Ethyl formate
[CAS# 109-94-4]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: Ethyl formate
• Synonyms: Ethyl methanoate; Formic acid ethyl ester
• Molecular Formula: C₃H₆O₂
• Molecular Weight: 74.08
• CAS Registry Number: 109-94-4
• EC Number: 203-721-0
• FEMA: 2434
• SMILES: CCC[N+](CCC)(CCC)CCC.O.O.O.[OH-].[Ru]

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*, 0.921 g/mL (Expl.)
• Melting point: -80 ºC (Expl.)
• Boiling point: 54.7±3.0 ºC 760 mmHg (Calc.)^*, 52 - 54 ºC (Expl.)
• Flash point: -19.4 ºC (Calc.)^*, -19 ºC (Expl.)
• Index of refraction: 1.356 (Calc.)^*, 1.359 (Expl.)

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

Safety Data

• Hazard Symbols: GHS03;GHS07 Danger
• Hazard Statements: H272-H315-H319-H335
• Precautionary Statements: P210-P220-P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P370+P378-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	2	H225
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	4	H312
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411

• Transport Information: UN 1190

Discovory and Applicatios

Ethyl formate is an organic ester with the chemical formula C₃H₆O₂, consisting of an ethyl group (C₂H₅) bonded to a formate group (HCOO). It is the ethyl ester of formic acid and appears as a colorless, volatile liquid with a pleasant, fruity odor often described as rum-like or similar to raspberries. Ethyl formate occurs naturally in certain fruits and beverages and is widely used in the food, fragrance, and chemical industries.

The synthesis and study of ethyl formate date back to the development of ester chemistry in the 19th century, when early organic chemists began systematically exploring reactions between carboxylic acids and alcohols. Ethyl formate is typically synthesized by Fischer esterification, involving the reaction of formic acid and ethanol in the presence of an acid catalyst. It can also be produced by the reaction of ethanol with formic acid derivatives such as formyl chloride or by transesterification methods.

Ethyl formate is naturally found in various fruits such as raspberries and in alcoholic beverages like rum, contributing to their characteristic aromas. Because of its agreeable odor and flavor profile, it is used as a flavoring agent in food and beverages, where it adds fruity or sweet notes. Regulatory authorities such as the U.S. Food and Drug Administration and the European Food Safety Authority allow its use as a flavor additive within established safety limits.

In the fragrance industry, ethyl formate is used in perfumes, soaps, and personal care products. Its high volatility makes it effective as a top note in fragrance formulations, where it provides an initial burst of fruity aroma. It also functions as a solvent for resins, oils, and other fragrance ingredients, enhancing product consistency and dispersion.

Ethyl formate has industrial and laboratory applications as well. It is used as a solvent in manufacturing processes involving cellulose nitrate, cellulose acetate, dyes, and lacquers. Due to its solvent power and relatively low toxicity, it is preferred in some specialized applications over more hazardous solvents. In the field of chemical synthesis, ethyl formate serves as a mild reagent and a solvent for reactions requiring a polar, protic medium. It is also used in organic synthesis for introducing formyl groups under specific reaction conditions.

In pest control and fumigation, ethyl formate has been used as an insecticidal fumigant for treating dried fruits, grains, and nuts. It offers an alternative to more toxic or ozone-depleting substances and breaks down quickly in the environment to harmless products such as ethanol and formic acid. These properties make it suitable for post-harvest protection in agricultural settings, although its use is subject to regulation and safety guidelines.

Ethyl formate is classified as a flammable liquid and should be handled with care. It has a flash point of approximately −20 °C and can form explosive mixtures with air. Adequate ventilation, proper storage, and avoidance of ignition sources are necessary for safe handling. While it has relatively low acute toxicity, it may cause irritation to the eyes, skin, and respiratory tract upon exposure. Occupational exposure should be minimized through the use of personal protective equipment and adherence to safety data sheet recommendations.

Environmental concerns related to ethyl formate are minimal due to its biodegradability and rapid breakdown in air and water. It does not persist in the environment and is not considered a significant ecological hazard under normal conditions of use.

In summary, ethyl formate is a simple and versatile ester valued for its pleasant aroma, natural occurrence, and functional properties as a flavoring agent, fragrance ingredient, solvent, and fumigant. Its applications span the food, cosmetics, chemical, and agricultural industries, reflecting its continued relevance in both commercial and scientific contexts.

References

2019. Comparison of the Efficacy and Phytotoxicity of Phosphine and Ethyl Formate for Controlling Pseudococcus longispinus (Hemiptera: Pseudococcidae) and Pseudococcus orchidicola on Imported Foliage Nursery Plants. Journal of Economic Entomology, 112(5).
DOI: 10.1093/jee/toz125

2011. Characterization of volatile fraction of typical Irpinian wines fermented with a new starter yeast. World Journal of Microbiology and Biotechnology, 28(4).
DOI: 10.1007/s11274-011-0943-8

2007. The proton inventory technique in a dual mechanistic system: the spontaneous hydrolysis of ethyl formate. Isotopes in Environmental and Health Studies, 43(1).
DOI: 10.1080/10256010600990401