Diethyl maleate

Summary description:

Diethyl maleate (DEM), also known as diethyl fumarate, has the CAS number 141-05-9, the molecular formula C₈H₁₂O₄, and a molecular weight of 172.18. It is an important organic chemical feedstock.

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Detailed Introduction

Diethyl maleate (DEM), also known as ethyl ester of maleic acid, has the CAS number 141-05-9, molecular formula C₈H₁₂O₄, and molecular weight 172.18. It is an important organic chemical feedstock.
- Appearance: Colorless, transparent oily liquid with a distinctive aromatic odor (reminiscent of fruit or wine).
-Physical properties: Boiling point 223°C (at atmospheric pressure), melting point −10°C, relative density 1.065 (at 20/4°C), refractive index 1.441–1.444 (at 20°C), flash point 100°C (closed cup), slightly soluble in water (approximately 0.3 g/100 mL), and readily soluble in ethanol, diethyl ether, acetone, benzene, and most other organic solvents.
- Chemical properties: The molecule contains a carbon–carbon double bond (C=C), making it chemically reactive and prone to electrophilic addition reactions with halogens (such as bromine), hydrogen halides, and water. In the presence of peroxide initiators, it can undergo bulk polymerization or copolymerization with other monomers (such as styrene and vinyl acetate). Under acidic or basic catalysis and upon heating, it undergoes hydrolysis to yield maleic acid and ethanol.
Uses
1. Polymer synthesis monomers: Used as comonomers in the production of polymers such as alkyd resins, polyvinyl chloride (PVC), and polystyrene (PS), these monomers can enhance the flexibility, impact resistance, and weatherability of the resins.
2. Organic synthesis intermediates: used in the synthesis of fine chemicals such as insecticides, fungicides, pharmaceuticals, fragrances, and lubricants.
3. Gas chromatography stationary liquid: Due to its excellent selective retention for certain organic compounds, it has been used as a stationary phase in gas chromatographic analysis.
4. Food additives: Used in small amounts for formulating food flavorings (FEMA No.: 2370).
5. Other: Used as a solvent, softening agent, and additive for lubricating oils.