2-methylundecanal

Structural formula
Structural formula without stereochemistry
General
Surname	2-methylundecanal
other names	( RS ) -2-methylundecanal ( R ) -2-methylundecanal ( S ) -2-methylundecanal rac -2-methylundecanal (±) -2-methylundecanal (+) - 2-methylundecanal (-) - 2-methylundecanal Methylnonylacetaldehyde Aldehyde C12 MNA METHYLUNDECANAL ( INCI )
Molecular formula	C 12 H 24 O
Brief description	colorless liquid with a fruity odor
External identifiers / databases
CAS number 110-41-8 EC number 203-765-0 ECHA InfoCard 100.003.424 PubChem 61031 Wikidata Q209447
properties
Molar mass	184.32 g mol −1
Physical state	liquid
density	0.83 g cm −3
boiling point	171 ° C
solubility	soluble in alcohol, insoluble in water
Refractive index	1.432 (20 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319-412 P: ?
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

2-methylundecanal is a chemical compound that became known as the first fully synthetic fragrance in 1921 in Chanel Nº 5 as a top note . It occurs naturally in the peel of the kumquat fruit. The compound smells herbaceous, like orange and amber . In high dilution it smells of honey and nuts. The compound is a colorless to slightly yellowish liquid that is easily soluble in organic solvents such as ethers and ethanol . It is used as a fragrance in soaps, detergents, and perfumes.

Chemical properties and extraction

2-Methylundecanal belongs to the group of aliphatic aldehydes .

The compound was first synthesized by Georges Darzens in 1904 from 2-undecanone ( methyl nonyl ketone) and chloroacetic acid using the Darzens reaction. The synthetic route is still in use today.

Two synthetic routes are being used industrially. One synthesis takes place via the reaction of 2-undecanone and alkyl chloroacetate with saponification and decarboxylation .

${\displaystyle \mathrm {CH_{3}(CH_{2})8C(O)CH_{3}+ClCH_{2}CO_{2}CH_{3}\longrightarrow } }$ ${\displaystyle \mathrm {CH_{3}(CH_{2})_{8}CH(CH_{3})OCH(CO_{2}R)+HCl} }$

${\displaystyle \mathrm {CH_{3}(CH_{2})_{8}CCH_{3}OCCO_{2}CH_{3}+H_{2}O\longrightarrow } }$ ${\displaystyle \mathrm {CH_{3}(CH_{2})_{8}CH(CH_{3})CHO+CO_{2}+ROH} }$

The second method starts with the conversion of undecanal with formaldehyde in the presence of a base followed by hydrogenation. The starting material undecanal can be obtained from 1-decene via hydroformylation .

${\displaystyle \mathrm {CH_{3}(CH_{2})_{7}CH_{2}=CH_{2}+H_{2}+CO\longrightarrow } }$ ${\displaystyle \mathrm {CH_{3}(CH_{2})_{10}CHO} }$

${\displaystyle \mathrm {CH_{3}(CH_{2})_{10}CHO+HCHO\longrightarrow } }$ ${\displaystyle \mathrm {CH_{3}(CH_{2})_{8}C(CH_{2})CHO+H_{2}O} }$

${\displaystyle \mathrm {CH_{3}(CH_{2})_{8}C(CH_{2})CHO+H_{2}\longrightarrow } }$ ${\displaystyle \mathrm {CH_{3}(CH_{2})_{8}CH(CH_{3})CHO} }$

Stereoisomerism

2-methylundecanal contains a stereocenter, so there are two enantiomers, ( R ) -2-methylundecanal (top) and ( S ) -2-methylundecanal (bottom):

The enantiomers can be specifically produced using Enders reagent (SAMP / RAMP method).

Individual evidence

1. ↑ Entry on METHYLUNDECANAL in the CosIng database of the EU Commission, accessed on March 11, 2020.
2. ↑ ^{a b c} thegoodscentscompany.com: Entry on 2-methyl undecanal (aldehyde C-12 mna) , accessed on June 10, 2013.
3. ↑ ^{a b} data sheet 2-methylundecanal from Sigma-Aldrich , accessed on September 9, 2010 ( PDF ).
4. ↑ Entry on 2-methylundecanal in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .
5. ↑ Molecule of the Month: Chanel No. 5 and 2-methylundecanal .
6. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-378.
7. ↑ Comptes Rendus Hebdomadaires of seances de l'Academie des Sciences.
8. ↑ Ullmann's Encyclopedia of Industrial Chemistry , 7th edition. Edition, John Wiley & Sons Inc., Hoboken 2009. l.
9. ^ Kurt Bauer, Dorothea Garbe, Horst Surburg: Common fragrance and flavor materials . Wiley-VCH, 1997, p. 14 ( limited preview in Google Book search).
10. ↑ Dieter Enders, Hubert Dyker: Synthesis and properties of the enantiomers of the two artificial fragrances lilial and methylundecanal. In: Liebig's annals of chemistry. 1990, 1990, pp. 1107-1110, doi : 10.1002 / jlac.1990199001200 .

literature

• John Emsley: Perfume, Port Wine, PVC ... Chemistry in Everyday Life , 1st edition, Wiley-VCH, 2003, ISBN 978-3-527-30789-0 .