4-Pentensäure - 4-Pentensäure

Structural formula
Structural formula of 4-pentenoic acid
Name 4-Pentensäure
other names
  • Allylessigsäure
  • 3-Vinylpropionsäure
Sum formula C 5 H 8 O 2
Brief description

colorless to light yellow [1] liquid

External identifiers / databases
CAS number 591-80-0
EC number 209-732-7
ECHA-InfoCard 100.008.849
PubChem 61138
Wikidata Q27116641
Molar mass 100.12 g · mol −1
Physical state



0,98 g·cm−3 (20 °C)[2]

Melting point

< −22 °C[2]

boiling point
  • 83–84 °C (12 mmHg)[3]
  • 187–189 °C[2]
Vapor pressure

0,267 mmHg (25 °C)[2][4]

Refractive index

1,4283 (20 °C, 589 nm)[4]

safety instructions
GHS hazard labeling [2]
05 - Corrosive 07 - Warning


H and P phrases H: 302​‐​314
P: 280​‐​301+330+331​‐​305+351+338​‐​309+310 [2]
Toxicological data
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

4-pentenoic acid is a linear, unsaturated carboxylic acid with a terminal double bond , which smells strongly of cheese and is used as a flavoring substance . [4]

In the future, 4-pentenoic acid (in addition to the isomeric 2-pentenoic acid and 3-pentenoic acid) could become important as a starting material for cellulose-based biofuels. [6]

In current considerations on the production of adipic acid , the intermediate product for polyamide 6.6 , from lignocellulose-containing biomass , 4-pentenoic acid [7] and its methyl ester, methyl 4-pentenoate, play an important role. [8] [9]

Occurrence and representation

Classic laboratory processes for the preparation of 4-pentenoic acid are the malonic ester synthesis and the acetoacetic ester synthesis with allyl bromide [10] or from 1,2,3-tribromopropane (practically quantitatively from allyl bromide and bromine ) [11] as modified malonic ester synthesis.

Synthesis of 4-pentenoic acid via malonic ester synthesis

The alkaline hydrolysis of the substituted malonic ester gives the substituted malonic ester, the second terminal bromine atom being split off as hydrogen bromide by the malonic ester anion. Hydrolysis and decarboxylation lead to the sodium salt of 4-bromo-4-pentenoic acid, which is reduced to 4-pentenoic acid by the action of ethanol and sodium. [12]

Oxidation of 4-pentenal (from cyclopentene [13] or acetaldehyde diallylacetal [14] ) with oxygen also produces 4-pentenoic acid in relatively modest yields (up to 38%). 4-pentenoic acid is also obtained in the reaction of propiolactone with vinyl magnesium bromide in the presence of copper (I) chloride as a catalyst in a yield of 59%. [15]

4-pentenoic acid from propiolactone and vinyl magnesium bromide

Allyl alcohol reacts with the Orthoester trimethyl under acid catalysis with propionic acid in the Johnson variant of the Claisen rearrangement to the 4-pentenoate, which gives 4-pentenoic acid in 70% yield after alkaline hydrolysis and acidification. [16]

4-pentenoic acid by Claisen rearrangement (Johnson variant)

The continuous isomerization, in particular of methyl 3-pentenoate to methyl 4-pentenoate, is of technical interest. [17] and hydrolysis to 4-pentenoic acid. The required methyl 3-pentenoate falls in yields of> 90% (as approx. 70% 3- ( E ) - trans - and 30% 3- ( Z ) - cis mixture) in the carbonylation of 1,3-butadiene with CO and methanol in a pyridine / 3-picoline mixture with dicobalt octacarbonyl as a catalyst. [18] Isomerization with palladium on acidic ion exchangersor zeolites provide isomer mixtures with up to 10 percent by weight of 4-pentenoic acid ester, which is removed from the mixture by distillation. [19] The 3-esters in the distillation bottoms are returned to the isomerization reaction.

Carbonylation of butadiene to 4-pentenoic acid

Despite recycling of the unchanged 3-pentenoic acid ester, this route to 4-pentenoic acid is hardly economical.

4-pentenoic acid is a component of in the ring-opening acid hydrolysis of γ-valerolactone resulting Pentensäuregemisches a total of five isomers: 4-pentenoic acid, 3-pentenoic acid (in cis - and trans - configuration) and the thermally stable 2-pentenoic acid (cis and trans ). [20] Under somewhat milder conditions and complete conversion of the starting materials, a γ-valerolactone / methanol mixture reacts to form the isomeric pentenoic acid esters, [9] from which 4-pentenoic acid can be isolated after hydrolysis.


4-pentenoic acid is corrosive and gives off a strong cheese odor.


Bromine compounds, such as. B. N-bromosuccinimide [21] or iodine [22] or iodine chloride [23] convert 4-pentenoic acid almost quantitatively into the corresponding halomethylbutyrolactones.

