YesY
    Key: NBBJYMSMWIIQGU-UHFFFAOYSA-N YesY
  • InChI=1/C3H6O/c1-2-3-4/h3H,2H2,1H3
    Key: NBBJYMSMWIIQGU-UHFFFAOYAZ
  • CCC=O
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 to 50 °C (115 to 122 °F; 319 to 323 K)
20 g/100 mL
Viscosity 0.6 cP at 20 °C
Structure
C1, O: sp2

C2, C3: sp3

2.52 D
Vapor pressure {{{value}}}
Related compounds
Related aldehydes
Acetaldehyde
Butyraldehyde
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
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]

Extraterrestrial occurrence

Astronomers have detected propionaldehyde (along with acrolein) in the molecular cloud Sagittarius B2 near the center of the Milky Way Galaxy, about 26,000 light years from Earth.[4][5][6]

On 30 July 2015, scientists reported that upon the first touchdown of the Philae lander on comet 67/P's surface, measurements by the COSAC and Ptolemy instruments revealed sixteen organic compounds, four of which were seen for the first time on a comet, including acetamide, acetone, methyl isocyanate and propionaldehyde.[7][8][9]

References

  1. 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
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  3. 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.
  4. Scientists Discover Two New Interstellar Molecules: Point to Probable Pathways for Chemical Evolution in Space, National Radio Astronomy Observatory, June 21, 2004
  5. Two newly found space molecules. By: Goho, Alexandra, Science News, 00368423, 7/24/2004, Vol. 166, Issue 4
  6. Chemical Precursors to Life Found in Space Scientists say that a universal prebiotic chemistry may be at work
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