Propionaldehyde

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Propionaldehyde
Skeletal formula of propionaldehyde (propanal)
Flat structure
Ball-and-stick model
Names
IUPAC name
Propanal
Systematic IUPAC name
Propanal
Other names
  • Methylacetaldehyde
  • Propionic aldehyde
  • Propaldehyde
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.204
UNII
UN number 1275
Properties
C3H6O
Molar mass 58.080 g·mol−1
Appearance Colorless liquid
Pungent, fruity 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
-34.32·10−6 cm3/mol
Viscosity 0.6 cP at 20 °C
Structure
C1, O: sp2

C2, C3: sp3

2.52 D
Hazards
GHS pictograms GHS02: Flammable GHS05: Corrosive GHS07: Harmful
GHS Signal word Danger
H225, H302, H332, H315, H318, H335[1]
P210, P261, P280, P304+340+312, P305+351+338, P310, P403+235[1]
NFPA 704 (fire diamond)
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no codeNFPA 704 four-colored diamond
3
2
2
Flash point −26 °C (−15 °F; 247 K)
175 °C (347 °F; 448 K)
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).
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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 colorless liquid with a slightly irritating, fruity odor.

Production[edit]

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.[2]

Laboratory preparation[edit]

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.[3]

Uses[edit]

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.[2]

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.[4]

Extraterrestrial occurrence[edit]

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.[5][6][7]

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.[8][9][10]

References[edit]

  1. ^ a b Record of Propanal in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 22 March 2020.
  2. ^ a b Anthony J. Papa "Propanal" In Ullmann's Encyclopedia of Industrial Chemistry, 2011, WIley-VCH, Weinheim. doi:10.1002/14356007.a22_157.pub2
  3. ^ Charles D. Hurd and R. N. Meinert (1943). "Propionaldehyde". Organic Syntheses.; Collective Volume, 2, p. 541
  4. ^ 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.
  5. ^ Scientists Discover Two New Interstellar Molecules: Point to Probable Pathways for Chemical Evolution in Space, National Radio Astronomy Observatory, June 21, 2004
  6. ^ Two newly found space molecules. By: Goho, Alexandra, Science News, 00368423, 7/24/2004, Vol. 166, Issue 4
  7. ^ Chemical Precursors to Life Found in Space Scientists say that a universal prebiotic chemistry may be at work
  8. ^ Jordans, Frank (30 July 2015). "Philae probe finds evidence that comets can be cosmic labs". The Washington Post. Associated Press. Retrieved 30 July 2015.
  9. ^ "Science on the Surface of a Comet". European Space Agency. 30 July 2015. Retrieved 30 July 2015.
  10. ^ Bibring, J.-P.; Taylor, M.G.G.T.; Alexander, C.; Auster, U.; Biele, J.; Finzi, A. Ercoli; Goesmann, F.; Klingehoefer, G.; Kofman, W.; Mottola, S.; Seidenstiker, K.J.; Spohn, T.; Wright, I. (31 July 2015). "Philae's First Days on the Comet - Introduction to Special Issue". Science. 349 (6247): 493. Bibcode:2015Sci...349..493B. doi:10.1126/science.aac5116. PMID 26228139.