# Propionaldehyde

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> Markdown URL: https://mediated.wiki/source/Propionaldehyde.md
> Source: https://en.wikipedia.org/wiki/Propionaldehyde
> Source revision: 1325133365
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{distinguish|text=[propan'''o'''l](/source/Propanol)}}
{{chembox
| Watchedfields  = changed
| verifiedrevid  = 464216678
| Name           = Propionaldehyde
| ImageFile      = 
| ImageFileL1    = Skeletal formula of propionaldehyde.svg
| ImageClassL1 = skin-invert-image
| ImageNameL1    = Skeletal formula of propionaldehyde (propanal)
| ImageFileR1    = Propionaldehyde_flat_structure.png
| ImageClassR1 = skin-invert-image
| ImageNameR1    = Flat structure
| ImageFile2     = Propionaldehyde-3D-balls.png
| ImageClass2 = bg-transparent
| ImageSize2     = 180px
| ImageName2     = Ball-and-stick model
| ImageFile3     = Propionaldehyde.jpg
| ImageSize3     = 220px
| IUPACName      = Propionaldehyde
| PIN            = Propanal
| OtherNames     = {{unbulleted list|Methylacetaldehyde|Propionic aldehyde|Propaldehyde|Propan-1-one}}
| Section1       = {{Chembox Identifiers
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = AMJ2B4M67V
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 17153
| SMILES = CCC=O
| PubChem = 527
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 275626
| KEGG = C00479
| 3DMet = B01258
| EC_number = 204-623-0
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C3H6O/c1-2-3-4/h3H,2H2,1H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = NBBJYMSMWIIQGU-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 123-38-6
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 512
| UNNumber = 1275
| RTECS = UE0350000
  }}
| Section2       = {{Chembox Properties
| C=3 | H=6 | O=1
| Appearance = Colourless liquid
| Odor = Pungent and fruity
| Density = 0.81 g cm<sup>−3</sup>
| Solubility = 20 g/100 mL
| MeltingPtC = −81
| BoilingPtC = 46 to 50
| Viscosity = 0.6 [cP](/source/Poise_(unit)) at 20&nbsp;°C
| MagSus = −34.32·10<sup>−6</sup> cm<sup>3</sup>/mol
  }}
| Section3       = {{Chembox Structure
| MolShape = C<sub>1</sub>, O: sp<sup>2</sup>
C<sub>2</sub>, C<sub>3</sub>: sp<sup>3</sup>
| Dipole = 2.52 [D](/source/Debye)
  }}
| Section4       = 
| Section5       = 
| Section6       = 
| Section7       = {{Chembox Hazards
| GHSPictograms = {{GHS02}} {{GHS05}} {{GHS07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|225|302|332|315|318|335}}<ref name="GESTIS">{{GESTIS|ZVG=13760 |CAS=123-38-6 |Name=Propanal |Date=22 March 2020 }}</ref>
| PPhrases = {{P-phrases|210|261|280|304+340+312|305+351+338|310|403+235}}<ref name=GESTIS/>
| ExternalSDS = 
| NFPA-H = 2
| NFPA-F = 3
| NFPA-R = 2
| FlashPtC = −26
| AutoignitionPtC = 175
  }}
| Section8       = {{Chembox Related
| OtherFunction_label = [aldehyde](/source/aldehyde)s
| OtherFunction = [Acetaldehyde](/source/Acetaldehyde)<br />[Butyraldehyde](/source/Butyraldehyde)
  }}
}}

'''Propionaldehyde''' or '''propanal''' is the [organic compound](/source/organic_compound) with the formula CH<sub>3</sub>CH<sub>2</sub>CHO. It is the 3-carbon [aldehyde](/source/aldehyde). It is a colourless, flammable liquid with a pungent and fruity odour. It is produced on a large scale industrially.

