Propionaldehyde

Structural formula
General
Surname	Propionaldehyde
other names	Propanal ( IUPAC ) Methyl acetaldehyde Propyl aldehyde
Molecular formula	C 3 H 6 O
Brief description	colorless liquid with a pungent odor
External identifiers / databases
CAS number 123-38-6 EC number 204-623-0 ECHA InfoCard 100.004.204 PubChem 527 ChemSpider 512 Wikidata Q422909
properties
Molar mass	58.08 g mol −1
Physical state	liquid
density	0.81 g cm −3
Melting point	−81 ° C
boiling point	49 ° C
Vapor pressure	341 h Pa (20 ° C) 516 hPa (30 ° C) 757 hPa (40 ° C) 1080 hPa (50 ° C)
solubility	Easily soluble in water (679 g l −1 at 25 ° C) miscible with ethanol and diethyl ether
Refractive index	1.3650
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 225-302 + 332-315-318-335 P: 210-261-280-304 + 340 + 312-305 + 351 + 338-310-403 + 235
Toxicological data	1410 mg kg −1 ( LD 50 ,  rat ,  oral ) 2460 mg kg −1 ( LD 50 ,  rabbit ,  transdermal )
Thermodynamic properties
ΔH f 0	−215.6 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Propionaldehyde (according to IUPAC nomenclature: propanal , sometimes also referred to as propylaldehyde ) is an organic-chemical compound from the group of aldehydes . It is an important basic and intermediate product in the chemical industry that is widely used.

Extraction and presentation

Propanal can be produced by the hydroformylation of ethene .

The oxidation of n- propanol with potassium dichromate and sulfuric acid also leads to propanal. Atmospheric oxygen in the presence of the catalysts copper or platinum can also be used as the oxidizing agent .

Propanal can also be synthesized by isomerizing propylene oxide at 300 ° C over silica gel :

Another synthesis option is the catalytic hydrogenation of acrolein :

Finally, the synthesis of propanal is also possible by a Grignard reaction of ethyl magnesium bromide with ethyl formate .

properties

Physical Properties

Propanal is a volatile, colorless liquid with a pungent odor. It boils at 49 ° C under normal pressure . The heat of vaporization at the boiling point is 28.3 kJ mol ⁻¹ . According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in Torr, T in ° C) with A = 7.26342, B = 1277.1176 and C = 242.556 in the temperature range from -38.65 to 231.25 ° C. It has a dynamic viscosity of 0.375 mPas at 20 ° C.

Compilation of the most important thermodynamic properties

property	Type	Value [unit]	Remarks
Standard enthalpy of formation	Δ f H 0 liquid Δ f H 0 gas	−218.3 kJ mol −1 −188.7 kJ mol −1
Standard entropy	S 0 l S 0 g	212.9 J mol −1 K −1 304.4 J mol −1 K −1	as a liquid as a gas
Enthalpy of combustion	Δ c H 0 liquid	−1816.5 kJ mol −1
Heat capacity	c p	159.1 J mol −1 K −1 (25 ° C) 80.73 J mol −1 K −1 (25 ° C)	as a liquid as a gas
Critical temperature	T c	504.4 K
Critical pressure	p c	52.6 bar
Critical density	ρ c	4.91 mol·l −1
Enthalpy of fusion	Δ f H	8.59 kJ mol −1	at the melting point
Enthalpy of evaporation	Δ V H 0	29.96 kJ mol −1

Chemical properties

The aldol addition of two molecules of propanal yields 2-methyl-3-hydroxypentanal, which can react further to form 2-methyl-2-pentenal with elimination of water as part of the aldol condensation . This β-dehydration takes place in particular with acid catalysis and heating.

use

Propionaldehyde is an important precursor and intermediate in industrial organic chemistry . It is mainly used for the production of plastics , plasticizers , rubber auxiliary products , vulcanization accelerators , phenolic resins , demulsifiers , flavor - and fragrances , agricultural chemicals , pesticides and pharmaceuticals . Technically, numerous products are synthesized from propionaldehyde. These include, in particular, 1-propanol , 1-propylamine , propionic acid , trimethylolethane , methacrolein and propionitrile . In addition, propionaldehyde is reacted with acetaldehyde to form copolymers . Propionaldehyde is also an important starting material for the production of alkyl pyridines , imidazoles , 3-methylindole and other heterocycles . In organic synthesis chemistry , propionaldehyde is used in acetalizations , imine formations , olefinations , organometallic and aldol reactions .

proof

Propanal reacts with the indicator Schiff's reagent . This aldehyde turns the reagent pink to purple in color.

