Propionaldehyde

Propionaldehyde

Names
IUPAC name Propionaldehyde
Preferred IUPAC name Propanal
Other names Methylacetaldehyde Propionic aldehyde Propaldehyde Propan-1-one
Identifiers
CAS Number	123-38-6 Y
3D model (JSmol)	Interactive image
3DMet	B01258
ChEBI	CHEBI:17153 Y
ChEMBL	ChEMBL275626 Y
ChemSpider	512 Y
ECHA InfoCard	100.004.204
EC Number	204-623-0
KEGG	C00479
PubChem CID	527
RTECS number	UE0350000
UNII	AMJ2B4M67V Y
UN number	1275
CompTox Dashboard (EPA)	DTXSID2021658
InChI InChI=1S/C3H6O/c1-2-3-4/h3H,2H2,1H3 Y Key: NBBJYMSMWIIQGU-UHFFFAOYSA-N Y
SMILES CCC=O
Properties
Chemical formula	C3H6O
Molar mass	58.080 g·mol−1
Appearance	Colourless liquid
Odor	Pungent, fruity
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)
Solubility in water	20 g/100 mL
Magnetic susceptibility (χ)	-34.32·10−6 cm3/mol
Viscosity	0.6 cP at 20 °C
Structure
Molecular shape	C1, O: sp2 C2, C3: sp3
Dipole moment	2.52 D
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H302, H315, H318, H332, H335
Precautionary statements	P210, P261, P280, P304+P340+P312, P305+P351+P338, P310, P403+P235
NFPA 704 (fire diamond)	2 3 2
Flash point	−26 °C (−15 °F; 247 K)
Autoignition temperature	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). Y verify (what is YN ?) Infobox references

Propionaldehyde or propanal is the organic compound with the formula CH₃CH₂CHO. It is the 3-carbon aldehyde. It is a colourless, flammable liquid with a slightly fruity odour. It is produced on a large scale industrially.

Production

Propionaldehyde is mainly produced industrially by hydroformylation of ethylene:

CO + H₂ + C₂H₄ → CH₃CH₂CHO

In this way, several hundred thousand tons are produced annually.

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.

Reactions

Propionaldehyde exhibits the reactions characteristic of alkyl aldehydes, e.g. hydrogenation, aldol condensations, oxidations, etc. It is the simplest aldehyde with a prochiral methylene such that α-functionalized derivatives (CH₃CH(X)CHO) are chiral.

Uses

It is predominantly 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. It is used in the synthesis of several common aroma compounds (cyclamen aldehyde, helional, lilial). Other applications include reduction to propanol and oxidation to propionic acid.

Laboratory uses

Propionaldehyde is a common reagent, being a building block to many compounds. Many of these uses exploit its participation in condensation reactions. With tert-butylamine it gives CH₃CH₂CH=N-t-Bu, a three-carbon building block used in organic synthesis.

Extraterrestrial occurrence

Propionaldehyde along with acrolein has been detected in the molecular cloud Sagittarius B2 near the center of the Milky Way Galaxy, about 26,000 light years from Earth.

Measurements by the COSAC and Ptolemy instruments on comet 67/P's surface, revealed sixteen organic compounds, four of which were seen for the first time on a comet, including acetamide, acetone, methyl isocyanate and propionaldehyde.

Safety

With an LD50 of 1690 mg/kg (oral), propionaldehyde exhibits low acute toxicity.

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