Pentyl acetate
Pentyl acetate (often also amyl acetate ) are the esters of acetic acid and the eight isomeric pentyl alcohols . Other names based on their chemical structure or their properties are: amyl acetate, amyl acetate, pentyl acetate, amyl acetate, pentanol acetate, pentyl ethanoate, pear oil, pear ether or banana oil.
They are colorless, aromatic-smelling liquids with a pear or banana odor, which are usually sold as a mixture of different isomers .
There are eight different constitutional isomers of acetic acid esters with the empirical formula C 7 H 14 O 2 . The compounds 2-pentyl acetate, 2-methylbutyl acetate and 1,2-dimethylpropyl acetate each form two more stereoisomers - more precisely enantiomers . Isoamyl acetate is also one of the flavors in wine . With an odor threshold of 1 milligram / l in white wine , it is a component of the cold fermentation aroma.
Properties of the isomers
| Amyl acetate | ||||||||||||
| Surname | 1-pentyl acetate | 2-pentyl acetate | 3-pentyl acetate | Isopentyl acetate | 1,1-dimethyl propyl acetate | 2-methylbutyl acetate | ||||||
| other names | 1-pentanol acetate n -amylacetate |
( RS ) -1-methylbutyl acetate ( RS ) -acetic acid-2-pentyl ester ( RS ) - sec -Amylacetat |
3-amyl acetic ester 3-pentacetate 3-pentyl acetate 3-amyl acetate |
Acetic acid (3-methylbutyl) ester 3-methylbutyl acetate isoamyl acetate i -amylacetate i -pentyl acetate 3-methyl-1-butyl acetate |
( RS ) -acetic acid- (2-methylbutyl) ester | |||||||
| Structural formula |
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| CAS number | 628-63-7 | 626-38-0 | 620-11-1 | 123-92-2 | 625-16-1 | 624-41-9 | ||||||
| PubChem | 12348 | 12278 | 69279 | 31276 | 12238 | 12209 | ||||||
| Molecular formula | C 7 H 14 O 2 | |||||||||||
| Molar mass | 130.19 g mol −1 | |||||||||||
| Physical state | liquid | |||||||||||
| Brief description | colorless, flammable liquids with a fruity, pear-like or banana-like odor | |||||||||||
| Melting point | −71 ° C | −78.7 ° C | ? | −79 ° C | ? | ? | ||||||
| boiling point | 149 ° C | 134 ° C | 132 ° C (988 hPa) | 142 ° C | 124 ° C | 138 ° C (988 hPa) | ||||||
| density | 0.88 g / cm 3 | 0.86 g / cm 3 | 0.87 g / cm 3 | 0.87 g / cm 3 | 0.87 g / cm 3 | 0.876 g / cm 3 | ||||||
| Refractive index | 1.4031 | 1.3969 | 1.3965 | 1.4003 | 1.4050 | 1.4019 | ||||||
| solubility | poorly soluble in water (1.7 g / l at 20 ° C), good in acetone and methanol |
practically insoluble in water | ? | poorly soluble in water (2.12 g / l at 19.2 ° C) |
poorly soluble in water (5.2 g / l at 25 ° C) |
slightly soluble in water | ||||||
| Vapor pressure | 5.3 mbar (20 ° C) | 9.3 mbar (20 ° C) | ? | 5.3 mbar (20 ° C) | ? | ? | ||||||
| Flash point | 41 ° C | 32 ° C | ? | 35 ° C | 20-25 ° C | 35 ° C | ||||||
| Ignition temperature | 350 ° C | 390 ° C | ? | 380 ° C | 410 ° C | ? | ||||||
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GHS labeling |
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| H and P phrases | 226 | 226 | 226 | 226 | see above | 226 | ||||||
| 066 | 066 | 066 | 066 | see above | 066 | |||||||
| 210 | ? | ? | 210 | see above | ? | |||||||
Values for the refractive indices were taken from the SciFinder database .
Manufacturing
Pentyl acetate is produced by esterifying acetic acid with pentanols with the addition of sulfuric acid. Thus, in the esterification with arises 1-pentanol of acetic n -pentylester (1-pentyl acetate), with 2-pentanol ( sec-amyl alcohol ) of the acetic acid sec -pentylester (2-pentyl), with 3-pentanol 1-ethyl propyl acetate (3-pentyl acetate), with 2-methyl-2-butanol ( tert-pentanol ) the acetic acid tert- amyl ester (1,1-dimethylpropyl acetate ) and with 3-methyl-1-butanol the acetic acid iso- amyl ester (3 -Methylbutyl acetate), also known as pear ether.
use
Pentyl acetate is used as a solvent for paints and resins , in chromatography , as an intermediate in the production of smokeless explosives and as a flavoring ( pear ether ) in the food and perfume industries.
Isoamyl acetate was used as fuel for the Hefner candle .
The vapors or an aerosol of isoamyl acetic acid esters are called banana gas due to their characteristic smell and are used for leak testing of respiratory masks . The substance is not harmful to health even in high concentrations, but its odor can be perceived even in low concentrations. This bananas gas test , also IPA Test called (derived from I to p entyl a acetate), an examination of the forms using strong irritating tear gas follow.
Natural occurrence
Isoamyl acetate are pheromones of honey bees and are used by them to attract other bees to a certain location. The pheromone is also released when a bee stings - which then leads to other bees being stimulated to defend themselves and also stinging. 2-Methylbutyl acetate occurs in apple juice, among other things, and is used there as one of the reference substances for the apple aroma index . Widely scented amylacetates are also formed when apple tree wood is broken down by the allegedly rare white rot pathogen Sarcodontia setosa (= S. crocea ).
Individual evidence
- ↑ How does the black currant actually get into the Scheurebe? (PDF; 2.1 MB), by Dr. Rainer Amann, State. Weinbauinstitut Freiburg, in Der Badische Winzer , October 2002 edition.
- ↑ a b c d e f g Entry for CAS no. 628-63-7 in the GESTIS substance database of the IFA , accessed on September 21, 2018(JavaScript required) .
- ↑ a b c d e f g Entry for CAS no. 626-38-0 in the GESTIS substance database of the IFA , accessed on September 21, 2018(JavaScript required) .
- ↑ a b c d Entry for CAS no. 620-11-1 in the GESTIS substance database of the IFA , accessed on September 21, 2018(JavaScript required) .
- ↑ a b c d e f g h Entry for CAS no. 123-92-2 in the GESTIS substance database of the IFA , accessed on September 21, 2018(JavaScript required) .
- ↑ a b c d e f g Entry for CAS no. 625-16-1 in the GESTIS substance database of the IFA , accessed on September 21, 2018(JavaScript required) .
- ↑ a b c d e f Entry for CAS no. 624-41-9 in the GESTIS substance database of the IFA , accessed on September 21, 2018(JavaScript required) .
- ^ A b c d e E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases, Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
- ↑ Data sheet for use as a mask test substance. (PDF; 39 kB) (No longer available online.) Archived from the original on September 17, 2010 ; Retrieved October 29, 2009 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. - Allegro Industries, Fit Check Ampules, Specifications, Rev E 11-14-12 (i.e. November 14, 2011), last accessed January 18, 2016.
- ^ Boch R, Shearer DA, Stone BC: Identification of isoamyl acetate as an active component in the sting pheromone of the honey bee. . In: Nature Publishing Group (ed.): Nature . 195, England, September 8, 1962, pp. 1018-1020. doi : 10.1038 / 1951018b0 . PMID 13870346 .
