Ethyl Lactate (EL): Properties, Uses & Lab Handling Guide

Ethyl lactate(EL) is a biodegradable, bio-derived ester solvent widely recognized for its low toxicity, excellent solvating power, and versatility across pharmaceutical, semiconductor, food-flavoring, and green chemistry applications.

Chemical Name

Ethyl (S)-(+)-lactate; Ethyl 2-hydroxypropanoate

CAS Number

687-47-8 (L-form); 97-64-3 (racemate)

Molecular Formula

C5H10O3

Molecular Weight

118.13 g/mol

Boiling Point

~154 °C at 760 mmHg

Appearance

Colorless to pale yellow liquid with a mild, fruity odor

Solubility

Miscible with water, ethanol, ethyl acetate, and most common organic solvents

Flash Point

~46 °C (closed cup)

Chemical Properties and Structure

Ethyl lactate (EL) is the ethyl ester of lactic acid, bearing the molecular formula C₅H₁₀O₃ and a molecular weight of 118.13 g/mol. The molecule contains both a hydroxyl (–OH) and an ester (–COO–) functional group, which together confer its strong, multidirectional solvating capability for polar and non-polar substrates alike.

The compound is chiral; the naturally derived L-enantiomer (CAS 687-47-8) is produced by fermentation of renewable feedstocks such as corn starch, while the racemic mixture (CAS 97-64-3) is also commercially available. Its refractive index is approximately 1.412, and its density is roughly 1.03 g/mL at 25 °C. The ester linkage is susceptible to hydrolysis under strongly acidic or basic aqueous conditions, regenerating lactic acid and ethanol — both non-toxic metabolites — which underpins its excellent environmental profile.

Applications in Research and Industry

Ethyl lactate is valued across multiple fields as a green alternative to conventional solvents such as N-methyl-2-pyrrolidone (NMP), toluene, and glycol ethers:

• Semiconductor and Microelectronics: EL is widely used as an edge-bead rinse and photoresist stripping solvent in semiconductor lithography processes, owing to its ability to dissolve a broad range of resins while remaining relatively safe for operators.
• Pharmaceutical and Cosmetic Synthesis: Its low toxicity and miscibility with both aqueous and organic phases make EL suitable as a reaction solvent and extraction medium for active pharmaceutical ingredients (APIs) and cosmetic formulations.
• Food and Flavor Industry: EL is approved as a flavoring agent (fruity, creamy note) and carries GRAS (Generally Recognized as Safe) status in many jurisdictions.
• Polymer and Coating Formulations: It is an effective solvent for cellulose derivatives, acrylics, and epoxy resins used in paints and coatings.
• Green Chemistry Research: EL serves as a bio-based, biodegradable reaction medium for organic transformations including extractions, catalysis, and nanoparticle synthesis.

Purity Grades and Selection Criteria

When procuring ethyl lactate for laboratory use, selecting the appropriate purity grade is essential to ensure reproducible results and avoid assay interference:

• Technical Grade: Suitable for large-scale solvent applications such as cleaning, degreasing, and industrial coating processes where trace impurities are tolerable.
• Reagent / Synthesis Grade: Recommended for general organic synthesis, extraction procedures, and formulation development. Typical purity ≥98%.
• High-Purity / Analytical Grade: Required for spectroscopic applications, HPLC mobile-phase preparation, and sensitive biological assays where even trace water or acidic impurities can interfere.
• Enantiopure Grade: Necessary when stereochemical integrity is critical, such as in asymmetric synthesis or chiral HPLC studies; confirm enantiomeric excess (ee) certification on the CoA.

Always request a Certificate of Analysis (CoA) and verify key parameters including purity (GC), water content (Karl Fischer), optical rotation (for chiral lots), and acid value before use.

Safe Handling, Storage, and Disposal

Hazard Classification: Ethyl lactate is a flammable liquid (Flash point ~46 °C, closed cup) and is classified as a Category 4 flammable liquid under GHS. It presents low acute toxicity by oral, dermal, and inhalation routes, and is not classified as carcinogenic, mutagenic, or reprotoxic (CMR) under current regulations.

Personal Protective Equipment (PPE): Wear chemical-splash goggles, nitrile or neoprene gloves, and a lab coat. Work in a well-ventilated area or under a fume hood when handling large quantities, as prolonged inhalation of vapors may cause mild irritation.

Storage: Store in tightly sealed containers away from heat, open flames, and oxidizing agents. Recommended storage temperature: 2–25 °C. Keep away from strong acids and bases to prevent ester hydrolysis. Shelf life is typically 2 years when stored under recommended conditions.

