Crotonic acid

Quality 0.50 · 1 view · Updated 2 months ago

title: "Crotonic acid" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["alkenoic-acids", "crotyl-compounds"] topic_path: "general/alkenoic-acids" source: "https://en.wikipedia.org/wiki/Crotonic_acid" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 460108491 | Name = Crotonic acid | ImageFile = Crotonic acid.svg | ImageClass = skin-invert | ImageSize = 160px | ImageAlt = Skeletal formula of crotonic acid | ImageFile1 = Crotonic acid 3D ball.png | ImageClass1 = bg-transparent | ImageAlt1 = Ball-and-stick model of the crotonic acid molecule | PIN = (2E)-But-2-enoic acid | OtherNames = (E)-But-2-enoic acid (E)-2-Butenoic acid Crotonic acid trans-2-Butenoic acid β-Methylacrylic acid 3-Methylacrylic acid |Section1={{Chembox Identifiers | ChemSpiderID_Ref = | ChemSpiderID = 552744 | ChEMBL_Ref = | ChEMBL = 1213528 | PubChem = 637090 | InChI = 1/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2+ | InChIKey = LDHQCZJRKDOVOX-NSCUHMNNBH | SMILES1 = O=C(O)/C=C/C | StdInChI_Ref = | StdInChI = 1S/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2+ | StdInChIKey_Ref = | StdInChIKey = LDHQCZJRKDOVOX-NSCUHMNNSA-N | CASNo_Ref = | CASNo = 107-93-7 | ChEBI_Ref = | ChEBI = 41131

| UNII_Ref = | UNII = YW5WZZ4O5Q

| DrugBank_Ref = | DrugBank = DB02074 | SMILES = C/C=C/C(O)=O |Section2={{Chembox Properties | C=4|H=6|O=2 | Density = 1.02 g/cm3 | MeltingPtC = 70 to 73 | MeltingPt_notes = | BoilingPtC = 185 to 189 | BoilingPt_notes = | pKa = 4.69 |Section3={{Chembox Hazards | ExternalSDS = SIRI.org |Section4={{Chembox Related | OtherAnions = crotonate | OtherFunction_label = carboxylic acids | OtherFunction = propionic acid acrylic acid butyric acid succinic acid malic acid tartaric acid fumaric acid pentanoic acid tetrolic acid | OtherCompounds = butanol butyraldehyde crotonaldehyde 2-butanone 3-Butenoic acid

Crotonic acid ((2E)-but-2-enoic acid) is a short-chain unsaturated carboxylic acid described by the formula CH3CH=CHCO2H. The name crotonic acid was given because it was erroneously thought to be a saponification product of croton oil. It crystallizes as colorless needles from hot water. With a cis-alkene, Isocrotonic acid is an isomer of crotonic acid. Crotonic acid is soluble in water and many organic solvents. Its odor is similar to that of butyric acid.

Production

Crotonic acid produced industrially by oxidation of crotonaldehyde: :

A number of other methods exist, including the Knoevenagel condensation of acetaldehyde with malonic acid in pyridine:

:[[File:Synthesis Crotonic acid A.svg|upright=2.5|Synthesis of crotonic acid by the Knoevenagel condensation of acetaldehyde and malonic acid]]

The alkaline hydrolysis of allyl cyanide followed by the intramolecular rearrangement of the double bond:

:[[File:Hydrolysis Allyl cyanide.svg|upright=1.5|Alkaline hydrolysis of allyl cyanide]]

Furthermore, it is formed during the distillation of 3-hydroxybutyric acid:

:[[File:Synthesis Crotonic acid D.svg|upright=1.5|Synthesis of crotonic acid from 3-hydroxybutyric acid]]

Properties

Crotonic acid crystallizes in the monoclinic crystal system in the space group P21/a (space group 14, position 3) with the lattice parameters , , and . The unit cell contains four formula units.