Halolactonization of 4-pentenoic acid

The 5-methylenebutyrolactone is obtained from the iodomethyl-butyrolactone by dehydrohalogenation using diazabicycloundecene DBU. [16]

Dehydrohalogenation to gamma methylenebutyrolactone synthesis

4-pentenoic acid is used to synthesize the monomer 2- (3-butenyl) -2-oxazoline,

Reaction sequence to poly (2- (3-butenyl) -2-oxazoline)

at the terminal double bond in homopolymers and copolymers in so-called thiol-ene- click addition reactions , thiol- functionalized molecules can be added very gently and efficiently. [24]

By incorporating 4-pentenoic acid into the neutral thermoresponsive polymer N-isopropylacrylamide , copolymeric spherical microgels are obtained, the diameter of which changes drastically with a shift in pH. [25]

4-pentenoic acid reacts with sulfuric acid [12] or iron triflate [26] with intramolecular cyclization to form γ-valerolactone.

Equilibrium between pentenoic acids and GVL

The reaction is reversible and gives mixtures of the isomeric pentenoic acids.

As a secondary product of the alkaline hydrolysis of γ-valerolactone, a platform chemical made from renewable raw materials , 4-pentenoic acid has recently attracted more attention. By decarboxylation of acidic zeolites n- arise butenes , [27] the (70 Amberlyst) in an overall yield of 77% to C at acidic ion exchangers 8+ di- or alkenes can be oligomerized. [6] [28] After hydrogenation, the alkenes obtained can be used as biogenic gasoline or diesel fuel.

Butadiene and higher alkenes from pentenoic acids

The isomeric pentenoic acids obtained in the acid hydrolysis of γ-valerolactone can be hydrogenated to valeric acid and reacted with alcohols to give the corresponding esters. The ethyl valerate has petrol-like properties, the higher esters can be used as a diesel substitute. [29]

The implementation of the isomeric pentenoic acid or pentenoic acid ester mixtures from the hydrolysis of γ-valerolactone for the production of the polyamide 6 monomer ε-caprolactam (after hydroformylation to 5-formylvaleric acid [30] and reductive amination ) or the polyamide 6.6 building block could have future potential Adipic acid [31] by carbonylation in the presence of water with palladium acetate and the phosphine ligand 1,2-bis (di-tert-butylphosphinomethyl) benzene with a shift of the double bond from the 2- and 3- to the 5-position [7]or dimethyl adipate by methoxycarbonylation in the presence of methanol and the hydroformylation catalyst system dicarbonylacetylacetonato-rhodium (I) [Rh (acac) CO) 2 ] / tri- (sodium-meta-sulfonatophenyl) -phosphane . [30] The diol component 1,6-hexanediol for polyester or hexamethylenediamine , the diamine building block for polyamide 6.6, is accessible from the adipic acid ester .

Polymer building blocks from pentenoic acids

In tests on animals and cell organelles, the inhibition of fatty acid oxidation and the blood sugar-lowering effect of 4-pentenoic acid could be demonstrated. [32] [33]

