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N-Ethylpyrrolidinone

September 3, 2026

N-Ethylpyrrolidinone (CAS 2687-91-4): Synthesis and Application of Fluorinated Horner Reagent with Full Analysis

1、 Product Overview

N-Ethylpyrrolidinone (NEP) is a high-polarity, high-boiling cyclic amide solvent that occupies an important position in specialty solvent and industrial chemical applications.

Its key value comes from the combination of strong solvency, complete miscibility with water, low vapor pressure, and good thermal stability. This makes NEP suitable for applications where conventional solvents may not provide sufficient solvency or where controlled evaporation and elevated-temperature processing are required.

NEP is mainly used as a specialty process solvent and formulation solvent, with applications extending across electronics and semiconductor processing, polymer and resin manufacturing, coatings and adhesives, agrochemical formulations, chemical synthesis, and industrial cleaning.

2、 Basic Product Information

Product Name: N-Ethylpyrrolidinone
Synonyms: 1-Ethyl-2-pyrrolidinone; 1-Ethyl-2-pyrrolidone; 1-Ethylpyrrolidin-2-one; 2-Pyrrolidinone, 1-ethyl-; N-Ethyl-2-pyrrolidinone; N-Ethylpyrrolidone; Agsol Ex 2; NEP
CAS NO.: 2687-91-4
EINECS NO.: 220-250-6
Molecular Formula: C₆H₁₁NO
Molecular Weight: 113.16 g/mol
Structural Formula:

Purity: ≥99%
Appearance: Colorless to pale yellow transparent liquid
Odor: Characteristic amine-like odor
Boiling Point: Approximately 212–213 °C at atmospheric pressure
Density: Approximately 0.99–1.00 g/mL at 20–25 °C
Refractive Index: Approximately 1.465–1.467
Flash Point: Approximately 91 °C (closed cup)
Water Solubility: Miscible with water
Vapor Pressure: Approximately 18 Pa at 20 °C
Product Manager Email: Cherry@coreychem.com

3、 Frequently Asked Questions (FAQ)

1) What is the difference between N-Ethylpyrrolidinone (NEP) and conventional polar solvents?

The main advantage of NEP is the combination of high solvency, high boiling point, low vapor pressure, and water miscibility within a single solvent system.

Compared with many conventional low-boiling solvents, NEP evaporates more slowly and can remain effective during elevated-temperature processing. Its cyclic amide structure also gives it strong solvating capability toward many organic compounds, resins, polymers, and formulation components.

This makes NEP particularly useful when a process requires both effective dissolution and controlled solvent evaporation rather than simply rapid drying.

2) What are the key physical and chemical properties of NEP, and what should be considered during operation?

NEP is a colorless to pale-yellow liquid with a characteristic amine-like odor. It has a boiling point of approximately 212–213 °C, low vapor pressure, and is completely miscible with water. Under normal conditions it is chemically stable, but it can react with strong oxidizing agents, strong acids, and strong bases.

During operation, adequate ventilation should be provided and unnecessary exposure to vapor or liquid should be avoided. Because NEP is combustible and has a relatively high flash point, ignition sources should be controlled during handling. Operators should also use appropriate protective equipment and follow the latest product SDS.

3) What fields can N-Ethylpyrrolidinone be applied to?

NEP is primarily used as a specialty solvent and process solvent. Its major application fields include:

Electronics and semiconductor processing
Polymer and resin manufacturing
Coatings, inks, and adhesives
Agrochemical formulations
Chemical synthesis
Industrial and precision cleaning
Specialty chemical manufacturing

Its most important functional advantage is its ability to dissolve a broad range of materials while maintaining performance under relatively high-temperature processing conditions. Industry sources specifically identify applications including agrochemical formulations, photoresist stripping, polyimide processing, and specialty chemical processing.

4) What special precautions should be taken during transportation, and how should NEP be handled after leakage or contact?

During transportation, NEP should be kept in tightly sealed, compatible containers and protected from excessive heat, ignition sources, and physical damage. Containers should remain closed to minimize unnecessary vapor exposure and contamination.

In the event of a spill, personnel should eliminate ignition sources, provide adequate ventilation, and prevent unnecessary contact with the liquid. The material should be collected using suitable absorbent material and transferred to an appropriate waste container in accordance with local regulations.

If NEP contacts the skin, wash the affected area thoroughly with water. In case of eye contact, rinse cautiously with water for several minutes and seek medical attention if irritation persists. Detailed emergency measures should follow the SDS for the specific product grade.

