Some physical and chemical properties of Maleic & Fumaric acid

Physical/Chemical properties Maleic acid COOHHOOC

Fumaric acid

HOOC

COOH State White solid White solid Stereochemistry Cis form or Z form Trans form or E form Melting Point 130◦C 287◦C Boiling Point Decompose below boiling point at 135◦C 200◦C sublime Sulubility in water 79 g/100 ml at 25◦C 0.7 g/100 ml at 25◦C Dipole moment More Less Stability Lower stability Higher stability Stereochemistry of addition reaction

Stereoselective reaction Stereoselective reaction

Addition of Br2 d/l mixture of dibromosuccinic acid via non classical C+ through trans addition

Meso dibromosuccinic acid via non classical C+ through trans addition

Kolbe electrolysis Produce acetylene Produce acetylene H2O/H+ at high T & P

Produce Malic acid COOHHOOC

OH

Produce Malic acid

Bromosuccinic acid on treatment with aqueous alkali/heat

Produce Maleic acid Produce fumaric acid

Reaction with alkaline KMnO4

Meso-Tartaric acid d/l Tartaric acid

pKa Values pKa1 1.92, pKa2 6.23 pKa1 3.02, pKa2 4.38 Dei-Alder reaction with butadiene

Cis-1,2,3,6-Tetrahydrophthalic acid Trans-1,2,3,6-Tetrahydrophthalic acid

Optical activity Optically inactive Optically inactive Catalytic Hydrogenation

Produce succinic acid Produce succinic acid

Addition of HBr Produce Bromosuccinic acid Produce Bromosuccinic acid Stereo relation Geometrical diastereomer Geometrical diastereomer H-Bonding Intramolecular Intermolecular Anhydride formation Form anhydride on heating Do not form anhydride Dipole moment of their ethyl derivatives

Dipole moment of diethylmaleate is 2.54D Dipole moment of diethylfumarate is 2.38D

Symmetry Less symmetrical More symmetrical Heat of combustion 22.7 kj/mol higher than trans (-1355 kj/mol) Lower Density 1.59 g/cm3 1.635 g/cm3 Boiling point of their

ethyl derivatives

225◦C 218◦C