Propionaldehyde

Propionaldehyde

Colorless liquid with a pungent, aromatic odor

Liquid

0.80 g · cm -3

-81 ° C

49 ° C

341 hPa ( 20 ° C)

• Good in water ( 200 g · l-1 at 20 ° C)
• Miscible with ethanol and diethyl ether

1.3650

Risk

1410 mg · kg -1 ( LD50, rat, oral)

-215.6 KJ / mol

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Propanal or propionaldehyde is one of the lower, more volatile aldehydes and is a mobile, colorless liquid.

Representation

Propanal can be prepared by the hydroformylation of ethylene.

The oxidation of n-propanol with sulfuric acid, potassium dichromate and also leads to propanal. As an oxidizing agent and copper, or platinum may be used.

By isomerization of propylene oxide at 300 ° C over silica gel can be synthesized propanal.

Another possibility is the synthesis of the catalytic hydrogenation of acrolein.

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

Use

Propanal is a starting material for the production of plastics, plasticizers, perfumes and pharmaceuticals. As a perfume propanal offers the scent characteristic: pungent, suffocating, pungent, fruity.

Reactions

The aldol addition of two molecules of propanal provides 2-methyl- 3- hydroxypentanal which can react further with elimination of water in the aldol condensation to form 2- methyl-2- pentenal. These β - dehydration runs especially from under acid catalysis and heating.

Proof

Propanal reacts with the indicator Schiff's reagent. The reagent is colored by this aldehyde pink to purple.

Safety

Propanal has a narcotic effect on prolonged inhalation, as a result of liver and kidney damage can occur.

The flash point is -40 ° C, the ignition temperature at 190 ° C, the Explosion limits: 2.3 and 21 percent by volume.