==Production==
Propionaldehyde is mainly produced industrially by [hydroformylation](/source/hydroformylation) of [ethylene](/source/ethylene):
:CO + H<sub>2</sub> + C<sub>2</sub>H<sub>4</sub> → CH<sub>3</sub>CH<sub>2</sub>CHO
In this way, several hundred thousand tons are produced annually.<ref name=Ullmann>{{Ullmann|doi= 10.1002/14356007.a22_157.pub3|title=Propanal|year=2018|last1=Hensel|first1=A.|isbn=978-3527306732}}</ref>

===Laboratory preparation===
Propionaldehyde may also be prepared by oxidizing [1-propanol](/source/1-propanol) with a mixture of [sulfuric acid](/source/sulfuric_acid) and [potassium dichromate](/source/potassium_dichromate). The reflux condenser contains water heated at 60&nbsp;°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](/source/propionic_acid).<ref>{{cite journal | doi= 10.15227/orgsyn.012.0064| volume = 12 | page = 64 | year = 1932 | title = Propionaldehyde | first1= Charles D.|last1=Hurd|first2=R. N.|last2=Meinert| journal = Organic Syntheses }}</ref>

==Reactions==
{{main|Aldehyde}}
Propionaldehyde exhibits the reactions characteristic of alkyl [aldehyde](/source/aldehyde)s, e.g. hydrogenation, [aldol condensation](/source/aldol_condensation)s, oxidations, etc. It is the simplest aldehyde with a prochiral methylene such that α-functionalized derivatives (CH<sub>3</sub>CH(X)CHO) are [chiral](/source/chiral).
If water is available, propionaldehyde exists in equilibrium with '''1,1-propanediol''', a [geminal diol](/source/geminal_diol).

[2-Methylpentanal](/source/2-Methylpentanal) ({{chem2|CH3CH2CH2CH(CH3)CHO}}) arises by [aldol condensation](/source/aldol_condensation) of propionaldehyde followed by dehydration and hydrogenation.

==Uses==
Both industrially and in the laboratory, propionaldehyde has primary application as a chemical building block.<ref name=Ullmann/>{{Rp|4}}<ref>{{cite journal |first1=Pius A.|last1=Wehrli|first2=Vera|last2=Chu|doi=10.15227/orgsyn.058.0079|title=Y-Ketoesters from Aldehydes Via Diethyl Acylsuccinates: Ethyl 4-Oxohexanoate|journal=Organic Syntheses|year=1978|volume=58|page=79}}</ref>  

It is predominantly used as a precursor to [trimethylolethane](/source/trimethylolethane) (CH<sub>3</sub>C(CH<sub>2</sub>OH)<sub>3</sub>) through a [condensation reaction](/source/condensation_reaction) with [formaldehyde](/source/formaldehyde). This triol is an important intermediate in the production of [alkyd](/source/alkyd) [resin](/source/resin)s. It is used in the synthesis of several common [aroma compound](/source/aroma_compound)s ([cyclamen aldehyde](/source/cyclamen_aldehyde), [helional](/source/helional), [lilial](/source/lilial)).<ref name=Ullmann/>

Reduction of propionaldehyde gives [''n''{{nbh}}propanol](/source/n-propanol), and [reductive amination](/source/reductive_amination) gives [propanamine](/source/propanamine).  Rising demand for non-chlorocarbon solvents has caused some manufacturers to substitutively brominate ''n''{{nbh}}propanol to [propyl bromide](/source/1-bromopropane).  However, the majority of applications use ''n''{{nbh}}propanol proper in [ester](/source/ester)s or [glycol ether](/source/glycol_ether)s, or as a gentle [alkylant](/source/alkylant) for primary and secondary [amine](/source/amine)s.<ref name=Ullmann/>{{rp|5}}  

Oxidants instead give [propionic acid](/source/propionic_acid) and propionates, typically used as [preservatives](/source/food_preservative).<ref name=Ullmann/>{{rp|5}}  

===Laboratory uses===
Many laboratory uses exploit its participation in condensation reactions.<ref>See, e.g., {{OrgSynth|title=3,4-Diethylpyrrole and 2,3,7,8,12,13,17,18-Octaethylporphyrin|first1=Jonathan L.|last1=Sessler|first2=Azadeh|last2=Mozaffari|first3=Martin R.|last3=Johnson|prep=CV9P0242|year=1992|volume=70|page=68|doi=10.15227/orgsyn.070.0068}}</ref>{{better source needed|date=October 2021}} With [''tert''-butylamine](/source/Tert-Butylamine) it gives CH<sub>3</sub>CH<sub>2</sub>CH=N-''t''-Bu, a three-carbon building block used in [organic synthesis](/source/organic_synthesis).<ref>Peralta, M. M. "Propionaldehyde t-Butylimine" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. {{doi|10.1002/047084289X.rp271}}.</ref>