Spill Management: Absorb small spills with inert material (vermiculite, dry sand) and collect in a labeled waste container. Do not flush to drain; dispose according to local regulations for flammable organic waste.

First Aid: In case of skin contact, wash thoroughly with soap and water. For eye contact, rinse immediately with plenty of water and seek medical attention. If inhaled in high concentrations, move to fresh air.

Quality Assurance and Regulatory Compliance

Aladdin Scientific supplies ethyl lactate (SKU: E1531717) with full batch-level quality documentation. Researchers should verify the following compliance aspects before use:

• Certificate of Analysis (CoA): Each lot is released with GC purity, refractive index, specific rotation (chiral lots), water content, and appearance data.
• REACH and RoHS: Ethyl lactate is not currently listed on SVHC (Substances of Very High Concern) candidate lists, supporting its adoption as an NMP replacement in formulations regulated under REACH.
• Food-Contact and Flavor Regulations: EL is listed in the EU Flavouring Regulation (EC) No 1334/2008 and holds FEMA GRAS status (FEMA No. 2440) for use as a flavor ingredient.
• Export Controls: Ethyl lactate is not subject to dual-use export restrictions under standard regulatory frameworks; however, end-users should verify local import regulations.

For GMP-grade or custom-purity requirements, contact Aladdin Scientific technical support for bespoke solutions.

Frequently asked questions

What makes ethyl lactate a 'green' solvent compared to conventional alternatives?

Ethyl lactate is derived from renewable fermentation feedstocks (e.g., corn starch), is fully biodegradable, and hydrolyzes to lactic acid and ethanol — both naturally occurring, non-toxic compounds. It has low acute toxicity, is not classified as a CMR substance, and is not listed on SVHC lists, making it a preferred drop-in replacement for hazardous solvents such as NMP, toluene, and glycol ethers in many formulation and synthesis applications.

Should I use the L-enantiomer (CAS 687-47-8) or the racemate (CAS 97-64-3) for my experiment?

For most solvent applications (semiconductor processing, coatings, general synthesis), the racemate is sufficient and more cost-effective. The enantiopure L-form is required when stereochemical purity affects the outcome, such as in asymmetric catalysis, chiral resolution studies, or pharmacokinetic research. Always confirm the stereochemical specification on the CoA before ordering.

How should ethyl lactate be stored to maintain purity and maximize shelf life?

Store ethyl lactate in tightly sealed, amber glass or compatible plastic containers at 2–25 °C, away from heat sources, open flames, strong acids, and oxidizing agents. Exposure to moisture or extremes of pH accelerates hydrolysis. Under recommended conditions, shelf life is typically two years. Re-verify purity by GC and check the acid value if the material has been stored for an extended period or if the container has been frequently opened.

Is ethyl lactate compatible with HPLC and other analytical instruments?

High-purity or analytical-grade ethyl lactate is compatible with reverse-phase and normal-phase HPLC systems. Its UV cutoff should be checked against the detection wavelength used (confirm with CoA or supplier data sheet). It is compatible with stainless steel, PTFE, and glass components. Avoid prolonged contact with certain elastomers; consult the instrument manufacturer's chemical compatibility guide before use.

What first aid should be taken in case of significant ethyl lactate exposure?

For skin contact, remove contaminated clothing and wash the affected area thoroughly with soap and water. For eye exposure, immediately flush with copious amounts of water for at least 15 minutes and seek prompt medical evaluation. If large quantities are inhaled, move the affected person to fresh air immediately and obtain medical attention if symptoms (dizziness, respiratory irritation) persist.

References

1. Pereira, C.S.M., Silva, V.M.T.M., Rodrigues, A.E. (2011). Ethyl lactate as a solvent: Properties, applications and production processes. Green Chemistry, 13(10), 2658–2671. doi:10.1039/c1gc15523g
2. European Parliament and Council. Regulation (EC) No 1334/2008 on flavourings and certain food ingredients with flavouring properties. Official Journal of the European Union, 2008.
3. FEMA (Flavor and Extract Manufacturers Association). GRAS Substance Registry: Ethyl L-lactate, FEMA No. 2440.
4. Datta, R., Henry, M. (2006). Lactic acid: Recent advances in products, processes and technologies — a review. Journal of Chemical Technology and Biotechnology, 81(7), 1119–1129. doi:10.1002/jctb.1486

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.