5) What substances can N-Ethylpyrrolidinone be used with to produce downstream products or formulations?

NEP is primarily used as a solvent or processing medium rather than as a reactive building block. It can be combined with polymers, resins, pigments, active ingredients, and other formulation components according to the requirements of the downstream process.

For example, NEP can dissolve selected polymeric materials and resin systems for coating or film formation, or act as a carrier solvent for agrochemical active ingredients. In polyimide processing, it can serve as a solvent during preparation of polyamic-acid precursor systems.

The final formulation and processing conditions should be established through compatibility, solubility, stability, and application testing.

4、 Application Cases

1) Electronics and Semiconductor Industry – Photoresist and Residue Removal

NEP can be used as a specialty solvent in semiconductor and electronic-material processing, particularly where strong solvency is required for removing polymeric residues.

For example, in selected photoresist stripping processes, NEP-containing formulations can soften or dissolve resist residues and other organic contaminants remaining after semiconductor processing. Its high boiling point and low vapor pressure can help maintain solvent performance during controlled-temperature cleaning operations.

This application takes advantage of NEP’s strong solvency while allowing formulators to design cleaning systems with controlled evaporation characteristics.

2) Polyimide and Advanced Polymer Materials – Film and Coating Processing

NEP can function as a solvent in polyimide and other high-performance polymer processing.

A representative application is the preparation of polymer precursor solutions for film casting or coating. NEP helps dissolve or maintain selected polymeric components in a homogeneous liquid phase, allowing the formulation to achieve suitable viscosity for coating and subsequent thermal processing.

This is particularly relevant to electronic materials and high-performance polymer films, where uniform solution quality and controlled processing behavior are important.

3) Agrochemical Formulations – Active Ingredient Carrier Solvent

NEP can be used as a carrier solvent in agrochemical formulations where active ingredients have limited solubility in conventional formulation solvents.

For example, NEP can help dissolve selected solid pesticide active ingredients and maintain a homogeneous formulation. Its high solvency and low vapor pressure can be beneficial when the formulation needs to remain stable during storage and application.

The actual solvent concentration and formulation system depend on the active ingredient, co-solvents, surfactants, temperature, and required storage stability.

4) Coatings, Inks, and Adhesives – Resin Dissolution and Processing

In coatings, inks, and adhesives, NEP can be used as a high-boiling solvent for resin and polymer systems.

For example, when a coating formulation contains a resin that is difficult to dissolve in lower-polarity solvents, NEP can help produce a more homogeneous solution. During application and drying, its relatively slow evaporation can provide additional time for film leveling and controlled solvent release.

This makes NEP useful in specialty formulations where strong resin solvency and controlled evaporation are more important than extremely rapid drying.

5) Chemical Synthesis – High-Boiling Reaction Solvent

NEP can serve as a polar aprotic reaction medium in selected organic synthesis and specialty chemical manufacturing processes.

For example, when reactants or intermediates require a highly polar environment or when the reaction benefits from elevated temperature, NEP can provide both strong solvency and a relatively high operating-temperature window.

After the reaction, NEP can be separated using an appropriate downstream recovery or purification process. Its selection should be based on reaction compatibility, product stability, solvent recovery requirements, and process economics.

6) Industrial Cleaning – Removal of Organic and Resinous Contaminants

NEP can be incorporated into industrial cleaning formulations designed to remove difficult organic residues.

Typical targets can include oils, resin residues, polymeric deposits, and other organic contaminants found on manufacturing equipment or industrial components. Its strong solvency allows it to attack contaminants that may be difficult to remove using water-based or low-polarity cleaning systems.

For precision applications, compatibility testing should be performed to ensure that the solvent effectively removes the contamination without damaging the substrate

5、 Safety and Storage

Store in a cool, dry, and well-ventilated area and keep the container tightly sealed.
Keep away from heat, sparks, open flames, and other ignition sources. NEP has a relatively high flash point, but it remains a combustible organic solvent.
Avoid unnecessary exposure to strong oxidizing agents, strong acids, and strong bases, as NEP can react with these materials.
Avoid prolonged exposure to moisture and contamination and keep the original container properly closed when not in use.
During handling, use adequate ventilation and appropriate personal protective equipment, especially when transferring large quantities or operating at elevated temperatures.
For transportation and long-term storage, use compatible, tightly sealed packaging and follow the latest SDS and applicable local transportation and chemical-storage regulations.