==Extraterrestrial occurrence==
Propionaldehyde along with [acrolein](/source/acrolein) has been detected in the [molecular cloud](/source/molecular_cloud) [Sagittarius B2](/source/Sagittarius_B2) near the center of the [Milky Way Galaxy](/source/Milky_Way_Galaxy), about 26,000 light years from Earth.<ref>[https://www.nrao.edu/pr/2004/GBTMolecules/ Scientists Discover Two New Interstellar Molecules: Point to Probable Pathways for Chemical Evolution in Space], National Radio Astronomy Observatory, June 21, 2004</ref><ref>Two newly found space molecules. By: Goho, Alexandra, Science News, 00368423, 7/24/2004, Vol. 166, Issue 4</ref><ref>[http://news.softpedia.com/news/Chemical-Precursors-to-Life-Found-in-Space-32259.shtml Chemical Precursors to Life Found in Space Scientists say that a universal prebiotic chemistry may be at work]</ref>

Measurements by the COSAC and Ptolemy instruments on [comet](/source/comet) [67/P](/source/67%2FP){{'s}} surface, revealed sixteen [organic compound](/source/organic_compound)s, four of which were seen for the first time on a comet, including [acetamide](/source/acetamide), [acetone](/source/acetone), [methyl isocyanate](/source/methyl_isocyanate) and propionaldehyde.<ref name="wapo20150730">{{cite news |url=https://www.washingtonpost.com/world/philae-probe-finds-evidence-that-comets-can-be-cosmic-labs/2015/07/30/63a2fc0e-36e5-11e5-ab7b-6416d97c73c2_story.html |archive-url=https://web.archive.org/web/20181223235109/https://www.washingtonpost.com/world/philae-probe-finds-evidence-that-comets-can-be-cosmic-labs/2015/07/30/63a2fc0e-36e5-11e5-ab7b-6416d97c73c2_story.html |url-status=dead |archive-date=23 December 2018 |title=Philae probe finds evidence that comets can be cosmic labs |newspaper=The Washington Post |agency=Associated Press |first=Frank |last=Jordans |date=30 July 2015 |access-date=30 July 2015}}</ref><ref name="esa20150730">{{cite web |url=https://www.esa.int/Our_Activities/Space_Science/Rosetta/Science_on_the_surface_of_a_comet |title=Science on the Surface of a Comet |publisher=European Space Agency |date=30 July 2015 |access-date=30 July 2015}}</ref><ref name="SCI-20150731">{{cite journal |last1=Bibring |first1=J.-P. |last2=Taylor |first2=M.G.G.T. |last3=Alexander |first3=C. |last4=Auster |first4=U. |last5=Biele |first5=J. |last6=Finzi |first6=A. Ercoli |last7=Goesmann |first7=F. |last8=Klingehoefer |first8=G. |last9=Kofman |first9=W. |last10=Mottola |first10=S. |last11=Seidenstiker |first11=K.J. |last12=Spohn |first12=T. |last13=Wright |first13=I. |title=Philae's First Days on the Comet - Introduction to Special Issue |date=31 July 2015 |journal=[Science](/source/Science_(journal)) |volume=349 |issue=6247 |page=493 |doi=10.1126/science.aac5116 |bibcode=2015Sci...349..493B |pmid=26228139|doi-access=free |url=https://elib.dlr.de/97953/1/Science-2015-Bibring-493.pdf }}</ref>

==Safety==
With an {{LD50}} of 1690 mg/kg (oral),<ref name=Ullmann/> propionaldehyde exhibits low acute toxicity, but is a lung and eye irritant and is a combustible liquid.

==References==
<references/>

{{Commons category}}

{{Molecules detected in outer space}}
{{Authority control}}

Category:Alkanals

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Adapted from the Wikipedia article [Propionaldehyde](https://en.wikipedia.org/wiki/Propionaldehyde) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Propionaldehyde?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.