Diethyl pimelate
[CAS# 2050-20-6]

Identification

• Classification: Chemical reagent >> Organic reagent >> Ester >> Ethyl ester compound
• Name: Diethyl pimelate
• Synonyms: Diethyl heptanedioate
• Molecular Formula: C₁₁H₂₀O₄
• Molecular Weight: 216.28
• CAS Registry Number: 2050-20-6
• EC Number: 218-083-9
• SMILES: CCOC(=O)CCCCCC(=O)OCC

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*, 0.995 g/mL (Expl.)
• Boiling point: 267.6 °C 760 mmHg (Calc.)^*, 280 - 282.4 °C (Expl.)
• Flash point: 117.4±16.9 °C (Calc.)^*
• Index of refraction: 1.434 (Calc.)^*, 1.43 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Discovery and Applications

Diethyl pimelate is an organic compound that belongs to the class of dialkyl esters derived from pimelic acid, a seven-carbon dicarboxylic acid. Its molecular formula is C₁₁H₂₀O₄, and its structure consists of a linear seven-carbon alkyl chain terminated at both ends by ethyl ester groups. It is commonly referred to as the diethyl ester of pimelic acid.

The synthesis of diethyl pimelate is typically carried out through the esterification of pimelic acid with ethanol in the presence of acid catalysts such as sulfuric acid or p-toluenesulfonic acid. The reaction is generally conducted under reflux with removal of water to drive the equilibrium toward ester formation. Purification is commonly achieved by distillation or recrystallization to yield high-purity diethyl pimelate.

Diethyl pimelate serves as an important intermediate in organic synthesis, polymer chemistry, and materials science. The bifunctional ester groups at both ends of the molecule allow it to participate in polycondensation reactions with diols or diamines, leading to the formation of polyesters or polyamides. The seven-carbon alkyl chain contributes to the flexibility, hydrophobicity, and thermal properties of the resulting polymers. Compared to shorter-chain analogs like adipates, polymers derived from pimelate esters generally exhibit enhanced flexibility and reduced crystallinity.

In addition to polymer production, diethyl pimelate is used in the manufacture of plasticizers, lubricants, and surfactants. Its ester functionalities can be chemically modified through hydrolysis, transesterification, or reduction to generate derivatives with tailored physical and chemical properties. The compound’s relatively low volatility and good chemical stability under ambient conditions make it suitable for incorporation into various formulation processes.

Physically, diethyl pimelate is typically a colorless liquid with moderate solubility in organic solvents such as alcohols, ethers, and chlorinated hydrocarbons, and limited solubility in water. It exhibits a relatively high boiling point compared to lower molecular weight esters due to the combined effects of its alkyl chain length and ester groups.

Diethyl pimelate also has relevance in bio-based chemical production. Pimelic acid, its parent acid, can be obtained from renewable sources such as microbial fermentation or oxidative cleavage of plant-derived fatty acids. Consequently, diethyl pimelate can be produced from bio-based feedstocks, aligning with green chemistry principles and sustainability efforts in the chemical industry.

The compound is stable under standard storage conditions but should be protected from strong acids, bases, and prolonged exposure to moisture to prevent hydrolysis of the ester bonds. Standard laboratory safety precautions apply during handling, as ester compounds may cause irritation upon contact.

Overall, diethyl pimelate is a versatile and valuable dialkyl ester intermediate with applications spanning polymer synthesis, specialty chemical production, and green chemistry initiatives. Its chemical properties, structural features, and renewable sourcing potential ensure its continued importance in industrial and academic contexts.

References

2017. Combination of ester biosynthesis and ω-oxidation for production of mono-ethyl dicarboxylic acids and di-ethyl esters in a whole-cell biocatalytic setup with Escherichia coli. Microbial Cell Factories, 16(1).
DOI: 10.1186/s12934-017-0803-9

2005. Short Asymmetric Synthesis of (-)- and (+)-cis-Lauthisan. Organic Letters, 7(8).
DOI: 10.1021/ol050620a

2013. Acyloin Condensation of Diesters. Science of Synthesis.
URL: https://science-of-synthesis.thieme.com/app/text/?id=SD-126-00029