Pentanal (also called valeraldehyde) is the organic compound with molecular formula C4H9CHO. Classified as an alkyl aldehyde, it is a colorless volatile liquid. Its odor is described as fermented, bready, fruity, nutty, berry.[4]
 | |
 | |
| Names | |
|---|---|
| Preferred IUPAC name Pentanal | |
| Other names Pentanaldehyde Valeraldehyde Valeric aldehyde | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.003.442 |
PubChem CID | |
| UNII | |
| UN number | 2058 |
CompTox Dashboard (EPA) | |
| |
| |
| Properties | |
| C5H10O | |
| Molar mass | 86.134 g·mol−1 |
| Appearance | Clear liquid |
| Odor | Strong, acrid, pungent |
| Density | 0.8095 at 20 °C |
| Melting point | −60 °C (−76 °F; 213 K) |
| Boiling point | 102 to 103 °C (216 to 217 °F; 375 to 376 K) |
| 14 g/L (20 °C) | |
| Vapor pressure | 0.35 kPa (20 °C)[3] |
| Viscosity | 0.6 mPa·s (20 °C) |
| Hazards | |
| GHS labelling: | |
  | |
| NFPA 704 (fire diamond) | |
| Flash point | 12 °C (54 °F; 285 K)[3] |
| 220 °C (428 °F; 493 K) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 3200 mg/kg (oral, rat) 4860 mg/kg (dermal, rabbit) |
LC50 (median concentration) | 14.3 ppm (rat, 4h) |
| NIOSH (US health exposure limits): | |
PEL (Permissible) | none[3] |
REL (Recommended) | TWA 50 ppm (175 mg/m3)[3] |
IDLH (Immediate danger) | N.D.[3] |
| Safety data sheet (SDS) | Fisher Scientific |
| Related compounds | |
Related aldehydes | Butyraldehyde |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Production
Pentanal is obtained by hydroformylation of butene. Also C4 mixtures can be used as starting material like the so-called raffinate II, which is produced by steam cracking and contains (Z)- and (E)-2-butene, 1-butene, butane and isobutane. The conversion to the product is accomplished with synthesis gas in the presence of a catalyst consisting of a rhodium-bisphosphite complex and a sterically hindered secondary amine with a selectivity toward pentanal of at least 90%.[5]
Use
Pentanal undergoes the reactions characteristic of any alkyl aldehyde, i.e., oxidations, condensations, and reductions. 2-Octanone, produced for use in the fragrance industry, is obtained by the condensation of acetone and pentanal, followed by hydrogenation of the alkene.[6]
2-Propyl-2-heptenal is obtained from pentanal by aldol condensation, which is hydrogenated to the saturated branched 2-propylheptanol. This alcohol serves as a starting material for the PVC plasticizer di-2-propylheptyl phthalate (DPHP).
Pentanal (valeraldehyde) is oxidized to give valeric acid.[7]