safety instructions

The vapors of propionaldehyde form with air explosive mixtures. Self-ignition can also occur when distributed over large surfaces . Propanal is mainly absorbed through the respiratory tract and skin . Furthermore, absorption via the digestive tract has been proven. Ingestion or exposure can cause acute irritation to the eyes , respiratory tract and skin. A narcotic effect is possible with prolonged inhalation . Liver and kidney damage can occur chronically . Sufficient information is not available on reproductive toxicity and carcinogenicity , but a certain mutagenic effect was determined in some tests , which, however, is inconsistent and is therefore controversial. Propionaldehyde has a lower explosion limit (LEL) of 2.3% by volume (55 g / m ³ ) and an upper explosion limit (UEL) of 21.0% by volume (510 g / m ³ ). The ignition temperature is 190 ° C. The substance therefore falls into temperature class T4 and explosion group IIB. The limit gap width was determined to be 0.84 mm. With a flash point of −40 ° C, propionaldehyde is very easily inflammable.

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n o p q} Entry on propionaldehyde in the GESTIS substance database of the IFA , accessed on April 19, 2019(JavaScript required) .
2. ↑ ^{a b c d} Entry on propionaldehyde. In: Römpp Online . Georg Thieme Verlag, accessed on April 19, 2019.
3. ↑ Entry on propionaldehyde in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on April 19, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-24.
5. ↑ JD Unruh, D. Pearson: n-Propyl Alcohol. In: Kirk-Othmer Encyclopedia of Chemical Technology . doi: 10.1002 / 0471238961.1618151621141821.a01 .
6. ↑ ^{a b c} C. D. Hurd, RN Meinert: Propionaldehyde In: Organic Syntheses . 12, 1932, p. 64, doi : 10.15227 / orgsyn.012.0064 ; Coll. Vol. 2, 1943, p. 541 ( PDF ).
7. ↑ P. Sabatier, J.-B. Sanderens: Dédoublement catalytique des alcools par les métaux divisés: alcools primaires forméniques. In: Compt. Rend. Hebd. 136, 1903, pp. 921ff. (Full text)
8. ↑ A. Trillat: Étude de l'oxidation catalytique des Alcools (cas de la spirale de platine). In: Bull. Soc. Chim. 3, 29, 1903, pp. 35ff. (Full text)
9. ↑ P. Sabatier, J.-B. Senderens: Nouvelles méthodes générales d'hydrogénation. In: Ann. phys. chim. 8, 4, 1905, p. 398. (full text)
10. ^ JF Counsel, DA Lee: Thermodynamic properties of organic oxygen compounds 30. Vapor heat capacity and enthalpy of vaporization of propanal. In: J. Chem. Thermodyn. 4, 1972, pp. 915-917, doi: 10.1016 / 0021-9614 (72) 90013-4 .
11. ^ Carl L. Yaws: The Yaws Handbook of Vapor Pressure - Antoine Coefficients. 2nd Edition. Elsevier, 2015, ISBN 978-0-12-802999-2 , p. 13, doi: 10.1016 / B978-0-12-802999-2.00004-0 .
12. ↑ ^{a b} K. B. Wiberg, LS Crocker, KM Morgan: Thermochemical studies of carbonyl compounds. 5. Enthalpies of reduction of carbonyl groups. In: J. Am. Chem. Soc. 113, 1991, pp. 3447-3450.
13. ↑ ^{a b c} A. D. Korkhov, IA Vasil'ev: Heat capacity and thermodynamic functions of propanal at low temperatures. In: Termodin. Org. Soedin. 6, 1977, pp. 34-37.
14. ↑ JE Connett: Chemical equilibria. 5. Measurement of equilibrium constants for the dehydrogenation of propanol by a vapor flow technique. In: J. Chem. Thermodyn. 4, 1972, pp. 233-237.
15. ↑ J. Tjebbes: Heats of combustion of propanal and 2-methyl propanal. In: Acta Chem. Scand. 16, 1962, pp. 953-957.
16. ^ J. Chao: Thermodynamic properties of key organic oxygen compounds in the carbon range C1 to C4. Part 2. Ideal gas properties. In: J. Phys. Chem. Ref. Data . 15, 1986, pp. 1369-1436.
17. ↑ ^{a b} A. S. Teja, DJ Rosenthal: The Critical Pressures and Temperatures of Twelve Substances Using A Low Residence Time Flow Apparatus. In: AIChE Symp. Ser. 86, 279, 1990, pp. 133-137.
18. ↑ MJ Anselme, AS Teja: The critical properties of rapidly reacting substances. In: AIChE Symp. Ser. 86, 279, 1990, pp. 128-132.
19. ^ V. Majer, V. Svoboda: Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation. Blackwell Scientific Publications, Oxford 1985, p. 300.

Web links

Commons : Propanal  - collection of images, videos and audio files

Wiktionary: Propionaldehyde  - explanations of meanings, word origins, synonyms, translations