| |||
 | |||
 | |||
| Names | |||
|---|---|---|---|
| IUPAC name Propionaldehyde | |||
| Preferred IUPAC name Propanal | |||
Other names
| |||
| Identifiers | |||
| |||
3D model (JSmol) | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
| ||
| ECHA InfoCard | 100.004.204 | ||
| EC Number |
| ||
| KEGG | |||
| RTECS number |
| ||
| UNII | |||
| UN number | 1275 | ||
| |||
| |||
| Properties | |||
| C3H6O | |||
| Molar mass | 58.080 g·mol−1 | ||
| Appearance | Colourless liquid | ||
| Odor | Pungent and 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) | ||
| 20 g/100 mL | |||
| −34.32·10−6 cm3/mol | |||
| Viscosity | 0.6cP at 20 °C | ||
| Structure | |||
| C1, O: sp2 C2, C3: sp3 | |||
| 2.52D | |||
| Hazards | |||
| GHS labelling: | |||
   | |||
| Danger | |||
| H225,H302,H315,H318,H332,H335[1] | |||
| P210,P261,P280,P304+P340+P312,P305+P351+P338,P310,P403+P235[1] | |||
| NFPA 704 (fire diamond) | |||
| Flash point | −26 °C (−15 °F; 247 K) | ||
| 175 °C (347 °F; 448 K) | |||
| Related compounds | |||
Relatedaldehydes | Acetaldehyde Butyraldehyde | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Propionaldehyde orpropanal is theorganic compound with the formula CH3CH2CHO. It is the 3-carbonaldehyde. It is a colourless, flammable liquid with a pungent and fruity odour. It is produced on a large scale industrially.
Propionaldehyde is mainly produced industrially byhydroformylation ofethylene:
In this way, several hundred thousand tons are produced annually.[2]
Propionaldehyde may also be prepared by oxidizing1-propanol with a mixture ofsulfuric acid andpotassium 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 topropionic acid.[3]
Propionaldehyde exhibits the reactions characteristic of alkylaldehydes, e.g. hydrogenation,aldol condensations, oxidations, etc. It is the simplest aldehyde with a prochiral methylene such that α-functionalized derivatives (CH3CH(X)CHO) arechiral.If water is available, propionaldehyde exists in equilibrium with1,1-propanediol, ageminal diol.
2-Methylpentanal (CH3CH2CH2CH(CH3)CHO) arises byaldol condensation of propionaldehyde followed by dehydration and hydrogenation.
Both industrially and in the laboratory, propionaldehyde has primary application as a chemical building block.[2]: 4 [4]
It is predominantly used as a precursor totrimethylolethane (CH3C(CH2OH)3) through acondensation reaction withformaldehyde. This triol is an important intermediate in the production ofalkydresins. It is used in the synthesis of several commonaroma compounds (cyclamen aldehyde,helional,lilial).[2]
Reduction of propionaldehyde givesn‑propanol, andreductive amination givespropanamine. Rising demand for non-chlorocarbon solvents has caused some manufacturers to substitutively brominaten‑propanol topropyl bromide. However, the majority of applications usen‑propanol proper inesters orglycol ethers, or as a gentlealkylant for primary and secondaryamines.[2]: 5
Oxidants instead givepropionic acid and propionates, typically used aspreservatives.[2]: 5
Many laboratory uses exploit its participation in condensation reactions.[5][better source needed] Withtert-butylamine it gives CH3CH2CH=N-t-Bu, a three-carbon building block used inorganic synthesis.[6]
Propionaldehyde along withacrolein has been detected in themolecular cloudSagittarius B2 near the center of theMilky Way Galaxy, about 26,000 light years from Earth.[7][8][9]
Measurements by the COSAC and Ptolemy instruments oncomet67/P's surface, revealed sixteenorganic compounds, four of which were seen for the first time on a comet, includingacetamide,acetone,methyl isocyanate and propionaldehyde.[10][11][12]
With anLD50 of 1690 mg/kg (oral),[2] propionaldehyde exhibits low acute toxicity, but is a lung and eye irritant and is a combustible liquid.
