Heptanal

• Enanthaldehyde
• N -heptanal

Colorless liquid with an unpleasant odor

Liquid

0.82 g · cm -3

-43 ° C

153 ° C

0.86 hPa ( 20 ° C)

Poorly in water ( 1.25 g · l-1 at 20 ° C)

1.4113 (20 ° C)

Risk

3200 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

Heptanal is an aldehyde and a colorless liquid with a sharp, unpleasant odor. The trivial name is heptaldehyde.

Occurrence and representation

Heptanal occurs naturally in the essential oils of ylang -ylang ( Cananga odorata ), clary sage (Salvia sclarea ), lemon (Citrus limon x ), bitter orange (Citrus aurantium x ), Rose (Rosa) and Hyacinth ( Hyacinthus ) ago. The formation of heptanal in the fractional distillation of castor oil has been described as early as 1878. The large-scale representation is based on the pyrolytic cleavage of Ricinolsäureestern ( Arkema ) method and on the hydroformylation of 1 -hexene with rhodium 2 -ethylhexanoate as a catalyst with the addition of 2- ethylhexanoic acid ( Oxea method).

Properties

Enanthaldehyde is an inflammatory little volatile colorless liquid from penetrating fruity to oily- greasy smell, which is miscible with alcohols and practically insoluble in water. Because of its sensitivity to oxidation hexanal is bottled under nitrogen and stabilized with 100 ppm hydroquinone.

Use

From heptanal can be produced by reduction with hydrogen addition 1- heptanol:

For the oxidation of oxygen- heptanal in the presence of rhodium catalysts at 50 ° C a yield of heptanoic acid is obtained in 95%.

In a Knoevenagel reaction of heptanal reacts with benzaldehyde under basic catalysis with high yield and selectivity (> 90 % ) for alpha- Pentylzimtaldehyd (because of the jasmine typical odor also Jasminaldehyd ) set up mostly as a cis / trans isomer mixture is used in perfume compositions.

As a by- product is formed by self-condensation of Heptanals the unpleasant rancid -smelling (Z )-2 -pentyl -2- nonenal. Heptanal can be virtually quantitatively converted to the presence of an aqueous boric acid for the azeotropic removal of the water in the (Z )-2- pentyl -2- nonenal.

Complete hydrogenation provides the accessible by Guerbet reaction of the branched primary alcohol is 2- heptanol Pentylnonan -1-ol.

Safety

The vapors of enanthaldehyde can form (40 ° C, ignition temperature 205 ° C flash point) with air to form an explosive mixture. Inhalation, ingestion or absorption through the skin may cause a health hazard. May cause respiratory, digestive tract and eye irritation: for example, burning, scratching. Can irritate the skin: eg burning, itching