Maleic Anhydride Chemical Reactions

  • Chemical Reactions

Maleic anhydride is a versatile organic compound that undergoes various chemical reactions due to its unique structure containing a carbon-carbon double bond and a cyclic anhydride group. Here, we will discuss the main chemical reactions of maleic anhydride, their methods, reaction mechanisms, and the corresponding chemical equations.

  • Hydrolysis

Maleic anhydride readily undergoes hydrolysis when exposed to water, forming maleic acid[1].

Reaction mechanism:

The anhydride group is attacked by a water molecule, breaking the carbon-oxygen bond and forming a tetrahedral intermediate.

The intermediate collapses, resulting in the formation of maleic acid.

Chemical equation:

C4H2O3 + H2O → C4H4O4

  • Diels-Alder Reaction

Maleic anhydride is an excellent dienophile in Diels-Alder reactions, reacting with various dienes to form cyclic adducts[2].

Reaction mechanism:

The diene and maleic anhydride undergo a [4+2] cycloaddition, forming a six-membered ring.

The reaction can lead to the formation of endo and exo isomers, depending on the orientation of the diene relative to maleic anhydride.

Chemical equation (example with furan):

C4H4O + C4H2O3 → C8H6O4

  • Esterification

Maleic anhydride can react with alcohols to form maleic acid esters[1].

Reaction mechanism:

The nucleophilic alcohol attacks one of the carbonyl groups of maleic anhydride, forming a tetrahedral intermediate.

The intermediate collapses, resulting in the formation of a maleic acid monoester and the loss of water.

Chemical equation (example with methanol):

C4H2O3 + CH3OH → C5H6O4 + H2O

  • Amidation

Maleic anhydride can react with amines to form maleamic acids or maleimides[3].

Reaction mechanism:

The nucleophilic amine attacks one of the carbonyl groups of maleic anhydride, forming a tetrahedral intermediate.

The intermediate collapses, resulting in the formation of a maleamic acid.

In some cases, the maleamic acid can undergo dehydration to form a maleimide.

Chemical equations:

C4H2O3 + R-NH2 → C4H3NO3 (maleamic acid)

C4H3NO3 → C4H3NO2 + H2O (maleimide formation)

  • Polymerization and Copolymerization

Maleic anhydride can undergo polymerization and copolymerization reactions with various monomers, such as styrene, acrylic acid, and unsaturated polyesters[4].

Reaction mechanism (example with styrene):

The carbon-carbon double bonds of maleic anhydride and styrene undergo free-radical polymerization.

The resulting copolymer contains alternating maleic anhydride and styrene units.

Chemical equation (example with styrene):

n C4H2O3 + n C8H8 → (C12H10O3)n

  • Oxidation Reactions

Maleic anhydride can be synthesized by the oxidation of various organic compounds, such as n-butane, benzene, or butadiene[5].

Reaction mechanism (example with n-butane):

n-Butane is oxidized over a vanadium-phosphorus oxide catalyst to form maleic anhydride.

The reaction involves the formation of various intermediates, such as butenes and 2,5-dihydrofuran.

Chemical equation (example with n-butane):

C4H10 + 3.5 O2 → C4H2O3 + 4 H2O

References

  1. Lanero, F., et al., Activation of Vegetable Oils by Reaction with Maleic Anhydride as a Renewable Source in Chemical Processes: New Experimental and Computational NMR Evidence.Molecules, 2022. 27(23).
  2. Abaee, M.S., et al., Synthesis of a series of cyclic 2,4-dienones and evaluation of their Diels–Alder reactivity with maleic anhydride.Journal of the Iranian Chemical Society, 2022: p. 1-8.
  3. Yu, K., et al., Highly efficient removal of Pb(2+) from wastewater by a maleic anhydride modified organic porous adsorbent.Environ Sci Pollut Res Int, 2023. 30(26): p. 68467-68476.
  4. Mazi, H. and B. Surmeli̇hi̇ndi̇, Temperature and Ph-sensıtıve Super absorbent Polymers based on Modıfıed Maleıc Anhydrıde.Journal of Chemical Sciences, 2021. 133: p. 1-14.
  5. 朱学军, et al. Method for synthesizing glyoxylic acid by means of ozonizing maleic anhydride and mixed solvents. 2016.
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