Reactions

Crotonic acid converts into butyric acid by hydrogenation or by reduction with zinc and sulfuric acid. :[[File:Hydration Crotonic acid.svg|upright=1.5|Hydrogenation of crotonic acid]]

Upon treatment with chlorine or bromine, crotonic acid converts to 2,3-dihalobutyric acids: :[[File:Chlorination Crotonic acid.svg|upright=1.5|Chlorination of butenoic acid]]

Crotonic acid adds hydrogen bromide to form 3-bromobutyric acid.

:[[File:Hydrobromination Crotonic acid.svg|upright=1.5|Reaction of crotonic acid with hydrogen bromide.]]

The reaction with alkaline potassium permanganate solution affords 2,3-dihydroxybutyric acid. :[[File:Oxidation Crotonic acid.svg|upright=1.5|Reaction of crotonic acid with alkaline potassium permanganate solution.]]

Upon heating with acetic anhydride, crotonic acid converts to the acid anhydride:

Esterification of crotonic acid using sulfuric acid as a catalyst provides the corresponding crotonate esters:

:[[File:Synthesis Ethyl crotonate.svg|upright=1.5|Preparation of crotonate esters.]]

Crotonic acid reacts with hypochlorous acid to 2-chloro-3-hydroxybutyric acid. This can either be reduced with sodium amalgam to butyric acid, can form with sulfuric acid 2-chlorobutenoic acid, react with hydrogen chloride to 2,3-dichlorobutenoic acid or with potassium ethoxide to 3-methyloxirane-2-carboxylic acid.

:[[File:Crotonic acid Reaction B.svg|upright=1.5|Reaction of crotonic acid into 2-chloro-3-hydroxybutanoic acid and subsequent reactions]]

Crotonic acid reacts with ammonia at the alpha position in the presence of mercury(II) acetate. This reaction provides -threonine.

Use

Crotonic acid is mainly used as a comonomer with vinyl acetate. The resulting copolymers are used in paints and adhesives.

Crotonyl chloride reacts with N-ethyl-2-methylaniline (N-ethyl-o-toluidine) to provide crotamiton, which is used as an agent against scabies.

:[[File:Crotamiton synthesis V.svg|none|550px|Crotamiton synthesis]]

Safety

Its is 1 g/kg (oral, rats). It irritates eyes, skin, and respiratory system.

References

References

  1. Dawson, R. M. C.. (1959). "Data for Biochemical Research". Clarendon Press.
  2. {{Cite EB1911
  3. (1984). "Organische Chemie". S. Hirzel Verlag.
  4. (1871). "Ueber das Allylcyanür oder Crotonitril". [[Justus Liebigs Annalen der Chemie]].
  5. (1906). "Ueber Allylcyanid und Allylsenföl". [[Justus Liebigs Annalen der Chemie]].
  6. (1893). "Handbuch der organischen Chemie". Verlag Leopold Voss.
  7. (1974). "Topochemical Studies. III. The Crystal and Molecular Structures of Crotonic Acid, CH3CH=CHCO2H, and Crotonamide, CH3CH=CHCONH2". Bulletin of the Chemical Society of Japan.
  8. (1953). "Crotonic acid". Dictionary of Organic Compounds.
  9. (1915). "Einige schwefelhaltige β-Substitutionsderivate der Buttersäure". [[Berichte der deutschen chemischen Gesellschaft]].
  10. (1903). "The Hydrolysis of Organic Peroxides and Peracids". [[American Chemical Journal]].
  11. (1893). "Handbuch der organischen Chemie". Verlag Leopold Voss.
  12. (1955). "''dl''-Threonine".
  13. "Pharmazeutische Wirkstoffe: Synthesen, Patente, Anwendungen". Georg Thieme Verlag.
  14. (2005). "Crotonaldehyde and Crotonic Acid".
  15. {{RömppOnline

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

alkenoic-acidscrotyl-compounds