Individual evidence

  1. a b Entry on 4-Pentenoic Acid at TCI Europe, accessed on May 15, 2017.
  2. a b c d e f g h Entry on 4-pentenoic acid in the GESTIS substance database of the IFA , accessed on May 15, 2017(JavaScript required) .
  3. Data sheet 4-Pentenoic Acid from Sigma-Aldrich , accessed on May 15, 2017 ( PDF ).
  4. a b c 4-Pentenoic acid. In: thegoodscentcompany.com. The Good Scent Co., abgerufen am 15. Mai 2017 (englisch).
  5. R. Madsen, B. Fraser-Reid: 4-Pentenoic Acid. In: e-EROS Encyclopedia of Reagents for Organic Synthesis. 2002, doi:10.1002/047084289X.ru00128.
  6. a b P. Palkovits: Pentenic acid as a trailblazer for cellulose-based biofuels . In: Angew. Chem. Band 122 , No. 26, 2010, S. 4434–4436 , doi : 10.1002 / ange.201002061 .
  7. a b Patent WO2012134397A1 : Synthesis of diacids. Filed on March 28, 2012 , published on October 4, 2012 , Applicant: Agency for Science, Technology and Research, Singapore, Inventor: PK Wong et al
  8. P.J. Deuss, K. Barta, J.G. de Vries: Homogeneous catalysis for the conversion of biomass and biomass-derived platform chemicals. In: Catal. Sci. Technol. Band 4, 2014, S. 1174–1196, doi:10.1039/C3CY01058A (rsc.org).
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  10. A. Messerschmidt: Investigations on the unsaturated acids. About allylacetic acid and valerolactone . In: Justus Liebigs Ann. Chem. Band 208 , No. 1–2, 1881, S. 92–104 , doi : 10.1002 / jlac.18812080107 .
  11. J.R. Johnson, W.L. McEwen: 1,2,3-Tribromopropane In: Organic Syntheses. 5, 1925, S. 99, doi:10.15227/orgsyn.005.0099; Coll. Vol. 1, 1941, S. 209 (PDF).
  12. a b F.C. Whitmore: Organic Chemistry, Volume 1, reissued 2012. Van Nostrand, New York 1951, ISBN 978-0-486-31115-9, S. 12.
  13. Patent US8362296B2: Process for preparing 4-pentenoic acid. Angemeldet am 19. August 2010, veröffentlicht am 29. Januar 2013, Anmelder: BASF SE, Erfinder: J.H. Teles, M. Schelper, K. Gumlich, M. Chabanas, C. Müller, A. Meier.
  14. S. Günther: Synthese von Polymeren ausgehend vom nachwachsenden Rohstoff Glycerin, Dissertation. Universität Hamburg 2012 (uni-hamburg.de [PDF]).
  15. T. Sato, T. Kawara, M. Kawashima, T. Fujisawa: Copper-catalyzed reaction of Grignard reagents with β-propiolactones: A convenient method for the synthesis of β-substituted propionic acids. In: Chem. Lett. Band 9 , No. 5, 1980, S. 571–574, doi:10.1246/cl.1980.571.
  16. a b V. Jäger, H.J. Günther: Synthesis of γ-methylene butyrolactones (4-penten-4-olides). In: Tetrahedron Lett. Band 18 , No. 29, 1977, S. 2543–2546 , doi : 10.1016 / S0040-4039 (01) 83815-6 .
  17. Patent EP0266689B1 : Process for the production of 4-pentenoic acid esters. Registered on October 30, 1987 , published on January 2, 1992 , applicant: BASF AG, inventor: W. Hoelderich, H. Aichinger, F. Naeumann, R. Fischer.
  18. Patent DE3040432A1 : Process for the production of 3-pentenoic acid esters. Applied on October 27, 1980 , published on May 19, 1981 , Applicants: Mitsubishi Gas Chemical Co., Inc., Inventors: N. Isogai, M. Hosokawa, T. Okawa, N. Wakui, T. Watanabe.
  19. Patent EP0157311A2: Verfahren zur Abtrennung von 4-Pentensäuremethylester aus solchen und 3-Pentensäuremethylester enthaltenden Gemischen. Angemeldet am 22. März 1985, veröffentlicht am 9. Oktober 1985, Anmelder: BASF AG, Erfinder: H.-W. Schneider, R. Kummer, D. Zimmerling.
  20. Patent WO2012134397A1: Synthesis of diacids. Angemeldet am 28. März 2012, veröffentlicht am 4. Oktober 2012, Anmelder: Agency for Science, Technology and Research, Erfinder: P.K. Wong et al..
  21. Y.A. Cheng et al.: Efficient medium ring size bromolactonization using a sulfur-based zwitterionic catalyst. In: J. Am. Chem. Soc. Band 134 , No. 40, 2012, S. 16492–16495 , doi : 10.1021 / ja307210n .
  22. R.D. Crouch, A. Tucker-Schwartz, K. Barker: Iodolactonization of 4-pentenoic acid. In: J. Chem. Educ. Band 83 , No. 6, 2006, S. 921 , doi : 10.1021 / ed083p921 .
  23. N. Windmon, V. Dragojlovic: Phase-vanishing halolactonization of neat substances. In: Beilstein J. Org. Chem. Band 4, 2008, S. 29 , doi : 10.3762 / bjoc.4.29 .
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  25. M. Karg, I. Pastoriza-Santos, B. Rodriguez-Gonzá, R. von Klitzing, S. Wellert, T. Hellweg: Temperature, pH, and ionic strength induced changes in the swelling behavior of PNIPAM-Poly(allyl acetic acid) copolymer microgels. In: Langmuir. Band 24 , No. 12, 2008, S. 6300–6306, doi:10.1021/la702996p.
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  27. J.Q. Bond, D. Wang, D.M. Alonso, J.A. Dumesic: Interconversion between γ-valerolactone and pentenoic acid combined with decarboxylation to form butene over silica/alumina. In: J. Catal. Band 281 , No. 2, 2011, S. 290–299, doi:10.1016/j.jcat.2011.05.011.
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  29. J.-P. Lange, R. Price, P.M. Ayoub, J. Louis, L. Petrus, L. Clark, H. Gosselink: Valeric biofuels: A platform of cellulosic transportation fuels. In: Angew. Chem. Band 122 , No. 26, 2010, S. 4581–4585 , doi : 10.1002 / ange.201000655 .
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  32. C. Corredor, K. Brendel, R. Bressler: Studies on the mechanism of the hypoglycemic action of 4-pentenoic acid. In: Proc. Natl. Acad. Sci. USA. Band 58 , No. 6, 1967, S. 2299-2306 , PMC 223835 (free full text).
  33. H. Schulz: Metabolism of 4-pentenoic acid and inhibition of thiolase by metabolites of 4-pentenoic acid. In: Biochemistry. Band 22 , No. 8, 1983, S. 1827–1832 , doi : 10.1021 / bi00277a013 .