Maleic Acid or cis-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Its chemical formula is HO2CCHCHCO2H. Maleic acid is the cis-isomer of butenedioic acid, whereas fumaric acid is the trans-isomer. It is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, maleic acid has few applications.
It is a less stable molecule than fumaric acid. The difference in heat of combustion is 22.7 kJ·mol−1. The heat of combustion is -1355 kJ/mole. Maleic acid is more soluble in water than fumaric acid. The melting point (135 °C) is also much lower than that of fumaric acid (287 °C). Both properties of maleic acid can be explained on account of the intramolecular hydrogen bonding that takes place in maleic acid at the expense of intermolecular interactions, and that are not possible in fumaric acid for geometric reasons.
In industry, maleic acid is derived by hydrolysis of maleic anhydride, the latter being produced by oxidation of benzene or butane. It acid is an industrial raw material for the production of glyoxylic acid by ozonolysis. Maleic acid may be used to form acid addition salts with drugs to make them more stable, such as indacaterol maleate. It is also used as an adhesion promoter for different substrates, such as nylon and zinc coated metals e.g galvanized steel, in methyl methacrylate based adhesives.
Source: Wikipedia
Maleic Acid
Chromatogram(s) using Benson Polymeric Columns
Part No.:
Eluent:
Flow Rate:
Detection:
Temperature:
Sample Size:
Column Size:
Resin Type:
0.003 N H2SO4
0.5 ml/min
Conductivity
Ambient
20 ul, 30 mg/ml
300 x 7.8 mm
8% H
2 – Maleic Acid
3 – Malic Acid
4 – Succinic Acid
5 – Formic Acid
6 – Acetic Acid
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