M0375 Sigma-Aldrich

Maleic acid

ReagentPlus®, ≥99% (HPLC)

Synonym: cis-Butenedioic acid, Toxilic acid

  • CAS Number 110-16-7

  • Linear Formula HO2CCH=CHCO2H

  • Molecular Weight 116.07

  •  Beilstein/REAXYS Number 605762

  •  EC Number 203-742-5

  •  MDL number MFCD00063177

  •  PubChem Substance ID 24896549

  •  NACRES NA.21



Related Categories Acids, Acids & Bases, Biochemicals and Reagents, Biological Buffers, Buffers A to Z,
Quality Level   200
grade   ReagentPlus®
assay   ≥99% (HPLC)
form   powder
impurities   ≤2.0% water
ign. residue   ≤0.1%
pKa (25 °C)   (1) 1.97, (2) 6.24
mp   130-135 °C (lit.)
density   1.59 g/mL at 25 °C (lit.)
SMILES string   OC(=O)\C=C/C(O)=O
InChI   1S/C4H4O4/c5-3(6)1-2-4(7)8/h1-2H,(H,5,6)(H,7,8)/b2-1-


General description

Maleic acid (MA) is a dicarboxylic acid that undergoes esterification with ethanol in the presence of cation-exchange resin catalysts to form diethyl maleate. Its crystalline structure has been analyzed. Reaction kinetics and mechanism of the isomerization of maleic acid to fumaric acid in the presence of ceric and bromide ions has been investigated. The reaction mechanism and reactivity ratios for the radical copolymerization of maleic acid with styrene have been determined.


Maleic acid has been used in the preparation of tris-maleate buffer and sodium maleate buffer. It has also been used for the pretreatment of poplar tracheid cell walls for the spectroscopic analysis of lignin. It may be used to synthesize superswelling acrylamide/maleic acid hydrogels.


1 kg in poly bottle

100, 500 g in poly bottle

25 kg in poly drum



Legal Information

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Safety & Documentation

Safety Information

Signal word 
Hazard statements 
UN 3077 9 / PGIII
WGK Germany 
Flash Point(F) 
260.6 °F
Flash Point(C) 
127 °C


Certificate of Analysis (COA)

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Certificate of Origin (COO)

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